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  1. /*
  2.  * Copyright (c) 2001-2003, David Janssens
  3.  * Copyright (c) 2002-2003, Yannick Verschueren
  4.  * Copyright (c) 2003-2005, Francois Devaux and Antonin Descampe
  5.  * Copyright (c) 2005, Hervé Drolon, FreeImage Team
  6.  * Copyright (c) 2002-2005, Communications and remote sensing Laboratory, Universite catholique de Louvain, Belgium
  7.  * All rights reserved.
  8.  *
  9.  * Redistribution and use in source and binary forms, with or without
  10.  * modification, are permitted provided that the following conditions
  11.  * are met:
  12.  * 1. Redistributions of source code must retain the above copyright
  13.  *    notice, this list of conditions and the following disclaimer.
  14.  * 2. Redistributions in binary form must reproduce the above copyright
  15.  *    notice, this list of conditions and the following disclaimer in the
  16.  *    documentation and/or other materials provided with the distribution.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
  19.  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20.  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21.  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  22.  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23.  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24.  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25.  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26.  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27.  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28.  * POSSIBILITY OF SUCH DAMAGE.
  29.  */
  30.  
  31. #include "opj_includes.h"
  32.  
  33. /** @defgroup BIO BIO - Individual bit input-output stream */
  34. /*@{*/
  35.  
  36. /** @name Local static functions */
  37. /*@{*/
  38.  
  39. /**
  40. Write a bit
  41. @param bio BIO handle
  42. @param b Bit to write (0 or 1)
  43. */
  44. static void bio_putbit(opj_bio_t *bio, int b);
  45. /**
  46. Read a bit
  47. @param bio BIO handle
  48. @return Returns the read bit
  49. */
  50. static int bio_getbit(opj_bio_t *bio);
  51. /**
  52. Write a byte
  53. @param bio BIO handle
  54. @return Returns 0 if successful, returns 1 otherwise
  55. */
  56. static int bio_byteout(opj_bio_t *bio);
  57. /**
  58. Read a byte
  59. @param bio BIO handle
  60. @return Returns 0 if successful, returns 1 otherwise
  61. */
  62. static int bio_bytein(opj_bio_t *bio);
  63.  
  64. /*@}*/
  65.  
  66. /*@}*/
  67.  
  68.  
  69. /*
  70. ==========================================================
  71.    local functions
  72. ==========================================================
  73. */
  74.  
  75. static int bio_byteout(opj_bio_t *bio) {
  76.         bio->buf = (bio->buf << 8) & 0xffff;
  77.         bio->ct = bio->buf == 0xff00 ? 7 : 8;
  78.         if (bio->bp >= bio->end) {
  79.                 return 1;
  80.         }
  81.         *bio->bp++ = bio->buf >> 8;
  82.         return 0;
  83. }
  84.  
  85. static int bio_bytein(opj_bio_t *bio) {
  86.         bio->buf = (bio->buf << 8) & 0xffff;
  87.         bio->ct = bio->buf == 0xff00 ? 7 : 8;
  88.         if (bio->bp >= bio->end) {
  89.                 return 1;
  90.         }
  91.         bio->buf |= *bio->bp++;
  92.         return 0;
  93. }
  94.  
  95. static void bio_putbit(opj_bio_t *bio, int b) {
  96.         if (bio->ct == 0) {
  97.                 bio_byteout(bio);
  98.         }
  99.         bio->ct--;
  100.         bio->buf |= b << bio->ct;
  101. }
  102.  
  103. /* MOD antonin */
  104. static int bio_getbit(opj_bio_t *bio) {
  105. /* DOM */
  106.         if (bio->ct == 0) {
  107.                 bio_bytein(bio);
  108.         }
  109.         bio->ct--;
  110.         return (bio->buf >> bio->ct) & 1;
  111. }
  112.  
  113. /*
  114. ==========================================================
  115.    Bit Input/Output interface
  116. ==========================================================
  117. */
  118.  
  119. opj_bio_t* bio_create() {
  120.         opj_bio_t *bio = (opj_bio_t*)opj_malloc(sizeof(opj_bio_t));
  121.         return bio;
  122. }
  123.  
  124. void bio_destroy(opj_bio_t *bio) {
  125.         if(bio) {
  126.                 opj_free(bio);
  127.         }
  128. }
  129.  
  130. int bio_numbytes(opj_bio_t *bio) {
  131.         return (bio->bp - bio->start);
  132. }
  133.  
  134. void bio_init_enc(opj_bio_t *bio, unsigned char *bp, int len) {
  135.         bio->start = bp;
  136.         bio->end = bp + len;
  137.         bio->bp = bp;
  138.         bio->buf = 0;
  139.         bio->ct = 8;
  140. }
  141.  
  142. void bio_init_dec(opj_bio_t *bio, unsigned char *bp, int len) {
  143.         bio->start = bp;
  144.         bio->end = bp + len;
  145.         bio->bp = bp;
  146.         bio->buf = 0;
  147.         bio->ct = 0;
  148. }
  149.  
  150. void bio_write(opj_bio_t *bio, int v, int n) {
  151.         int i;
  152.         for (i = n - 1; i >= 0; i--) {
  153.                 bio_putbit(bio, (v >> i) & 1);
  154.         }
  155. }
  156.  
  157. int bio_read(opj_bio_t *bio, int n) {
  158.         int i, v;
  159.         v = 0;
  160.         for (i = n - 1; i >= 0; i--) {
  161.                 v += bio_getbit(bio) << i;
  162.         }
  163.         return v;
  164. }
  165.  
  166. int bio_flush(opj_bio_t *bio) {
  167.         bio->ct = 0;
  168.         if (bio_byteout(bio)) {
  169.                 return 1;
  170.         }
  171.         if (bio->ct == 7) {
  172.                 bio->ct = 0;
  173.                 if (bio_byteout(bio)) {
  174.                         return 1;
  175.                 }
  176.         }
  177.         return 0;
  178. }
  179.  
  180. int bio_inalign(opj_bio_t *bio) {
  181.         bio->ct = 0;
  182.         if ((bio->buf & 0xff) == 0xff) {
  183.                 if (bio_bytein(bio)) {
  184.                         return 1;
  185.                 }
  186.                 bio->ct = 0;
  187.         }
  188.         return 0;
  189. }
  190.