/usr/include/segyio/segy.h is in libsegyio-dev 1.5.2-1.
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 | #ifndef SEGYIO_SEGY_H
#define SEGYIO_SEGY_H
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#define SEGY_BINARY_HEADER_SIZE 400
#define SEGY_TEXT_HEADER_SIZE 3200
#define SEGY_TRACE_HEADER_SIZE 240
#ifdef __cplusplus
extern "C" {
#endif // __cplusplus
/*
* About signatures:
* If a function returns `int` you can assume the return value is an error
* code. 0 will always indicate success. If a function returns something else
* than an int it's typically an operation that cannot fail assuming the passed
* buffer is of the correct size. Any exceptions will be clearly stated.
*
* Function signatures are typically:
* 1) input parameters
* 2) output parameters
* 3) low-level file structure information
*
* Output parameters are non-const pointers, input parameters are const
* pointers or plain values. All functions are namespace-prefix'd with segy_.
* Some functions return values, notably the family concerned with the binary
* header such as segy_trace0, that should be used in consecutive segy function
* calls that use the same name for one of its parameters.
*/
struct segy_file_handle;
typedef struct segy_file_handle segy_file;
segy_file* segy_open( const char* path, const char* mode );
int segy_mmap( segy_file* );
int segy_flush( segy_file*, bool async );
int segy_close( segy_file* );
/* binary header operations */
/*
* The binheader buffer passed to these functions must be of *at least*
* `segy_binheader_size`. Returns size, not an error code.
*/
int segy_binheader_size( void );
int segy_binheader( segy_file*, char* buf );
int segy_write_binheader( segy_file*, const char* buf );
/*
* exception: the int returned is the number of samples (the segy standard only
* allocates 2 octets for this, so it comfortably sits inside an int
*/
int segy_samples( const char* binheader );
int segy_sample_interval( segy_file*, float fallback , float* dt );
/* exception: the int returned is an enum, SEGY_SORTING, not an error code */
int segy_format( const char* binheader );
int segy_get_field( const char* traceheader, int field, int32_t* f );
int segy_get_bfield( const char* binheader, int field, int32_t* f );
int segy_set_field( char* traceheader, int field, int32_t val );
int segy_set_bfield( char* binheader, int field, int32_t val );
int segy_field_forall( segy_file*,
int field,
int start,
int stop,
int step,
int* buf,
long trace0,
int trace_bsize );
/*
* exception: segy_trace_bsize computes the size of the traces in bytes. Cannot
* fail.
*/
int segy_trace_bsize( int samples );
/* byte-offset of the first trace header. */
long segy_trace0( const char* binheader );
/*
* number of traces in this file.
* if this function fails, the input argument is not modified.
*/
int segy_traces( segy_file*, int*, long trace0, int trace_bsize );
int segy_sample_indices( segy_file*,
float t0,
float dt,
int count,
float* buf );
/* text header operations */
/* buf in all read functions should be minimum segy_textheader_size() in size */
/* all read_textheader function outputs are zero-terminated C strings */
int segy_read_textheader( segy_file*, char *buf);
int segy_textheader_size( void );
/*
* read the extended textual headers. `pos = 0` gives the first *extended*
* header, i.e. the first textual header following the binary header.
* Behaviour is undefined if the file does not have extended headers
*/
int segy_read_ext_textheader( segy_file*, int pos, char* buf );
int segy_write_textheader( segy_file*, int pos, const char* buf );
/* Read the trace header at `traceno` into `buf`. */
int segy_traceheader( segy_file*,
int traceno,
char* buf,
long trace0,
int trace_bsize );
/* Read the trace header at `traceno` into `buf`. */
int segy_write_traceheader( segy_file*,
int traceno,
const char* buf,
long trace0,
int trace_bsize );
/*
* The sorting type will be written to `sorting` if the function can figure out
* how the file is sorted.
*/
int segy_sorting( segy_file*,
int il,
int xl,
int tr_offset,
int* sorting,
long trace0,
int trace_bsize );
/*
* Number of offsets in this file, written to `offsets`. 1 if a 3D data set, >1
* if a 4D data set.
*/
int segy_offsets( segy_file*,
int il,
int xl,
int traces,
int* out,
long trace0,
int trace_bsize );
/*
* The names of the individual offsets. `out` must be a buffer of
* `segy_offsets` elements.
*/
int segy_offset_indices( segy_file*,
int offset_field,
int offsets,
int* out,
long trace0,
int trace_bsize );
/*
* read/write traces. Does not manipulate the buffers at all, i.e. in order to
* make sense of the read trace it must be converted to native floats, and the
* buffer sent to write must be converted to target float.
*/
int segy_readtrace( segy_file*,
int traceno,
float* buf,
long trace0,
int trace_bsize );
int segy_writetrace( segy_file*,
int traceno,
const float* buf,
long trace0,
int trace_bsize );
/*
* read/write sub traces, with the same assumption and requirements as
* segy_readtrace. start and stop are *indices*, not byte offsets, so
* segy_readsubtr(fp, traceno, 10, 12, ...) reads samples 10 through 12, and
* not bytes 10 through 12.
*
* start and stop are in the range [start,stop), so start=0, stop=5, step=2
* yields [0, 2, 4], whereas stop=4 yields [0, 2]
*
* When step is negative, the subtrace will be read in reverse. If step is
* negative and [0,n) is desired, pass use -1 for stop. Other negative values
* are undefined. If the range [n, m) where m is larger than the samples is
* considered undefined. Any [n, m) where distance(n,m) > samples is undefined.
*
* The parameter rangebuf is a pointer to a buffer of at least abs(stop-start)
* size. This is largely intended for script-C boundaries. In code paths where
* step is not 1 or -1, and mmap is not activated, these functions will
* *allocate* a buffer to read data from file in chunks. This is a significant
* speedup over multiple fread calls, at the cost of a clunkier interface. This
* is a tradeoff, since this function is often called in an inner loop. If
* you're fine with these functions allocating and freeing this buffer for you,
* rangebuf can be NULL.
*/
int segy_readsubtr( segy_file*,
int traceno,
int start,
int stop,
int step,
float* buf,
float* rangebuf,
long trace0,
int trace_bsize );
int segy_writesubtr( segy_file*,
int traceno,
int start,
int stop,
int step,
const float* buf,
float* rangebuf,
long trace0,
int trace_bsize );
/*
* convert to/from native float from segy formats (likely IBM or IEEE). Size
* parameter is long long because it needs to know the number of *samples*,
* which can be very large for bulk conversion of a collection of traces.
*/
int segy_to_native( int format,
long long size,
float* buf );
int segy_from_native( int format,
long long size,
float* buf );
int segy_read_line( segy_file* fp,
int line_trace0,
int line_length,
int stride,
int offsets,
float* buf,
long trace0,
int trace_bsize );
int segy_write_line( segy_file* fp,
int line_trace0,
int line_length,
int stride,
int offsets,
const float* buf,
long trace0,
int trace_bsize );
/*
* Count inlines and crosslines. Use this function to determine how large buffer
* the functions `segy_inline_indices` and `segy_crossline_indices` expect. If
* the file is sorted on inlines, `field` should the trace header field for the
* crossline number, and the inline number if the file is sorted on crosslines.
* If the file is sorted on inlines, `l1out` will contain the number of
* inlines, and `l2out` crosslines, and the other way around if the file is
* sorted on crosslines.
*
* `offsets` is the number of offsets in the file and be found with
* `segy_offsets`.
*
* If the file has only 1 trace (or, for pre-stack files, 1-trace-per-offset),
* segyio considers this as 1 line in each direction.
*/
int segy_count_lines( segy_file*,
int field,
int offsets,
int* l1out,
int* l2out,
long trace0,
int trace_bsize );
/*
* Alternative interface for segy_count_lines. If you have information about
* sorting this is easier to use, but requires both the inline and crossline
* header field positions. Does the argument shuffling needed to call
* segy_count_lines.
*/
int segy_lines_count( segy_file*,
int il,
int xl,
int sorting,
int offsets,
int* il_count,
int* xl_count,
long trace0,
int trace_bsize );
/*
* Find the `line_length` for the inlines. Assumes all inlines, crosslines and
* traces don't vary in length.
*
* `inline_count` and `crossline_count` are the two values obtained with
* `segy_count_lines`.
*
* These functions cannot fail and return the length, not an error code.
*/
int segy_inline_length(int crossline_count);
int segy_crossline_length(int inline_count);
/*
* Find the indices of the inlines and write to `buf`. `offsets` are the number
* of offsets for this file as returned by `segy_offsets`
*/
int segy_inline_indices( segy_file*,
int il,
int sorting,
int inline_count,
int crossline_count,
int offsets,
int* buf,
long trace0,
int trace_bsize );
int segy_crossline_indices( segy_file*,
int xl,
int sorting,
int inline_count,
int crossline_count,
int offsets,
int* buf,
long trace0,
int trace_bsize );
/*
* Find the first `traceno` of the line `lineno`. `linenos` should be the line
* indices returned by `segy_inline_indices` or `segy_crossline_indices`. The
* stride depends on the sorting and is given by `segy_inline_stride` or
* `segy_crossline_stride`. `offsets` is given by `segy_offsets` function, and
* is the number of offsets in this file (1 for post stack data). `line_length`
* is the length, i.e. traces per line, given by `segy_inline_length` or
* `segy_crossline_length`.
*
* To read/write an inline, read `line_length` starting at `traceno`,
* incrementing `traceno` with `stride` `line_length` times.
*/
int segy_line_trace0( int lineno,
int line_length,
int stride,
int offsets,
const int* linenos,
int linenos_sz,
int* traceno );
/*
* Find the `rotation` of the survey in radians.
*
* Returns the clock-wise rotation around north, i.e. the angle between the
* first line given and north axis. In this context, north is the direction
* that yields a higher CDP-Y coordinate, and east is the direction that yields
* a higher CDP-X coordinate.
*
* N
* |
* |
* | +
* | |~~/``````/
* | | /------/
* | |/,,,,,,/
* |
* +--------------- E
*
*
* When the survey is as depicted, and the first line is starting in the
* south-west corner and goes north, the angle (~~) is < pi/4. If the first
* line is parallel with equator moving east, the angle is pi/2.
*
* The return value is in the domain [0, 2pi)
*/
int segy_rotation_cw( segy_file*,
int line_length,
int stride,
int offsets,
const int* linenos,
int linenos_sz,
float* rotation,
long trace0,
int trace_bsize );
/*
* Find the stride needed for an inline/crossline traversal.
*/
int segy_inline_stride( int sorting,
int inline_count,
int* stride );
int segy_crossline_stride( int sorting,
int crossline_count,
int* stride );
typedef enum {
SEGY_TR_SEQ_LINE = 1,
SEGY_TR_SEQ_FILE = 5,
SEGY_TR_FIELD_RECORD = 9,
SEGY_TR_NUMBER_ORIG_FIELD = 13,
SEGY_TR_ENERGY_SOURCE_POINT = 17,
SEGY_TR_ENSEMBLE = 21,
SEGY_TR_NUM_IN_ENSEMBLE = 25,
SEGY_TR_TRACE_ID = 29,
SEGY_TR_SUMMED_TRACES = 31,
SEGY_TR_STACKED_TRACES = 33,
SEGY_TR_DATA_USE = 35,
SEGY_TR_OFFSET = 37,
SEGY_TR_RECV_GROUP_ELEV = 41,
SEGY_TR_SOURCE_SURF_ELEV = 45,
SEGY_TR_SOURCE_DEPTH = 49,
SEGY_TR_RECV_DATUM_ELEV = 53,
SEGY_TR_SOURCE_DATUM_ELEV = 57,
SEGY_TR_SOURCE_WATER_DEPTH = 61,
SEGY_TR_GROUP_WATER_DEPTH = 65,
SEGY_TR_ELEV_SCALAR = 69,
SEGY_TR_SOURCE_GROUP_SCALAR = 71,
SEGY_TR_SOURCE_X = 73,
SEGY_TR_SOURCE_Y = 77,
SEGY_TR_GROUP_X = 81,
SEGY_TR_GROUP_Y = 85,
SEGY_TR_COORD_UNITS = 89,
SEGY_TR_WEATHERING_VELO = 91,
SEGY_TR_SUBWEATHERING_VELO = 93,
SEGY_TR_SOURCE_UPHOLE_TIME = 95,
SEGY_TR_GROUP_UPHOLE_TIME = 97,
SEGY_TR_SOURCE_STATIC_CORR = 99,
SEGY_TR_GROUP_STATIC_CORR = 101,
SEGY_TR_TOT_STATIC_APPLIED = 103,
SEGY_TR_LAG_A = 105,
SEGY_TR_LAG_B = 107,
SEGY_TR_DELAY_REC_TIME = 109,
SEGY_TR_MUTE_TIME_START = 111,
SEGY_TR_MUTE_TIME_END = 113,
SEGY_TR_SAMPLE_COUNT = 115,
SEGY_TR_SAMPLE_INTER = 117,
SEGY_TR_GAIN_TYPE = 119,
SEGY_TR_INSTR_GAIN_CONST = 121,
SEGY_TR_INSTR_INIT_GAIN = 123,
SEGY_TR_CORRELATED = 125,
SEGY_TR_SWEEP_FREQ_START = 127,
SEGY_TR_SWEEP_FREQ_END = 129,
SEGY_TR_SWEEP_LENGTH = 131,
SEGY_TR_SWEEP_TYPE = 133,
SEGY_TR_SWEEP_TAPERLEN_START = 135,
SEGY_TR_SWEEP_TAPERLEN_END = 137,
SEGY_TR_TAPER_TYPE = 139,
SEGY_TR_ALIAS_FILT_FREQ = 141,
SEGY_TR_ALIAS_FILT_SLOPE = 143,
SEGY_TR_NOTCH_FILT_FREQ = 145,
SEGY_TR_NOTCH_FILT_SLOPE = 147,
SEGY_TR_LOW_CUT_FREQ = 149,
SEGY_TR_HIGH_CUT_FREQ = 151,
SEGY_TR_LOW_CUT_SLOPE = 153,
SEGY_TR_HIGH_CUT_SLOPE = 155,
SEGY_TR_YEAR_DATA_REC = 157,
SEGY_TR_DAY_OF_YEAR = 159,
SEGY_TR_HOUR_OF_DAY = 161,
SEGY_TR_MIN_OF_HOUR = 163,
SEGY_TR_SEC_OF_MIN = 165,
SEGY_TR_TIME_BASE_CODE = 167,
SEGY_TR_WEIGHTING_FAC = 169,
SEGY_TR_GEOPHONE_GROUP_ROLL1 = 171,
SEGY_TR_GEOPHONE_GROUP_FIRST = 173,
SEGY_TR_GEOPHONE_GROUP_LAST = 175,
SEGY_TR_GAP_SIZE = 177,
SEGY_TR_OVER_TRAVEL = 179,
SEGY_TR_CDP_X = 181,
SEGY_TR_CDP_Y = 185,
SEGY_TR_INLINE = 189,
SEGY_TR_CROSSLINE = 193,
SEGY_TR_SHOT_POINT = 197,
SEGY_TR_SHOT_POINT_SCALAR = 201,
SEGY_TR_MEASURE_UNIT = 203,
SEGY_TR_TRANSDUCTION_MANT = 205,
SEGY_TR_TRANSDUCTION_EXP = 209,
SEGY_TR_TRANSDUCTION_UNIT = 211,
SEGY_TR_DEVICE_ID = 213,
SEGY_TR_SCALAR_TRACE_HEADER = 215,
SEGY_TR_SOURCE_TYPE = 217,
SEGY_TR_SOURCE_ENERGY_DIR_MANT = 219,
SEGY_TR_SOURCE_ENERGY_DIR_EXP = 223,
SEGY_TR_SOURCE_MEASURE_MANT = 225,
SEGY_TR_SOURCE_MEASURE_EXP = 229,
SEGY_TR_SOURCE_MEASURE_UNIT = 231,
SEGY_TR_UNASSIGNED1 = 233,
SEGY_TR_UNASSIGNED2 = 237
} SEGY_FIELD;
typedef enum {
SEGY_BIN_JOB_ID = 3201,
SEGY_BIN_LINE_NUMBER = 3205,
SEGY_BIN_REEL_NUMBER = 3209,
SEGY_BIN_TRACES = 3213,
SEGY_BIN_AUX_TRACES = 3215,
SEGY_BIN_INTERVAL = 3217,
SEGY_BIN_INTERVAL_ORIG = 3219,
SEGY_BIN_SAMPLES = 3221,
SEGY_BIN_SAMPLES_ORIG = 3223,
SEGY_BIN_FORMAT = 3225,
SEGY_BIN_ENSEMBLE_FOLD = 3227,
SEGY_BIN_SORTING_CODE = 3229,
SEGY_BIN_VERTICAL_SUM = 3231,
SEGY_BIN_SWEEP_FREQ_START = 3233,
SEGY_BIN_SWEEP_FREQ_END = 3235,
SEGY_BIN_SWEEP_LENGTH = 3237,
SEGY_BIN_SWEEP = 3239,
SEGY_BIN_SWEEP_CHANNEL = 3241,
SEGY_BIN_SWEEP_TAPER_START = 3243,
SEGY_BIN_SWEEP_TAPER_END = 3245,
SEGY_BIN_TAPER = 3247,
SEGY_BIN_CORRELATED_TRACES = 3249,
SEGY_BIN_BIN_GAIN_RECOVERY = 3251,
SEGY_BIN_AMPLITUDE_RECOVERY = 3253,
SEGY_BIN_MEASUREMENT_SYSTEM = 3255,
SEGY_BIN_IMPULSE_POLARITY = 3257,
SEGY_BIN_VIBRATORY_POLARITY = 3259,
SEGY_BIN_UNASSIGNED1 = 3261,
SEGY_BIN_SEGY_REVISION = 3501,
SEGY_BIN_TRACE_FLAG = 3503,
SEGY_BIN_EXT_HEADERS = 3505,
SEGY_BIN_UNASSIGNED2 = 3507,
} SEGY_BINFIELD;
typedef enum {
SEGY_IBM_FLOAT_4_BYTE = 1,
SEGY_SIGNED_INTEGER_4_BYTE = 2,
SEGY_SIGNED_SHORT_2_BYTE = 3,
SEGY_FIXED_POINT_WITH_GAIN_4_BYTE = 4, // Obsolete
SEGY_IEEE_FLOAT_4_BYTE = 5,
SEGY_NOT_IN_USE_1 = 6,
SEGY_NOT_IN_USE_2 = 7,
SEGY_SIGNED_CHAR_1_BYTE = 8
} SEGY_FORMAT;
typedef enum {
SEGY_UNKNOWN_SORTING = 0,
SEGY_CROSSLINE_SORTING = 1,
SEGY_INLINE_SORTING = 2,
} SEGY_SORTING;
typedef enum {
SEGY_OK = 0,
SEGY_FOPEN_ERROR,
SEGY_FSEEK_ERROR,
SEGY_FREAD_ERROR,
SEGY_FWRITE_ERROR,
SEGY_INVALID_FIELD,
SEGY_INVALID_SORTING,
SEGY_MISSING_LINE_INDEX,
SEGY_INVALID_OFFSETS,
SEGY_TRACE_SIZE_MISMATCH,
SEGY_INVALID_ARGS,
SEGY_MMAP_ERROR,
SEGY_MMAP_INVALID,
SEGY_READONLY,
SEGY_NOTFOUND,
} SEGY_ERROR;
#ifdef __cplusplus
}
#endif // __cplusplus
#endif //SEGYIO_SEGY_H
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