avcodec: Constify AVCodecs

[ffmpeg] / libavcodec / dstdec.c

diff --git a/libavcodec/dstdec.c b/libavcodec/dstdec.c
index 771887faf9136c770519aa06f3e8c7f2ba2ae91d..7be97126ca0ae3e40b0ef8c84ad3767f0d554c6c 100644 (file)
--- a/libavcodec/dstdec.c
+++ b/libavcodec/dstdec.c
@@ -27,6 +27,7 @@
 
 #include "libavutil/avassert.h"
 #include "libavutil/intreadwrite.h"
+#include "libavutil/mem_internal.h"
 #include "internal.h"
 #include "get_bits.h"
 #include "avcodec.h"
@@ -56,7 +57,6 @@ static const int8_t probs_code_pred_coeff[3][3] = {
 typedef struct ArithCoder {
     unsigned int a;
     unsigned int c;
-    int overread;
 } ArithCoder;
 
 typedef struct Table {
@@ -86,6 +86,12 @@ static av_cold int decode_init(AVCodecContext *avctx)
         return AVERROR_PATCHWELCOME;
     }
 
+    // the sample rate is only allowed to be 64,128,256 * 44100 by ISO/IEC 14496-3:2005(E)
+    // We are a bit more tolerant here, but this check is needed to bound the size and duration
+    if (avctx->sample_rate > 512 * 44100)
+        return AVERROR_INVALIDDATA;
+
+
     if (DST_SAMPLES_PER_FRAME(avctx->sample_rate) & 7) {
         return AVERROR_PATCHWELCOME;
     }
@@ -181,7 +187,6 @@ static void ac_init(ArithCoder *ac, GetBitContext *gb)
 {
     ac->a = 4095;
     ac->c = get_bits(gb, 12);
-    ac->overread = 0;
 }
 
 static av_always_inline void ac_get(ArithCoder *ac, GetBitContext *gb, int p, int *e)
@@ -201,8 +206,6 @@ static av_always_inline void ac_get(ArithCoder *ac, GetBitContext *gb, int p, in
     if (ac->a < 2048) {
         int n = 11 - av_log2(ac->a);
         ac->a <<= n;
-        if (get_bits_left(gb) < n)
-            ac->overread ++;
         ac->c = (ac->c << n) | get_bits(gb, n);
     }
 }
@@ -355,9 +358,6 @@ static int decode_frame(AVCodecContext *avctx, void *data,
                 prob = 128;
             }
 
-            if (ac->overread > 16)
-                return AVERROR_INVALIDDATA;
-
             ac_get(ac, gb, prob, &residual);
             v = ((predict >> 15) ^ residual) & 1;
             dsd[((i >> 3) * channels + ch) << 2] |= v << (7 - (i & 0x7 ));
@@ -379,7 +379,7 @@ dsd:
     return avpkt->size;
 }
 
-AVCodec ff_dst_decoder = {
+const AVCodec ff_dst_decoder = {
     .name           = "dst",
     .long_name      = NULL_IF_CONFIG_SMALL("DST (Digital Stream Transfer)"),
     .type           = AVMEDIA_TYPE_AUDIO,
@@ -390,4 +390,5 @@ AVCodec ff_dst_decoder = {
     .capabilities   = AV_CODEC_CAP_DR1,
     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
                                                       AV_SAMPLE_FMT_NONE },
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
 };