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Merge commit '90bc423212396e96a02edc1118982ab7f7766a63'

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* commit '90bc423212396e96a02edc1118982ab7f7766a63':
  mov: Wrap stsc index and count compare in a separate function

The mov_stsc_index_valid() function is replaced with a macro to prevent
signdness issues (index is not always signed, and count is always
unsigned currently).

The comparison is also adjusted to reduce the risk of overflows.

Merged-by: Clément Bœsch <u@pkh.me>
This commit is contained in:
Clément Bœsch
2017-02-01 15:35:56 +01:00
parent 37557b28b9 90bc423212
commit e26e6240b6
1 changed files with 7 additions and 5 deletions
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12
libavformat/mov.c
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@@ -2432,12 +2432,14 @@ static int mov_read_stsc(MOVContext *c, AVIOContext *pb, MOVAtom atom)
return 0; return 0;
} }
#define mov_stsc_index_valid(index, count) ((index) < (count) - 1)
/* Compute the samples value for the stsc entry at the given index. */ /* Compute the samples value for the stsc entry at the given index. */
static inline int mov_get_stsc_samples(MOVStreamContext *sc, int index) static inline int mov_get_stsc_samples(MOVStreamContext *sc, int index)
{ {
int chunk_count; int chunk_count;
if (index < sc->stsc_count - 1) if (mov_stsc_index_valid(index, sc->stsc_count))
chunk_count = sc->stsc_data[index + 1].first - sc->stsc_data[index].first; chunk_count = sc->stsc_data[index + 1].first - sc->stsc_data[index].first;
else else
chunk_count = sc->chunk_count - (sc->stsc_data[index].first - 1); chunk_count = sc->chunk_count - (sc->stsc_data[index].first - 1);
@@ -3353,7 +3355,7 @@ static void mov_build_index(MOVContext *mov, AVStream *st)
for (i = 0; i < sc->chunk_count; i++) { for (i = 0; i < sc->chunk_count; i++) {
int64_t next_offset = i+1 < sc->chunk_count ? sc->chunk_offsets[i+1] : INT64_MAX; int64_t next_offset = i+1 < sc->chunk_count ? sc->chunk_offsets[i+1] : INT64_MAX;
current_offset = sc->chunk_offsets[i]; current_offset = sc->chunk_offsets[i];
while (stsc_index + 1 < sc->stsc_count && while (mov_stsc_index_valid(stsc_index, sc->stsc_count) &&
i + 1 == sc->stsc_data[stsc_index + 1].first) i + 1 == sc->stsc_data[stsc_index + 1].first)
stsc_index++; stsc_index++;
@@ -3476,7 +3478,7 @@ static void mov_build_index(MOVContext *mov, AVStream *st)
count = (chunk_samples+1023) / 1024; count = (chunk_samples+1023) / 1024;
} }
if (i < sc->stsc_count - 1) if (mov_stsc_index_valid(i, sc->stsc_count))
chunk_count = sc->stsc_data[i+1].first - sc->stsc_data[i].first; chunk_count = sc->stsc_data[i+1].first - sc->stsc_data[i].first;
else else
chunk_count = sc->chunk_count - (sc->stsc_data[i].first - 1); chunk_count = sc->chunk_count - (sc->stsc_data[i].first - 1);
@@ -3497,7 +3499,7 @@ static void mov_build_index(MOVContext *mov, AVStream *st)
// populate index // populate index
for (i = 0; i < sc->chunk_count; i++) { for (i = 0; i < sc->chunk_count; i++) {
current_offset = sc->chunk_offsets[i]; current_offset = sc->chunk_offsets[i];
if (stsc_index + 1 < sc->stsc_count && if (mov_stsc_index_valid(stsc_index, sc->stsc_count) &&
i + 1 == sc->stsc_data[stsc_index + 1].first) i + 1 == sc->stsc_data[stsc_index + 1].first)
stsc_index++; stsc_index++;
chunk_samples = sc->stsc_data[stsc_index].count; chunk_samples = sc->stsc_data[stsc_index].count;
@@ -6265,7 +6267,7 @@ static int mov_read_packet(AVFormatContext *s, AVPacket *pkt)
/* Keep track of the stsc index for the given sample, then check /* Keep track of the stsc index for the given sample, then check
* if the stsd index is different from the last used one. */ * if the stsd index is different from the last used one. */
sc->stsc_sample++; sc->stsc_sample++;
if (sc->stsc_index < sc->stsc_count - 1 && if (mov_stsc_index_valid(sc->stsc_index, sc->stsc_count) &&
mov_get_stsc_samples(sc, sc->stsc_index) == sc->stsc_sample) { mov_get_stsc_samples(sc, sc->stsc_index) == sc->stsc_sample) {
sc->stsc_index++; sc->stsc_index++;
sc->stsc_sample = 0; sc->stsc_sample = 0;