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      1 /*
      2  * The copyright in this software is being made available under the 2-clauses
      3  * BSD License, included below. This software may be subject to other third
      4  * party and contributor rights, including patent rights, and no such rights
      5  * are granted under this license.
      6  *
      7  * Copyright (c) 2002-2014, Universite catholique de Louvain (UCL), Belgium
      8  * Copyright (c) 2002-2014, Professor Benoit Macq
      9  * Copyright (c) 2001-2003, David Janssens
     10  * Copyright (c) 2002-2003, Yannick Verschueren
     11  * Copyright (c) 2003-2007, Francois-Olivier Devaux
     12  * Copyright (c) 2003-2014, Antonin Descampe
     13  * Copyright (c) 2005, Herve Drolon, FreeImage Team
     14  * All rights reserved.
     15  *
     16  * Redistribution and use in source and binary forms, with or without
     17  * modification, are permitted provided that the following conditions
     18  * are met:
     19  * 1. Redistributions of source code must retain the above copyright
     20  *    notice, this list of conditions and the following disclaimer.
     21  * 2. Redistributions in binary form must reproduce the above copyright
     22  *    notice, this list of conditions and the following disclaimer in the
     23  *    documentation and/or other materials provided with the distribution.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
     26  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
     29  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35  * POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 
     38 #include "opj_includes.h"
     39 
     40 /** @defgroup BIO BIO - Individual bit input-output stream */
     41 /*@{*/
     42 
     43 /** @name Local static functions */
     44 /*@{*/
     45 
     46 /**
     47 Write a bit
     48 @param bio BIO handle
     49 @param b Bit to write (0 or 1)
     50 */
     51 static void opj_bio_putbit(opj_bio_t *bio, OPJ_UINT32 b);
     52 /**
     53 Read a bit
     54 @param bio BIO handle
     55 @return Returns the read bit
     56 */
     57 static OPJ_UINT32 opj_bio_getbit(opj_bio_t *bio);
     58 /**
     59 Write a byte
     60 @param bio BIO handle
     61 @return Returns OPJ_TRUE if successful, returns OPJ_FALSE otherwise
     62 */
     63 static OPJ_BOOL opj_bio_byteout(opj_bio_t *bio);
     64 /**
     65 Read a byte
     66 @param bio BIO handle
     67 @return Returns OPJ_TRUE if successful, returns OPJ_FALSE otherwise
     68 */
     69 static OPJ_BOOL opj_bio_bytein(opj_bio_t *bio);
     70 
     71 /*@}*/
     72 
     73 /*@}*/
     74 
     75 /*
     76 ==========================================================
     77    local functions
     78 ==========================================================
     79 */
     80 
     81 static OPJ_BOOL opj_bio_byteout(opj_bio_t *bio)
     82 {
     83     bio->buf = (bio->buf << 8) & 0xffff;
     84     bio->ct = bio->buf == 0xff00 ? 7 : 8;
     85     if ((OPJ_SIZE_T)bio->bp >= (OPJ_SIZE_T)bio->end) {
     86         return OPJ_FALSE;
     87     }
     88     *bio->bp++ = (OPJ_BYTE)(bio->buf >> 8);
     89     return OPJ_TRUE;
     90 }
     91 
     92 static OPJ_BOOL opj_bio_bytein(opj_bio_t *bio)
     93 {
     94     bio->buf = (bio->buf << 8) & 0xffff;
     95     bio->ct = bio->buf == 0xff00 ? 7 : 8;
     96     if ((OPJ_SIZE_T)bio->bp >= (OPJ_SIZE_T)bio->end) {
     97         return OPJ_FALSE;
     98     }
     99     bio->buf |= *bio->bp++;
    100     return OPJ_TRUE;
    101 }
    102 
    103 static void opj_bio_putbit(opj_bio_t *bio, OPJ_UINT32 b)
    104 {
    105     if (bio->ct == 0) {
    106         opj_bio_byteout(
    107             bio); /* MSD: why not check the return value of this function ? */
    108     }
    109     bio->ct--;
    110     bio->buf |= b << bio->ct;
    111 }
    112 
    113 static OPJ_UINT32 opj_bio_getbit(opj_bio_t *bio)
    114 {
    115     if (bio->ct == 0) {
    116         opj_bio_bytein(
    117             bio); /* MSD: why not check the return value of this function ? */
    118     }
    119     bio->ct--;
    120     return (bio->buf >> bio->ct) & 1;
    121 }
    122 
    123 /*
    124 ==========================================================
    125    Bit Input/Output interface
    126 ==========================================================
    127 */
    128 
    129 opj_bio_t* opj_bio_create(void)
    130 {
    131     opj_bio_t *bio = (opj_bio_t*)opj_malloc(sizeof(opj_bio_t));
    132     return bio;
    133 }
    134 
    135 void opj_bio_destroy(opj_bio_t *bio)
    136 {
    137     if (bio) {
    138         opj_free(bio);
    139     }
    140 }
    141 
    142 ptrdiff_t opj_bio_numbytes(opj_bio_t *bio)
    143 {
    144     return (bio->bp - bio->start);
    145 }
    146 
    147 void opj_bio_init_enc(opj_bio_t *bio, OPJ_BYTE *bp, OPJ_UINT32 len)
    148 {
    149     bio->start = bp;
    150     bio->end = bp + len;
    151     bio->bp = bp;
    152     bio->buf = 0;
    153     bio->ct = 8;
    154 }
    155 
    156 void opj_bio_init_dec(opj_bio_t *bio, OPJ_BYTE *bp, OPJ_UINT32 len)
    157 {
    158     bio->start = bp;
    159     bio->end = bp + len;
    160     bio->bp = bp;
    161     bio->buf = 0;
    162     bio->ct = 0;
    163 }
    164 
    165 void opj_bio_write(opj_bio_t *bio, OPJ_UINT32 v, OPJ_UINT32 n)
    166 {
    167     OPJ_INT32 i;
    168 
    169     assert((n > 0U) && (n <= 32U));
    170     for (i = (OPJ_INT32)n - 1; i >= 0; i--) {
    171         opj_bio_putbit(bio, (v >> i) & 1);
    172     }
    173 }
    174 
    175 OPJ_UINT32 opj_bio_read(opj_bio_t *bio, OPJ_UINT32 n)
    176 {
    177     OPJ_INT32 i;
    178     OPJ_UINT32 v;
    179 
    180     assert((n > 0U) /* && (n <= 32U)*/);
    181 #ifdef OPJ_UBSAN_BUILD
    182     /* This assert fails for some corrupted images which are gracefully rejected */
    183     /* Add this assert only for ubsan build. */
    184     /* This is the condition for overflow not to occur below which is needed because of OPJ_NOSANITIZE */
    185     assert(n <= 32U);
    186 #endif
    187     v = 0U;
    188     for (i = (OPJ_INT32)n - 1; i >= 0; i--) {
    189         v |= opj_bio_getbit(bio) <<
    190              i; /* can't overflow, opj_bio_getbit returns 0 or 1 */
    191     }
    192     return v;
    193 }
    194 
    195 OPJ_BOOL opj_bio_flush(opj_bio_t *bio)
    196 {
    197     if (! opj_bio_byteout(bio)) {
    198         return OPJ_FALSE;
    199     }
    200     if (bio->ct == 7) {
    201         if (! opj_bio_byteout(bio)) {
    202             return OPJ_FALSE;
    203         }
    204     }
    205     return OPJ_TRUE;
    206 }
    207 
    208 OPJ_BOOL opj_bio_inalign(opj_bio_t *bio)
    209 {
    210     if ((bio->buf & 0xff) == 0xff) {
    211         if (! opj_bio_bytein(bio)) {
    212             return OPJ_FALSE;
    213         }
    214     }
    215     bio->ct = 0;
    216     return OPJ_TRUE;
    217 }
    218