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rockbox/firmware/id3.c
Magnus Holmgren f11d07c61f Correct genre parsing by making code match comment (and specification) :) 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@3987 a1c6a512-1295-4272-9138-f99709370657
2003-10-26 12:53:21 +00:00

784 lines
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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.
*
*/
/* tagResolver and associated code copyright 2003 Thomas Paul Diffenbach
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdbool.h>
#include <stddef.h>
#include <ctype.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)))
/*
HOW TO ADD ADDITIONAL ID3 VERSION 2 TAGS
Code and comments by Thomas Paul Diffenbach
To add another ID3v2 Tag, do the following:
1. add a char* named for the tag to struct mp3entry in id3.h,
(I (tpd) prefer to use char* rather than ints, even for what seems like
numerical values, for cases where a number won't do, e.g.,
YEAR: "circa 1765", "1790/1977" (composed/performed), "28 Feb 1969"
TRACK: "1/12", "1 of 12", GENRE: "Freeform genre name"
Text is more flexible, and as the main use of id3 data is to
display it, converting it to an int just means reconverting to
display it, at a runtime cost.)
2. If any special processing beyond copying the tag value from the Id3
block to the struct mp3entry is rrequired (such as converting to an
int), write a function to perform this special processing.
This function's prototype must match that of
typedef tagPostProcessFunc, that is it must be:
int func( struct mp3entry*, char* tag, int bufferpos )
the first argument is a pointer to the current mp3entry structure the
second argument is a pointer to the null terminated string value of the
tag found the third argument is the offset of the next free byte in the
mp3entry's buffer your function should return the corrected offset; if
you don't lengthen or shorten the tag string, you can return the third
argument unchanged.
Unless you have a good reason no to, make the function static.
TO JUST COPY THE TAG NO SPECIAL PROCESSING FUNCTION IS NEEDED.
3. add one or more entries to the tagList array, using the format:
char* ID3 Tag symbolic name -- see the ID3 specification for these,
sizeof() that name minus 1,
offsetof( struct mp3entry, variable_name_in_struct_mp3entry ),
pointer to your special processing function or NULL
if you need no special processing
Many ID3 symbolic names come in more than one form. You can add both
forms, each referencing the same variable in struct mp3entry.
If both forms are present, the last found will be used.
4. Alternately, use the TAG_LIST_ENTRY macro with
ID3 tag symbolic name,
variable in struct mp3entry,
special processing function address
5. Add code to wps-display.c function get_tag to assign a printf-like
format specifier for the tag */
/* Structure for ID3 Tag extraction information */
struct tag_resolver {
const char* tag;
int tag_length;
size_t offset;
int (*ppFunc)(struct mp3entry*, char* tag, int bufferpos);
};
static int unsynchronize(char* tag, int len)
{
int i;
unsigned char c;
unsigned char *rp, *wp;
bool ff_found = false;
wp = rp = tag;
rp = (unsigned char *)tag;
for(i = 0;i < len;i++) {
/* Read the next byte and write it back, but don't increment the
write pointer */
c = *rp++;
*wp = c;
if(ff_found) {
/* Increment the write pointer if it isn't an unsynch pattern */
if(c != 0)
wp++;
ff_found = false;
} else {
if(c == 0xff)
ff_found = true;
wp++;
}
}
return (int)wp - (int)tag;
}
/* parse numeric value from string */
static int parsetracknum( struct mp3entry* entry, char* tag, int bufferpos )
{
entry->tracknum = atoi( tag );
return bufferpos;
}
/* parse numeric value from string */
static int parseyearnum( struct mp3entry* entry, char* tag, int bufferpos )
{
entry->year = atoi( tag );
return bufferpos;
}
/* parse numeric genre from string, version 2.2 and 2.3 */
static int parsegenre( struct mp3entry* entry, char* tag, int bufferpos )
{
if(entry->id3version >= ID3_VER_2_4) {
/* In version 2.4 and up, there are no parentheses, and the genre frame
is a list of strings, either numbers or text. */
/* Is it a number? */
if(isdigit(tag[0])) {
entry->genre = atoi( tag );
entry->genre_string = 0;
return tag - entry->id3v2buf;
} else {
entry->genre = 0xFF;
return bufferpos;
}
} else {
if( tag[0] == '(' && tag[1] != '(' ) {
entry->genre = atoi( tag + 1 );
entry->genre_string = 0;
return tag - entry->id3v2buf;
}
else {
entry->genre = 0xFF;
return bufferpos;
}
}
}
static struct tag_resolver taglist[] = {
{ "TPE1", 4, offsetof(struct mp3entry, artist), NULL },
{ "TP1", 3, offsetof(struct mp3entry, artist), NULL },
{ "TIT2", 4, offsetof(struct mp3entry, title), NULL },
{ "TT2", 3, offsetof(struct mp3entry, title), NULL },
{ "TALB", 4, offsetof(struct mp3entry, album), NULL },
{ "TAL", 3, offsetof(struct mp3entry, album), NULL },
{ "TRK", 3, offsetof(struct mp3entry, track_string), &parsetracknum },
{ "TRCK", 4, offsetof(struct mp3entry, track_string), &parsetracknum },
{ "TYER", 4, offsetof(struct mp3entry, year_string), &parseyearnum },
{ "TYE", 3, offsetof(struct mp3entry, year_string), &parseyearnum },
{ "TCON", 4, offsetof(struct mp3entry, genre_string), &parsegenre },
{ "TCO", 3, offsetof(struct mp3entry, genre_string), &parsegenre },
{ "TCOM", 4, offsetof(struct mp3entry, composer), NULL }
};
#define TAGLIST_SIZE ((int)(sizeof(taglist) / sizeof(taglist[0])))
/* 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;
}
/*
* 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];
char tmp[4];
unsigned char version;
char *buffer = entry->id3v2buf;
int bytesread = 0;
int buffersize = sizeof(entry->id3v2buf);
unsigned char global_flags;
int flags;
int skip;
bool global_unsynch = false;
bool unsynch = false;
int data_length_ind;
int i;
/* 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 = 0;
entry->genre = 0xff;
entry->title = entry->artist = entry->album = NULL;
global_flags = header[5];
/* Skip the extended header if it is present */
if(version >= ID3_VER_2_4) {
if(global_flags & 0x40) {
if(4 != read(fd, header, 4))
return;
framelen = UNSYNC(header[0], header[1],
header[2], header[3]);
lseek(fd, framelen - 4, SEEK_CUR);
}
}
/* Is unsynchronization applied? */
if(global_flags & 0x80) {
global_unsynch = true;
}
/*
* 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;
unsynch = false;
data_length_ind = 0;
if(flags)
{
skip = 0;
if(flags & 0x0040) { /* Grouping identity */
lseek(fd, 1, SEEK_CUR); /* Skip 1 byte */
framelen--;
}
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;
}
if(flags & 0x0002) /* Unsynchronization */
unsynch = true;
if(flags & 0x0001) { /* Data length indicator */
if(4 != read(fd, tmp, 4))
return;
data_length_ind = UNSYNC(tmp[0], tmp[1], tmp[2], tmp[3]);
framelen -= 4;
}
}
/* 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
'size' is the amount of frame bytes remaining. We decrement it by
the amount of bytes we read. If we fail to read as many bytes as
we expect, we assume that we can't read from this file, and bail
out.
For each frame. we will iterate over the list of supported tags,
and read the tag into entry's buffer. All tags will be kept as
strings, for cases where a number won't do, e.g., YEAR: "circa
1765", "1790/1977" (composed/performed), "28 Feb 1969" TRACK:
"1/12", "1 of 12", GENRE: "Freeform genre name" Text is more
flexible, and as the main use of id3 data is to display it,
converting it to an int just means reconverting to display it, at a
runtime cost.
For tags that the current code does convert to ints, a post
processing function will be called via a pointer to function. */
for (i=0; i<TAGLIST_SIZE; i++) {
struct tag_resolver* tr = &taglist[i];
char** ptag = (char**) (((char*)entry) + tr->offset);
char* tag;
if( !*ptag && !memcmp( header, tr->tag, tr->tag_length ) ) {
/* found a tag matching one in tagList, and not yet filled */
bytesread = read(fd, buffer + bufferpos, framelen);
if( bytesread != framelen )
return;
size -= bytesread;
*ptag = buffer + bufferpos;
if(global_unsynch || unsynch)
bytesread = unsynchronize(*ptag, bytesread);
unicode_munge( ptag, &bytesread );
tag = *ptag;
tag[bytesread + 1] = 0;
bufferpos += bytesread + 2;
if( tr->ppFunc )
bufferpos = tr->ppFunc(entry, tag, bufferpos);
break;
}
}
if( i == TAGLIST_SIZE ) {
/* no tag in tagList was found, or it was a repeat.
skip it using the total size */
/* We may need to compensate for the unsynchronization scheme */
if(global_unsynch && !data_length_ind) {
bool ff_found = false;
for(i = 0;i < totframelen;i++) {
unsigned char c;
bytesread = read(fd, &c, 1);
if(ff_found) {
if(c == 0)
/* Found an unsynch pattern, counting it */
totframelen++;
ff_found = false;
} else {
if(c == 0xff)
ff_found = true;
}
}
} else {
if(data_length_ind)
totframelen = data_length_ind;
size -= totframelen;
if( lseek(fd, totframelen, SEEK_CUR) == -1 )
return;
}
}
}
}
/*
* 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;
mp3.album = "Bogus";
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"
" Genre: %s (%d) \n"
" Composer: %s\n"
" Year: %s (%d)\n"
" Track: %s (%d)\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>",
mp3.genre_string?mp3.genre_string:"<blank>",
mp3.genre,
mp3.composer?mp3.composer:"<blank>",
mp3.year_string?mp3.year_string:"<blank>",
mp3.year,
mp3.track_string?mp3.track_string:"<blank>",
mp3.tracknum,
secs2str(mp3.length),
mp3.length/1000,
mp3.bitrate,
mp3.frequency);
}
return 0;
}
#endif
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