[FFmpeg-devel] [PATCH 2/2] avformat/mov: simplify allocating stts/ctts arrays

[James Almer]

No point using av_fast_realloc() in a loop when we want to allocate all
entries to begin with, and any duplicate stts/ctts will just replace the
old arrays.
Furthermore, these are temporary arrays that will be merged into tts_data
when building the index.

Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavformat/isom.h |  2 --
 libavformat/mov.c  | 40 ++++++----------------------------------
 2 files changed, 6 insertions(+), 36 deletions(-)

diff --git a/libavformat/isom.h b/libavformat/isom.h
index ccdead7192..16981dc918 100644
--- a/libavformat/isom.h
+++ b/libavformat/isom.h
@@ -183,12 +183,10 @@ typedef struct MOVStreamContext {
     unsigned int tts_allocated_size;
     MOVTimeToSample *tts_data;
     unsigned int stts_count;
-    unsigned int stts_allocated_size;
     MOVStts *stts_data;
     unsigned int sdtp_count;
     uint8_t *sdtp_data;
     unsigned int ctts_count;
-    unsigned int ctts_allocated_size;
     MOVCtts *ctts_data;
     unsigned int stsc_count;
     MOVStsc *stsc_data;
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 138120488a..f310cb8d49 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -3498,22 +3498,14 @@ static int mov_read_stts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
         av_log(c->fc, AV_LOG_WARNING, "Duplicated STTS atom\n");
     av_freep(&sc->stts_data);
     sc->stts_count = 0;
-    if (entries >= INT_MAX / sizeof(*sc->stts_data))
+
+    sc->stts_data = av_malloc_array(entries, sizeof(*sc->stts_data));
+    if (!sc->stts_data)
         return AVERROR(ENOMEM);
 
     for (i = 0; i < entries && !pb->eof_reached; i++) {
         unsigned int sample_duration;
         unsigned int sample_count;
-        unsigned int min_entries = FFMIN(FFMAX(i + 1, 1024 * 1024), entries);
-        MOVStts *stts_data = av_fast_realloc(sc->stts_data, &sc->stts_allocated_size,
-                                             min_entries * sizeof(*sc->stts_data));
-        if (!stts_data) {
-            av_freep(&sc->stts_data);
-            sc->stts_count = 0;
-            return AVERROR(ENOMEM);
-        }
-        sc->stts_count = min_entries;
-        sc->stts_data = stts_data;
 
         sample_count    = avio_rb32(pb);
         sample_duration = avio_rb32(pb);
@@ -3656,20 +3648,12 @@ static int mov_read_ctts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 
     if (!entries)
         return 0;
-    if (entries >= UINT_MAX / sizeof(*sc->ctts_data))
-        return AVERROR_INVALIDDATA;
     av_freep(&sc->ctts_data);
-    sc->ctts_data = av_fast_realloc(NULL, &sc->ctts_allocated_size, entries * sizeof(*sc->ctts_data));
+    sc->ctts_data = av_malloc_array(entries, sizeof(*sc->ctts_data));
     if (!sc->ctts_data)
         return AVERROR(ENOMEM);
 
     for (i = 0; i < entries && !pb->eof_reached; i++) {
-        MOVCtts *ctts_data;
-        const size_t min_size_needed = (ctts_count + 1) * sizeof(MOVCtts);
-        const size_t requested_size =
-            min_size_needed > sc->ctts_allocated_size ?
-            FFMAX(min_size_needed, 2 * sc->ctts_allocated_size) :
-            min_size_needed;
         int count    = avio_rb32(pb);
         int duration = avio_rb32(pb);
 
@@ -3680,18 +3664,8 @@ static int mov_read_ctts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
             continue;
         }
 
-        if (ctts_count >= UINT_MAX / sizeof(MOVCtts) - 1)
-            return AVERROR(ENOMEM);
-
-        ctts_data = av_fast_realloc(sc->ctts_data, &sc->ctts_allocated_size, requested_size);
-
-        if (!ctts_data)
-            return AVERROR(ENOMEM);
-
-        sc->ctts_data = ctts_data;
-
-        ctts_data[ctts_count].count = count;
-        ctts_data[ctts_count].offset = duration;
+        sc->ctts_data[ctts_count].count = count;
+        sc->ctts_data[ctts_count].offset = duration;
         ctts_count++;
 
         av_log(c->fc, AV_LOG_TRACE, "count=%d, duration=%d\n",
@@ -4585,7 +4559,6 @@ static int mov_merge_tts_data(MOVContext *mov, AVStream *st, int flags)
     } else
         sc->ctts_count = 0;
     av_freep(&sc->ctts_data);
-    sc->ctts_allocated_size = 0;
 
     idx = 0;
     if (stts) {
@@ -4610,7 +4583,6 @@ static int mov_merge_tts_data(MOVContext *mov, AVStream *st, int flags)
     } else
         sc->stts_count = 0;
     av_freep(&sc->stts_data);
-    sc->stts_allocated_size = 0;
 
     return 0;
 }
-- 
2.48.0