b127949860
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30280 a1c6a512-1295-4272-9138-f99709370657
148 lines
3.9 KiB
C
148 lines
3.9 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <inttypes.h>
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#include "system.h"
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#include "metadata.h"
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#include "metadata_common.h"
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#include "metadata_parsers.h"
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#include "rbunicode.h"
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/* Taken from blargg's Game_Music_Emu library */
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typedef unsigned char byte;
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/* AY file header */
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enum { header_size = 0x14 };
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struct header_t
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{
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byte tag[8];
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byte vers;
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byte player;
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byte unused[2];
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byte author[2];
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byte comment[2];
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byte max_track;
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byte first_track;
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byte track_info[2];
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};
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struct file_t {
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struct header_t const* header;
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byte const* tracks;
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byte const* end; /* end of file data */
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};
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static int get_be16( const void *a )
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{
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return get_short_be( (void*) a );
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}
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/* Given pointer to 2-byte offset of data, returns pointer to data, or NULL if
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* offset is 0 or there is less than min_size bytes of data available. */
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static byte const* get_data( struct file_t const* file, byte const ptr [], int min_size )
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{
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int offset = (int16_t) get_be16( ptr );
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int pos = ptr - (byte const*) file->header;
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int size = file->end - (byte const*) file->header;
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int limit = size - min_size;
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if ( limit < 0 || !offset || (unsigned) (pos + offset) > (unsigned) limit )
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return NULL;
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return ptr + offset;
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}
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static const char *parse_header( byte const in [], int size, struct file_t* out )
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{
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if ( size < header_size )
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return "wrong file type";
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out->header = (struct header_t const*) in;
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out->end = in + size;
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struct header_t const* h = (struct header_t const*) in;
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if ( memcmp( h->tag, "ZXAYEMUL", 8 ) )
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return "wrong file type";
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out->tracks = get_data( out, h->track_info, (h->max_track + 1) * 4 );
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if ( !out->tracks )
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return "missing track data";
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return 0;
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}
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static void copy_ay_fields( struct file_t const* file, struct mp3entry* id3, int track )
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{
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int track_count = file->header->max_track + 1;
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/* calculate track length based on number of subtracks */
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if (track_count > 1) {
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id3->length = file->header->max_track * 1000;
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} else {
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byte const* track_info = get_data( file, file->tracks + track * 4 + 2, 6 );
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if (track_info)
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id3->length = get_be16( track_info + 4 ) * (1000 / 50); /* frames to msec */
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else id3->length = 120 * 1000;
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}
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if ( id3->length <= 0 )
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id3->length = 120 * 1000; /* 2 minutes */
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/* If meta info was found in the m3u skip next step */
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if (id3->title && id3->title[0]) return;
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/* If file has more than one track will
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use file name as title */
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char * tmp;
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if (track_count <= 1) {
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tmp = (char *) get_data( file, file->tracks + track * 4, 1 );
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if ( tmp ) id3->title = tmp;
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}
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/* Author */
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tmp = (char *) get_data( file, file->header->author, 1 );
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if (tmp) id3->artist = tmp;
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/* Comment */
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tmp = (char *) get_data( file, file->header->comment, 1 );
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if (tmp) id3->comment = tmp;
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}
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static bool parse_ay_header(int fd, struct mp3entry *id3)
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{
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/* Use the trackname part of the id3 structure as a temporary buffer */
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unsigned char* buf = (unsigned char *)id3->id3v2buf;
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struct file_t file;
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int read_bytes;
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lseek(fd, 0, SEEK_SET);
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if ((read_bytes = read(fd, buf, ID3V2_BUF_SIZE)) < header_size)
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return false;
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buf [ID3V2_BUF_SIZE] = '\0';
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if ( parse_header( buf, read_bytes, &file ) )
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return false;
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copy_ay_fields( &file, id3, 0 );
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return true;
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}
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bool get_ay_metadata(int fd, struct mp3entry* id3)
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{
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char ay_type[8];
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if ((lseek(fd, 0, SEEK_SET) < 0) ||
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read(fd, ay_type, 8) < 8)
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return false;
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id3->vbr = false;
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id3->filesize = filesize(fd);
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id3->bitrate = 706;
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id3->frequency = 44100;
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/* Make sure this is a ZX Ay file */
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if (memcmp( ay_type, "ZXAYEMUL", 8 ) != 0)
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return false;
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return parse_ay_header(fd, id3);
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}
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