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			121 lines
		
	
	
	
		
			2.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			121 lines
		
	
	
	
		
			2.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Some mp3 related code for Sega/Mega CD.
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|  * Uses the Helix Fixed-point MP3 decoder
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|  * (C) notaz, 2007-2009
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|  *
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|  * This work is licensed under the terms of MAME license.
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|  * See COPYING file in the top-level directory.
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|  */
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| 
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| #include <stdio.h>
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| #include <string.h>
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| #include <dlfcn.h>
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| 
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| #include <pico/pico_int.h>
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| #include "helix/pub/mp3dec.h"
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| #include "mp3.h"
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| 
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| static HMP3Decoder mp3dec;
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| static unsigned char mp3_input_buffer[2 * 1024];
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| 
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| #ifdef __GP2X__
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| #define mp3dec_decode _mp3dec_decode
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| #define mp3dec_start _mp3dec_start
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| #endif
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| 
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| static void *libhelix;
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| HMP3Decoder (*p_MP3InitDecoder)(void);
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| void (*p_MP3FreeDecoder)(HMP3Decoder);
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| int (*p_MP3Decode)(HMP3Decoder, unsigned char **, int *, short *, int);
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| 
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| int mp3dec_decode(FILE *f, int *file_pos, int file_len)
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| {
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| 	unsigned char *readPtr;
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| 	int bytesLeft;
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| 	int offset; // mp3 frame offset from readPtr
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| 	int had_err;
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| 	int err = 0;
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| 	int retry = 3;
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| 
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| 	do
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| 	{
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| 		if (*file_pos >= file_len)
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| 			return 1; /* EOF, nothing to do */
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| 
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| 		fseek(f, *file_pos, SEEK_SET);
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| 		bytesLeft = fread(mp3_input_buffer, 1, sizeof(mp3_input_buffer), f);
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| 
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| 		offset = mp3_find_sync_word(mp3_input_buffer, bytesLeft);
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| 		if (offset < 0) {
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| 			lprintf("find_sync_word (%i/%i) err %i\n",
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| 				*file_pos, file_len, offset);
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| 			*file_pos = file_len;
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| 			return 1; // EOF
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| 		}
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| 		readPtr = mp3_input_buffer + offset;
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| 		bytesLeft -= offset;
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| 
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| 		had_err = err;
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| 		err = p_MP3Decode(mp3dec, &readPtr, &bytesLeft, cdda_out_buffer, 0);
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| 		if (err) {
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| 			if (err == ERR_MP3_MAINDATA_UNDERFLOW && !had_err) {
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| 				// just need another frame
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| 				*file_pos += readPtr - mp3_input_buffer;
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| 				continue;
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| 			}
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| 			if (err == ERR_MP3_INDATA_UNDERFLOW && !had_err) {
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| 				if (offset == 0)
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| 					// something's really wrong here, frame had to fit
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| 					*file_pos = file_len;
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| 				else
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| 					*file_pos += offset;
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| 				continue;
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| 			}
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| 			if (-12 <= err && err <= -6) {
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| 				// ERR_MP3_INVALID_FRAMEHEADER, ERR_MP3_INVALID_*
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| 				// just try to skip the offending frame..
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| 				*file_pos += offset + 1;
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| 				continue;
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| 			}
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| 			lprintf("MP3Decode err (%i/%i) %i\n",
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| 				*file_pos, file_len, err);
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| 			*file_pos = file_len;
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| 			return 1;
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| 		}
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| 		*file_pos += readPtr - mp3_input_buffer;
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| 	}
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| 	while (err && --retry > 0);
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| 
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| 	return !!err;
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| }
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| 
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| int mp3dec_start(FILE *f, int fpos_start)
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| {
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| 	if (libhelix == NULL) {
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| 		libhelix = dlopen("./libhelix.so", RTLD_NOW);
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| 		if (libhelix == NULL) {
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| 			lprintf("mp3dec: load libhelix.so: %s\n", dlerror());
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| 			return -1;
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| 		}
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| 
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| 		p_MP3InitDecoder = dlsym(libhelix, "MP3InitDecoder");
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| 		p_MP3FreeDecoder = dlsym(libhelix, "MP3FreeDecoder");
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| 		p_MP3Decode = dlsym(libhelix, "MP3Decode");
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| 
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| 		if (p_MP3InitDecoder == NULL || p_MP3FreeDecoder == NULL
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| 		    || p_MP3Decode == NULL)
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| 		{
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| 			lprintf("mp3dec: missing symbol(s) in libhelix.so\n");
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| 			dlclose(libhelix);
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| 			libhelix = NULL;
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| 			return -1;
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| 		}
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| 	}
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| 
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| 	// must re-init decoder for new track
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| 	if (mp3dec)
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| 		p_MP3FreeDecoder(mp3dec);
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| 	mp3dec = p_MP3InitDecoder();
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| 
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| 	return (mp3dec == 0) ? -1 : 0;
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| }
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