| 1 | ;;; GNU Guix --- Functional package management for GNU |
| 2 | ;;; Copyright © 2019 Pierre Neidhardt <mail@ambrevar.xyz> |
| 3 | ;;; Copyright © 2019 Ludovic Courtès <ludo@gnu.org> |
| 4 | ;;; |
| 5 | ;;; This file is part of GNU Guix. |
| 6 | ;;; |
| 7 | ;;; GNU Guix is free software; you can redistribute it and/or modify it |
| 8 | ;;; under the terms of the GNU General Public License as published by |
| 9 | ;;; the Free Software Foundation; either version 3 of the License, or (at |
| 10 | ;;; your option) any later version. |
| 11 | ;;; |
| 12 | ;;; GNU Guix is distributed in the hope that it will be useful, but |
| 13 | ;;; WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | ;;; GNU General Public License for more details. |
| 16 | ;;; |
| 17 | ;;; You should have received a copy of the GNU General Public License |
| 18 | ;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>. |
| 19 | |
| 20 | (define-module (guix lzlib) |
| 21 | #:use-module (rnrs bytevectors) |
| 22 | #:use-module (rnrs arithmetic bitwise) |
| 23 | #:use-module (ice-9 binary-ports) |
| 24 | #:use-module (ice-9 match) |
| 25 | #:use-module (system foreign) |
| 26 | #:use-module (guix config) |
| 27 | #:use-module (srfi srfi-11) |
| 28 | #:export (lzlib-available? |
| 29 | make-lzip-input-port |
| 30 | make-lzip-output-port |
| 31 | make-lzip-input-port/compressed |
| 32 | call-with-lzip-input-port |
| 33 | call-with-lzip-output-port |
| 34 | %default-member-length-limit |
| 35 | %default-compression-level)) |
| 36 | |
| 37 | ;;; Commentary: |
| 38 | ;;; |
| 39 | ;;; Bindings to the lzlib / liblz API. Some convenience functions are also |
| 40 | ;;; provided (see the export). |
| 41 | ;;; |
| 42 | ;;; While the bindings are complete, the convenience functions only support |
| 43 | ;;; single member archives. To decompress single member archives, we loop |
| 44 | ;;; until lz-decompress-read returns 0. This is simpler. To support multiple |
| 45 | ;;; members properly, we need (among others) to call lz-decompress-finish and |
| 46 | ;;; loop over lz-decompress-read until lz-decompress-finished? returns #t. |
| 47 | ;;; Otherwise a multi-member archive starting with an empty member would only |
| 48 | ;;; decompress the empty member and stop there, resulting in truncated output. |
| 49 | |
| 50 | ;;; Code: |
| 51 | |
| 52 | (define %lzlib |
| 53 | ;; File name of lzlib's shared library. When updating via 'guix pull', |
| 54 | ;; '%liblz' might be undefined so protect against it. |
| 55 | (delay (dynamic-link (if (defined? '%liblz) |
| 56 | %liblz |
| 57 | "liblz")))) |
| 58 | |
| 59 | (define (lzlib-available?) |
| 60 | "Return true if lzlib is available, #f otherwise." |
| 61 | (false-if-exception (force %lzlib))) |
| 62 | |
| 63 | (define (lzlib-procedure ret name parameters) |
| 64 | "Return a procedure corresponding to C function NAME in liblz, or #f if |
| 65 | either lzlib or the function could not be found." |
| 66 | (match (false-if-exception (dynamic-func name (force %lzlib))) |
| 67 | ((? pointer? ptr) |
| 68 | (pointer->procedure ret ptr parameters)) |
| 69 | (#f |
| 70 | #f))) |
| 71 | |
| 72 | (define-wrapped-pointer-type <lz-decoder> |
| 73 | ;; Scheme counterpart of the 'LZ_Decoder' opaque type. |
| 74 | lz-decoder? |
| 75 | pointer->lz-decoder |
| 76 | lz-decoder->pointer |
| 77 | (lambda (obj port) |
| 78 | (format port "#<lz-decoder ~a>" |
| 79 | (number->string (object-address obj) 16)))) |
| 80 | |
| 81 | (define-wrapped-pointer-type <lz-encoder> |
| 82 | ;; Scheme counterpart of the 'LZ_Encoder' opaque type. |
| 83 | lz-encoder? |
| 84 | pointer->lz-encoder |
| 85 | lz-encoder->pointer |
| 86 | (lambda (obj port) |
| 87 | (format port "#<lz-encoder ~a>" |
| 88 | (number->string (object-address obj) 16)))) |
| 89 | |
| 90 | ;; From lzlib.h |
| 91 | (define %error-number-ok 0) |
| 92 | (define %error-number-bad-argument 1) |
| 93 | (define %error-number-mem-error 2) |
| 94 | (define %error-number-sequence-error 3) |
| 95 | (define %error-number-header-error 4) |
| 96 | (define %error-number-unexpected-eof 5) |
| 97 | (define %error-number-data-error 6) |
| 98 | (define %error-number-library-error 7) |
| 99 | |
| 100 | \f |
| 101 | ;; Compression bindings. |
| 102 | |
| 103 | (define lz-compress-open |
| 104 | (let ((proc (lzlib-procedure '* "LZ_compress_open" (list int int uint64))) |
| 105 | ;; member-size is an "unsigned long long", and the C standard guarantees |
| 106 | ;; a minimum range of 0..2^64-1. |
| 107 | (unlimited-size (- (expt 2 64) 1))) |
| 108 | (lambda* (dictionary-size match-length-limit #:optional (member-size unlimited-size)) |
| 109 | "Initialize the internal stream state for compression and returns a |
| 110 | pointer that can only be used as the encoder argument for the other |
| 111 | lz-compress functions, or a null pointer if the encoder could not be |
| 112 | allocated. |
| 113 | |
| 114 | See the manual: (lzlib) Compression functions." |
| 115 | (let ((encoder-ptr (proc dictionary-size match-length-limit member-size))) |
| 116 | (if (not (= (lz-compress-error encoder-ptr) -1)) |
| 117 | (pointer->lz-encoder encoder-ptr) |
| 118 | (throw 'lzlib-error 'lz-compress-open)))))) |
| 119 | |
| 120 | (define lz-compress-close |
| 121 | (let ((proc (lzlib-procedure int "LZ_compress_close" '(*)))) |
| 122 | (lambda (encoder) |
| 123 | "Close encoder. ENCODER can no longer be used as an argument to any |
| 124 | lz-compress function. " |
| 125 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 126 | (if (= ret -1) |
| 127 | (throw 'lzlib-error 'lz-compress-close ret) |
| 128 | ret))))) |
| 129 | |
| 130 | (define lz-compress-finish |
| 131 | (let ((proc (lzlib-procedure int "LZ_compress_finish" '(*)))) |
| 132 | (lambda (encoder) |
| 133 | "Tell that all the data for this member have already been written (with |
| 134 | the `lz-compress-write' function). It is safe to call `lz-compress-finish' as |
| 135 | many times as needed. After all the produced compressed data have been read |
| 136 | with `lz-compress-read' and `lz-compress-member-finished?' returns #t, a new |
| 137 | member can be started with 'lz-compress-restart-member'." |
| 138 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 139 | (if (= ret -1) |
| 140 | (throw 'lzlib-error 'lz-compress-finish (lz-compress-error encoder)) |
| 141 | ret))))) |
| 142 | |
| 143 | (define lz-compress-restart-member |
| 144 | (let ((proc (lzlib-procedure int "LZ_compress_restart_member" (list '* uint64)))) |
| 145 | (lambda (encoder member-size) |
| 146 | "Start a new member in a multimember data stream. |
| 147 | Call this function only after `lz-compress-member-finished?' indicates that the |
| 148 | current member has been fully read (with the `lz-compress-read' function)." |
| 149 | (let ((ret (proc (lz-encoder->pointer encoder) member-size))) |
| 150 | (if (= ret -1) |
| 151 | (throw 'lzlib-error 'lz-compress-restart-member |
| 152 | (lz-compress-error encoder)) |
| 153 | ret))))) |
| 154 | |
| 155 | (define lz-compress-sync-flush |
| 156 | (let ((proc (lzlib-procedure int "LZ_compress_sync_flush" (list '*)))) |
| 157 | (lambda (encoder) |
| 158 | "Make available to `lz-compress-read' all the data already written with |
| 159 | the `LZ-compress-write' function. First call `lz-compress-sync-flush'. Then |
| 160 | call 'lz-compress-read' until it returns 0. |
| 161 | |
| 162 | Repeated use of `LZ-compress-sync-flush' may degrade compression ratio, |
| 163 | so use it only when needed. " |
| 164 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 165 | (if (= ret -1) |
| 166 | (throw 'lzlib-error 'lz-compress-sync-flush |
| 167 | (lz-compress-error encoder)) |
| 168 | ret))))) |
| 169 | |
| 170 | (define lz-compress-read |
| 171 | (let ((proc (lzlib-procedure int "LZ_compress_read" (list '* '* int)))) |
| 172 | (lambda* (encoder lzfile-bv #:optional (start 0) (count (bytevector-length lzfile-bv))) |
| 173 | "Read up to COUNT bytes from the encoder stream, storing the results in LZFILE-BV. |
| 174 | Return the number of uncompressed bytes written, a positive integer." |
| 175 | (let ((ret (proc (lz-encoder->pointer encoder) |
| 176 | (bytevector->pointer lzfile-bv start) |
| 177 | count))) |
| 178 | (if (= ret -1) |
| 179 | (throw 'lzlib-error 'lz-compress-read (lz-compress-error encoder)) |
| 180 | ret))))) |
| 181 | |
| 182 | (define lz-compress-write |
| 183 | (let ((proc (lzlib-procedure int "LZ_compress_write" (list '* '* int)))) |
| 184 | (lambda* (encoder bv #:optional (start 0) (count (bytevector-length bv))) |
| 185 | "Write up to COUNT bytes from BV to the encoder stream. Return the |
| 186 | number of uncompressed bytes written, a strictly positive integer." |
| 187 | (let ((ret (proc (lz-encoder->pointer encoder) |
| 188 | (bytevector->pointer bv start) |
| 189 | count))) |
| 190 | (if (< ret 0) |
| 191 | (throw 'lzlib-error 'lz-compress-write (lz-compress-error encoder)) |
| 192 | ret))))) |
| 193 | |
| 194 | (define lz-compress-write-size |
| 195 | (let ((proc (lzlib-procedure int "LZ_compress_write_size" '(*)))) |
| 196 | (lambda (encoder) |
| 197 | "The maximum number of bytes that can be immediately written through the |
| 198 | `lz-compress-write' function. |
| 199 | |
| 200 | It is guaranteed that an immediate call to `lz-compress-write' will accept a |
| 201 | SIZE up to the returned number of bytes. " |
| 202 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 203 | (if (= ret -1) |
| 204 | (throw 'lzlib-error 'lz-compress-write-size (lz-compress-error encoder)) |
| 205 | ret))))) |
| 206 | |
| 207 | (define lz-compress-error |
| 208 | (let ((proc (lzlib-procedure int "LZ_compress_errno" '(*)))) |
| 209 | (lambda (encoder) |
| 210 | "ENCODER can be a Scheme object or a pointer." |
| 211 | (let* ((error-number (proc (if (lz-encoder? encoder) |
| 212 | (lz-encoder->pointer encoder) |
| 213 | encoder)))) |
| 214 | error-number)))) |
| 215 | |
| 216 | (define lz-compress-finished? |
| 217 | (let ((proc (lzlib-procedure int "LZ_compress_finished" '(*)))) |
| 218 | (lambda (encoder) |
| 219 | "Return #t if all the data have been read and `lz-compress-close' can |
| 220 | be safely called. Otherwise return #f." |
| 221 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 222 | (match ret |
| 223 | (1 #t) |
| 224 | (0 #f) |
| 225 | (_ (throw 'lzlib-error 'lz-compress-finished? (lz-compress-error encoder)))))))) |
| 226 | |
| 227 | (define lz-compress-member-finished? |
| 228 | (let ((proc (lzlib-procedure int "LZ_compress_member_finished" '(*)))) |
| 229 | (lambda (encoder) |
| 230 | "Return #t if the current member, in a multimember data stream, has |
| 231 | been fully read and 'lz-compress-restart-member' can be safely called. |
| 232 | Otherwise return #f." |
| 233 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 234 | (match ret |
| 235 | (1 #t) |
| 236 | (0 #f) |
| 237 | (_ (throw 'lzlib-error 'lz-compress-member-finished? (lz-compress-error encoder)))))))) |
| 238 | |
| 239 | (define lz-compress-data-position |
| 240 | (let ((proc (lzlib-procedure uint64 "LZ_compress_data_position" '(*)))) |
| 241 | (lambda (encoder) |
| 242 | "Return the number of input bytes already compressed in the current |
| 243 | member." |
| 244 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 245 | (if (= ret -1) |
| 246 | (throw 'lzlib-error 'lz-compress-data-position |
| 247 | (lz-compress-error encoder)) |
| 248 | ret))))) |
| 249 | |
| 250 | (define lz-compress-member-position |
| 251 | (let ((proc (lzlib-procedure uint64 "LZ_compress_member_position" '(*)))) |
| 252 | (lambda (encoder) |
| 253 | "Return the number of compressed bytes already produced, but perhaps |
| 254 | not yet read, in the current member." |
| 255 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 256 | (if (= ret -1) |
| 257 | (throw 'lzlib-error 'lz-compress-member-position |
| 258 | (lz-compress-error encoder)) |
| 259 | ret))))) |
| 260 | |
| 261 | (define lz-compress-total-in-size |
| 262 | (let ((proc (lzlib-procedure uint64 "LZ_compress_total_in_size" '(*)))) |
| 263 | (lambda (encoder) |
| 264 | "Return the total number of input bytes already compressed." |
| 265 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 266 | (if (= ret -1) |
| 267 | (throw 'lzlib-error 'lz-compress-total-in-size |
| 268 | (lz-compress-error encoder)) |
| 269 | ret))))) |
| 270 | |
| 271 | (define lz-compress-total-out-size |
| 272 | (let ((proc (lzlib-procedure uint64 "LZ_compress_total_out_size" '(*)))) |
| 273 | (lambda (encoder) |
| 274 | "Return the total number of compressed bytes already produced, but |
| 275 | perhaps not yet read." |
| 276 | (let ((ret (proc (lz-encoder->pointer encoder)))) |
| 277 | (if (= ret -1) |
| 278 | (throw 'lzlib-error 'lz-compress-total-out-size |
| 279 | (lz-compress-error encoder)) |
| 280 | ret))))) |
| 281 | |
| 282 | \f |
| 283 | ;; Decompression bindings. |
| 284 | |
| 285 | (define lz-decompress-open |
| 286 | (let ((proc (lzlib-procedure '* "LZ_decompress_open" '()))) |
| 287 | (lambda () |
| 288 | "Initializes the internal stream state for decompression and returns a |
| 289 | pointer that can only be used as the decoder argument for the other |
| 290 | lz-decompress functions, or a null pointer if the decoder could not be |
| 291 | allocated. |
| 292 | |
| 293 | See the manual: (lzlib) Decompression functions." |
| 294 | (let ((decoder-ptr (proc))) |
| 295 | (if (not (= (lz-decompress-error decoder-ptr) -1)) |
| 296 | (pointer->lz-decoder decoder-ptr) |
| 297 | (throw 'lzlib-error 'lz-decompress-open)))))) |
| 298 | |
| 299 | (define lz-decompress-close |
| 300 | (let ((proc (lzlib-procedure int "LZ_decompress_close" '(*)))) |
| 301 | (lambda (decoder) |
| 302 | "Close decoder. DECODER can no longer be used as an argument to any |
| 303 | lz-decompress function. " |
| 304 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 305 | (if (= ret -1) |
| 306 | (throw 'lzlib-error 'lz-decompress-close ret) |
| 307 | ret))))) |
| 308 | |
| 309 | (define lz-decompress-finish |
| 310 | (let ((proc (lzlib-procedure int "LZ_decompress_finish" '(*)))) |
| 311 | (lambda (decoder) |
| 312 | "Tell that all the data for this stream have already been written (with |
| 313 | the `lz-decompress-write' function). It is safe to call |
| 314 | `lz-decompress-finish' as many times as needed." |
| 315 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 316 | (if (= ret -1) |
| 317 | (throw 'lzlib-error 'lz-decompress-finish (lz-decompress-error decoder)) |
| 318 | ret))))) |
| 319 | |
| 320 | (define lz-decompress-reset |
| 321 | (let ((proc (lzlib-procedure int "LZ_decompress_reset" '(*)))) |
| 322 | (lambda (decoder) |
| 323 | "Reset the internal state of DECODER as it was just after opening it |
| 324 | with the `lz-decompress-open' function. Data stored in the internal buffers |
| 325 | is discarded. Position counters are set to 0." |
| 326 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 327 | (if (= ret -1) |
| 328 | (throw 'lzlib-error 'lz-decompress-reset |
| 329 | (lz-decompress-error decoder)) |
| 330 | ret))))) |
| 331 | |
| 332 | (define lz-decompress-sync-to-member |
| 333 | (let ((proc (lzlib-procedure int "LZ_decompress_sync_to_member" '(*)))) |
| 334 | (lambda (decoder) |
| 335 | "Reset the error state of DECODER and enters a search state that lasts |
| 336 | until a new member header (or the end of the stream) is found. After a |
| 337 | successful call to `lz-decompress-sync-to-member', data written with |
| 338 | `lz-decompress-write' will be consumed and 'lz-decompress-read' will return 0 |
| 339 | until a header is found. |
| 340 | |
| 341 | This function is useful to discard any data preceding the first member, or to |
| 342 | discard the rest of the current member, for example in case of a data |
| 343 | error. If the decoder is already at the beginning of a member, this function |
| 344 | does nothing." |
| 345 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 346 | (if (= ret -1) |
| 347 | (throw 'lzlib-error 'lz-decompress-sync-to-member |
| 348 | (lz-decompress-error decoder)) |
| 349 | ret))))) |
| 350 | |
| 351 | (define lz-decompress-read |
| 352 | (let ((proc (lzlib-procedure int "LZ_decompress_read" (list '* '* int)))) |
| 353 | (lambda* (decoder file-bv #:optional (start 0) (count (bytevector-length file-bv))) |
| 354 | "Read up to COUNT bytes from the decoder stream, storing the results in FILE-BV. |
| 355 | Return the number of uncompressed bytes written, a non-negative positive integer." |
| 356 | (let ((ret (proc (lz-decoder->pointer decoder) |
| 357 | (bytevector->pointer file-bv start) |
| 358 | count))) |
| 359 | (if (< ret 0) |
| 360 | (throw 'lzlib-error 'lz-decompress-read (lz-decompress-error decoder)) |
| 361 | ret))))) |
| 362 | |
| 363 | (define lz-decompress-write |
| 364 | (let ((proc (lzlib-procedure int "LZ_decompress_write" (list '* '* int)))) |
| 365 | (lambda* (decoder bv #:optional (start 0) (count (bytevector-length bv))) |
| 366 | "Write up to COUNT bytes from BV to the decoder stream. Return the |
| 367 | number of uncompressed bytes written, a non-negative integer." |
| 368 | (let ((ret (proc (lz-decoder->pointer decoder) |
| 369 | (bytevector->pointer bv start) |
| 370 | count))) |
| 371 | (if (< ret 0) |
| 372 | (throw 'lzlib-error 'lz-decompress-write (lz-decompress-error decoder)) |
| 373 | ret))))) |
| 374 | |
| 375 | (define lz-decompress-write-size |
| 376 | (let ((proc (lzlib-procedure int "LZ_decompress_write_size" '(*)))) |
| 377 | (lambda (decoder) |
| 378 | "Return the maximum number of bytes that can be immediately written |
| 379 | through the `lz-decompress-write' function. |
| 380 | |
| 381 | It is guaranteed that an immediate call to `lz-decompress-write' will accept a |
| 382 | SIZE up to the returned number of bytes. " |
| 383 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 384 | (if (= ret -1) |
| 385 | (throw 'lzlib-error 'lz-decompress-write-size (lz-decompress-error decoder)) |
| 386 | ret))))) |
| 387 | |
| 388 | (define lz-decompress-error |
| 389 | (let ((proc (lzlib-procedure int "LZ_decompress_errno" '(*)))) |
| 390 | (lambda (decoder) |
| 391 | "DECODER can be a Scheme object or a pointer." |
| 392 | (let* ((error-number (proc (if (lz-decoder? decoder) |
| 393 | (lz-decoder->pointer decoder) |
| 394 | decoder)))) |
| 395 | error-number)))) |
| 396 | |
| 397 | (define lz-decompress-finished? |
| 398 | (let ((proc (lzlib-procedure int "LZ_decompress_finished" '(*)))) |
| 399 | (lambda (decoder) |
| 400 | "Return #t if all the data have been read and `lz-decompress-close' can |
| 401 | be safely called. Otherwise return #f." |
| 402 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 403 | (match ret |
| 404 | (1 #t) |
| 405 | (0 #f) |
| 406 | (_ (throw 'lzlib-error 'lz-decompress-finished? (lz-decompress-error decoder)))))))) |
| 407 | |
| 408 | (define lz-decompress-member-finished? |
| 409 | (let ((proc (lzlib-procedure int "LZ_decompress_member_finished" '(*)))) |
| 410 | (lambda (decoder) |
| 411 | "Return #t if the current member, in a multimember data stream, has |
| 412 | been fully read and `lz-decompress-restart-member' can be safely called. |
| 413 | Otherwise return #f." |
| 414 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 415 | (match ret |
| 416 | (1 #t) |
| 417 | (0 #f) |
| 418 | (_ (throw 'lzlib-error 'lz-decompress-member-finished? (lz-decompress-error decoder)))))))) |
| 419 | |
| 420 | (define lz-decompress-member-version |
| 421 | (let ((proc (lzlib-procedure int "LZ_decompress_member_version" '(*)))) |
| 422 | (lambda (decoder) |
| 423 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 424 | "Return the version of current member from member header." |
| 425 | (if (= ret -1) |
| 426 | (throw 'lzlib-error 'lz-decompress-data-position |
| 427 | (lz-decompress-error decoder)) |
| 428 | ret))))) |
| 429 | |
| 430 | (define lz-decompress-dictionary-size |
| 431 | (let ((proc (lzlib-procedure int "LZ_decompress_dictionary_size" '(*)))) |
| 432 | (lambda (decoder) |
| 433 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 434 | "Return the dictionary size of current member from member header." |
| 435 | (if (= ret -1) |
| 436 | (throw 'lzlib-error 'lz-decompress-member-position |
| 437 | (lz-decompress-error decoder)) |
| 438 | ret))))) |
| 439 | |
| 440 | (define lz-decompress-data-crc |
| 441 | (let ((proc (lzlib-procedure unsigned-int "LZ_decompress_data_crc" '(*)))) |
| 442 | (lambda (decoder) |
| 443 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 444 | "Return the 32 bit Cyclic Redundancy Check of the data decompressed |
| 445 | from the current member. The returned value is valid only when |
| 446 | `lz-decompress-member-finished' returns #t. " |
| 447 | (if (= ret -1) |
| 448 | (throw 'lzlib-error 'lz-decompress-member-position |
| 449 | (lz-decompress-error decoder)) |
| 450 | ret))))) |
| 451 | |
| 452 | (define lz-decompress-data-position |
| 453 | (let ((proc (lzlib-procedure uint64 "LZ_decompress_data_position" '(*)))) |
| 454 | (lambda (decoder) |
| 455 | "Return the number of decompressed bytes already produced, but perhaps |
| 456 | not yet read, in the current member." |
| 457 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 458 | (if (= ret -1) |
| 459 | (throw 'lzlib-error 'lz-decompress-data-position |
| 460 | (lz-decompress-error decoder)) |
| 461 | ret))))) |
| 462 | |
| 463 | (define lz-decompress-member-position |
| 464 | (let ((proc (lzlib-procedure uint64 "LZ_decompress_member_position" '(*)))) |
| 465 | (lambda (decoder) |
| 466 | "Return the number of input bytes already decompressed in the current |
| 467 | member." |
| 468 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 469 | (if (= ret -1) |
| 470 | (throw 'lzlib-error 'lz-decompress-member-position |
| 471 | (lz-decompress-error decoder)) |
| 472 | ret))))) |
| 473 | |
| 474 | (define lz-decompress-total-in-size |
| 475 | (let ((proc (lzlib-procedure uint64 "LZ_decompress_total_in_size" '(*)))) |
| 476 | (lambda (decoder) |
| 477 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 478 | "Return the total number of input bytes already compressed." |
| 479 | (if (= ret -1) |
| 480 | (throw 'lzlib-error 'lz-decompress-total-in-size |
| 481 | (lz-decompress-error decoder)) |
| 482 | ret))))) |
| 483 | |
| 484 | (define lz-decompress-total-out-size |
| 485 | (let ((proc (lzlib-procedure uint64 "LZ_decompress_total_out_size" '(*)))) |
| 486 | (lambda (decoder) |
| 487 | (let ((ret (proc (lz-decoder->pointer decoder)))) |
| 488 | "Return the total number of compressed bytes already produced, but |
| 489 | perhaps not yet read." |
| 490 | (if (= ret -1) |
| 491 | (throw 'lzlib-error 'lz-decompress-total-out-size |
| 492 | (lz-decompress-error decoder)) |
| 493 | ret))))) |
| 494 | |
| 495 | \f |
| 496 | ;; High level functions. |
| 497 | |
| 498 | (define* (lzread! decoder port bv |
| 499 | #:optional (start 0) (count (bytevector-length bv))) |
| 500 | "Read up to COUNT bytes from PORT into BV at offset START. Return the |
| 501 | number of uncompressed bytes actually read; it is zero if COUNT is zero or if |
| 502 | the end-of-stream has been reached." |
| 503 | (define (feed-decoder! decoder) |
| 504 | ;; Feed DECODER with data read from PORT. |
| 505 | (match (get-bytevector-n port (lz-decompress-write-size decoder)) |
| 506 | ((? eof-object? eof) eof) |
| 507 | (bv (lz-decompress-write decoder bv)))) |
| 508 | |
| 509 | (let loop ((read 0) |
| 510 | (start start)) |
| 511 | (cond ((< read count) |
| 512 | (match (lz-decompress-read decoder bv start (- count read)) |
| 513 | (0 (cond ((lz-decompress-finished? decoder) |
| 514 | read) |
| 515 | ((eof-object? (feed-decoder! decoder)) |
| 516 | (lz-decompress-finish decoder) |
| 517 | (loop read start)) |
| 518 | (else ;read again |
| 519 | (loop read start)))) |
| 520 | (n (loop (+ read n) (+ start n))))) |
| 521 | (else |
| 522 | read)))) |
| 523 | |
| 524 | (define (lzwrite! encoder source source-offset source-count |
| 525 | target target-offset target-count) |
| 526 | "Write up to SOURCE-COUNT bytes from SOURCE to ENCODER, and read up to |
| 527 | TARGET-COUNT bytes into TARGET at TARGET-OFFSET. Return two values: the |
| 528 | number of bytes read from SOURCE, and the number of bytes written to TARGET, |
| 529 | possibly zero." |
| 530 | (define read |
| 531 | (if (> (lz-compress-write-size encoder) 0) |
| 532 | (match (lz-compress-write encoder source source-offset source-count) |
| 533 | (0 (lz-compress-finish encoder) 0) |
| 534 | (n n)) |
| 535 | 0)) |
| 536 | |
| 537 | (define written |
| 538 | (lz-compress-read encoder target target-offset target-count)) |
| 539 | |
| 540 | (values read written)) |
| 541 | |
| 542 | (define* (lzwrite encoder bv lz-port |
| 543 | #:optional (start 0) (count (bytevector-length bv))) |
| 544 | "Write up to COUNT bytes from BV at offset START into LZ-PORT. Return |
| 545 | the number of uncompressed bytes written, a non-negative integer." |
| 546 | (let ((written 0) |
| 547 | (read 0)) |
| 548 | (while (and (< 0 (lz-compress-write-size encoder)) |
| 549 | (< written count)) |
| 550 | (set! written (+ written |
| 551 | (lz-compress-write encoder bv (+ start written) (- count written))))) |
| 552 | (when (= written 0) |
| 553 | (lz-compress-finish encoder)) |
| 554 | (let ((lz-bv (make-bytevector written))) |
| 555 | (let loop ((rd 0)) |
| 556 | (set! rd (lz-compress-read encoder lz-bv 0 (bytevector-length lz-bv))) |
| 557 | (put-bytevector lz-port lz-bv 0 rd) |
| 558 | (set! read (+ read rd)) |
| 559 | (unless (= rd 0) |
| 560 | (loop rd)))) |
| 561 | ;; `written' is the total byte count of uncompressed data. |
| 562 | written)) |
| 563 | |
| 564 | \f |
| 565 | ;;; |
| 566 | ;;; Port interface. |
| 567 | ;;; |
| 568 | |
| 569 | ;; Alist of (levels (dictionary-size match-length-limit)). 0 is the fastest. |
| 570 | ;; See bbexample.c in lzlib's source. |
| 571 | (define %compression-levels |
| 572 | `((0 (65535 16)) |
| 573 | (1 (,(bitwise-arithmetic-shift-left 1 20) 5)) |
| 574 | (2 (,(bitwise-arithmetic-shift-left 3 19) 6)) |
| 575 | (3 (,(bitwise-arithmetic-shift-left 1 21) 8)) |
| 576 | (4 (,(bitwise-arithmetic-shift-left 3 20) 12)) |
| 577 | (5 (,(bitwise-arithmetic-shift-left 1 22) 20)) |
| 578 | (6 (,(bitwise-arithmetic-shift-left 1 23) 36)) |
| 579 | (7 (,(bitwise-arithmetic-shift-left 1 24) 68)) |
| 580 | (8 (,(bitwise-arithmetic-shift-left 3 23) 132)) |
| 581 | (9 (,(bitwise-arithmetic-shift-left 1 25) 273)))) |
| 582 | |
| 583 | (define %default-compression-level |
| 584 | 6) |
| 585 | |
| 586 | (define* (make-lzip-input-port port) |
| 587 | "Return an input port that decompresses data read from PORT, a file port. |
| 588 | PORT is automatically closed when the resulting port is closed." |
| 589 | (define decoder (lz-decompress-open)) |
| 590 | |
| 591 | (define (read! bv start count) |
| 592 | (lzread! decoder port bv start count)) |
| 593 | |
| 594 | (make-custom-binary-input-port "lzip-input" read! #f #f |
| 595 | (lambda () |
| 596 | (lz-decompress-close decoder) |
| 597 | (close-port port)))) |
| 598 | |
| 599 | (define* (make-lzip-output-port port |
| 600 | #:key |
| 601 | (level %default-compression-level)) |
| 602 | "Return an output port that compresses data at the given LEVEL, using PORT, |
| 603 | a file port, as its sink. PORT is automatically closed when the resulting |
| 604 | port is closed." |
| 605 | (define encoder (apply lz-compress-open |
| 606 | (car (assoc-ref %compression-levels level)))) |
| 607 | |
| 608 | (define (write! bv start count) |
| 609 | (lzwrite encoder bv port start count)) |
| 610 | |
| 611 | (make-custom-binary-output-port "lzip-output" write! #f #f |
| 612 | (lambda () |
| 613 | (lz-compress-finish encoder) |
| 614 | ;; "lz-read" the trailing metadata added by `lz-compress-finish'. |
| 615 | (let ((lz-bv (make-bytevector (* 64 1024)))) |
| 616 | (let loop ((rd 0)) |
| 617 | (set! rd (lz-compress-read encoder lz-bv 0 (bytevector-length lz-bv))) |
| 618 | (put-bytevector port lz-bv 0 rd) |
| 619 | (unless (= rd 0) |
| 620 | (loop rd)))) |
| 621 | (lz-compress-close encoder) |
| 622 | (close-port port)))) |
| 623 | |
| 624 | (define* (make-lzip-input-port/compressed port |
| 625 | #:key |
| 626 | (level %default-compression-level)) |
| 627 | "Return an input port that compresses data read from PORT, with the given LEVEL. |
| 628 | PORT is automatically closed when the resulting port is closed." |
| 629 | (define encoder (apply lz-compress-open |
| 630 | (car (assoc-ref %compression-levels level)))) |
| 631 | |
| 632 | (define input-buffer (make-bytevector 8192)) |
| 633 | (define input-len 0) |
| 634 | (define input-offset 0) |
| 635 | |
| 636 | (define input-eof? #f) |
| 637 | |
| 638 | (define (read! bv start count) |
| 639 | (cond |
| 640 | (input-eof? |
| 641 | (match (lz-compress-read encoder bv start count) |
| 642 | (0 (if (lz-compress-finished? encoder) |
| 643 | 0 |
| 644 | (read! bv start count))) |
| 645 | (n n))) |
| 646 | ((= input-offset input-len) |
| 647 | (match (get-bytevector-n! port input-buffer 0 |
| 648 | (bytevector-length input-buffer)) |
| 649 | ((? eof-object?) |
| 650 | (set! input-eof? #t) |
| 651 | (lz-compress-finish encoder)) |
| 652 | (count |
| 653 | (set! input-offset 0) |
| 654 | (set! input-len count))) |
| 655 | (read! bv start count)) |
| 656 | (else |
| 657 | (let-values (((read written) |
| 658 | (lzwrite! encoder |
| 659 | input-buffer input-offset |
| 660 | (- input-len input-offset) |
| 661 | bv start count))) |
| 662 | (set! input-offset (+ input-offset read)) |
| 663 | |
| 664 | ;; Make sure we don't return zero except on EOF. |
| 665 | (if (= 0 written) |
| 666 | (read! bv start count) |
| 667 | written))))) |
| 668 | |
| 669 | (make-custom-binary-input-port "lzip-input/compressed" |
| 670 | read! #f #f |
| 671 | (lambda () |
| 672 | (close-port port)))) |
| 673 | |
| 674 | (define* (call-with-lzip-input-port port proc) |
| 675 | "Call PROC with a port that wraps PORT and decompresses data read from it. |
| 676 | PORT is closed upon completion." |
| 677 | (let ((lzip (make-lzip-input-port port))) |
| 678 | (dynamic-wind |
| 679 | (const #t) |
| 680 | (lambda () |
| 681 | (proc lzip)) |
| 682 | (lambda () |
| 683 | (close-port lzip))))) |
| 684 | |
| 685 | (define* (call-with-lzip-output-port port proc |
| 686 | #:key |
| 687 | (level %default-compression-level)) |
| 688 | "Call PROC with an output port that wraps PORT and compresses data. PORT is |
| 689 | close upon completion." |
| 690 | (let ((lzip (make-lzip-output-port port |
| 691 | #:level level))) |
| 692 | (dynamic-wind |
| 693 | (const #t) |
| 694 | (lambda () |
| 695 | (proc lzip)) |
| 696 | (lambda () |
| 697 | (close-port lzip))))) |
| 698 | |
| 699 | ;;; lzlib.scm ends here |