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avformat/ty: Remove write-only array and variable

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Up until now, the TiVo demuxer parse an array of SEQ entries, yet it has
never ever made any use of them. In fact, parse_master, the function
parsing said table, only influenced the outside world in three ways: Via
an excessive amount of error message in case a certain parameter is not
what it expected; via an allocation (the aforementioned write-only
array); and by setting a certain parameter (ty->cur_chunk_pos), but that
parameter is always overwritten before it is used (it is overwritten
in get_chunk() on success and if get_chunk() fails, the error is
returned to the caller anyway). So remove the array and the function
used to parse it.

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2020-08-11 02:28:16 +02:00
parent 4b7189848f
commit 7ad4928580
1 changed files with 1 additions and 67 deletions
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68
libavformat/ty.c
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@ -72,11 +72,6 @@ typedef enum {
TIVO_AUDIO_MPEG
} TiVo_audio;
typedef struct TySeqTable {
uint64_t timestamp;
uint8_t chunk_bitmask[8];
} TySeqTable;
typedef struct TYDemuxContext {
unsigned cur_chunk;
unsigned cur_chunk_pos;
@ -90,7 +85,6 @@ typedef struct TYDemuxContext {
int pes_buf_cnt; /* how many bytes in our buffer */
size_t ac3_pkt_size; /* length of ac3 pkt we've seen so far */
uint64_t last_ty_pts; /* last TY timestamp we've seen */
unsigned seq_table_size; /* number of entries in SEQ table */
int64_t first_audio_pts;
int64_t last_audio_pts;
@ -99,8 +93,6 @@ typedef struct TYDemuxContext {
TyRecHdr *rec_hdrs; /* record headers array */
int cur_rec; /* current record in this chunk */
int num_recs; /* number of recs in this chunk */
int seq_rec; /* record number where seq start is */
TySeqTable *seq_table; /* table of SEQ entries from mstr chk */
int first_chunk;
uint8_t chunk[CHUNK_SIZE];
@ -339,58 +331,6 @@ static int ty_read_header(AVFormatContext *s)
return 0;
}
/* parse a master chunk, filling the SEQ table and other variables.
* We assume the stream is currently pointing to it.
*/
static void parse_master(AVFormatContext *s)
{
TYDemuxContext *ty = s->priv_data;
unsigned map_size; /* size of bitmask, in bytes */
unsigned i, j;
/* Note that the entries in the SEQ table in the stream may have
different sizes depending on the bits per entry. We store them
all in the same size structure, so we have to parse them out one
by one. If we had a dynamic structure, we could simply read the
entire table directly from the stream into memory in place. */
/* clear the SEQ table */
av_freep(&ty->seq_table);
/* parse header info */
map_size = AV_RB32(ty->chunk + 20); /* size of bitmask, in bytes */
i = AV_RB32(ty->chunk + 28); /* size of SEQ table, in bytes */
ty->seq_table_size = i / (8LL + map_size);
if (ty->seq_table_size == 0) {
ty->seq_table = NULL;
return;
}
/* parse all the entries */
ty->seq_table = av_calloc(ty->seq_table_size, sizeof(TySeqTable));
if (ty->seq_table == NULL) {
ty->seq_table_size = 0;
return;
}
ty->cur_chunk_pos = 32;
for (j = 0; j < ty->seq_table_size; j++) {
if (ty->cur_chunk_pos >= CHUNK_SIZE - 8)
return;
ty->seq_table[j].timestamp = AV_RB64(ty->chunk + ty->cur_chunk_pos);
ty->cur_chunk_pos += 8;
if (map_size > 8) {
av_log(s, AV_LOG_ERROR, "Unsupported SEQ bitmap size in master chunk.\n");
ty->cur_chunk_pos += map_size;
} else {
memcpy(ty->seq_table[j].chunk_bitmask, ty->chunk + ty->cur_chunk_pos, map_size);
}
}
}
static int get_chunk(AVFormatContext *s)
{
TYDemuxContext *ty = s->priv_data;
@ -413,7 +353,7 @@ static int get_chunk(AVFormatContext *s)
/* check if it's a PART Header */
if (AV_RB32(ty->chunk) == TIVO_PES_FILEID) {
parse_master(s); /* parse master chunk */
/* skip master chunk and read new chunk */
return get_chunk(s);
}
@ -421,14 +361,9 @@ static int get_chunk(AVFormatContext *s)
if (ty->chunk[3] & 0x80) {
/* 16 bit rec cnt */
ty->num_recs = num_recs = (ty->chunk[1] << 8) + ty->chunk[0];
ty->seq_rec = (ty->chunk[3] << 8) + ty->chunk[2];
if (ty->seq_rec != 0xffff) {
ty->seq_rec &= ~0x8000;
}
} else {
/* 8 bit reclen - TiVo 1.3 format */
ty->num_recs = num_recs = ty->chunk[0];
ty->seq_rec = ty->chunk[1];
}
ty->cur_rec = 0;
ty->first_chunk = 0;
@ -770,7 +705,6 @@ static int ty_read_close(AVFormatContext *s)
{
TYDemuxContext *ty = s->priv_data;
av_freep(&ty->seq_table);
av_freep(&ty->rec_hdrs);
return 0;