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rockbox/firmware/id3.c
Linus Nielsen Feltzing 6b6f97ddda Tidied up the ID3V2 parser a little 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@3475 a1c6a512-1295-4272-9138-f99709370657
2003-03-18 01:31:35 +00:00

616 lines
17 KiB
C
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Daniel Stenberg
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/*
* Parts of this code has been stolen from the Ample project and was written
* by David Härdeman. It has since been extended and enhanced pretty much by
* all sorts of friendly Rockbox people.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdbool.h>
#include "file.h"
#include "debug.h"
#include "atoi.h"
#include "id3.h"
#include "mp3data.h"
#define UNSYNC(b0,b1,b2,b3) (((b0 & 0x7F) << (3*7)) | \
((b1 & 0x7F) << (2*7)) | \
((b2 & 0x7F) << (1*7)) | \
((b3 & 0x7F) << (0*7)))
#define BYTES2INT(b0,b1,b2,b3) (((b0 & 0xFF) << (3*8)) | \
((b1 & 0xFF) << (2*8)) | \
((b2 & 0xFF) << (1*8)) | \
((b3 & 0xFF) << (0*8)))
/* Checks to see if the passed in string is a 16-bit wide Unicode v2
string. If it is, we attempt to convert it to a 8-bit ASCII string
(for valid 8-bit ASCII characters). If it's not unicode, we leave
it alone. At some point we should fully support unicode strings */
static int unicode_munge(char** string, int *len) {
int tmp;
bool le = false;
int i;
char *str = *string;
char *outstr = *string;
if(str[0] > 0x03) {
/* Plain old string */
return 0;
}
/* Type 0x00 is ordinary ISO 8859-1 */
if(str[0] == 0x00) {
(*len)--;
(*string)++; /* Skip the encoding type byte */
return 0;
}
/* Unicode with or without BOM */
if(str[0] == 0x01 || str[0] == 0x02) {
str++;
tmp = BYTES2INT(0, 0, str[0], str[1]);
/* Now check if there is a BOM (zero-width non-breaking space, 0xfeff)
and if it is in little or big endian format */
if(tmp == 0xfffe) { /* Little endian? */
le = true;
str += 2;
}
if(tmp == 0xfeff) /* Big endian? */
str += 2;
i = 0;
do {
if(le) {
if(str[1])
outstr[i++] = '.';
else
outstr[i++] = str[0];
} else {
if(str[0])
outstr[i++] = '.';
else
outstr[i++] = str[1];
}
str += 2;
} while(str[0] || str[1]);
*len = i;
return 0;
}
/* If we come here, the string was of an unsupported type */
*len = 1;
outstr[0] = 0;
return -1;
}
/*
* Sets the title of an MP3 entry based on its ID3v1 tag.
*
* Arguments: file - the MP3 file to scen for a ID3v1 tag
* entry - the entry to set the title in
*
* Returns: true if a title was found and created, else false
*/
static bool setid3v1title(int fd, struct mp3entry *entry)
{
unsigned char buffer[128];
static char offsets[] = {3, 33, 63, 93, 125, 127};
int i, j;
if (-1 == lseek(fd, -128, SEEK_END))
return false;
if (read(fd, buffer, sizeof buffer) != sizeof buffer)
return false;
if (strncmp(buffer, "TAG", 3))
return false;
entry->id3v1len = 128;
entry->id3version = ID3_VER_1_0;
for (i=0; i < (int)sizeof offsets; i++) {
char* ptr = buffer + offsets[i];
if (i<3) {
/* kill trailing space in strings */
for (j=29; j && ptr[j]==' '; j--)
ptr[j] = 0;
}
switch(i) {
case 0:
strncpy(entry->id3v1buf[2], ptr, 30);
entry->title = entry->id3v1buf[2];
break;
case 1:
strncpy(entry->id3v1buf[0], ptr, 30);
entry->artist = entry->id3v1buf[0];
break;
case 2:
strncpy(entry->id3v1buf[1], ptr, 30);
entry->album = entry->id3v1buf[1];
break;
case 3:
ptr[4] = 0;
entry->year = atoi(ptr);
break;
case 4:
/* id3v1.1 uses last two bytes of comment field for track
number: first must be 0 and second is track num */
if (!ptr[0] && ptr[1]) {
entry->tracknum = ptr[1];
entry->id3version = ID3_VER_1_1;
}
break;
case 5:
/* genre */
entry->genre = ptr[0];
break;
}
}
return true;
}
static int read_frame(int fd, unsigned char *buf, char **destptr, int framelen)
{
int bytesread;
bytesread = read(fd, buf, framelen);
if(bytesread < 0)
return bytesread * 10 - 1;
if(bytesread < framelen)
return -1;
*destptr = buf;
if(unicode_munge(destptr, &bytesread) < 0)
return -2;
(*destptr)[bytesread] = '\0';
return bytesread + 1;
}
/*
* Sets the title of an MP3 entry based on its ID3v2 tag.
*
* Arguments: file - the MP3 file to scan for a ID3v2 tag
* entry - the entry to set the title in
*
* Returns: true if a title was found and created, else false
*/
static void setid3v2title(int fd, struct mp3entry *entry)
{
int minframesize;
int size;
int bufferpos = 0, totframelen, framelen;
char header[10];
unsigned char version;
char *buffer = entry->id3v2buf;
char *tmp = NULL;
int bytesread = 0;
int buffersize = sizeof(entry->id3v2buf);
int flags;
int skip;
/* Bail out if the tag is shorter than 10 bytes */
if(entry->id3v2len < 10)
return;
/* Read the ID3 tag version from the header */
lseek(fd, 0, SEEK_SET);
if(10 != read(fd, header, 10))
return;
/* Get the total ID3 tag size */
size = entry->id3v2len - 10;
version = header[3];
switch ( version ) {
case 2:
version = ID3_VER_2_2;
minframesize = 8;
break;
case 3:
version = ID3_VER_2_3;
minframesize = 12;
break;
case 4:
version = ID3_VER_2_4;
minframesize = 12;
break;
default:
/* unsupported id3 version */
return;
}
entry->id3version = version;
entry->tracknum = entry->year = entry->genre = 0;
entry->title = entry->artist = entry->album = NULL;
/* Skip the extended header if it is present */
if(version >= ID3_VER_2_4) {
if(header[5] & 0x40) {
if(4 != read(fd, header, 4))
return;
framelen = UNSYNC(header[0], header[1],
header[2], header[3]);
lseek(fd, framelen - 4, SEEK_CUR);
}
}
/*
* We must have at least minframesize bytes left for the
* remaining frames to be interesting
*/
while(size > minframesize) {
flags = 0;
/* Read frame header and check length */
if(version >= ID3_VER_2_3) {
if(10 != read(fd, header, 10))
return;
/* Adjust for the 10 bytes we read */
size -= 10;
flags = BYTES2INT(0, 0, header[8], header[9]);
if (version >= ID3_VER_2_4) {
framelen = UNSYNC(header[4], header[5],
header[6], header[7]);
} else {
/* version .3 files don't use synchsafe ints for
* size */
framelen = BYTES2INT(header[4], header[5],
header[6], header[7]);
}
} else {
if(6 != read(fd, header, 6))
return;
/* Adjust for the 6 bytes we read */
size -= 6;
framelen = BYTES2INT(0, header[3], header[4], header[5]);
}
/* Keep track of the total size */
totframelen = framelen;
if(framelen == 0)
return;
if(flags)
{
skip = 0;
if(flags & 0x0040) /* Grouping identity */
skip++;
if(flags & 0x000c) /* Compression or encryption */
{
/* Skip it using the total size in case
it was truncated */
size -= totframelen;
lseek(fd, totframelen, SEEK_CUR);
continue;
}
/* The Unsynchronization flag can't be trusted, so we
don't check it for now... */
if(flags & 0x0001) /* Data length indicator */
skip += 4;
if(skip)
{
lseek(fd, skip, SEEK_CUR);
framelen -= skip;
}
}
/* If the frame is larger than the remaining buffer space we try
to read as much as would fit in the buffer */
if(framelen >= buffersize - bufferpos)
framelen = buffersize - bufferpos - 1;
DEBUGF("id3v2 frame: %.4s\n", header);
/* Check for certain frame headers */
if (!entry->artist &&
(!strncmp(header, "TPE1", strlen("TPE1")) ||
!strncmp(header, "TP1", strlen("TP1")))) {
bytesread = read_frame(fd, buffer + bufferpos,
&entry->artist, framelen);
if(bytesread < 0)
return;
bufferpos += bytesread;
size -= framelen;
}
else if (!entry->title &&
(!strncmp(header, "TIT2", strlen("TIT2")) ||
!strncmp(header, "TT2", strlen("TT2")))) {
bytesread = read_frame(fd, buffer + bufferpos,
&entry->title, framelen);
if(bytesread < 0)
return;
bufferpos += bytesread;
size -= framelen;
}
else if( !entry->album &&
!strncmp(header, "TALB", strlen("TALB"))) {
bytesread = read_frame(fd, buffer + bufferpos,
&entry->album, framelen);
if(bytesread < 0)
return;
bufferpos += bytesread;
size -= framelen;
}
else if (!entry->tracknum &&
!strncmp(header, "TRCK", strlen("TRCK"))) {
bytesread = read_frame(fd, buffer + bufferpos,
&tmp, framelen);
if(bytesread < 0)
return;
entry->tracknum = atoi(tmp);
size -= framelen;
}
else if (!entry->year &&
(!strncmp(header, "TYER", 4) ||
!strncmp(header, "TYR", 3))) {
bytesread = read_frame(fd, buffer + bufferpos,
&tmp, framelen);
if(bytesread < 0)
return;
entry->year = atoi(tmp);
size -= bytesread;
}
else if (!entry->genre &&
!strncmp(header, "TCON", 4)) {
char* ptr = buffer + bufferpos;
bytesread = read(fd, ptr, framelen);
if(bytesread < 0 || bytesread < framelen)
return;
if (ptr[1] == '(' && ptr[2] != '(')
entry->genre = atoi(ptr+2);
bufferpos += bytesread + 1;
size -= bytesread;
}
else {
/* Unknown frame, skip it using the total size in case
it was truncated */
size -= totframelen;
lseek(fd, totframelen, SEEK_CUR);
}
}
}
/*
* Calculates the size of the ID3v2 tag.
*
* Arguments: file - the file to search for a tag.
*
* Returns: the size of the tag or 0 if none was found
*/
static int getid3v2len(int fd)
{
char buf[6];
int offset;
/* Make sure file has a ID3 tag */
if((-1 == lseek(fd, 0, SEEK_SET)) ||
(read(fd, buf, 6) != 6) ||
(strncmp(buf, "ID3", strlen("ID3")) != 0))
offset = 0;
/* Now check what the ID3v2 size field says */
else if(read(fd, buf, 4) != 4)
offset = 0;
else
offset = UNSYNC(buf[0], buf[1], buf[2], buf[3]) + 10;
DEBUGF("ID3V2 Length: 0x%x\n", offset);
return offset;
}
/*
* Calculates the length (in milliseconds) of an MP3 file.
*
* Modified to only use integers.
*
* Arguments: file - the file to calculate the length upon
* entry - the entry to update with the length
*
* Returns: the song length in milliseconds,
* 0 means that it couldn't be calculated
*/
static int getsonglength(int fd, struct mp3entry *entry)
{
unsigned int filetime = 0;
struct mp3info info;
int bytecount;
/* Start searching after ID3v2 header */
if(-1 == lseek(fd, entry->id3v2len, SEEK_SET))
return 0;
bytecount = get_mp3file_info(fd, &info);
DEBUGF("Space between ID3V2 tag and first audio frame: 0x%x bytes\n",
bytecount);
if(bytecount < 0)
return -1;
bytecount += entry->id3v2len;
entry->bitrate = info.bitrate;
entry->frequency = info.frequency;
entry->version = info.version;
entry->layer = info.layer;
/* If the file time hasn't been established, this may be a fixed
rate MP3, so just use the default formula */
filetime = info.file_time;
if(filetime == 0)
{
/*
* Now song length is
* ((filesize)/(bytes per frame))*(time per frame)
*/
filetime = entry->filesize/info.frame_size*info.frame_time;
}
entry->tpf = info.frame_time;
entry->bpf = info.frame_size;
entry->vbr = info.is_vbr;
entry->has_toc = info.has_toc;
memcpy(entry->toc, info.toc, sizeof(info.toc));
entry->vbr_header_pos = info.vbr_header_pos;
/* Update the seek point for the first playable frame */
entry->first_frame_offset = bytecount;
DEBUGF("First frame is at %x\n", entry->first_frame_offset);
return filetime;
}
/*
* Checks all relevant information (such as ID3v1 tag, ID3v2 tag, length etc)
* about an MP3 file and updates it's entry accordingly.
*
* Arguments: entry - the entry to check and update with the new information
*
* Returns: void
*/
bool mp3info(struct mp3entry *entry, char *filename)
{
int fd;
fd = open(filename, O_RDONLY);
if(-1 == fd)
return true;
memset(entry, 0, sizeof(struct mp3entry));
strncpy(entry->path, filename, sizeof(entry->path));
entry->title = NULL;
entry->filesize = filesize(fd);
entry->id3v2len = getid3v2len(fd);
entry->tracknum = 0;
entry->genre = 0xff;
if (entry->id3v2len)
setid3v2title(fd, entry);
entry->length = getsonglength(fd, entry);
/* Subtract the meta information from the file size to get
the true size of the MP3 stream */
entry->filesize -= entry->first_frame_offset;
/* only seek to end of file if no id3v2 tags were found */
if (!entry->id3v2len) {
if(!entry->title)
setid3v1title(fd, entry);
}
close(fd);
if(!entry->length || (entry->filesize < 8 ))
/* no song length or less than 8 bytes is hereby considered to be an
invalid mp3 and won't be played by us! */
return true;
return false;
}
#ifdef DEBUG_STANDALONE
char *secs2str(int ms)
{
static char buffer[32];
int secs = ms/1000;
ms %= 1000;
snprintf(buffer, sizeof(buffer), "%d:%02d.%d", secs/60, secs%60, ms/100);
return buffer;
}
int main(int argc, char **argv)
{
int i;
for(i=1; i<argc; i++) {
struct mp3entry mp3;
if(mp3info(&mp3, argv[i])) {
printf("Failed to get %s\n", argv[i]);
return 0;
}
printf("****** File: %s\n"
" Title: %s\n"
" Artist: %s\n"
" Album: %s\n"
" Length: %s / %d s\n"
" Bitrate: %d\n"
" Frequency: %d\n",
argv[i],
mp3.title?mp3.title:"<blank>",
mp3.artist?mp3.artist:"<blank>",
mp3.album?mp3.album:"<blank>",
secs2str(mp3.length),
mp3.length/1000,
mp3.bitrate,
mp3.frequency);
}
return 0;
}
#endif
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