This file is indexed.

/usr/include/d/4.8/std/stream.d is in libphobos-4.8-dev 4.8.5-4ubuntu2.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
// Written in the D programming language

/**
 * $(RED Warning: This module is considered out-dated and not up to Phobos'
 *       current standards. It will remain until we have a suitable replacement,
 *       but be aware that it will not remain long term.)
 *
 * Source:    $(PHOBOSSRC std/_stream.d)
 * Macros:
 *      WIKI = Phobos/StdStream
 */

/*
 * Copyright (c) 2001-2005
 * Pavel "EvilOne" Minayev
 *  with buffering and endian support added by Ben Hinkle
 *  with buffered readLine performance improvements by Dave Fladebo
 *  with opApply inspired by (and mostly copied from) Regan Heath
 *  with bug fixes and MemoryStream/SliceStream enhancements by Derick Eddington
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Author makes no representations about
 * the suitability of this software for any purpose. It is provided
 * "as is" without express or implied warranty.
 */

/* NOTE: This file has been patched from the original DMD distribution to
   work with the GDC compiler.
 */

module std.stream;


/* Class structure:
 *  InputStream       interface for reading
 *  OutputStream      interface for writing
 *  Stream            abstract base of stream implementations
 *    File            an OS file stream
 *    FilterStream    a base-class for wrappers around another stream
 *      BufferedStream  a buffered stream wrapping another stream
 *        BufferedFile  a buffered File
 *      EndianStream    a wrapper stream for swapping byte order and BOMs
 *      SliceStream     a portion of another stream
 *    MemoryStream    a stream entirely stored in main memory
 *    TArrayStream    a stream wrapping an array-like buffer
 */

/// A base class for stream exceptions.
class StreamException: Exception {
  /// Construct a StreamException with given error message.
  this(string msg) { super(msg); }
}

/// Thrown when unable to read data from Stream.
class ReadException: StreamException {
  /// Construct a ReadException with given error message.
  this(string msg) { super(msg); }
}

/// Thrown when unable to write data to Stream.
class WriteException: StreamException {
  /// Construct a WriteException with given error message.
  this(string msg) { super(msg); }
}

/// Thrown when unable to move Stream pointer.
class SeekException: StreamException {
  /// Construct a SeekException with given error message.
  this(string msg) { super(msg); }
}

// seek whence...
enum SeekPos {
  Set,
  Current,
  End
}

private {
  import std.conv;
  import std.algorithm;
  import std.ascii;
  import std.format;
  import std.system;    // for Endian enumeration
  import std.utf;
  import core.bitop; // for bswap
  import core.vararg;
  import std.file;
}

/// InputStream is the interface for readable streams.

interface InputStream {

  /***
   * Read exactly size bytes into the buffer.
   *
   * Throws a ReadException if it is not correct.
   */
  void readExact(void* buffer, size_t size);

  /***
   * Read a block of data big enough to fill the given array buffer.
   *
   * Returns: the actual number of bytes read. Unfilled bytes are not modified.
   */
  size_t read(ubyte[] buffer);

  /***
   * Read a basic type or counted string.
   *
   * Throw a ReadException if it could not be read.
   * Outside of byte, ubyte, and char, the format is
   * implementation-specific and should not be used except as opposite actions
   * to write.
   */
  void read(out byte x);
  void read(out ubyte x);       /// ditto
  void read(out short x);       /// ditto
  void read(out ushort x);      /// ditto
  void read(out int x);         /// ditto
  void read(out uint x);        /// ditto
  void read(out long x);        /// ditto
  void read(out ulong x);       /// ditto
  void read(out float x);       /// ditto
  void read(out double x);      /// ditto
  void read(out real x);        /// ditto
  void read(out ifloat x);      /// ditto
  void read(out idouble x);     /// ditto
  void read(out ireal x);       /// ditto
  void read(out cfloat x);      /// ditto
  void read(out cdouble x);     /// ditto
  void read(out creal x);       /// ditto
  void read(out char x);        /// ditto
  void read(out wchar x);       /// ditto
  void read(out dchar x);       /// ditto

  // reads a string, written earlier by write()
  void read(out char[] s);      /// ditto

  // reads a Unicode string, written earlier by write()
  void read(out wchar[] s);     /// ditto

  /***
   * Read a line that is terminated with some combination of carriage return and
   * line feed or end-of-file.
   *
   * The terminators are not included. The wchar version
   * is identical. The optional buffer parameter is filled (reallocating
   * it if necessary) and a slice of the result is returned.
   */
  char[] readLine();
  char[] readLine(char[] result);       /// ditto
  wchar[] readLineW();                  /// ditto
  wchar[] readLineW(wchar[] result);    /// ditto

  /***
   * Overload foreach statements to read the stream line by line and call the
   * supplied delegate with each line or with each line with line number.
   *
   * The string passed in line may be reused between calls to the delegate.
   * Line numbering starts at 1.
   * Breaking out of the foreach will leave the stream
   * position at the beginning of the next line to be read.
   * For example, to echo a file line-by-line with line numbers run:
   * ------------------------------------
   * Stream file = new BufferedFile("sample.txt");
   * foreach(ulong n, char[] line; file)
   * {
   *     writefln("line %d: %s", n, line);
   * }
   * file.close();
   * ------------------------------------
   */

  // iterate through the stream line-by-line
  int opApply(scope int delegate(ref char[] line) dg);
  int opApply(scope int delegate(ref ulong n, ref char[] line) dg);  /// ditto
  int opApply(scope int delegate(ref wchar[] line) dg);            /// ditto
  int opApply(scope int delegate(ref ulong n, ref wchar[] line) dg); /// ditto

  /// Read a string of the given length,
  /// throwing ReadException if there was a problem.
  char[] readString(size_t length);

  /***
   * Read a string of the given length, throwing ReadException if there was a
   * problem.
   *
   * The file format is implementation-specific and should not be used
   * except as opposite actions to <b>write</b>.
   */

  wchar[] readStringW(size_t length);


  /***
   * Read and return the next character in the stream.
   *
   * This is the only method that will handle ungetc properly.
   * getcw's format is implementation-specific.
   * If EOF is reached then getc returns char.init and getcw returns wchar.init.
   */

  char getc();
  wchar getcw(); /// ditto

  /***
   * Push a character back onto the stream.
   *
   * They will be returned in first-in last-out order from getc/getcw.
   * Only has effect on further calls to getc() and getcw().
   */
  char ungetc(char c);
  wchar ungetcw(wchar c); /// ditto

  /***
   * Scan a string from the input using a similar form to C's scanf
   * and <a href="std_format.html">std.format</a>.
   *
   * An argument of type string is interpreted as a format string.
   * All other arguments must be pointer types.
   * If a format string is not present a default will be supplied computed from
   * the base type of the pointer type. An argument of type string* is filled
   * (possibly with appending characters) and a slice of the result is assigned
   * back into the argument. For example the following readf statements
   * are equivalent:
   * --------------------------
   * int x;
   * double y;
   * string s;
   * file.readf(&x, " hello ", &y, &s);
   * file.readf("%d hello %f %s", &x, &y, &s);
   * file.readf("%d hello %f", &x, &y, "%s", &s);
   * --------------------------
   */
  int vreadf(TypeInfo[] arguments, va_list args);
  int readf(...); /// ditto

  /// Retrieve the number of bytes available for immediate reading.
  @property size_t available();

  /***
   * Return whether the current file position is the same as the end of the
   * file.
   *
   * This does not require actually reading past the end, as with stdio. For
   * non-seekable streams this might only return true after attempting to read
   * past the end.
   */

  @property bool eof();

  @property bool isOpen();        /// Return true if the stream is currently open.
}

/// Interface for writable streams.
interface OutputStream {

  /***
   * Write exactly size bytes from buffer, or throw a WriteException if that
   * could not be done.
   */
  void writeExact(const void* buffer, size_t size);

  /***
   * Write as much of the buffer as possible,
   * returning the number of bytes written.
   */
  size_t write(const(ubyte)[] buffer);

  /***
   * Write a basic type.
   *
   * Outside of byte, ubyte, and char, the format is implementation-specific
   * and should only be used in conjunction with read.
   * Throw WriteException on error.
   */
  void write(byte x);
  void write(ubyte x);          /// ditto
  void write(short x);          /// ditto
  void write(ushort x);         /// ditto
  void write(int x);            /// ditto
  void write(uint x);           /// ditto
  void write(long x);           /// ditto
  void write(ulong x);          /// ditto
  void write(float x);          /// ditto
  void write(double x);         /// ditto
  void write(real x);           /// ditto
  void write(ifloat x);         /// ditto
  void write(idouble x);        /// ditto
  void write(ireal x);          /// ditto
  void write(cfloat x);         /// ditto
  void write(cdouble x);        /// ditto
  void write(creal x);          /// ditto
  void write(char x);           /// ditto
  void write(wchar x);          /// ditto
  void write(dchar x);          /// ditto

  /***
   * Writes a string, together with its length.
   *
   * The format is implementation-specific
   * and should only be used in conjunction with read.
   * Throw WriteException on error.
   */
    void write(const(char)[] s);
    void write(const(wchar)[] s); /// ditto

  /***
   * Write a line of text,
   * appending the line with an operating-system-specific line ending.
   *
   * Throws WriteException on error.
   */
  void writeLine(const(char)[] s);

  /***
   * Write a line of text,
   * appending the line with an operating-system-specific line ending.
   *
   * The format is implementation-specific.
   * Throws WriteException on error.
   */
    void writeLineW(const(wchar)[] s);

  /***
   * Write a string of text.
   *
   * Throws WriteException if it could not be fully written.
   */
    void writeString(const(char)[] s);

  /***
   * Write a string of text.
   *
   * The format is implementation-specific.
   * Throws WriteException if it could not be fully written.
   */
  void writeStringW(const(wchar)[] s);

  /***
   * Print a formatted string into the stream using printf-style syntax,
   * returning the number of bytes written.
   */
  size_t vprintf(const(char)[] format, va_list args);
  size_t printf(const(char)[] format, ...);    /// ditto

  /***
   * Print a formatted string into the stream using writef-style syntax.
   * References: <a href="std_format.html">std.format</a>.
   * Returns: self to chain with other stream commands like flush.
   */
  OutputStream writef(...);
  OutputStream writefln(...); /// ditto
  OutputStream writefx(TypeInfo[] arguments, va_list argptr, int newline = false);  /// ditto

  void flush(); /// Flush pending output if appropriate.
  void close(); /// Close the stream, flushing output if appropriate.
  @property bool isOpen(); /// Return true if the stream is currently open.
}


/***
 * Stream is the base abstract class from which the other stream classes derive.
 *
 * Stream's byte order is the format native to the computer.
 *
 * Reading:
 * These methods require that the readable flag be set.
 * Problems with reading result in a ReadException being thrown.
 * Stream implements the InputStream interface in addition to the
 * readBlock method.
 *
 * Writing:
 * These methods require that the writeable flag be set. Problems with writing
 * result in a WriteException being thrown. Stream implements the OutputStream
 * interface in addition to the following methods:
 * writeBlock
 * copyFrom
 * copyFrom
 *
 * Seeking:
 * These methods require that the seekable flag be set.
 * Problems with seeking result in a SeekException being thrown.
 * seek, seekSet, seekCur, seekEnd, position, size, toString, toHash
 */

// not really abstract, but its instances will do nothing useful
class Stream : InputStream, OutputStream {
  private import std.string, std.digest.crc, std.c.stdlib, std.c.stdio;

  // stream abilities
  bool readable = false;        /// Indicates whether this stream can be read from.
  bool writeable = false;       /// Indicates whether this stream can be written to.
  bool seekable = false;        /// Indicates whether this stream can be seeked within.
  protected bool isopen = true; /// Indicates whether this stream is open.

  protected bool readEOF = false; /** Indicates whether this stream is at eof
                                   * after the last read attempt.
                                   */

  protected bool prevCr = false; /** For a non-seekable stream indicates that
                                  * the last readLine or readLineW ended on a
                                  * '\r' character.
                                  */

  this() {}

  /***
   * Read up to size bytes into the buffer and return the number of bytes
   * actually read. A return value of 0 indicates end-of-file.
   */
  abstract size_t readBlock(void* buffer, size_t size);

  // reads block of data of specified size,
  // throws ReadException on error
  void readExact(void* buffer, size_t size) {
    for(;;) {
      if (!size) return;
      size_t readsize = readBlock(buffer, size); // return 0 on eof
      if (readsize == 0) break;
      buffer += readsize;
      size -= readsize;
    }
    if (size != 0)
      throw new ReadException("not enough data in stream");
  }

  // reads block of data big enough to fill the given
  // array, returns actual number of bytes read
  size_t read(ubyte[] buffer) {
    return readBlock(buffer.ptr, buffer.length);
  }

  // read a single value of desired type,
  // throw ReadException on error
  void read(out byte x) { readExact(&x, x.sizeof); }
  void read(out ubyte x) { readExact(&x, x.sizeof); }
  void read(out short x) { readExact(&x, x.sizeof); }
  void read(out ushort x) { readExact(&x, x.sizeof); }
  void read(out int x) { readExact(&x, x.sizeof); }
  void read(out uint x) { readExact(&x, x.sizeof); }
  void read(out long x) { readExact(&x, x.sizeof); }
  void read(out ulong x) { readExact(&x, x.sizeof); }
  void read(out float x) { readExact(&x, x.sizeof); }
  void read(out double x) { readExact(&x, x.sizeof); }
  void read(out real x) { readExact(&x, x.sizeof); }
  void read(out ifloat x) { readExact(&x, x.sizeof); }
  void read(out idouble x) { readExact(&x, x.sizeof); }
  void read(out ireal x) { readExact(&x, x.sizeof); }
  void read(out cfloat x) { readExact(&x, x.sizeof); }
  void read(out cdouble x) { readExact(&x, x.sizeof); }
  void read(out creal x) { readExact(&x, x.sizeof); }
  void read(out char x) { readExact(&x, x.sizeof); }
  void read(out wchar x) { readExact(&x, x.sizeof); }
  void read(out dchar x) { readExact(&x, x.sizeof); }

  // reads a string, written earlier by write()
  void read(out char[] s) {
    size_t len;
    read(len);
    s = readString(len);
  }

  // reads a Unicode string, written earlier by write()
  void read(out wchar[] s) {
    size_t len;
    read(len);
    s = readStringW(len);
  }

  // reads a line, terminated by either CR, LF, CR/LF, or EOF
  char[] readLine() {
    return readLine(null);
  }

  // reads a line, terminated by either CR, LF, CR/LF, or EOF
  // reusing the memory in buffer if result will fit and otherwise
  // allocates a new string
  char[] readLine(char[] result) {
    size_t strlen = 0;
    char ch = getc();
    while (readable) {
      switch (ch) {
      case '\r':
        if (seekable) {
          ch = getc();
          if (ch != '\n')
            ungetc(ch);
        } else {
          prevCr = true;
        }
        goto case;
      case '\n':
      case char.init:
        result.length = strlen;
        return result;

      default:
        if (strlen < result.length) {
          result[strlen] = ch;
        } else {
          result ~= ch;
        }
        strlen++;
      }
      ch = getc();
    }
    result.length = strlen;
    return result;
  }

  // reads a Unicode line, terminated by either CR, LF, CR/LF,
  // or EOF; pretty much the same as the above, working with
  // wchars rather than chars
  wchar[] readLineW() {
    return readLineW(null);
  }

  // reads a Unicode line, terminated by either CR, LF, CR/LF,
  // or EOF;
  // fills supplied buffer if line fits and otherwise allocates a new string.
  wchar[] readLineW(wchar[] result) {
    size_t strlen = 0;
    wchar c = getcw();
    while (readable) {
      switch (c) {
      case '\r':
        if (seekable) {
          c = getcw();
          if (c != '\n')
            ungetcw(c);
        } else {
          prevCr = true;
        }
        goto case;
      case '\n':
      case wchar.init:
        result.length = strlen;
        return result;

      default:
        if (strlen < result.length) {
          result[strlen] = c;
        } else {
          result ~= c;
        }
        strlen++;
      }
      c = getcw();
    }
    result.length = strlen;
    return result;
  }

  // iterate through the stream line-by-line - due to Regan Heath
  int opApply(scope int delegate(ref char[] line) dg) {
    int res = 0;
    char[128] buf;
    while (!eof) {
      char[] line = readLine(buf);
      res = dg(line);
      if (res) break;
    }
    return res;
  }

  // iterate through the stream line-by-line with line count and string
  int opApply(scope int delegate(ref ulong n, ref char[] line) dg) {
    int res = 0;
    ulong n = 1;
    char[128] buf;
    while (!eof) {
      auto line = readLine(buf);
      res = dg(n,line);
      if (res) break;
      n++;
    }
    return res;
  }

  // iterate through the stream line-by-line with wchar[]
  int opApply(scope int delegate(ref wchar[] line) dg) {
    int res = 0;
    wchar[128] buf;
    while (!eof) {
      auto line = readLineW(buf);
      res = dg(line);
      if (res) break;
    }
    return res;
  }

  // iterate through the stream line-by-line with line count and wchar[]
  int opApply(scope int delegate(ref ulong n, ref wchar[] line) dg) {
    int res = 0;
    ulong n = 1;
    wchar[128] buf;
    while (!eof) {
      auto line = readLineW(buf);
      res = dg(n,line);
      if (res) break;
      n++;
    }
    return res;
  }

  // reads a string of given length, throws
  // ReadException on error
  char[] readString(size_t length) {
    char[] result = new char[length];
    readExact(result.ptr, length);
    return result;
  }

  // reads a Unicode string of given length, throws
  // ReadException on error
  wchar[] readStringW(size_t length) {
    auto result = new wchar[length];
    readExact(result.ptr, result.length * wchar.sizeof);
    return result;
  }

  // unget buffer
  private wchar[] unget;
  final bool ungetAvailable() { return unget.length > 1; }

  // reads and returns next character from the stream,
  // handles characters pushed back by ungetc()
  // returns char.init on eof.
  char getc() {
    char c;
    if (prevCr) {
      prevCr = false;
      c = getc();
      if (c != '\n')
        return c;
    }
    if (unget.length > 1) {
      c = cast(char)unget[unget.length - 1];
      unget.length = unget.length - 1;
    } else {
      readBlock(&c,1);
    }
    return c;
  }

  // reads and returns next Unicode character from the
  // stream, handles characters pushed back by ungetc()
  // returns wchar.init on eof.
  wchar getcw() {
    wchar c;
    if (prevCr) {
      prevCr = false;
      c = getcw();
      if (c != '\n')
        return c;
    }
    if (unget.length > 1) {
      c = unget[unget.length - 1];
      unget.length = unget.length - 1;
    } else {
      void* buf = &c;
      size_t n = readBlock(buf,2);
      if (n == 1 && readBlock(buf+1,1) == 0)
          throw new ReadException("not enough data in stream");
    }
    return c;
  }

  // pushes back character c into the stream; only has
  // effect on further calls to getc() and getcw()
  char ungetc(char c) {
    if (c == c.init) return c;
    // first byte is a dummy so that we never set length to 0
    if (unget.length == 0)
      unget.length = 1;
    unget ~= c;
    return c;
  }

  // pushes back Unicode character c into the stream; only
  // has effect on further calls to getc() and getcw()
  wchar ungetcw(wchar c) {
    if (c == c.init) return c;
    // first byte is a dummy so that we never set length to 0
    if (unget.length == 0)
      unget.length = 1;
    unget ~= c;
    return c;
  }

  int vreadf(TypeInfo[] arguments, va_list args) {
    string fmt;
    int j = 0;
    int count = 0, i = 0;
    char c = getc();
    while ((j < arguments.length || i < fmt.length) && !eof) {
      if (fmt.length == 0 || i == fmt.length) {
        i = 0;
        if (arguments[j] is typeid(char[])) {
          fmt = va_arg!(string)(args);
          j++;
          continue;
        } else if (arguments[j] is typeid(int*) ||
                   arguments[j] is typeid(byte*) ||
                   arguments[j] is typeid(short*) ||
                   arguments[j] is typeid(long*)) {
          fmt = "%d";
        } else if (arguments[j] is typeid(uint*) ||
                   arguments[j] is typeid(ubyte*) ||
                   arguments[j] is typeid(ushort*) ||
                   arguments[j] is typeid(ulong*)) {
          fmt = "%d";
        } else if (arguments[j] is typeid(float*) ||
                   arguments[j] is typeid(double*) ||
                   arguments[j] is typeid(real*)) {
          fmt = "%f";
        } else if (arguments[j] is typeid(char[]*) ||
                   arguments[j] is typeid(wchar[]*) ||
                   arguments[j] is typeid(dchar[]*)) {
          fmt = "%s";
        } else if (arguments[j] is typeid(char*)) {
          fmt = "%c";
        }
      }
      if (fmt[i] == '%') {      // a field
        i++;
        bool suppress = false;
        if (fmt[i] == '*') {    // suppress assignment
          suppress = true;
          i++;
        }
        // read field width
        int width = 0;
        while (isDigit(fmt[i])) {
          width = width * 10 + (fmt[i] - '0');
          i++;
        }
        if (width == 0)
          width = -1;
        // skip any modifier if present
        if (fmt[i] == 'h' || fmt[i] == 'l' || fmt[i] == 'L')
          i++;
        // check the typechar and act accordingly
        switch (fmt[i]) {
        case 'd':       // decimal/hexadecimal/octal integer
        case 'D':
        case 'u':
        case 'U':
        case 'o':
        case 'O':
        case 'x':
        case 'X':
        case 'i':
        case 'I':
          {
            while (isWhite(c)) {
              c = getc();
              count++;
            }
            bool neg = false;
            if (c == '-') {
              neg = true;
              c = getc();
              count++;
            } else if (c == '+') {
              c = getc();
              count++;
            }
            char ifmt = cast(char)(fmt[i] | 0x20);
            if (ifmt == 'i')    { // undetermined base
              if (c == '0')     { // octal or hex
                c = getc();
                count++;
                if (c == 'x' || c == 'X')       { // hex
                  ifmt = 'x';
                  c = getc();
                  count++;
                } else {        // octal
                  ifmt = 'o';
                }
              }
              else      // decimal
                ifmt = 'd';
            }
            long n = 0;
            switch (ifmt)
            {
                case 'd':       // decimal
                case 'u': {
                  while (isDigit(c) && width) {
                    n = n * 10 + (c - '0');
                    width--;
                    c = getc();
                    count++;
                  }
                } break;

                case 'o': {     // octal
                  while (isOctalDigit(c) && width) {
                    n = n * 8 + (c - '0');
                    width--;
                    c = getc();
                    count++;
                  }
                } break;

                case 'x': {     // hexadecimal
                  while (isHexDigit(c) && width) {
                    n *= 0x10;
                    if (isDigit(c))
                      n += c - '0';
                    else
                      n += 0xA + (c | 0x20) - 'a';
                    width--;
                    c = getc();
                    count++;
                  }
                } break;

                default:
                    assert(0);
            }
            if (neg)
              n = -n;
            if (arguments[j] is typeid(int*)) {
              int* p = va_arg!(int*)(args);
              *p = cast(int)n;
            } else if (arguments[j] is typeid(short*)) {
              short* p = va_arg!(short*)(args);
              *p = cast(short)n;
            } else if (arguments[j] is typeid(byte*)) {
              byte* p = va_arg!(byte*)(args);
              *p = cast(byte)n;
            } else if (arguments[j] is typeid(long*)) {
              long* p = va_arg!(long*)(args);
              *p = n;
            } else if (arguments[j] is typeid(uint*)) {
              uint* p = va_arg!(uint*)(args);
              *p = cast(uint)n;
            } else if (arguments[j] is typeid(ushort*)) {
              ushort* p = va_arg!(ushort*)(args);
              *p = cast(ushort)n;
            } else if (arguments[j] is typeid(ubyte*)) {
              ubyte* p = va_arg!(ubyte*)(args);
              *p = cast(ubyte)n;
            } else if (arguments[j] is typeid(ulong*)) {
              ulong* p = va_arg!(ulong*)(args);
              *p = cast(ulong)n;
            }
            j++;
            i++;
          } break;

        case 'f':       // float
        case 'F':
        case 'e':
        case 'E':
        case 'g':
        case 'G':
          {
            while (isWhite(c)) {
              c = getc();
              count++;
            }
            bool neg = false;
            if (c == '-') {
              neg = true;
              c = getc();
              count++;
            } else if (c == '+') {
              c = getc();
              count++;
            }
            real n = 0;
            while (isDigit(c) && width) {
              n = n * 10 + (c - '0');
              width--;
              c = getc();
              count++;
            }
            if (width && c == '.') {
              width--;
              c = getc();
              count++;
              double frac = 1;
              while (isDigit(c) && width) {
                n = n * 10 + (c - '0');
                frac *= 10;
                width--;
                c = getc();
                count++;
              }
              n /= frac;
            }
            if (width && (c == 'e' || c == 'E')) {
              width--;
              c = getc();
              count++;
              if (width) {
                bool expneg = false;
                if (c == '-') {
                  expneg = true;
                  width--;
                  c = getc();
                  count++;
                } else if (c == '+') {
                  width--;
                  c = getc();
                  count++;
                }
                real exp = 0;
                while (isDigit(c) && width) {
                  exp = exp * 10 + (c - '0');
                  width--;
                  c = getc();
                  count++;
                }
                if (expneg) {
                  while (exp--)
                    n /= 10;
                } else {
                  while (exp--)
                    n *= 10;
                }
              }
            }
            if (neg)
              n = -n;
            if (arguments[j] is typeid(float*)) {
              float* p = va_arg!(float*)(args);
              *p = n;
            } else if (arguments[j] is typeid(double*)) {
              double* p = va_arg!(double*)(args);
              *p = n;
            } else if (arguments[j] is typeid(real*)) {
              real* p = va_arg!(real*)(args);
              *p = n;
            }
            j++;
            i++;
          } break;

        case 's': {     // string
          while (isWhite(c)) {
            c = getc();
            count++;
          }
          char[] s;
          char[]* p;
          size_t strlen;
          if (arguments[j] is typeid(char[]*)) {
            p = va_arg!(char[]*)(args);
            s = *p;
          }
          while (!isWhite(c) && c != char.init) {
            if (strlen < s.length) {
              s[strlen] = c;
            } else {
              s ~= c;
            }
            strlen++;
            c = getc();
            count++;
          }
          s = s[0 .. strlen];
          if (arguments[j] is typeid(char[]*)) {
            *p = s;
          } else if (arguments[j] is typeid(char*)) {
            s ~= 0;
            auto q = va_arg!(char*)(args);
            q[0 .. s.length] = s[];
          } else if (arguments[j] is typeid(wchar[]*)) {
            auto q = va_arg!(const(wchar)[]*)(args);
            *q = toUTF16(s);
          } else if (arguments[j] is typeid(dchar[]*)) {
            auto q = va_arg!(const(dchar)[]*)(args);
            *q = toUTF32(s);
          }
          j++;
          i++;
        } break;

        case 'c': {     // character(s)
          char* s = va_arg!(char*)(args);
          if (width < 0)
            width = 1;
          else
            while (isWhite(c)) {
            c = getc();
            count++;
          }
          while (width-- && !eof) {
            *(s++) = c;
            c = getc();
            count++;
          }
          j++;
          i++;
        } break;

        case 'n': {     // number of chars read so far
          int* p = va_arg!(int*)(args);
          *p = count;
          j++;
          i++;
        } break;

        default:        // read character as is
          goto nws;
        }
      } else if (isWhite(fmt[i])) {     // skip whitespace
        while (isWhite(c))
          c = getc();
        i++;
      } else {  // read character as is
      nws:
        if (fmt[i] != c)
          break;
        c = getc();
        i++;
      }
    }
    ungetc(c);
    return count;
  }

  int readf(...) {
    return vreadf(_arguments, _argptr);
  }

  // returns estimated number of bytes available for immediate reading
  @property size_t available() { return 0; }

  /***
   * Write up to size bytes from buffer in the stream, returning the actual
   * number of bytes that were written.
   */
  abstract size_t writeBlock(const void* buffer, size_t size);

  // writes block of data of specified size,
  // throws WriteException on error
  void writeExact(const void* buffer, size_t size) {
    const(void)* p = buffer;
    for(;;) {
      if (!size) return;
      size_t writesize = writeBlock(p, size);
      if (writesize == 0) break;
      p += writesize;
      size -= writesize;
    }
    if (size != 0)
      throw new WriteException("unable to write to stream");
  }

  // writes the given array of bytes, returns
  // actual number of bytes written
  size_t write(const(ubyte)[] buffer) {
    return writeBlock(buffer.ptr, buffer.length);
  }

  // write a single value of desired type,
  // throw WriteException on error
  void write(byte x) { writeExact(&x, x.sizeof); }
  void write(ubyte x) { writeExact(&x, x.sizeof); }
  void write(short x) { writeExact(&x, x.sizeof); }
  void write(ushort x) { writeExact(&x, x.sizeof); }
  void write(int x) { writeExact(&x, x.sizeof); }
  void write(uint x) { writeExact(&x, x.sizeof); }
  void write(long x) { writeExact(&x, x.sizeof); }
  void write(ulong x) { writeExact(&x, x.sizeof); }
  void write(float x) { writeExact(&x, x.sizeof); }
  void write(double x) { writeExact(&x, x.sizeof); }
  void write(real x) { writeExact(&x, x.sizeof); }
  void write(ifloat x) { writeExact(&x, x.sizeof); }
  void write(idouble x) { writeExact(&x, x.sizeof); }
  void write(ireal x) { writeExact(&x, x.sizeof); }
  void write(cfloat x) { writeExact(&x, x.sizeof); }
  void write(cdouble x) { writeExact(&x, x.sizeof); }
  void write(creal x) { writeExact(&x, x.sizeof); }
  void write(char x) { writeExact(&x, x.sizeof); }
  void write(wchar x) { writeExact(&x, x.sizeof); }
  void write(dchar x) { writeExact(&x, x.sizeof); }

  // writes a string, together with its length
  void write(const(char)[] s) {
    write(s.length);
    writeString(s);
  }

  // writes a Unicode string, together with its length
  void write(const(wchar)[] s) {
    write(s.length);
    writeStringW(s);
  }

  // writes a line, throws WriteException on error
  void writeLine(const(char)[] s) {
    writeString(s);
    version (Windows)
      writeString("\r\n");
    else version (Mac)
      writeString("\r");
    else
      writeString("\n");
  }

  // writes a Unicode line, throws WriteException on error
  void writeLineW(const(wchar)[] s) {
    writeStringW(s);
    version (Windows)
      writeStringW("\r\n");
    else version (Mac)
      writeStringW("\r");
    else
      writeStringW("\n");
  }

  // writes a string, throws WriteException on error
  void writeString(const(char)[] s) {
    writeExact(s.ptr, s.length);
  }

  // writes a Unicode string, throws WriteException on error
  void writeStringW(const(wchar)[] s) {
    writeExact(s.ptr, s.length * wchar.sizeof);
  }

  // writes data to stream using vprintf() syntax,
  // returns number of bytes written
  size_t vprintf(const(char)[] format, va_list args) {
    // shamelessly stolen from OutBuffer,
    // by Walter's permission
    char[1024] buffer;
    char* p = buffer.ptr;
    auto f = toStringz(format);
    size_t psize = buffer.length;
    size_t count;
    while (true) {
      version (Windows) {
        count = _vsnprintf(p, psize, f, args);
        if (count != -1)
          break;
        psize *= 2;
        p = cast(char*) alloca(psize);
      } else version (Posix) {
        count = vsnprintf(p, psize, f, args);
        if (count == -1)
          psize *= 2;
        else if (count >= psize)
          psize = count + 1;
        else
          break;
        p = cast(char*) alloca(psize);
      } else
          throw new Exception("unsupported platform");
    }
    writeString(p[0 .. count]);
    return count;
  }

  // writes data to stream using printf() syntax,
  // returns number of bytes written
  version (GNU)
  size_t printf(const(char)[] format, ...) {
      return vprintf(format, _argptr);
  }
  else version (Win64)
  size_t printf(const(char)[] format, ...) {
    return vprintf(format, _argptr);
  }
  else version (X86_64)
  size_t printf(const(char)[] format, ...) {
    va_list ap;
    va_start(ap, __va_argsave);
    auto result = vprintf(format, ap);
    va_end(ap);
    return result;
  }
  else
  size_t printf(const(char)[] format, ...) {
    va_list ap;
    ap = cast(va_list) &format;
    ap += format.sizeof;
    return vprintf(format, ap);
  }

  private void doFormatCallback(dchar c) {
    char[4] buf;
    auto b = std.utf.toUTF8(buf, c);
    writeString(b);
  }

  // writes data to stream using writef() syntax,
  OutputStream writef(...) {
    return writefx(_arguments,_argptr,0);
  }

  // writes data with trailing newline
  OutputStream writefln(...) {
    return writefx(_arguments,_argptr,1);
  }

  // writes data with optional trailing newline
  OutputStream writefx(TypeInfo[] arguments, va_list argptr, int newline=false) {
    doFormat(&doFormatCallback,arguments,argptr);
    if (newline)
      writeLine("");
    return this;
  }

  /***
   * Copies all data from s into this stream.
   * This may throw ReadException or WriteException on failure.
   * This restores the file position of s so that it is unchanged.
   */
  void copyFrom(Stream s) {
    if (seekable) {
      ulong pos = s.position;
      s.position = 0;
      copyFrom(s, s.size);
      s.position = pos;
    } else {
      ubyte[128] buf;
      while (!s.eof) {
        size_t m = s.readBlock(buf.ptr, buf.length);
        writeExact(buf.ptr, m);
      }
    }
  }

  /***
   * Copy a specified number of bytes from the given stream into this one.
   * This may throw ReadException or WriteException on failure.
   * Unlike the previous form, this doesn't restore the file position of s.
   */
  void copyFrom(Stream s, ulong count) {
    ubyte[128] buf;
    while (count > 0) {
      size_t n = cast(size_t)(count<buf.length ? count : buf.length);
      s.readExact(buf.ptr, n);
      writeExact(buf.ptr, n);
      count -= n;
    }
  }

  /***
   * Change the current position of the stream. whence is either SeekPos.Set, in
   which case the offset is an absolute index from the beginning of the stream,
   SeekPos.Current, in which case the offset is a delta from the current
   position, or SeekPos.End, in which case the offset is a delta from the end of
   the stream (negative or zero offsets only make sense in that case). This
   returns the new file position.
   */
  abstract ulong seek(long offset, SeekPos whence);

  /***
   * Aliases for their normal seek counterparts.
   */
  ulong seekSet(long offset) { return seek (offset, SeekPos.Set); }
  ulong seekCur(long offset) { return seek (offset, SeekPos.Current); } /// ditto
  ulong seekEnd(long offset) { return seek (offset, SeekPos.End); }     /// ditto

  /***
   * Sets file position. Equivalent to calling seek(pos, SeekPos.Set).
   */
  @property void position(ulong pos) { seek(cast(long)pos, SeekPos.Set); }

  /***
   * Returns current file position. Equivalent to seek(0, SeekPos.Current).
   */
  @property ulong position() { return seek(0, SeekPos.Current); }

  /***
   * Retrieve the size of the stream in bytes.
   * The stream must be seekable or a SeekException is thrown.
   */
  @property ulong size() {
    assertSeekable();
    ulong pos = position, result = seek(0, SeekPos.End);
    position = pos;
    return result;
  }

  // returns true if end of stream is reached, false otherwise
  @property bool eof() {
    // for unseekable streams we only know the end when we read it
    if (readEOF && !ungetAvailable())
      return true;
    else if (seekable)
      return position == size;
    else
      return false;
  }

  // returns true if the stream is open
  @property bool isOpen() { return isopen; }

  // flush the buffer if writeable
  void flush() {
    if (unget.length > 1)
      unget.length = 1; // keep at least 1 so that data ptr stays
  }

  // close the stream somehow; the default just flushes the buffer
  void close() {
    if (isopen)
      flush();
    readEOF = prevCr = isopen = readable = writeable = seekable = false;
  }

  /***
   * Read the entire stream and return it as a string.
   * If the stream is not seekable the contents from the current position to eof
   * is read and returned.
   */
  override string toString() {
    if (!readable)
      return super.toString();
    try
    {
        size_t pos;
        size_t rdlen;
        size_t blockSize;
        char[] result;
        if (seekable) {
          ulong orig_pos = position;
          scope(exit) position = orig_pos;
          position = 0;
          blockSize = cast(size_t)size;
          result = new char[blockSize];
          while (blockSize > 0) {
            rdlen = readBlock(&result[pos], blockSize);
            pos += rdlen;
            blockSize -= rdlen;
          }
        } else {
          blockSize = 4096;
          result = new char[blockSize];
          while ((rdlen = readBlock(&result[pos], blockSize)) > 0) {
            pos += rdlen;
            blockSize += rdlen;
            result.length = result.length + blockSize;
          }
        }
        return cast(string) result[0 .. pos];
    }
    catch (Throwable)
    {
        return super.toString();
    }
  }

  /***
   * Get a hash of the stream by reading each byte and using it in a CRC-32
   * checksum.
   */
  override size_t toHash() @trusted {
    if (!readable || !seekable)
      return super.toHash();
    try
    {
        ulong pos = position;
        scope(exit) position = pos;
        CRC32 crc;
        crc.start();
        position = 0;
        ulong len = size;
        for (ulong i = 0; i < len; i++)
        {
          ubyte c;
          read(c);
          crc.put(c);
        }

        union resUnion
        {
            size_t hash;
            ubyte[4] crcVal;
        }
        resUnion res;
        res.crcVal = crc.finish();
        return res.hash;
    }
    catch (Throwable)
    {
        return super.toHash();
    }
  }

  // helper for checking that the stream is readable
  final protected void assertReadable() {
    if (!readable)
      throw new ReadException("Stream is not readable");
  }
  // helper for checking that the stream is writeable
  final protected void assertWriteable() {
    if (!writeable)
      throw new WriteException("Stream is not writeable");
  }
  // helper for checking that the stream is seekable
  final protected void assertSeekable() {
    if (!seekable)
      throw new SeekException("Stream is not seekable");
  }
}

/***
 * A base class for streams that wrap a source stream with additional
 * functionality.
 *
 * The method implementations forward read/write/seek calls to the
 * source stream. A FilterStream can change the position of the source stream
 * arbitrarily and may not keep the source stream state in sync with the
 * FilterStream, even upon flushing and closing the FilterStream. It is
 * recommended to not make any assumptions about the state of the source position
 * and read/write state after a FilterStream has acted upon it. Specifc subclasses
 * of FilterStream should document how they modify the source stream and if any
 * invariants hold true between the source and filter.
 */
class FilterStream : Stream {
  private Stream s;              // source stream

  /// Property indicating when this stream closes to close the source stream as
  /// well.
  /// Defaults to true.
  bool nestClose = true;

  /// Construct a FilterStream for the given source.
  this(Stream source) {
    s = source;
    resetSource();
  }

  // source getter/setter

  /***
   * Get the current source stream.
   */
  final Stream source(){return s;}

  /***
   * Set the current source stream.
   *
   * Setting the source stream closes this stream before attaching the new
   * source. Attaching an open stream reopens this stream and resets the stream
   * state.
   */
  void source(Stream s) {
    close();
    this.s = s;
    resetSource();
  }

  /***
   * Indicates the source stream changed state and that this stream should reset
   * any readable, writeable, seekable, isopen and buffering flags.
   */
  void resetSource() {
    if (s !is null) {
      readable = s.readable;
      writeable = s.writeable;
      seekable = s.seekable;
      isopen = s.isOpen;
    } else {
      readable = writeable = seekable = false;
      isopen = false;
    }
    readEOF = prevCr = false;
  }

  // read from source
  override size_t readBlock(void* buffer, size_t size) {
    size_t res = s.readBlock(buffer,size);
    readEOF = res == 0;
    return res;
  }

  // write to source
  override size_t writeBlock(const void* buffer, size_t size) {
    return s.writeBlock(buffer,size);
  }

  // close stream
  override void close() {
    if (isopen) {
      super.close();
      if (nestClose)
        s.close();
    }
  }

  // seek on source
  override ulong seek(long offset, SeekPos whence) {
    readEOF = false;
    return s.seek(offset,whence);
  }

  override @property size_t available() { return s.available; }
  override void flush() { super.flush(); s.flush(); }
}

/***
 * This subclass is for buffering a source stream.
 *
 * A buffered stream must be
 * closed explicitly to ensure the final buffer content is written to the source
 * stream. The source stream position is changed according to the block size so
 * reading or writing to the BufferedStream may not change the source stream
 * position by the same amount.
 */
class BufferedStream : FilterStream {
  ubyte[] buffer;       // buffer, if any
  size_t bufferCurPos;    // current position in buffer
  size_t bufferLen;       // amount of data in buffer
  bool bufferDirty = false;
  size_t bufferSourcePos; // position in buffer of source stream position
  ulong streamPos;      // absolute position in source stream

  /* Example of relationship between fields:
   *
   *  s             ...01234567890123456789012EOF
   *  buffer                |--                     --|
   *  bufferCurPos                       |
   *  bufferLen             |--            --|
   *  bufferSourcePos                        |
   *
   */

  invariant() {
    assert(bufferSourcePos <= bufferLen);
    assert(bufferCurPos <= bufferLen);
    assert(bufferLen <= buffer.length);
  }

  enum size_t DefaultBufferSize = 8192;

  /***
   * Create a buffered stream for the stream source with the buffer size
   * bufferSize.
   */
  this(Stream source, size_t bufferSize = DefaultBufferSize) {
    super(source);
    if (bufferSize)
      buffer = new ubyte[bufferSize];
  }

  override protected void resetSource() {
    super.resetSource();
    streamPos = 0;
    bufferLen = bufferSourcePos = bufferCurPos = 0;
    bufferDirty = false;
  }

  // reads block of data of specified size using any buffered data
  // returns actual number of bytes read
  override size_t readBlock(void* result, size_t len) {
    if (len == 0) return 0;

    assertReadable();

    ubyte* outbuf = cast(ubyte*)result;
    size_t readsize = 0;

    if (bufferCurPos + len < bufferLen) {
      // buffer has all the data so copy it
      outbuf[0 .. len] = buffer[bufferCurPos .. bufferCurPos+len];
      bufferCurPos += len;
      readsize = len;
      goto ExitRead;
    }

    readsize = bufferLen - bufferCurPos;
    if (readsize > 0) {
      // buffer has some data so copy what is left
      outbuf[0 .. readsize] = buffer[bufferCurPos .. bufferLen];
      outbuf += readsize;
      bufferCurPos += readsize;
      len -= readsize;
    }

    flush();

    if (len >= buffer.length) {
      // buffer can't hold the data so fill output buffer directly
      size_t siz = super.readBlock(outbuf, len);
      readsize += siz;
      streamPos += siz;
    } else {
      // read a new block into buffer
        bufferLen = super.readBlock(buffer.ptr, buffer.length);
        if (bufferLen < len) len = bufferLen;
        outbuf[0 .. len] = buffer[0 .. len];
        bufferSourcePos = bufferLen;
        streamPos += bufferLen;
        bufferCurPos = len;
        readsize += len;
    }

  ExitRead:
    return readsize;
  }

  // write block of data of specified size
  // returns actual number of bytes written
  override size_t writeBlock(const void* result, size_t len) {
    assertWriteable();

    ubyte* buf = cast(ubyte*)result;
    size_t writesize = 0;

    if (bufferLen == 0) {
      // buffer is empty so fill it if possible
      if ((len < buffer.length) && (readable)) {
        // read in data if the buffer is currently empty
        bufferLen = s.readBlock(buffer.ptr, buffer.length);
        bufferSourcePos = bufferLen;
        streamPos += bufferLen;

      } else if (len >= buffer.length) {
        // buffer can't hold the data so write it directly and exit
        writesize = s.writeBlock(buf,len);
        streamPos += writesize;
        goto ExitWrite;
      }
    }

    if (bufferCurPos + len <= buffer.length) {
      // buffer has space for all the data so copy it and exit
      buffer[bufferCurPos .. bufferCurPos+len] = buf[0 .. len];
      bufferCurPos += len;
      bufferLen = bufferCurPos > bufferLen ? bufferCurPos : bufferLen;
      writesize = len;
      bufferDirty = true;
      goto ExitWrite;
    }

    writesize = buffer.length - bufferCurPos;
    if (writesize > 0) {
      // buffer can take some data
      buffer[bufferCurPos .. buffer.length] = buf[0 .. writesize];
      bufferCurPos = bufferLen = buffer.length;
      buf += writesize;
      len -= writesize;
      bufferDirty = true;
    }

    assert(bufferCurPos == buffer.length);
    assert(bufferLen == buffer.length);

    flush();

    writesize += writeBlock(buf,len);

  ExitWrite:
    return writesize;
  }

  override ulong seek(long offset, SeekPos whence) {
    assertSeekable();

    if ((whence != SeekPos.Current) ||
        (offset + bufferCurPos < 0) ||
        (offset + bufferCurPos >= bufferLen)) {
      flush();
      streamPos = s.seek(offset,whence);
    } else {
      bufferCurPos += offset;
    }
    readEOF = false;
    return streamPos-bufferSourcePos+bufferCurPos;
  }

  // Buffered readLine - Dave Fladebo
  // reads a line, terminated by either CR, LF, CR/LF, or EOF
  // reusing the memory in buffer if result will fit, otherwise
  // will reallocate (using concatenation)
  template TreadLine(T) {
      T[] readLine(T[] inBuffer)
      {
          size_t    lineSize = 0;
          bool    haveCR = false;
          T       c = '\0';
          size_t    idx = 0;
          ubyte*  pc = cast(ubyte*)&c;

        L0:
          for(;;) {
              size_t start = bufferCurPos;
            L1:
              foreach(ubyte b; buffer[start .. bufferLen]) {
                  bufferCurPos++;
                  pc[idx] = b;
                  if(idx < T.sizeof - 1) {
                      idx++;
                      continue L1;
                  } else {
                      idx = 0;
                  }
                  if(c == '\n' || haveCR) {
                      if(haveCR && c != '\n') bufferCurPos--;
                      break L0;
                  } else {
                      if(c == '\r') {
                          haveCR = true;
                      } else {
                          if(lineSize < inBuffer.length) {
                              inBuffer[lineSize] = c;
                          } else {
                              inBuffer ~= c;
                          }
                          lineSize++;
                      }
                  }
              }
              flush();
              size_t res = super.readBlock(buffer.ptr, buffer.length);
              if(!res) break L0; // EOF
              bufferSourcePos = bufferLen = res;
              streamPos += res;
          }
          return inBuffer[0 .. lineSize];
      }
  } // template TreadLine(T)

  override char[] readLine(char[] inBuffer) {
    if (ungetAvailable())
      return super.readLine(inBuffer);
    else
      return TreadLine!(char).readLine(inBuffer);
  }
  alias Stream.readLine readLine;

  override wchar[] readLineW(wchar[] inBuffer) {
    if (ungetAvailable())
      return super.readLineW(inBuffer);
    else
      return TreadLine!(wchar).readLine(inBuffer);
  }
  alias Stream.readLineW readLineW;

  override void flush()
  out {
    assert(bufferCurPos == 0);
    assert(bufferSourcePos == 0);
    assert(bufferLen == 0);
  }
  body {
    if (writeable && bufferDirty) {
      if (bufferSourcePos != 0 && seekable) {
        // move actual file pointer to front of buffer
        streamPos = s.seek(-bufferSourcePos, SeekPos.Current);
      }
      // write buffer out
      bufferSourcePos = s.writeBlock(buffer.ptr, bufferLen);
      if (bufferSourcePos != bufferLen) {
        throw new WriteException("Unable to write to stream");
      }
    }
    super.flush();
    long diff = cast(long)bufferCurPos-bufferSourcePos;
    if (diff != 0 && seekable) {
      // move actual file pointer to current position
      streamPos = s.seek(diff, SeekPos.Current);
    }
    // reset buffer data to be empty
    bufferSourcePos = bufferCurPos = bufferLen = 0;
    bufferDirty = false;
  }

  // returns true if end of stream is reached, false otherwise
  override @property bool eof() {
    if ((buffer.length == 0) || !readable) {
      return super.eof;
    }
    // some simple tests to avoid flushing
    if (ungetAvailable() || bufferCurPos != bufferLen)
      return false;
    if (bufferLen == buffer.length)
      flush();
    size_t res = super.readBlock(&buffer[bufferLen],buffer.length-bufferLen);
    bufferSourcePos +=  res;
    bufferLen += res;
    streamPos += res;
    return readEOF;
  }

  // returns size of stream
  override @property ulong size() {
    if (bufferDirty) flush();
    return s.size;
  }

  // returns estimated number of bytes available for immediate reading
  override @property size_t available() {
    return bufferLen - bufferCurPos;
  }
}

/// An exception for File errors.
class StreamFileException: StreamException {
  /// Construct a StreamFileException with given error message.
  this(string msg) { super(msg); }
}

/// An exception for errors during File.open.
class OpenException: StreamFileException {
  /// Construct an OpenFileException with given error message.
  this(string msg) { super(msg); }
}

// access modes; may be or'ed
enum FileMode {
  In = 1,
  Out = 2,
  OutNew = 6, // includes FileMode.Out
  Append = 10 // includes FileMode.Out
}

version (Windows) {
  private import std.c.windows.windows;
  extern (Windows) {
    void FlushFileBuffers(HANDLE hFile);
    DWORD  GetFileType(HANDLE hFile);
  }
}
version (Posix) {
  private import core.sys.posix.fcntl;
  private import core.sys.posix.unistd;
  alias int HANDLE;
}

/// This subclass is for unbuffered file system streams.
class File: Stream {

  version (Windows) {
    private HANDLE hFile;
  }
  version (Posix) {
    private HANDLE hFile = -1;
  }

  this() {
    super();
    version (Windows) {
      hFile = null;
    }
    version (Posix) {
      hFile = -1;
    }
    isopen = false;
  }

  // opens existing handle; use with care!
  this(HANDLE hFile, FileMode mode) {
    super();
    this.hFile = hFile;
    readable = cast(bool)(mode & FileMode.In);
    writeable = cast(bool)(mode & FileMode.Out);
    version(Windows) {
      seekable = GetFileType(hFile) == 1; // FILE_TYPE_DISK
    } else {
      auto result = lseek(hFile, 0, 0);
      seekable = (result != ~0);
    }
  }

  /***
   * Create the stream with no open file, an open file in read mode, or an open
   * file with explicit file mode.
   * mode, if given, is a combination of FileMode.In
   * (indicating a file that can be read) and FileMode.Out (indicating a file
   * that can be written).
   * Opening a file for reading that doesn't exist will error.
   * Opening a file for writing that doesn't exist will create the file.
   * The FileMode.OutNew mode will open the file for writing and reset the
   * length to zero.
   * The FileMode.Append mode will open the file for writing and move the
   * file position to the end of the file.
   */
  this(string filename, FileMode mode = FileMode.In)
  {
      this();
      open(filename, mode);
  }


  /***
   * Open a file for the stream, in an identical manner to the constructors.
   * If an error occurs an OpenException is thrown.
   */
  void open(string filename, FileMode mode = FileMode.In) {
    close();
    int access, share, createMode;
    parseMode(mode, access, share, createMode);
    seekable = true;
    readable = cast(bool)(mode & FileMode.In);
    writeable = cast(bool)(mode & FileMode.Out);
    version (Windows) {
      hFile = CreateFileW(std.utf.toUTF16z(filename), access, share,
                          null, createMode, 0, null);
      isopen = hFile != INVALID_HANDLE_VALUE;
    }
    version (Posix) {
      hFile = core.sys.posix.fcntl.open(toStringz(filename), access | createMode, share);
      isopen = hFile != -1;
    }
    if (!isopen)
      throw new OpenException(cast(string) ("Cannot open or create file '"
                                            ~ filename ~ "'"));
    else if ((mode & FileMode.Append) == FileMode.Append)
      seekEnd(0);
  }

  private void parseMode(int mode,
                         out int access,
                         out int share,
                         out int createMode) {
    version (Windows) {
      share |= FILE_SHARE_READ | FILE_SHARE_WRITE;
      if (mode & FileMode.In) {
        access |= GENERIC_READ;
        createMode = OPEN_EXISTING;
      }
      if (mode & FileMode.Out) {
        access |= GENERIC_WRITE;
        createMode = OPEN_ALWAYS; // will create if not present
      }
      if ((mode & FileMode.OutNew) == FileMode.OutNew) {
        createMode = CREATE_ALWAYS; // resets file
      }
    }
    version (Posix) {
      share = octal!666;
      if (mode & FileMode.In) {
        access = O_RDONLY;
      }
      if (mode & FileMode.Out) {
        createMode = O_CREAT; // will create if not present
        access = O_WRONLY;
      }
      if (access == (O_WRONLY | O_RDONLY)) {
        access = O_RDWR;
      }
      if ((mode & FileMode.OutNew) == FileMode.OutNew) {
        access |= O_TRUNC; // resets file
      }
    }
  }

  /// Create a file for writing.
  void create(string filename) {
    create(filename, FileMode.OutNew);
  }

  /// ditto
  void create(string filename, FileMode mode) {
    close();
    open(filename, mode | FileMode.OutNew);
  }

  /// Close the current file if it is open; otherwise it does nothing.
  override void close() {
    if (isopen) {
      super.close();
      if (hFile) {
        version (Windows) {
          CloseHandle(hFile);
          hFile = null;
        } else version (Posix) {
          core.sys.posix.unistd.close(hFile);
          hFile = -1;
        }
      }
    }
  }

  // destructor, closes file if still opened
  ~this() { close(); }

  version (Windows) {
    // returns size of stream
    override @property ulong size() {
      assertSeekable();
      uint sizehi;
      uint sizelow = GetFileSize(hFile,&sizehi);
      return (cast(ulong)sizehi << 32) + sizelow;
    }
  }

  override size_t readBlock(void* buffer, size_t size) {
    assertReadable();
    version (Windows) {
      auto dwSize = to!DWORD(size);
      ReadFile(hFile, buffer, dwSize, &dwSize, null);
      size = dwSize;
    } else version (Posix) {
      size = core.sys.posix.unistd.read(hFile, buffer, size);
      if (size == -1)
        size = 0;
    }
    readEOF = (size == 0);
    return size;
  }

  override size_t writeBlock(const void* buffer, size_t size) {
    assertWriteable();
    version (Windows) {
      auto dwSize = to!DWORD(size);
      WriteFile(hFile, buffer, dwSize, &dwSize, null);
      size = dwSize;
    } else version (Posix) {
      size = core.sys.posix.unistd.write(hFile, buffer, size);
      if (size == -1)
        size = 0;
    }
    return size;
  }

  override ulong seek(long offset, SeekPos rel) {
    assertSeekable();
    version (Windows) {
      int hi = cast(int)(offset>>32);
      uint low = SetFilePointer(hFile, cast(int)offset, &hi, rel);
      if ((low == INVALID_SET_FILE_POINTER) && (GetLastError() != 0))
        throw new SeekException("unable to move file pointer");
      ulong result = (cast(ulong)hi << 32) + low;
    } else version (Posix) {
      auto result = lseek(hFile, cast(int)offset, rel);
      if (result == cast(typeof(result))-1)
        throw new SeekException("unable to move file pointer");
    }
    readEOF = false;
    return cast(ulong)result;
  }

  /***
   * For a seekable file returns the difference of the size and position and
   * otherwise returns 0.
   */

  override @property size_t available() {
    if (seekable) {
      ulong lavail = size - position;
      if (lavail > size_t.max) lavail = size_t.max;
      return cast(size_t)lavail;
    }
    return 0;
  }

  // OS-specific property, just in case somebody wants
  // to mess with underlying API
  HANDLE handle() { return hFile; }

  // run a few tests
  unittest {
    File file = new File;
    int i = 666;
    file.create("stream.$$$");
    // should be ok to write
    assert(file.writeable);
    file.writeLine("Testing stream.d:");
    file.writeString("Hello, world!");
    file.write(i);
    // string#1 + string#2 + int should give exacly that
    version (Windows)
      assert(file.position == 19 + 13 + 4);
    version (Posix)
      assert(file.position == 18 + 13 + 4);
    // we must be at the end of file
    assert(file.eof);
    file.close();
    // no operations are allowed when file is closed
    assert(!file.readable && !file.writeable && !file.seekable);
    file.open("stream.$$$");
    // should be ok to read
    assert(file.readable);
    assert(file.available == file.size);
    char[] line = file.readLine();
    char[] exp = "Testing stream.d:".dup;
    assert(line[0] == 'T');
    assert(line.length == exp.length);
    assert(!std.algorithm.cmp(line, "Testing stream.d:"));
    // jump over "Hello, "
    file.seek(7, SeekPos.Current);
    version (Windows)
      assert(file.position == 19 + 7);
    version (Posix)
      assert(file.position == 18 + 7);
    assert(!std.algorithm.cmp(file.readString(6), "world!"));
    i = 0; file.read(i);
    assert(i == 666);
    // string#1 + string#2 + int should give exacly that
    version (Windows)
      assert(file.position == 19 + 13 + 4);
    version (Posix)
      assert(file.position == 18 + 13 + 4);
    // we must be at the end of file
    assert(file.eof);
    file.close();
    file.open("stream.$$$",FileMode.OutNew | FileMode.In);
    file.writeLine("Testing stream.d:");
    file.writeLine("Another line");
    file.writeLine("");
    file.writeLine("That was blank");
    file.position = 0;
    char[][] lines;
    foreach(char[] line; file) {
      lines ~= line.dup;
    }
    assert( lines.length == 4 );
    assert( lines[0] == "Testing stream.d:");
    assert( lines[1] == "Another line");
    assert( lines[2] == "");
    assert( lines[3] == "That was blank");
    file.position = 0;
    lines = new char[][4];
    foreach(ulong n, char[] line; file) {
      lines[cast(size_t)(n-1)] = line.dup;
    }
    assert( lines[0] == "Testing stream.d:");
    assert( lines[1] == "Another line");
    assert( lines[2] == "");
    assert( lines[3] == "That was blank");
    file.close();
    remove("stream.$$$");
  }
}

/***
 * This subclass is for buffered file system streams.
 *
 * It is a convenience class for wrapping a File in a BufferedStream.
 * A buffered stream must be closed explicitly to ensure the final buffer
 * content is written to the file.
 */
class BufferedFile: BufferedStream {

  /// opens file for reading
  this() { super(new File()); }

  /// opens file in requested mode and buffer size
  this(string filename, FileMode mode = FileMode.In,
       size_t bufferSize = DefaultBufferSize) {
    super(new File(filename,mode),bufferSize);
  }

  /// opens file for reading with requested buffer size
  this(File file, size_t bufferSize = DefaultBufferSize) {
    super(file,bufferSize);
  }

  /// opens existing handle; use with care!
  this(HANDLE hFile, FileMode mode, size_t buffersize = DefaultBufferSize) {
    super(new File(hFile,mode),buffersize);
  }

  /// opens file in requested mode
  void open(string filename, FileMode mode = FileMode.In) {
    File sf = cast(File)s;
    sf.open(filename,mode);
    resetSource();
  }

  /// creates file in requested mode
  void create(string filename, FileMode mode = FileMode.OutNew) {
    File sf = cast(File)s;
    sf.create(filename,mode);
    resetSource();
  }

  // run a few tests same as File
  unittest {
    BufferedFile file = new BufferedFile;
    int i = 666;
    file.create("stream.$$$");
    // should be ok to write
    assert(file.writeable);
    file.writeLine("Testing stream.d:");
    file.writeString("Hello, world!");
    file.write(i);
    // string#1 + string#2 + int should give exacly that
    version (Windows)
      assert(file.position == 19 + 13 + 4);
    version (Posix)
      assert(file.position == 18 + 13 + 4);
    // we must be at the end of file
    assert(file.eof);
    long oldsize = cast(long)file.size;
    file.close();
    // no operations are allowed when file is closed
    assert(!file.readable && !file.writeable && !file.seekable);
    file.open("stream.$$$");
    // should be ok to read
    assert(file.readable);
    // test getc/ungetc and size
    char c1 = file.getc();
    file.ungetc(c1);
    assert( file.size == oldsize );
    assert(!std.algorithm.cmp(file.readLine(), "Testing stream.d:"));
    // jump over "Hello, "
    file.seek(7, SeekPos.Current);
    version (Windows)
      assert(file.position == 19 + 7);
    version (Posix)
      assert(file.position == 18 + 7);
    assert(!std.algorithm.cmp(file.readString(6), "world!"));
    i = 0; file.read(i);
    assert(i == 666);
    // string#1 + string#2 + int should give exacly that
    version (Windows)
      assert(file.position == 19 + 13 + 4);
    version (Posix)
      assert(file.position == 18 + 13 + 4);
    // we must be at the end of file
    assert(file.eof);
    file.close();
    remove("stream.$$$");
  }

}

/// UTF byte-order-mark signatures
enum BOM {
        UTF8,           /// UTF-8
        UTF16LE,        /// UTF-16 Little Endian
        UTF16BE,        /// UTF-16 Big Endian
        UTF32LE,        /// UTF-32 Little Endian
        UTF32BE,        /// UTF-32 Big Endian
}

private enum int NBOMS = 5;
immutable Endian[NBOMS] BOMEndian =
[ std.system.endian,
  Endian.littleEndian, Endian.bigEndian,
  Endian.littleEndian, Endian.bigEndian
  ];

immutable ubyte[][NBOMS] ByteOrderMarks =
[ [0xEF, 0xBB, 0xBF],
  [0xFF, 0xFE],
  [0xFE, 0xFF],
  [0xFF, 0xFE, 0x00, 0x00],
  [0x00, 0x00, 0xFE, 0xFF]
  ];


/***
 * This subclass wraps a stream with big-endian or little-endian byte order
 * swapping.
 *
 * UTF Byte-Order-Mark (BOM) signatures can be read and deduced or
 * written.
 * Note that an EndianStream should not be used as the source of another
 * FilterStream since a FilterStream call the source with byte-oriented
 * read/write requests and the EndianStream will not perform any byte swapping.
 * The EndianStream reads and writes binary data (non-getc functions) in a
 * one-to-one
 * manner with the source stream so the source stream's position and state will be
 * kept in sync with the EndianStream if only non-getc functions are called.
 */
class EndianStream : FilterStream {

  Endian endian;        /// Endianness property of the source stream.

  /***
   * Create the endian stream for the source stream source with endianness end.
   * The default endianness is the native byte order.
   * The Endian type is defined
   * in the std.system module.
   */
  this(Stream source, Endian end = std.system.endian) {
    super(source);
    endian = end;
  }

  /***
   * Return -1 if no BOM and otherwise read the BOM and return it.
   *
   * If there is no BOM or if bytes beyond the BOM are read then the bytes read
   * are pushed back onto the ungetc buffer or ungetcw buffer.
   * Pass ungetCharSize == 2 to use
   * ungetcw instead of ungetc when no BOM is present.
   */
  int readBOM(int ungetCharSize = 1) {
    ubyte[4] BOM_buffer;
    int n = 0;       // the number of read bytes
    int result = -1; // the last match or -1
    for (int i=0; i < NBOMS; ++i) {
      int j;
      immutable ubyte[] bom = ByteOrderMarks[i];
      for (j=0; j < bom.length; ++j) {
        if (n <= j) { // have to read more
          if (eof)
            break;
          readExact(&BOM_buffer[n++],1);
        }
        if (BOM_buffer[j] != bom[j])
          break;
      }
      if (j == bom.length) // found a match
        result = i;
    }
    ptrdiff_t m = 0;
    if (result != -1) {
      endian = BOMEndian[result]; // set stream endianness
      m = ByteOrderMarks[result].length;
    }
    if ((ungetCharSize == 1 && result == -1) || (result == BOM.UTF8)) {
      while (n-- > m)
        ungetc(BOM_buffer[n]);
    } else { // should eventually support unget for dchar as well
      if (n & 1) // make sure we have an even number of bytes
        readExact(&BOM_buffer[n++],1);
      while (n > m) {
        n -= 2;
        wchar cw = *(cast(wchar*)&BOM_buffer[n]);
        fixBO(&cw,2);
        ungetcw(cw);
      }
    }
    return result;
  }

  /***
   * Correct the byte order of buffer to match native endianness.
   * size must be even.
   */
  final void fixBO(const(void)* buffer, size_t size) {
    if (endian != std.system.endian) {
      ubyte* startb = cast(ubyte*)buffer;
      uint* start = cast(uint*)buffer;
      switch (size) {
      case 0: break;
      case 2: {
        ubyte x = *startb;
        *startb = *(startb+1);
        *(startb+1) = x;
        break;
      }
      case 4: {
        *start = bswap(*start);
        break;
      }
      default: {
        uint* end = cast(uint*)(buffer + size - uint.sizeof);
        while (start < end) {
          uint x = bswap(*start);
          *start = bswap(*end);
          *end = x;
          ++start;
          --end;
        }
        startb = cast(ubyte*)start;
        ubyte* endb = cast(ubyte*)end;
        auto len = uint.sizeof - (startb - endb);
        if (len > 0)
          fixBO(startb,len);
      }
      }
    }
  }

  /***
   * Correct the byte order of the given buffer in blocks of the given size and
   * repeated the given number of times.
   * size must be even.
   */
  final void fixBlockBO(void* buffer, uint size, size_t repeat) {
    while (repeat--) {
      fixBO(buffer,size);
      buffer += size;
    }
  }

  override void read(out byte x) { readExact(&x, x.sizeof); }
  override void read(out ubyte x) { readExact(&x, x.sizeof); }
  override void read(out short x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out ushort x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out int x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out uint x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out long x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out ulong x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out float x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out double x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out real x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out ifloat x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out idouble x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out ireal x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out cfloat x) { readExact(&x, x.sizeof); fixBlockBO(&x,float.sizeof,2); }
  override void read(out cdouble x) { readExact(&x, x.sizeof); fixBlockBO(&x,double.sizeof,2); }
  override void read(out creal x) { readExact(&x, x.sizeof); fixBlockBO(&x,real.sizeof,2); }
  override void read(out char x) { readExact(&x, x.sizeof); }
  override void read(out wchar x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }
  override void read(out dchar x) { readExact(&x, x.sizeof); fixBO(&x,x.sizeof); }

  override wchar getcw() {
    wchar c;
    if (prevCr) {
      prevCr = false;
      c = getcw();
      if (c != '\n')
        return c;
    }
    if (unget.length > 1) {
      c = unget[unget.length - 1];
      unget.length = unget.length - 1;
    } else {
      void* buf = &c;
      size_t n = readBlock(buf,2);
      if (n == 1 && readBlock(buf+1,1) == 0)
          throw new ReadException("not enough data in stream");
      fixBO(&c,c.sizeof);
    }
    return c;
  }

  override wchar[] readStringW(size_t length) {
    wchar[] result = new wchar[length];
    readExact(result.ptr, length * wchar.sizeof);
    fixBlockBO(result.ptr, wchar.sizeof, length);
    return result;
  }

  /// Write the specified BOM b to the source stream.
  void writeBOM(BOM b) {
    immutable ubyte[] bom = ByteOrderMarks[b];
    writeBlock(bom.ptr, bom.length);
  }

  override void write(byte x) { writeExact(&x, x.sizeof); }
  override void write(ubyte x) { writeExact(&x, x.sizeof); }
  override void write(short x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(ushort x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(int x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(uint x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(long x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(ulong x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(float x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(double x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(real x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(ifloat x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(idouble x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(ireal x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(cfloat x) { fixBlockBO(&x,float.sizeof,2); writeExact(&x, x.sizeof); }
  override void write(cdouble x) { fixBlockBO(&x,double.sizeof,2); writeExact(&x, x.sizeof); }
  override void write(creal x) { fixBlockBO(&x,real.sizeof,2); writeExact(&x, x.sizeof);  }
  override void write(char x) { writeExact(&x, x.sizeof); }
  override void write(wchar x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }
  override void write(dchar x) { fixBO(&x,x.sizeof); writeExact(&x, x.sizeof); }

  override void writeStringW(const(wchar)[] str) {
    foreach(wchar cw;str) {
      fixBO(&cw,2);
      s.writeExact(&cw, 2);
    }
  }

  override @property bool eof() { return s.eof && !ungetAvailable();  }
  override @property ulong size() { return s.size;  }

  unittest {
    MemoryStream m;
    m = new MemoryStream ();
    EndianStream em = new EndianStream(m,Endian.bigEndian);
    uint x = 0x11223344;
    em.write(x);
    assert( m.data[0] == 0x11 );
    assert( m.data[1] == 0x22 );
    assert( m.data[2] == 0x33 );
    assert( m.data[3] == 0x44 );
    em.position = 0;
    ushort x2 = 0x5566;
    em.write(x2);
    assert( m.data[0] == 0x55 );
    assert( m.data[1] == 0x66 );
    em.position = 0;
    static ubyte[12] x3 = [1,2,3,4,5,6,7,8,9,10,11,12];
    em.fixBO(x3.ptr,12);
    if (std.system.endian == Endian.littleEndian) {
      assert( x3[0] == 12 );
      assert( x3[1] == 11 );
      assert( x3[2] == 10 );
      assert( x3[4] == 8 );
      assert( x3[5] == 7 );
      assert( x3[6] == 6 );
      assert( x3[8] == 4 );
      assert( x3[9] == 3 );
      assert( x3[10] == 2 );
      assert( x3[11] == 1 );
    }
    em.endian = Endian.littleEndian;
    em.write(x);
    assert( m.data[0] == 0x44 );
    assert( m.data[1] == 0x33 );
    assert( m.data[2] == 0x22 );
    assert( m.data[3] == 0x11 );
    em.position = 0;
    em.write(x2);
    assert( m.data[0] == 0x66 );
    assert( m.data[1] == 0x55 );
    em.position = 0;
    em.fixBO(x3.ptr,12);
    if (std.system.endian == Endian.bigEndian) {
      assert( x3[0] == 12 );
      assert( x3[1] == 11 );
      assert( x3[2] == 10 );
      assert( x3[4] == 8 );
      assert( x3[5] == 7 );
      assert( x3[6] == 6 );
      assert( x3[8] == 4 );
      assert( x3[9] == 3 );
      assert( x3[10] == 2 );
      assert( x3[11] == 1 );
    }
    em.writeBOM(BOM.UTF8);
    assert( m.position == 3 );
    assert( m.data[0] == 0xEF );
    assert( m.data[1] == 0xBB );
    assert( m.data[2] == 0xBF );
    em.writeString ("Hello, world");
    em.position = 0;
    assert( m.position == 0 );
    assert( em.readBOM() == BOM.UTF8 );
    assert( m.position == 3 );
    assert( em.getc() == 'H' );
    em.position = 0;
    em.writeBOM(BOM.UTF16BE);
    assert( m.data[0] == 0xFE );
    assert( m.data[1] == 0xFF );
    em.position = 0;
    em.writeBOM(BOM.UTF16LE);
    assert( m.data[0] == 0xFF );
    assert( m.data[1] == 0xFE );
    em.position = 0;
    em.writeString ("Hello, world");
    em.position = 0;
    assert( em.readBOM() == -1 );
    assert( em.getc() == 'H' );
    assert( em.getc() == 'e' );
    assert( em.getc() == 'l' );
    assert( em.getc() == 'l' );
    em.position = 0;
  }
}

/***
 * Parameterized subclass that wraps an array-like buffer with a stream
 * interface.
 *
 * The type Buffer must support the length property, opIndex and opSlice.
 * Compile in release mode when directly instantiating a TArrayStream to avoid
 * link errors.
 */
class TArrayStream(Buffer): Stream {
  Buffer buf; // current data
  ulong len;  // current data length
  ulong cur;  // current file position

  /// Create the stream for the the buffer buf. Non-copying.
  this(Buffer buf) {
    super ();
    this.buf = buf;
    this.len = buf.length;
    readable = writeable = seekable = true;
  }

  // ensure subclasses don't violate this
  invariant() {
    assert(len <= buf.length);
    assert(cur <= len);
  }

  override size_t readBlock(void* buffer, size_t size) {
    assertReadable();
    ubyte* cbuf = cast(ubyte*) buffer;
    if (len - cur < size)
      size = cast(size_t)(len - cur);
    ubyte[] ubuf = cast(ubyte[])buf[cast(size_t)cur .. cast(size_t)(cur + size)];
    cbuf[0 .. size] = ubuf[];
    cur += size;
    return size;
  }

  override size_t writeBlock(const void* buffer, size_t size) {
    assertWriteable();
    ubyte* cbuf = cast(ubyte*) buffer;
    ulong blen = buf.length;
    if (cur + size > blen)
      size = cast(size_t)(blen - cur);
    ubyte[] ubuf = cast(ubyte[])buf[cast(size_t)cur .. cast(size_t)(cur + size)];
    ubuf[] = cbuf[0 .. size];
    cur += size;
    if (cur > len)
      len = cur;
    return size;
  }

  override ulong seek(long offset, SeekPos rel) {
    assertSeekable();
    long scur; // signed to saturate to 0 properly

    switch (rel) {
    case SeekPos.Set: scur = offset; break;
    case SeekPos.Current: scur = cast(long)(cur + offset); break;
    case SeekPos.End: scur = cast(long)(len + offset); break;
    default:
        assert(0);
    }

    if (scur < 0)
      cur = 0;
    else if (scur > len)
      cur = len;
    else
      cur = cast(ulong)scur;

    return cur;
  }

  override @property size_t available () { return cast(size_t)(len - cur); }

  /// Get the current memory data in total.
  @property ubyte[] data() {
    if (len > size_t.max)
      throw new StreamException("Stream too big");
    const(void)[] res = buf[0 .. cast(size_t)len];
    return cast(ubyte[])res;
  }

  override string toString() {
      // assume data is UTF8
      return to!(string)(cast(char[])data);
  }
}

/* Test the TArrayStream */
unittest {
  char[100] buf;
  TArrayStream!(char[]) m;

  m = new TArrayStream!(char[]) (buf);
  assert (m.isOpen);
  m.writeString ("Hello, world");
  assert (m.position == 12);
  assert (m.available == 88);
  assert (m.seekSet (0) == 0);
  assert (m.available == 100);
  assert (m.seekCur (4) == 4);
  assert (m.available == 96);
  assert (m.seekEnd (-8) == 92);
  assert (m.available == 8);
  assert (m.size == 100);
  assert (m.seekSet (4) == 4);
  assert (m.readString (4) == "o, w");
  m.writeString ("ie");
  assert (buf[0..12] == "Hello, wield");
  assert (m.position == 10);
  assert (m.available == 90);
  assert (m.size == 100);
  m.seekSet (0);
  assert (m.printf ("Answer is %d", 42) == 12);
  assert (buf[0..12] == "Answer is 42");
}

/// This subclass reads and constructs an array of bytes in memory.
class MemoryStream: TArrayStream!(ubyte[]) {

  /// Create the output buffer and setup for reading, writing, and seeking.
  // clear to an empty buffer.
  this() { this(cast(ubyte[]) null); }

  /***
   * Create the output buffer and setup for reading, writing, and seeking.
   * Load it with specific input data.
   */
  this(ubyte[] buf) { super (buf); }
  this(byte[] buf) { this(cast(ubyte[]) buf); } /// ditto
  this(char[] buf) { this(cast(ubyte[]) buf); } /// ditto

  /// Ensure the stream can hold count bytes.
  void reserve(size_t count) {
    if (cur + count > buf.length)
      buf.length = cast(uint)((cur + count) * 2);
  }

  override size_t writeBlock(const void* buffer, size_t size) {
    reserve(size);
    return super.writeBlock(buffer,size);
  }

  unittest {
    MemoryStream m;

    m = new MemoryStream ();
    assert (m.isOpen);
    m.writeString ("Hello, world");
    assert (m.position == 12);
    assert (m.seekSet (0) == 0);
    assert (m.available == 12);
    assert (m.seekCur (4) == 4);
    assert (m.available == 8);
    assert (m.seekEnd (-8) == 4);
    assert (m.available == 8);
    assert (m.size == 12);
    assert (m.readString (4) == "o, w");
    m.writeString ("ie");
    assert (cast(char[]) m.data == "Hello, wield");
    m.seekEnd (0);
    m.writeString ("Foo");
    assert (m.position == 15);
    assert (m.available == 0);
    m.writeString ("Foo foo foo foo foo foo foo");
    assert (m.position == 42);
    m.position = 0;
    assert (m.available == 42);
    m.writef("%d %d %s",100,345,"hello");
    auto str = m.toString();
    assert (str[0..13] == "100 345 hello", str[0 .. 13]);
    assert (m.available == 29);
    assert (m.position == 13);

    MemoryStream m2;
    m.position = 3;
    m2 = new MemoryStream ();
    m2.writeString("before");
    m2.copyFrom(m,10);
    str = m2.toString();
    assert (str[0..16] == "before 345 hello");
    m2.position = 3;
    m2.copyFrom(m);
    auto str2 = m.toString();
    str = m2.toString();
    assert (str == ("bef" ~ str2));
  }
}

import std.mmfile;

/***
 * This subclass wraps a memory-mapped file with the stream API.
 * See std.mmfile module.
 */
class MmFileStream : TArrayStream!(MmFile) {

  /// Create stream wrapper for file.
  this(MmFile file) {
    super (file);
    MmFile.Mode mode = file.mode();
    writeable = mode > MmFile.Mode.read;
  }

  override void flush() {
    if (isopen) {
      super.flush();
      buf.flush();
    }
  }

  override void close() {
    if (isopen) {
      super.close();
      delete buf;
      buf = null;
    }
  }
}

unittest {
  MmFile mf = new MmFile("testing.txt",MmFile.Mode.readWriteNew,100,null);
  MmFileStream m;
  m = new MmFileStream (mf);
  m.writeString ("Hello, world");
  assert (m.position == 12);
  assert (m.seekSet (0) == 0);
  assert (m.seekCur (4) == 4);
  assert (m.seekEnd (-8) == 92);
  assert (m.size == 100);
  assert (m.seekSet (4));
  assert (m.readString (4) == "o, w");
  m.writeString ("ie");
  ubyte[] dd = m.data;
  assert ((cast(char[]) dd)[0 .. 12] == "Hello, wield");
  m.position = 12;
  m.writeString ("Foo");
  assert (m.position == 15);
  m.writeString ("Foo foo foo foo foo foo foo");
  assert (m.position == 42);
  m.close();
  mf = new MmFile("testing.txt");
  m = new MmFileStream (mf);
  assert (!m.writeable);
  char[] str = m.readString(12);
  assert (str == "Hello, wield");
  m.close();
  std.file.remove("testing.txt");
}


/***
 * This subclass slices off a portion of another stream, making seeking relative
 * to the boundaries of the slice.
 *
 * It could be used to section a large file into a
 * set of smaller files, such as with tar archives. Reading and writing a
 * SliceStream does not modify the position of the source stream if it is
 * seekable.
 */
class SliceStream : FilterStream {
  private {
    ulong pos;  // our position relative to low
    ulong low; // low stream offset.
    ulong high; // high stream offset.
    bool bounded; // upper-bounded by high.
  }

  /***
   * Indicate both the source stream to use for reading from and the low part of
   * the slice.
   *
   * The high part of the slice is dependent upon the end of the source
   * stream, so that if you write beyond the end it resizes the stream normally.
   */
  this (Stream s, ulong low)
  in {
    assert (low <= s.size);
  }
  body {
    super(s);
    this.low = low;
    this.high = 0;
    this.bounded = false;
  }

  /***
   * Indicate the high index as well.
   *
   * Attempting to read or write past the high
   * index results in the end being clipped off.
   */
  this (Stream s, ulong low, ulong high)
  in {
    assert (low <= high);
    assert (high <= s.size);
  }
  body {
    super(s);
    this.low = low;
    this.high = high;
    this.bounded = true;
  }

  invariant() {
    if (bounded)
      assert (pos <= high - low);
    else
      // size() does not appear to be const, though it should be
      assert (pos <= (cast()s).size - low);
  }

  override size_t readBlock (void *buffer, size_t size) {
    assertReadable();
    if (bounded && size > high - low - pos)
        size = cast(size_t)(high - low - pos);
    ulong bp = s.position;
    if (seekable)
      s.position = low + pos;
    size_t ret = super.readBlock(buffer, size);
    if (seekable) {
      pos = s.position - low;
      s.position = bp;
    }
    return ret;
  }

  override size_t writeBlock (const void *buffer, size_t size) {
    assertWriteable();
    if (bounded && size > high - low - pos)
        size = cast(size_t)(high - low - pos);
    ulong bp = s.position;
    if (seekable)
      s.position = low + pos;
    size_t ret = s.writeBlock(buffer, size);
    if (seekable) {
      pos = s.position - low;
      s.position = bp;
    }
    return ret;
  }

  override ulong seek(long offset, SeekPos rel) {
    assertSeekable();
    long spos;

    switch (rel) {
      case SeekPos.Set:
        spos = offset;
        break;
      case SeekPos.Current:
        spos = cast(long)(pos + offset);
        break;
      case SeekPos.End:
        if (bounded)
          spos = cast(long)(high - low + offset);
        else
          spos = cast(long)(s.size - low + offset);
        break;
      default:
        assert(0);
    }

    if (spos < 0)
      pos = 0;
    else if (bounded && spos > high - low)
      pos = high - low;
    else if (!bounded && spos > s.size - low)
      pos = s.size - low;
    else
      pos = cast(ulong)spos;

    readEOF = false;
    return pos;
  }

  override @property size_t available() {
    size_t res = s.available;
    ulong bp = s.position;
    if (bp <= pos+low && pos+low <= bp+res) {
      if (!bounded || bp+res <= high)
        return cast(size_t)(bp + res - pos - low);
      else if (high <= bp+res)
        return cast(size_t)(high - pos - low);
    }
    return 0;
  }

  unittest {
    MemoryStream m;
    SliceStream s;

    m = new MemoryStream ((cast(char[])"Hello, world").dup);
    s = new SliceStream (m, 4, 8);
    assert (s.size == 4);
    assert (m.position == 0);
    assert (s.position == 0);
    assert (m.available == 12);
    assert (s.available == 4);

    assert (s.writeBlock (cast(char *) "Vroom", 5) == 4);
    assert (m.position == 0);
    assert (s.position == 4);
    assert (m.available == 12);
    assert (s.available == 0);
    assert (s.seekEnd (-2) == 2);
    assert (s.available == 2);
    assert (s.seekEnd (2) == 4);
    assert (s.available == 0);
    assert (m.position == 0);
    assert (m.available == 12);

    m.seekEnd(0);
    m.writeString("\nBlaho");
    assert (m.position == 18);
    assert (m.available == 0);
    assert (s.position == 4);
    assert (s.available == 0);

    s = new SliceStream (m, 4);
    assert (s.size == 14);
    assert (s.toString () == "Vrooorld\nBlaho");
    s.seekEnd (0);
    assert (s.available == 0);

    s.writeString (", etcetera.");
    assert (s.position == 25);
    assert (s.seekSet (0) == 0);
    assert (s.size == 25);
    assert (m.position == 18);
    assert (m.size == 29);
    assert (m.toString() == "HellVrooorld\nBlaho, etcetera.");
  }
}