#include "string.h"
#include "mp4.h"
+/**
+ * The three states of the mp4 parser. The parser only loads the audio specific
+ * values and tables when it is in the second state.
+ */
+enum audio_track_state {
+ /** We haven't encountered an mp4a atom so far. */
+ ATS_INITIAL,
+ /** We have seen an mp4a atom but no subsequent trak atom yet. */
+ ATS_SEEN_MP4A,
+ /** A trak atom was seen *after* the mp4a atom. */
+ ATS_TRACK_CHANGE,
+};
+
struct mp4_track {
+ /* determines which atoms we still need to parse. */
+ enum audio_track_state state;
+
/* mp4a */
uint16_t channel_count;
uint16_t sample_rate;
uint64_t duration;
};
-#define MAX_TRACKS 1024
-
struct mp4 {
const struct mp4_callback *cb;
- int64_t current_position;
uint64_t moov_offset;
uint64_t moov_size;
uint32_t udta_size;
uint8_t last_atom;
- uint64_t file_size;
-
- /* incremental track index while reading the file */
- int32_t total_tracks;
- /* track data */
- struct mp4_track *track[MAX_TRACKS];
- /* the first audio track found */
- struct mp4_track *audio_track;
-
- /* metadata */
+ struct mp4_track track;
struct mp4_metadata meta;
};
/*
- * Returns -1, 0, or 1 on errors/EOF/success. Partial reads followed by EOF or
- * read errors are treated as errors.
+ * Returns -E_MP4_READ, 0, or 1 on errors/EOF/success. Partial reads followed
+ * by EOF or read errors are treated as errors.
*/
static int read_data(struct mp4 *f, void *data, size_t size)
{
continue;
/* regard EAGAIN as an error as reads should be blocking. */
if (ret <= 0)
- return ret < 0? -1 : 0;
- f->current_position += ret;
+ return ret < 0? -E_MP4_READ : 0;
size -= ret;
}
return 1;
uint8_t data[8];
int ret = read_data(f, data, 8);
- if (ret > 0 && result)
+ if (ret > 0)
*result = read_u64_be(data);
return ret;
}
uint8_t data[4];
int ret = read_data(f, data, 4);
- if (ret > 0 && result)
+ if (ret > 0)
*result = read_u32_be(data);
return ret;
}
-static int read_int24(struct mp4 *f, uint32_t *result)
-{
- uint8_t data[3];
- int ret = read_data(f, data, 3);
-
- if (ret > 0 && result)
- *result = read_u24_be(data);
- return ret;
-}
-
static int read_int16(struct mp4 *f, uint16_t *result)
{
uint8_t data[2];
int ret = read_data(f, data, 2);
- if (ret > 0 && result)
+ if (ret > 0)
*result = read_u16_be(data);
return ret;
}
-static uint8_t read_int8(struct mp4 *f, uint8_t *result)
-{
- uint8_t data[1];
- int ret = read_data(f, data, 1);
-
- if (ret > 0 && result)
- *result = data[0];
- return ret;
-}
-
#define ATOM_ITEMS \
ATOM_ITEM(MOOV, 'm', 'o', 'o', 'v') \
ATOM_ITEM(TRAK, 't', 'r', 'a', 'k') \
} else {
if (header_size)
*header_size = 8;
- if (atom_size)
- *atom_size = size;
+ *atom_size = size;
}
*atom_type = atom_name_to_type(atom_header + 4);
return 1;
}
-static int64_t get_position(const struct mp4 *f)
+static off_t get_position(const struct mp4 *f)
{
- return f->current_position;
+ return f->cb->seek(f->cb->user_data, 0, SEEK_CUR);
}
-static int32_t set_position(struct mp4 *f, int64_t position)
+static void set_position(struct mp4 *f, off_t position)
{
- f->cb->seek(f->cb->user_data, position);
- f->current_position = position;
+ f->cb->seek(f->cb->user_data, position, SEEK_SET);
+}
- return 0;
+static void skip_bytes(struct mp4 *f, off_t num_skip)
+{
+ f->cb->seek(f->cb->user_data, num_skip, SEEK_CUR);
}
static int read_stsz(struct mp4 *f)
{
int ret;
- int32_t i;
- struct mp4_track *t;
+ struct mp4_track *t = &f->track;
- if (f->total_tracks == 0)
- return -1;
- t = f->track[f->total_tracks - 1];
- ret = read_int8(f, NULL); /* version */
- if (ret <= 0)
- return ret;
- ret = read_int24(f, NULL); /* flags */
- if (ret <= 0)
- return ret;
+ if (t->state != ATS_SEEN_MP4A || t->stsz_table)
+ return 1;
+ skip_bytes(f, 4); /* version (1), flags (3) */
ret = read_int32(f, &t->stsz_sample_size);
if (ret <= 0)
return ret;
if (t->stsz_sample_size != 0)
return 1;
t->stsz_table = para_malloc(t->stsz_sample_count * sizeof(int32_t));
- for (i = 0; i < t->stsz_sample_count; i++) {
- ret = read_int32(f, &t->stsz_table[i]);
+ for (uint32_t n = 0; n < t->stsz_sample_count; n++) {
+ ret = read_int32(f, &t->stsz_table[n]);
if (ret <= 0)
return ret;
}
static int read_stts(struct mp4 *f)
{
int ret;
- int32_t i;
- struct mp4_track *t;
+ struct mp4_track *t = &f->track;
- if (f->total_tracks == 0)
- return -1;
- t = f->track[f->total_tracks - 1];
- if (t->stts_entry_count)
- return 0;
- ret = read_int8(f, NULL); /* version */
- if (ret <= 0)
- return ret;
- ret = read_int24(f, NULL); /* flags */
- if (ret <= 0)
- return ret;
+ if (t->state != ATS_SEEN_MP4A || t->stts_sample_count)
+ return 1;
+ skip_bytes(f, 4); /* version (1), flags (3) */
ret = read_int32(f, &t->stts_entry_count);
if (ret <= 0)
return ret;
t->stts_sample_count = para_malloc(t->stts_entry_count
* sizeof(int32_t));
- for (i = 0; i < t->stts_entry_count; i++) {
- ret = read_int32(f, &t->stts_sample_count[i]);
- if (ret <= 0)
- return ret;
- ret = read_int32(f, NULL); /* sample delta */
+ for (uint32_t n = 0; n < t->stts_entry_count; n++) {
+ ret = read_int32(f, &t->stts_sample_count[n]);
if (ret <= 0)
return ret;
+ skip_bytes(f, 4); /* sample delta */
}
return 1;
}
static int read_stsc(struct mp4 *f)
{
int ret;
- int32_t i;
- struct mp4_track *t;
+ struct mp4_track *t = &f->track;
- if (f->total_tracks == 0)
- return -1;
- t = f->track[f->total_tracks - 1];
-
- ret = read_int8(f, NULL); /* version */
- if (ret <= 0)
- return ret;
- ret = read_int24(f, NULL); /* flags */
- if (ret <= 0)
- return ret;
+ if (t->state != ATS_SEEN_MP4A)
+ return 1;
+ if (t->stsc_first_chunk || t->stsc_samples_per_chunk)
+ return 1;
+ skip_bytes(f, 4); /* version (1), flags (3) */
ret = read_int32(f, &t->stsc_entry_count);
if (ret <= 0)
return ret;
t->stsc_first_chunk = para_malloc(t->stsc_entry_count * sizeof(int32_t));
t->stsc_samples_per_chunk = para_malloc(t->stsc_entry_count
* sizeof (int32_t));
- for (i = 0; i < t->stsc_entry_count; i++) {
- ret = read_int32(f, &t->stsc_first_chunk[i]);
- if (ret <= 0)
- return ret;
- ret = read_int32(f, &t->stsc_samples_per_chunk[i]);
+ for (uint32_t n = 0; n < t->stsc_entry_count; n++) {
+ ret = read_int32(f, &t->stsc_first_chunk[n]);
if (ret <= 0)
return ret;
- ret = read_int32(f, NULL); /* sample desc index */
+ ret = read_int32(f, &t->stsc_samples_per_chunk[n]);
if (ret <= 0)
return ret;
+ skip_bytes(f, 4); /* sample desc index */
}
return 1;
}
static int read_stco(struct mp4 *f)
{
int ret;
- int32_t i;
- struct mp4_track *t;
+ struct mp4_track *t = &f->track;
- if (f->total_tracks == 0)
- return -1;
- t = f->track[f->total_tracks - 1];
-
- ret = read_int8(f, NULL); /* version */
- if (ret <= 0)
- return ret;
- ret = read_int24(f, NULL); /* flags */
- if (ret <= 0)
- return ret;
+ if (t->state != ATS_SEEN_MP4A || t->stco_chunk_offset)
+ return 1;
+ skip_bytes(f, 4); /* version (1), flags (3) */
ret = read_int32(f, &t->stco_entry_count);
if (ret <= 0)
return ret;
t->stco_chunk_offset = para_malloc(t->stco_entry_count
* sizeof(int32_t));
- for (i = 0; i < t->stco_entry_count; i++) {
- ret = read_int32(f, &t->stco_chunk_offset[i]);
+ for (uint32_t n = 0; n < t->stco_entry_count; n++) {
+ ret = read_int32(f, &t->stco_chunk_offset[n]);
if (ret <= 0)
return ret;
}
return 1;
}
-static int read_mp4a(struct mp4 *f)
-{
- int ret;
- int32_t i;
- struct mp4_track *t;
-
- if (f->total_tracks == 0)
- return -1;
- t = f->track[f->total_tracks - 1];
-
- for (i = 0; i < 6; i++) {
- ret = read_int8(f, NULL); /* reserved */
- if (ret <= 0)
- return ret;
- }
- ret = read_int16(f, NULL); /* data_reference_index */
- if (ret <= 0)
- return ret;
- ret = read_int32(f, NULL); /* reserved */
- if (ret <= 0)
- return ret;
- ret = read_int32(f, NULL); /* reserved */
- if (ret <= 0)
- return ret;
- ret = read_int16(f, &t->channel_count);
- if (ret <= 0)
- return ret;
- ret = read_int16(f, NULL);
- if (ret <= 0)
- return ret;
- ret = read_int16(f, NULL);
- if (ret <= 0)
- return ret;
- ret = read_int16(f, NULL);
- if (ret <= 0)
- return ret;
- return read_int16(f, &t->sample_rate);
-}
-
static int read_stsd(struct mp4 *f)
{
int ret;
- uint32_t i, entry_count;
- struct mp4_track *t;
+ uint32_t entry_count;
- if (f->total_tracks == 0)
- return -1;
- t = f->track[f->total_tracks - 1];
- ret = read_int8(f, NULL); /* version */
- if (ret <= 0)
- return ret;
- ret = read_int24(f, NULL); /* flags */
- if (ret <= 0)
- return ret;
+ if (f->track.state != ATS_INITIAL)
+ return 1;
+ skip_bytes(f, 4); /* version (1), flags (3) */
ret = read_int32(f, &entry_count);
if (ret <= 0)
return ret;
- for (i = 0; i < entry_count; i++) {
+ for (uint32_t n = 0; n < entry_count; n++) {
uint64_t skip = get_position(f);
uint64_t size;
uint8_t atom_type = 0;
if (ret <= 0)
return ret;
skip += size;
- if (!f->audio_track && atom_type == ATOM_MP4A) {
- f->audio_track = t;
- read_mp4a(f);
+ if (atom_type == ATOM_MP4A) {
+ f->track.state = ATS_SEEN_MP4A;
+ /* reserved (6), data reference index (2), reserved (8) */
+ skip_bytes(f, 16);
+ ret = read_int16(f, &f->track.channel_count);
+ if (ret <= 0)
+ return ret;
+ skip_bytes(f, 6);
+ ret = read_int16(f, &f->track.sample_rate);
+ if (ret <= 0)
+ return ret;
}
set_position(f, skip);
}
destpos = get_position(f) + subsize - header_size;
if (atom_type != ATOM_DATA)
continue;
- ret = read_int8(f, NULL); /* version */
- if (ret <= 0)
- goto fail;
- ret = read_int24(f, NULL); /* flags */
- if (ret <= 0)
- goto fail;
- ret = read_int32(f, NULL); /* reserved */
- if (ret <= 0)
- goto fail;
- ret = -ERRNO_TO_PARA_ERROR(EINVAL);
+ skip_bytes(f, 8); /* version (1), flags (3), reserved (4) */
+ ret = -E_MP4_CORRUPT;
if (subsize < header_size + 8 || subsize > UINT_MAX)
goto fail;
len = subsize - (header_size + 8);
value[len] = '\0';
}
if (!value)
- return -ERRNO_TO_PARA_ERROR(EINVAL);
+ return -E_MP4_CORRUPT;
f->meta.tags = para_realloc(f->meta.tags, (f->meta.count + 1)
* sizeof(struct mp4_tag));
tag = f->meta.tags + f->meta.count;
tag->item = para_strdup(get_metadata_name(parent));
tag->value = value;
- tag->len = len;
f->meta.count++;
return 1;
fail:
{
int ret;
uint32_t version;
- struct mp4_track *t;
-
- if (f->total_tracks == 0)
- return -1;
- t = f->track[f->total_tracks - 1];
+ struct mp4_track *t = &f->track;
+ if (t->state != ATS_INITIAL)
+ return 1;
ret = read_int32(f, &version);
if (ret <= 0)
return ret;
if (version == 1) {
- ret = read_int64(f, NULL); /* creation-time */
- if (ret <= 0)
- return ret;
- ret = read_int64(f, NULL); /* modification-time */
- if (ret <= 0)
- return ret;
+ skip_bytes(f, 16); /* creation time (8), modification time (8) */
ret = read_int32(f, &t->time_scale);
if (ret <= 0)
return ret;
ret = read_int64(f, &t->duration);
if (ret <= 0)
return ret;
- } else { //version == 0
+ } else { /* version == 0 */
uint32_t temp;
- ret = read_int32(f, NULL); /* creation-time */
- if (ret <= 0)
- return ret;
- ret = read_int32(f, NULL); /* modification-time */
- if (ret <= 0)
- return ret;
+ skip_bytes(f, 8); /* creation time (4), modification time (4) */
ret = read_int32(f, &t->time_scale);
if (ret <= 0)
return ret;
t->duration = (temp == (uint32_t) (-1))?
(uint64_t) (-1) : (uint64_t) (temp);
}
- ret = read_int16(f, NULL);
- if (ret <= 0)
- return ret;
- ret = read_int16(f, NULL);
- if (ret <= 0)
- return ret;
+ skip_bytes(f, 4);
return 1;
}
-static int32_t read_ilst(struct mp4 *f, int32_t size)
+static int read_ilst(struct mp4 *f, int32_t size)
{
int ret;
uint64_t sumsize = 0;
return 1;
}
-static int32_t read_meta(struct mp4 *f, uint64_t size)
+static int read_meta(struct mp4 *f, uint64_t size)
{
int ret;
uint64_t subsize, sumsize = 0;
uint8_t atom_type;
uint8_t header_size = 0;
- ret = read_int8(f, NULL); /* version */
- if (ret <= 0)
- return ret;
- ret = read_int24(f, NULL); /* flags */
- if (ret <= 0)
- return ret;
+ skip_bytes(f, 4); /* version (1), flags (3) */
while (sumsize < (size - (header_size + 4))) {
ret = atom_read_header(f, &atom_type, &header_size, &subsize);
if (ret <= 0)
if (ret <= 0)
return ret;
if (size == 0)
- return -1;
+ return -E_MP4_CORRUPT;
dest = get_position(f) + size - header_size;
- if (atom_type == ATOM_TRAK) {
- if (f->total_tracks >= MAX_TRACKS)
- return -1;
- f->total_tracks++;
- f->track[f->total_tracks - 1] = para_calloc(
- sizeof(struct mp4_track));
- } else if (atom_type == ATOM_UDTA) {
+ if (atom_type == ATOM_TRAK && f->track.state == ATS_SEEN_MP4A) {
+ f->track.state = ATS_TRACK_CHANGE;
+ continue;
+ }
+ if (atom_type == ATOM_UDTA) {
f->udta_offset = get_position(f) - header_size;
f->udta_size = size;
}
return 1;
}
+void mp4_close(struct mp4 *f)
+{
+ free(f->track.stsz_table);
+ free(f->track.stts_sample_count);
+ free(f->track.stsc_first_chunk);
+ free(f->track.stsc_samples_per_chunk);
+ free(f->track.stco_chunk_offset);
+ for (uint32_t n = 0; n < f->meta.count; n++) {
+ free(f->meta.tags[n].item);
+ free(f->meta.tags[n].value);
+ }
+ free(f->meta.tags);
+ free(f);
+}
+
static int open_file(const struct mp4_callback *cb, bool meta_only, struct mp4 **result)
{
int ret;
f->cb = cb;
while ((ret = atom_read_header(f, &atom_type, &header_size, &size)) > 0) {
- f->file_size += size;
f->last_atom = atom_type;
if (atom_type != ATOM_MOOV || size <= header_size) { /* skip */
set_position(f, get_position(f) + size - header_size);
if (ret <= 0)
break;
}
- if (ret < 0) {
- ret = -E_MP4_OPEN;
+ if (ret < 0)
goto fail;
- }
ret = -E_MP4_TRACK;
- if (!f->audio_track)
+ if (f->track.channel_count == 0)
+ goto fail;
+ ret = -E_MP4_BAD_SAMPLERATE;
+ if (f->track.sample_rate == 0)
+ goto fail;
+ ret = -E_MP4_MISSING_ATOM;
+ if (f->udta_size == 0 || f->meta_size == 0 || f->ilst_size == 0)
goto fail;
*result = f;
return 1;
fail:
*result = NULL;
- free(f);
+ mp4_close(f);
return ret;
}
-int mp4_open_read(const struct mp4_callback *cb, struct mp4 **result)
+int mp4_open(const struct mp4_callback *cb, struct mp4 **result)
{
- return open_file(cb, false, result);
-}
+ struct mp4 *f;
+ int ret;
-void mp4_close(struct mp4 *f)
-{
- int32_t i;
-
- for (i = 0; i < f->total_tracks; i++) {
- if (f->track[i]) {
- free(f->track[i]->stsz_table);
- free(f->track[i]->stts_sample_count);
- free(f->track[i]->stsc_first_chunk);
- free(f->track[i]->stsc_samples_per_chunk);
- free(f->track[i]->stco_chunk_offset);
- free(f->track[i]);
- }
- }
- for (i = 0; i < f->meta.count; i++) {
- free(f->meta.tags[i].item);
- free(f->meta.tags[i].value);
- }
- free(f->meta.tags);
- free(f);
+ *result = NULL;
+ ret = open_file(cb, false, &f);
+ if (ret < 0)
+ return ret;
+ ret = -E_MP4_BAD_SAMPLE_COUNT;
+ if (f->track.stsz_sample_count == 0)
+ goto fail;
+ ret = -E_MP4_CORRUPT;
+ if (f->track.time_scale == 0)
+ goto fail;
+ *result = f;
+ return 1;
+fail:
+ mp4_close(f);
+ return ret;
}
static int32_t chunk_of_sample(const struct mp4 *f, int32_t sample,
int32_t *chunk)
{
- const struct mp4_track *t = f->audio_track;
+ const struct mp4_track *t = &f->track;
uint32_t *fc = t->stsc_first_chunk, *spc = t->stsc_samples_per_chunk;
- int32_t chunk1, chunk1samples, n, total, i;
+ uint32_t chunk1, chunk1samples, n, total, k;
- for (i = 1, total = 0; i < t->stsc_entry_count; i++, total += n) {
- n = (fc[i] - fc[i - 1]) * spc[i - 1]; /* number of samples */
+ for (k = 1, total = 0; k < t->stsc_entry_count; k++, total += n) {
+ n = (fc[k] - fc[k - 1]) * spc[k - 1]; /* number of samples */
if (sample < total + n)
break;
}
- chunk1 = fc[i - 1];
- chunk1samples = spc[i - 1];
+ chunk1 = fc[k - 1];
+ chunk1samples = spc[k - 1];
if (chunk1samples != 0)
*chunk = (sample - total) / chunk1samples + chunk1;
else
*/
uint64_t mp4_get_duration(const struct mp4 *f)
{
- const struct mp4_track *t = f->audio_track;
+ const struct mp4_track *t = &f->track;
- if (t->time_scale == 0)
- return 0;
return t->duration * 1000 / t->time_scale;
}
-int mp4_set_sample_position(struct mp4 *f, int32_t sample)
+int mp4_set_sample_position(struct mp4 *f, uint32_t sample)
{
- const struct mp4_track *t = f->audio_track;
+ const struct mp4_track *t = &f->track;
int32_t offset, chunk, chunk_sample;
uint32_t n, srs; /* sample range size */
return 1;
}
-int32_t mp4_get_sample_size(const struct mp4 *f, int sample)
+int mp4_get_sample_size(const struct mp4 *f, uint32_t sample, uint32_t *result)
{
- const struct mp4_track *t = f->audio_track;
+ const struct mp4_track *t = &f->track;
+ if (sample >= t->stsz_sample_count)
+ return -ERRNO_TO_PARA_ERROR(EINVAL);
if (t->stsz_sample_size != 0)
- return t->stsz_sample_size;
- return t->stsz_table[sample];
+ *result = t->stsz_sample_size;
+ else
+ *result = t->stsz_table[sample];
+ return 1;
}
-uint32_t mp4_get_sample_rate(const struct mp4 *f)
+uint16_t mp4_get_sample_rate(const struct mp4 *f)
{
- return f->audio_track->sample_rate;
+ return f->track.sample_rate;
}
-uint32_t mp4_get_channel_count(const struct mp4 *f)
+uint16_t mp4_get_channel_count(const struct mp4 *f)
{
- return f->audio_track->channel_count;
+ return f->track.channel_count;
}
-int32_t mp4_num_samples(const struct mp4 *f)
+uint32_t mp4_num_samples(const struct mp4 *f)
{
- const struct mp4_track *t = f->audio_track;
- int32_t i;
- int32_t total = 0;
-
- for (i = 0; i < t->stts_entry_count; i++)
- total += t->stts_sample_count[i];
- return total;
+ return f->track.stsz_sample_count;
}
int mp4_open_meta(const struct mp4_callback *cb, struct mp4 **result)
if (ret < 0)
return ret;
- if (f->udta_size == 0 || f->meta_size == 0 || f->ilst_size == 0) {
- mp4_close(f);
- *result = NULL;
- return -E_MP4_MISSING_ATOM;
- }
*result = f;
return 1;
}
{
int ret;
uint64_t total_base = f->moov_offset + 8;
- uint32_t total_size = (uint32_t) (f->moov_size - 8);
+ uint32_t total_size = f->moov_size - 8;
uint32_t new_ilst_size = 0;
void *out_buffer;
uint8_t *p_out;
return out_buffer;
}
-static int32_t write_data(struct mp4 *f, void *data, uint32_t size)
+static int write_data(struct mp4 *f, void *data, size_t size)
{
- int32_t result = 1;
-
- result = f->cb->write(f->cb->user_data, data, size);
-
- f->current_position += size;
-
- return result;
+ while (size > 0) {
+ ssize_t ret = f->cb->write(f->cb->user_data, data, size);
+ if (ret < 0) {
+ if (errno == EINTR)
+ continue;
+ return -ERRNO_TO_PARA_ERROR(errno);
+ }
+ size -= ret;
+ }
+ return 1;
}
-int32_t mp4_meta_update(struct mp4 *f)
+int mp4_update_meta(struct mp4 *f)
{
void *new_moov_data;
uint32_t new_moov_size;
- uint8_t buf[4];
+ uint8_t buf[8] = "----moov";
+ int ret;
set_position(f, 0);
new_moov_data = modify_moov(f, &new_moov_size);
}
if (f->last_atom != ATOM_MOOV) {
set_position(f, f->moov_offset + 4);
- write_data(f, "free", 4); /* rename old moov to free */
- set_position(f, f->file_size); /* write new moov atom at EOF */
+ ret = write_data(f, "free", 4); /* rename old moov to free */
+ if (ret < 0)
+ goto free_moov;
+ /* write new moov atom at EOF */
+ f->cb->seek(f->cb->user_data, 0, SEEK_END);
} else /* overwrite old moov atom */
set_position(f, f->moov_offset);
write_u32_be(buf, new_moov_size + 8);
- write_data(f, buf, 4);
- write_data(f, "moov", 4);
- write_data(f, new_moov_data, new_moov_size);
+ ret = write_data(f, buf, sizeof(buf));
+ if (ret < 0)
+ goto free_moov;
+ ret = write_data(f, new_moov_data, new_moov_size);
+ if (ret < 0)
+ goto free_moov;
+ ret = f->cb->truncate(f->cb->user_data);
+ if (ret < 0)
+ ret = -ERRNO_TO_PARA_ERROR(errno);
+free_moov:
free(new_moov_data);
- f->cb->truncate(f->cb->user_data);
- return 1;
-}
-
-static char *meta_find_by_name(const struct mp4 *f, const char *item)
-{
- uint32_t i;
-
- for (i = 0; i < f->meta.count; i++)
- if (!strcasecmp(f->meta.tags[i].item, item))
- return para_strdup(f->meta.tags[i].value);
- return NULL;
+ return ret;
}
/**
- * Return the value of the artist meta tag of an mp4 file.
+ * Return the value of the given tag item.
*
* \param f Must not be NULL.
+ * \param item "artist", "title", "album", "comment", or "date".
*
- * \return If the file does not contain this metadata tag, the function returns
- * NULL. Otherwise, a copy of the tag value is returned. The caller should free
- * this memory when it is no longer needed.
+ * \return The function always returns NULL if the given item is not in the
+ * above list. Otherwise, if the file does not contain a tag for the given
+ * item, the function also returns NULL. Otherwise a copy of the tag value is
+ * returned and the caller should free this memory when it is no longer needed.
*/
-char *mp4_meta_get_artist(const struct mp4 *f)
+char *mp4_get_tag_value(const struct mp4 *f, const char *item)
{
- return meta_find_by_name(f, "artist");
-}
-
-/**
- * Return the value of the title meta tag of an mp4 file.
- *
- * \param f See \ref mp4_meta_get_artist().
- * \return See \ref mp4_meta_get_artist().
- */
-char *mp4_meta_get_title(const struct mp4 *f)
-{
- return meta_find_by_name(f, "title");
-}
-
-/**
- * Return the value of the date meta tag of an mp4 file.
- *
- * \param f See \ref mp4_meta_get_artist().
- * \return See \ref mp4_meta_get_artist().
- */
-char *mp4_meta_get_date(const struct mp4 *f)
-{
- return meta_find_by_name(f, "date");
-}
-
-/**
- * Return the value of the album meta tag of an mp4 file.
- *
- * \param f See \ref mp4_meta_get_artist().
- * \return See \ref mp4_meta_get_artist().
- */
-char *mp4_meta_get_album(const struct mp4 *f)
-{
- return meta_find_by_name(f, "album");
-}
-
-/**
- * Return the value of the comment meta tag of an mp4 file.
- *
- * \param f See \ref mp4_meta_get_artist().
- * \return See \ref mp4_meta_get_artist().
- */
-char *mp4_meta_get_comment(const struct mp4 *f)
-{
- return meta_find_by_name(f, "comment");
+ for (unsigned n = 0; n < f->meta.count; n++)
+ if (!strcasecmp(f->meta.tags[n].item, item))
+ return para_strdup(f->meta.tags[n].value);
+ return NULL;
}
projects / paraslash.git / blobdiff