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authorAndree Buschmann <AndreeBuschmann@t-online.de>2011-03-18 07:08:25 +0000
committerAndree Buschmann <AndreeBuschmann@t-online.de>2011-03-18 07:08:25 +0000
commite209002c13de2c3c5d1145c200b936e4fafb30a3 (patch)
treec75e477c8870c98a380a904af3de557feb57493f /apps/mp3data.c
parentc59a086da6ef1e768b53d7cfb5e55ba41cb68f89 (diff)
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Optimize memory consumption in the mp3data parser. The vbr-header parser will never need 1.800 byte of data. The maximum amount of data needed is 1/10 of this.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29610 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/mp3data.c')
-rw-r--r--apps/mp3data.c33
1 files changed, 19 insertions, 14 deletions
diff --git a/apps/mp3data.c b/apps/mp3data.c
index aa54761c07..697797279e 100644
--- a/apps/mp3data.c
+++ b/apps/mp3data.c
@@ -63,6 +63,9 @@
#define ORIGINAL_MASK (1L << 2)
#define EMPHASIS_MASK (3L)
+/* Maximum number of bytes needed by Xing/Info/VBRI parser. */
+#define VBR_HEADER_MAX_SIZE (180)
+
/* MPEG Version table, sorted by version index */
static const signed char version_table[4] = {
MPEG_VERSION2_5, -1, MPEG_VERSION2, MPEG_VERSION1
@@ -465,7 +468,10 @@ static void get_xing_info(struct mp3info *info, unsigned char *buf)
/* Extract information from a 'VBRI' header. */
static void get_vbri_info(struct mp3info *info, unsigned char *buf)
{
+ /* We don't parse the TOC, since we don't yet know how to (FIXME) */
+ /*
int i, num_offsets, offset = 0;
+ */
info->is_vbr = true; /* Yes, it is a FhG VBR file */
info->has_toc = false; /* We don't parse the TOC (yet) */
@@ -482,21 +488,23 @@ static void get_vbri_info(struct mp3info *info, unsigned char *buf)
else
info->bitrate = info->byte_count / (info->file_time >> 3);
- /* We don't parse the TOC, since we don't yet know how to (FIXME) */
- num_offsets = bytes2int(0, 0, buf[18], buf[19]);
VDEBUGF("Frame size (%dkpbs): %d bytes (0x%x)\n",
info->bitrate, info->frame_size, info->frame_size);
VDEBUGF("Frame count: %lx\n", info->frame_count);
VDEBUGF("Byte count: %lx\n", info->byte_count);
+
+ /* We don't parse the TOC, since we don't yet know how to (FIXME) */
+ /*
+ num_offsets = bytes2int(0, 0, buf[18], buf[19]);
VDEBUGF("Offsets: %d\n", num_offsets);
- VDEBUGF("Frames/entry: %ld\n",
- bytes2int(0, 0, buf[24], buf[25]));
+ VDEBUGF("Frames/entry: %ld\n", bytes2int(0, 0, buf[24], buf[25]));
for(i = 0; i < num_offsets; i++)
{
offset += bytes2int(0, 0, buf[26+i*2], buf[27+i*2]);;
VDEBUGF("%03d: %lx\n", i, offset - bytecount,);
}
+ */
}
/* Seek to next mpeg header and extract relevant information. */
@@ -521,9 +529,9 @@ static int get_next_header_info(int fd, long *bytecount, struct mp3info *info,
int get_mp3file_info(int fd, struct mp3info *info)
{
- unsigned char frame[1800], *vbrheader;
+ unsigned char frame[VBR_HEADER_MAX_SIZE], *vbrheader;
long bytecount = 0;
- int result;
+ int result, buf_size;
/* Initialize info and frame */
memset(info, 0, sizeof(struct mp3info));
@@ -539,16 +547,13 @@ int get_mp3file_info(int fd, struct mp3info *info)
result = get_next_header_info(fd, &bytecount, info, true);
if(result)
return result;
-
- /* OK, we have found a frame. Let's see if it has a Xing header */
- if (info->frame_size-4 >= (int)sizeof(frame))
- {
- DEBUGF("Error: Invalid id3 header, frame_size: %d\n", info->frame_size);
- return -8;
- }
- if(read(fd, frame, info->frame_size-4) < 0)
+ /* Read the amount of frame data to the buffer that is required for the
+ * vbr tag parsing. Skip the rest. */
+ buf_size = MIN(info->frame_size-4, (int)sizeof(frame));
+ if(read(fd, frame, buf_size) < 0)
return -3;
+ lseek(fd, info->frame_size - 4 - buf_size, SEEK_CUR);
/* Calculate position of a possible VBR header */
if (info->version == MPEG_VERSION1) {