/usr/share/acl2-8.0dfsg/books/misc/fast-coerce.lisp is in acl2-books-source 8.0dfsg-1.
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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 | ; fast-coerce.lisp
; Copyright (C) 2008 Kookamara LLC
;
; Contact:
;
; Kookamara LLC
; 11410 Windermere Meadows
; Austin, TX 78759, USA
; http://www.kookamara.com/
;
; License: (An MIT/X11-style license)
;
; Permission is hereby granted, free of charge, to any person obtaining a
; copy of this software and associated documentation files (the "Software"),
; to deal in the Software without restriction, including without limitation
; the rights to use, copy, modify, merge, publish, distribute, sublicense,
; and/or sell copies of the Software, and to permit persons to whom the
; Software is furnished to do so, subject to the following conditions:
;
; The above copyright notice and this permission notice shall be included in
; all copies or substantial portions of the Software.
;
; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
; DEALINGS IN THE SOFTWARE.
;
; Original author: Jared Davis <jared@kookamara.com>
(in-package "ACL2")
; This is a sometimes-faster version of coerce.
;
; - It is the same as ACL2's regular coerce when converting character lists
; into strings.
;
; - It is sometimes faster when converting strings into character lists.
;
; "Fast-coerce is _____ than regular coerce"
;
; - Allegro: negligibly faster
; - Clisp: negligibly slower
; - GCL: 50-60% faster
; - CMUCL: 40% faster & uses 30% less memory
; - SBCL: 50% faster & uses 8% less memory
; - Old CCL: 90% faster & uses 56% less memory
; - New CCL: 18% slower
;
; We would like to tailor the :exec part of the definition to fit the Lisp we
; are using via features, but we think this would break the ability to share
; certificates across Lisps. Ugh. For now we are just going to leave it as
; is, and say don't use it if your primary environment is the new version of
; CCL.
;
; Ideally we should get rid of this file and simply improve each Lisp.
;
; On Nemesis. (32-bit) -- fast-coerce -------- coerce ------
;
; /p/bin/acl2 10.6s 27s
;
; /p/bin/acl2-allegro 46.4s 48.5s
; 1.040 GB 1.040 GB
;
; /p/bin/acl2-cmucl 10.3s 17.1s
; 1.040 GB 1.440 GB
;
; /p/bin/acl2-clisp 44.35s 42.6s
; 1.040 GB 1.040 GB
;
; On Lhug-3. (64-bit) --- fast-coerce -------- coerce ------
;
;
; /p/bin/acl2-gcl 18.8s 39.7s
;
; /p/bin/acl2-openmcl 5.5s 64s (OLDER VERSION)
; 2.080 GB 4.64 GB
;
; /p/bin/acl2-sbcl 5.6s 10.94s
; 2.080 GB 2.240 GB
;
;
; On FV-1 (64-bit) --- fast-coerce -------- coerce ------
;
; acl2-ccl 4.96s 4.07s (NEW VERSION)
; 2.080 GB 2.080 GB
#||
(time$ (loop for i fixnum from 1 to 10000000 do
(coerce "Hello, World!" 'list)))
(time$ (loop for i fixnum from 1 to 10000000 do
(fast-coerce "Hello, World!" 'list)))
||#
(local (include-book "arithmetic/top-with-meta" :dir :system))
(local (include-book "data-structures/list-defthms" :dir :system))
(defund fast-coerce-aux1 (x i len)
(declare (type string x)
(type (signed-byte 30) i)
(type (signed-byte 30) len)
(xargs :guard (and (stringp x)
(natp i)
(natp len)
(= len (length x))
(<= i len))
:measure (nfix (- (nfix len) (nfix i)))))
(if (mbe :logic (zp (- (nfix len) (nfix i)))
:exec (= (the-fixnum i)
(the-fixnum len)))
nil
(cons (the character
(char (the string x)
(the (signed-byte 30) i)))
(fast-coerce-aux1 x
(the-fixnum
(+ (the-fixnum 1)
(mbe :logic (nfix i)
:exec (the-fixnum i))))
(the-fixnum len)))))
(defund fast-coerce-aux2 (x i len)
(declare (type string x)
(type integer i)
(type integer len)
(xargs :guard (and (stringp x)
(natp i)
(natp len)
(= len (length x))
(<= i len))
:guard-debug t
:measure (nfix (- (nfix len) (nfix i)))))
(if (mbe :logic (zp (- (nfix len) (nfix i)))
:exec (= (the integer i) (the integer len)))
nil
(cons (char x i)
(fast-coerce-aux2 x
(+ (the integer 1)
(mbe :logic (nfix i)
:exec (the integer i)))
len))))
(local (defthm lemma
(implies (and (natp i)
(< i (len x)))
(equal (cons (nth i x)
(cdr (nthcdr i x)))
(nthcdr i x)))))
(local (defthm lemma2
(equal (nthcdr i (cdr x))
(cdr (nthcdr i x)))))
(local (defthm lemma3
(implies (and (stringp x)
(natp i)
(<= i (length x)))
(equal (fast-coerce-aux2 x i (len (coerce x 'list)))
(nthcdr i (coerce x 'list))))
:hints(("Goal"
:in-theory (enable fast-coerce-aux2)))))
(local (defthm fast-coerce-aux2-equiv
(equal (fast-coerce-aux1 x i len)
(fast-coerce-aux2 x i len))
:hints(("Goal" :in-theory (enable fast-coerce-aux2
fast-coerce-aux1)))))
(defun fast-coerce (x y)
(declare (xargs :guard (case y
(list (stringp x))
(string (character-listp x)))))
(mbe :logic (coerce x y)
:exec
;; I'd like to just use
;; (if (eq y 'list)
;; (coerce x 'list)
;; (coerce x 'string))
;; when running on CLISP or CCL, and the loop below for other Lisps. But
;; this would break certificate-compatibility, so I just leave it as is.
(if (eq y 'list)
(let ((length (length x)))
(if (< (the integer length)
(the integer 536870912))
(fast-coerce-aux1 (the string x)
(the (signed-byte 30) 0)
(the (signed-byte 30) length))
(fast-coerce-aux2 (the string x)
(the integer 0)
(the integer length))))
(coerce x y))))
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