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  1. /*
  2.  * Copyright (c) 2002-2007, Communications and Remote Sensing Laboratory, Universite catholique de Louvain (UCL), Belgium
  3.  * Copyright (c) 2002-2007, Professor Benoit Macq
  4.  * Copyright (c) 2001-2003, David Janssens
  5.  * Copyright (c) 2002-2003, Yannick Verschueren
  6.  * Copyright (c) 2003-2007, Francois-Olivier Devaux and Antonin Descampe
  7.  * Copyright (c) 2005, Herve Drolon, FreeImage Team
  8.  * All rights reserved.
  9.  *
  10.  * Redistribution and use in source and binary forms, with or without
  11.  * modification, are permitted provided that the following conditions
  12.  * are met:
  13.  * 1. Redistributions of source code must retain the above copyright
  14.  *    notice, this list of conditions and the following disclaimer.
  15.  * 2. Redistributions in binary form must reproduce the above copyright
  16.  *    notice, this list of conditions and the following disclaimer in the
  17.  *    documentation and/or other materials provided with the distribution.
  18.  *
  19.  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
  20.  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21.  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22.  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  23.  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24.  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25.  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26.  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27.  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28.  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29.  * POSSIBILITY OF SUCH DAMAGE.
  30.  */
  31.  
  32. #include "opj_includes.h"
  33.  
  34. /** @defgroup BIO BIO - Individual bit input-output stream */
  35. /*@{*/
  36.  
  37. /** @name Local static functions */
  38. /*@{*/
  39.  
  40. /**
  41. Write a bit
  42. @param bio BIO handle
  43. @param b Bit to write (0 or 1)
  44. */
  45. static void bio_putbit(opj_bio_t *bio, int b);
  46. /**
  47. Read a bit
  48. @param bio BIO handle
  49. @return Returns the read bit
  50. */
  51. static int bio_getbit(opj_bio_t *bio);
  52. /**
  53. Write a byte
  54. @param bio BIO handle
  55. @return Returns 0 if successful, returns 1 otherwise
  56. */
  57. static int bio_byteout(opj_bio_t *bio);
  58. /**
  59. Read a byte
  60. @param bio BIO handle
  61. @return Returns 0 if successful, returns 1 otherwise
  62. */
  63. static int bio_bytein(opj_bio_t *bio);
  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. static int bio_getbit(opj_bio_t *bio) {
  104.         if (bio->ct == 0) {
  105.                 bio_bytein(bio);
  106.         }
  107.         bio->ct--;
  108.         return (bio->buf >> bio->ct) & 1;
  109. }
  110.  
  111. /*
  112. ==========================================================
  113.    Bit Input/Output interface
  114. ==========================================================
  115. */
  116.  
  117. opj_bio_t* bio_create(void) {
  118.         opj_bio_t *bio = (opj_bio_t*)opj_malloc(sizeof(opj_bio_t));
  119.         return bio;
  120. }
  121.  
  122. void bio_destroy(opj_bio_t *bio) {
  123.         if(bio) {
  124.                 opj_free(bio);
  125.         }
  126. }
  127.  
  128. int bio_numbytes(opj_bio_t *bio) {
  129.         return (bio->bp - bio->start);
  130. }
  131.  
  132. void bio_init_enc(opj_bio_t *bio, unsigned char *bp, int len) {
  133.         bio->start = bp;
  134.         bio->end = bp + len;
  135.         bio->bp = bp;
  136.         bio->buf = 0;
  137.         bio->ct = 8;
  138. }
  139.  
  140. void bio_init_dec(opj_bio_t *bio, unsigned char *bp, int len) {
  141.         bio->start = bp;
  142.         bio->end = bp + len;
  143.         bio->bp = bp;
  144.         bio->buf = 0;
  145.         bio->ct = 0;
  146. }
  147.  
  148. void bio_write(opj_bio_t *bio, int v, int n) {
  149.         int i;
  150.         for (i = n - 1; i >= 0; i--) {
  151.                 bio_putbit(bio, (v >> i) & 1);
  152.         }
  153. }
  154.  
  155. int bio_read(opj_bio_t *bio, int n) {
  156.         int i, v;
  157.         v = 0;
  158.         for (i = n - 1; i >= 0; i--) {
  159.                 v += bio_getbit(bio) << i;
  160.         }
  161.         return v;
  162. }
  163.  
  164. int bio_flush(opj_bio_t *bio) {
  165.         bio->ct = 0;
  166.         if (bio_byteout(bio)) {
  167.                 return 1;
  168.         }
  169.         if (bio->ct == 7) {
  170.                 bio->ct = 0;
  171.                 if (bio_byteout(bio)) {
  172.                         return 1;
  173.                 }
  174.         }
  175.         return 0;
  176. }
  177.  
  178. int bio_inalign(opj_bio_t *bio) {
  179.         bio->ct = 0;
  180.         if ((bio->buf & 0xff) == 0xff) {
  181.                 if (bio_bytein(bio)) {
  182.                         return 1;
  183.                 }
  184.                 bio->ct = 0;
  185.         }
  186.         return 0;
  187. }
  188.