libavcodec/smacker.c:306: error: Null Dereference
  pointer `&gb->buffer` last assigned on line 304 could be null and is dereferenced by call to `get_bits1()` at line 306, column 9.

libavcodec/smacker.c:295:1: start of procedure decode_header_trees()
293. }
294. 
295. static int decode_header_trees(SmackVContext *smk) {
     ^
296.     GetBitContext gb;
297.     int mmap_size, mclr_size, full_size, type_size;

libavcodec/smacker.c:299:5: 
297.     int mmap_size, mclr_size, full_size, type_size;
298. 
299.     mmap_size = AV_RL32(smk->avctx->extradata);
         ^
300.     mclr_size = AV_RL32(smk->avctx->extradata + 4);
301.     full_size = AV_RL32(smk->avctx->extradata + 8);

libavcodec/smacker.c:300:5: 
298. 
299.     mmap_size = AV_RL32(smk->avctx->extradata);
300.     mclr_size = AV_RL32(smk->avctx->extradata + 4);
         ^
301.     full_size = AV_RL32(smk->avctx->extradata + 8);
302.     type_size = AV_RL32(smk->avctx->extradata + 12);

libavcodec/smacker.c:301:5: 
299.     mmap_size = AV_RL32(smk->avctx->extradata);
300.     mclr_size = AV_RL32(smk->avctx->extradata + 4);
301.     full_size = AV_RL32(smk->avctx->extradata + 8);
         ^
302.     type_size = AV_RL32(smk->avctx->extradata + 12);
303. 

libavcodec/smacker.c:302:5: 
300.     mclr_size = AV_RL32(smk->avctx->extradata + 4);
301.     full_size = AV_RL32(smk->avctx->extradata + 8);
302.     type_size = AV_RL32(smk->avctx->extradata + 12);
         ^
303. 
304.     init_get_bits(&gb, smk->avctx->extradata + 16, (smk->avctx->extradata_size - 16) * 8);

libavcodec/smacker.c:304:5: 
302.     type_size = AV_RL32(smk->avctx->extradata + 12);
303. 
304.     init_get_bits(&gb, smk->avctx->extradata + 16, (smk->avctx->extradata_size - 16) * 8);
         ^
305. 
306.     if(!get_bits1(&gb)) {

libavcodec/get_bits.h:375:1: start of procedure init_get_bits()
  373.  * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
  374.  */
  375. static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
       ^
  376.                                 int bit_size)
  377. {

libavcodec/get_bits.h:379:5: 
  377. {
  378.     int buffer_size;
  379.     int ret = 0;
           ^
  380. 
  381.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {

libavcodec/get_bits.h:381:9: Taking true branch
  379.     int ret = 0;
  380. 
  381.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
               ^
  382.         buffer_size = bit_size = 0;
  383.         buffer      = NULL;

libavcodec/get_bits.h:382:9: 
  380. 
  381.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
  382.         buffer_size = bit_size = 0;
               ^
  383.         buffer      = NULL;
  384.         ret         = AVERROR_INVALIDDATA;

libavcodec/get_bits.h:383:9: 
  381.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
  382.         buffer_size = bit_size = 0;
  383.         buffer      = NULL;
               ^
  384.         ret         = AVERROR_INVALIDDATA;
  385.     }

libavcodec/get_bits.h:384:9: 
  382.         buffer_size = bit_size = 0;
  383.         buffer      = NULL;
  384.         ret         = AVERROR_INVALIDDATA;
               ^
  385.     }
  386. 

libavcodec/get_bits.h:387:5: 
  385.     }
  386. 
  387.     buffer_size = (bit_size + 7) >> 3;
           ^
  388. 
  389.     s->buffer             = buffer;

libavcodec/get_bits.h:389:5: 
  387.     buffer_size = (bit_size + 7) >> 3;
  388. 
  389.     s->buffer             = buffer;
           ^
  390.     s->size_in_bits       = bit_size;
  391. #if !UNCHECKED_BITSTREAM_READER

libavcodec/get_bits.h:390:5: 
  388. 
  389.     s->buffer             = buffer;
  390.     s->size_in_bits       = bit_size;
           ^
  391. #if !UNCHECKED_BITSTREAM_READER
  392.     s->size_in_bits_plus8 = bit_size + 8;

libavcodec/get_bits.h:392:5: 
  390.     s->size_in_bits       = bit_size;
  391. #if !UNCHECKED_BITSTREAM_READER
  392.     s->size_in_bits_plus8 = bit_size + 8;
           ^
  393. #endif
  394.     s->buffer_end         = buffer + buffer_size;

libavcodec/get_bits.h:394:5: 
  392.     s->size_in_bits_plus8 = bit_size + 8;
  393. #endif
  394.     s->buffer_end         = buffer + buffer_size;
           ^
  395.     s->index              = 0;
  396. 

libavcodec/get_bits.h:395:5: 
  393. #endif
  394.     s->buffer_end         = buffer + buffer_size;
  395.     s->index              = 0;
           ^
  396. 
  397.     return ret;

libavcodec/get_bits.h:397:5: 
  395.     s->index              = 0;
  396. 
  397.     return ret;
           ^
  398. }
  399. 

libavcodec/get_bits.h:398:1: return from a call to init_get_bits
  396. 
  397.     return ret;
  398. }
       ^
  399. 
  400. /**

libavcodec/smacker.c:306:9: 
304.     init_get_bits(&gb, smk->avctx->extradata + 16, (smk->avctx->extradata_size - 16) * 8);
305. 
306.     if(!get_bits1(&gb)) {
             ^
307.         av_log(smk->avctx, AV_LOG_INFO, "Skipping MMAP tree\n");
308.         smk->mmap_tbl = av_malloc(sizeof(int) * 2);

libavcodec/get_bits.h:271:1: start of procedure get_bits1()
  269. }
  270. 
  271. static inline unsigned int get_bits1(GetBitContext *s)
       ^
  272. {
  273.     unsigned int index = s->index;

libavcodec/get_bits.h:273:5: 
  271. static inline unsigned int get_bits1(GetBitContext *s)
  272. {
  273.     unsigned int index = s->index;
           ^
  274.     uint8_t result     = s->buffer[index >> 3];
  275. #ifdef BITSTREAM_READER_LE

libavcodec/get_bits.h:274:5: 
  272. {
  273.     unsigned int index = s->index;
  274.     uint8_t result     = s->buffer[index >> 3];
           ^
  275. #ifdef BITSTREAM_READER_LE
  276.     result >>= index & 7;

static int decode_header_trees(SmackVContext *smk) {
    GetBitContext gb;
    int mmap_size, mclr_size, full_size, type_size;
    mmap_size = AV_RL32(smk->avctx->extradata);
    mclr_size = AV_RL32(smk->avctx->extradata + 4);
    full_size = AV_RL32(smk->avctx->extradata + 8);
    type_size = AV_RL32(smk->avctx->extradata + 12);
    init_get_bits(&gb, smk->avctx->extradata + 16, (smk->avctx->extradata_size - 16) * 8);
    if(!get_bits1(&gb)) {
        av_log(smk->avctx, AV_LOG_INFO, "Skipping MMAP tree\n");
        smk->mmap_tbl = av_malloc(sizeof(int) * 2);
        if (!smk->mmap_tbl)
            return AVERROR(ENOMEM);
        smk->mmap_tbl[0] = 0;
        smk->mmap_last[0] = smk->mmap_last[1] = smk->mmap_last[2] = 1;
    } else {
        if (smacker_decode_header_tree(smk, &gb, &smk->mmap_tbl, smk->mmap_last, mmap_size))
            return -1;
    }
    if(!get_bits1(&gb)) {
        av_log(smk->avctx, AV_LOG_INFO, "Skipping MCLR tree\n");
        smk->mclr_tbl = av_malloc(sizeof(int) * 2);
        if (!smk->mclr_tbl)
            return AVERROR(ENOMEM);
        smk->mclr_tbl[0] = 0;
        smk->mclr_last[0] = smk->mclr_last[1] = smk->mclr_last[2] = 1;
    } else {
        if (smacker_decode_header_tree(smk, &gb, &smk->mclr_tbl, smk->mclr_last, mclr_size))
            return -1;
    }
    if(!get_bits1(&gb)) {
        av_log(smk->avctx, AV_LOG_INFO, "Skipping FULL tree\n");
        smk->full_tbl = av_malloc(sizeof(int) * 2);
        if (!smk->full_tbl)
            return AVERROR(ENOMEM);
        smk->full_tbl[0] = 0;
        smk->full_last[0] = smk->full_last[1] = smk->full_last[2] = 1;
    } else {
        if (smacker_decode_header_tree(smk, &gb, &smk->full_tbl, smk->full_last, full_size))
            return -1;
    }
    if(!get_bits1(&gb)) {
        av_log(smk->avctx, AV_LOG_INFO, "Skipping TYPE tree\n");
        smk->type_tbl = av_malloc(sizeof(int) * 2);
        if (!smk->type_tbl)
            return AVERROR(ENOMEM);
        smk->type_tbl[0] = 0;
        smk->type_last[0] = smk->type_last[1] = smk->type_last[2] = 1;
    } else {
        if (smacker_decode_header_tree(smk, &gb, &smk->type_tbl, smk->type_last, type_size))
            return -1;
    }
    return 0;
}
['static int decode_header_trees(SmackVContext *smk) {\n    GetBitContext gb;\n    int mmap_size, mclr_size, full_size, type_size;\n    mmap_size = AV_RL32(smk->avctx->extradata);\n    mclr_size = AV_RL32(smk->avctx->extradata + 4);\n    full_size = AV_RL32(smk->avctx->extradata + 8);\n    type_size = AV_RL32(smk->avctx->extradata + 12);\n    init_get_bits(&gb, smk->avctx->extradata + 16, (smk->avctx->extradata_size - 16) * 8);\n    if(!get_bits1(&gb)) {\n        av_log(smk->avctx, AV_LOG_INFO, "Skipping MMAP tree\\n");\n        smk->mmap_tbl = av_malloc(sizeof(int) * 2);\n        if (!smk->mmap_tbl)\n            return AVERROR(ENOMEM);\n        smk->mmap_tbl[0] = 0;\n        smk->mmap_last[0] = smk->mmap_last[1] = smk->mmap_last[2] = 1;\n    } else {\n        if (smacker_decode_header_tree(smk, &gb, &smk->mmap_tbl, smk->mmap_last, mmap_size))\n            return -1;\n    }\n    if(!get_bits1(&gb)) {\n        av_log(smk->avctx, AV_LOG_INFO, "Skipping MCLR tree\\n");\n        smk->mclr_tbl = av_malloc(sizeof(int) * 2);\n        if (!smk->mclr_tbl)\n            return AVERROR(ENOMEM);\n        smk->mclr_tbl[0] = 0;\n        smk->mclr_last[0] = smk->mclr_last[1] = smk->mclr_last[2] = 1;\n    } else {\n        if (smacker_decode_header_tree(smk, &gb, &smk->mclr_tbl, smk->mclr_last, mclr_size))\n            return -1;\n    }\n    if(!get_bits1(&gb)) {\n        av_log(smk->avctx, AV_LOG_INFO, "Skipping FULL tree\\n");\n        smk->full_tbl = av_malloc(sizeof(int) * 2);\n        if (!smk->full_tbl)\n            return AVERROR(ENOMEM);\n        smk->full_tbl[0] = 0;\n        smk->full_last[0] = smk->full_last[1] = smk->full_last[2] = 1;\n    } else {\n        if (smacker_decode_header_tree(smk, &gb, &smk->full_tbl, smk->full_last, full_size))\n            return -1;\n    }\n    if(!get_bits1(&gb)) {\n        av_log(smk->avctx, AV_LOG_INFO, "Skipping TYPE tree\\n");\n        smk->type_tbl = av_malloc(sizeof(int) * 2);\n        if (!smk->type_tbl)\n            return AVERROR(ENOMEM);\n        smk->type_tbl[0] = 0;\n        smk->type_last[0] = smk->type_last[1] = smk->type_last[2] = 1;\n    } else {\n        if (smacker_decode_header_tree(smk, &gb, &smk->type_tbl, smk->type_last, type_size))\n            return -1;\n    }\n    return 0;\n}', 'static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,\n                                int bit_size)\n{\n    int buffer_size;\n    int ret = 0;\n    if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {\n        buffer_size = bit_size = 0;\n        buffer      = NULL;\n        ret         = AVERROR_INVALIDDATA;\n    }\n    buffer_size = (bit_size + 7) >> 3;\n    s->buffer             = buffer;\n    s->size_in_bits       = bit_size;\n#if !UNCHECKED_BITSTREAM_READER\n    s->size_in_bits_plus8 = bit_size + 8;\n#endif\n    s->buffer_end         = buffer + buffer_size;\n    s->index              = 0;\n    return ret;\n}', 'static inline unsigned int get_bits1(GetBitContext *s)\n{\n    unsigned int index = s->index;\n    uint8_t result     = s->buffer[index >> 3];\n#ifdef BITSTREAM_READER_LE\n    result >>= index & 7;\n    result  &= 1;\n#else\n    result <<= index & 7;\n    result >>= 8 - 1;\n#endif\n#if !UNCHECKED_BITSTREAM_READER\n    if (s->index < s->size_in_bits_plus8)\n#endif\n        index++;\n    s->index = index;\n    return result;\n}']