music_mod.c
author Sam Lantinga <slouken@libsdl.org>
Tue, 13 Apr 2010 22:28:38 -0700
changeset 487 485a29de2b2d
parent 479 3d8a5a7b1249
child 518 8bc9b5fd2aae
permissions -rw-r--r--
Fixed uninitialized variable which could definitely have caused problems.
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/*
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    SDL_mixer:  An audio mixer library based on the SDL library
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    Copyright (C) 1997-2009 Sam Lantinga
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    This library is free software; you can redistribute it and/or
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    modify it under the terms of the GNU Library General Public
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    License as published by the Free Software Foundation; either
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    version 2 of the License, or (at your option) any later version.
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    This library is distributed in the hope that it will be useful,
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    but WITHOUT ANY WARRANTY; without even the implied warranty of
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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    Library General Public License for more details.
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    You should have received a copy of the GNU Library General Public
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    License along with this library; if not, write to the Free
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    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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    Sam Lantinga
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    slouken@libsdl.org
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*/
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/* $Id: music_mod.c 4211 2008-12-08 00:27:32Z slouken $ */
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#ifdef MOD_MUSIC
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/* This file supports MOD tracker music streams */
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#include "SDL_mixer.h"
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#include "dynamic_mod.h"
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#include "music_mod.h"
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#include "mikmod.h"
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#define SDL_SURROUND
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#ifdef SDL_SURROUND
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#define MAX_OUTPUT_CHANNELS 6
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#else
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#define MAX_OUTPUT_CHANNELS 2
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#endif
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/* Reference for converting mikmod output to 4/6 channels */
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static int current_output_channels;
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static Uint16 current_output_format;
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static int music_swap8;
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static int music_swap16;
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/* Initialize the MOD player, with the given mixer settings
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   This function returns 0, or -1 if there was an error.
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 */
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int MOD_init(SDL_AudioSpec *mixerfmt)
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{
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	CHAR *list;
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	if ( !Mix_Init(MIX_INIT_MOD) ) {
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		return -1;
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	}
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	/* Set the MikMod music format */
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	music_swap8 = 0;
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	music_swap16 = 0;
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	switch (mixerfmt->format) {
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		case AUDIO_U8:
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		case AUDIO_S8: {
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			if ( mixerfmt->format == AUDIO_S8 ) {
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				music_swap8 = 1;
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			}
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			*mikmod.md_mode = 0;
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		}
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		break;
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		case AUDIO_S16LSB:
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		case AUDIO_S16MSB: {
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			/* See if we need to correct MikMod mixing */
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#if SDL_BYTEORDER == SDL_LIL_ENDIAN
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			if ( mixerfmt->format == AUDIO_S16MSB ) {
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#else
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			if ( mixerfmt->format == AUDIO_S16LSB ) {
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#endif
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				music_swap16 = 1;
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			}
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			*mikmod.md_mode = DMODE_16BITS;
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		}
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		break;
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		default: {
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			Mix_SetError("Unknown hardware audio format");
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			return -1;
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		}
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	}
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	current_output_channels = mixerfmt->channels;
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	current_output_format = mixerfmt->format;
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	if ( mixerfmt->channels > 1 ) {
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		if ( mixerfmt->channels > MAX_OUTPUT_CHANNELS ) {
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			Mix_SetError("Hardware uses more channels than mixerfmt");
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			return -1;
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		}
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		*mikmod.md_mode |= DMODE_STEREO;
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	}
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	*mikmod.md_mixfreq = mixerfmt->freq;
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	*mikmod.md_device  = 0;
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	*mikmod.md_volume  = 96;
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	*mikmod.md_musicvolume = 128;
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	*mikmod.md_sndfxvolume = 128;
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	*mikmod.md_pansep  = 128;
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	*mikmod.md_reverb  = 0;
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	*mikmod.md_mode    |= DMODE_HQMIXER|DMODE_SOFT_MUSIC|DMODE_SURROUND;
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	list = mikmod.MikMod_InfoDriver();
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	if ( list )
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	  free(list);
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	else
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	  mikmod.MikMod_RegisterDriver(mikmod.drv_nos);
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	list = mikmod.MikMod_InfoLoader();
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	if ( list )
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	  free(list);
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	else
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	  mikmod.MikMod_RegisterAllLoaders();
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	if ( mikmod.MikMod_Init(NULL) ) {
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		Mix_SetError("%s", mikmod.MikMod_strerror(*mikmod.MikMod_errno));
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		return -1;
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	}
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	return 0;
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}
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/* Uninitialize the music players */
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void MOD_exit(void)
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{
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	if (mikmod.MikMod_Exit) {
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		mikmod.MikMod_Exit();
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	}
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}
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/* Set the volume for a MOD stream */
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void MOD_setvolume(MODULE *music, int volume)
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{
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	mikmod.Player_SetVolume((SWORD)volume);
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}
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/* Load a MOD stream from the given file */
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MODULE *MOD_new(const char *file)
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{
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	SDL_RWops *rw;
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	rw = SDL_RWFromFile(file, "rb");
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	if ( rw == NULL ) {
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		/* FIXME: Free rw, need to free on delete */
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		SDL_SetError("Couldn't open %s", file);
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		return NULL;
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	}
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	return MOD_new_RW(rw);
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}
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typedef struct
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{
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	MREADER mr;
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	long offset;
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	long eof;
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	SDL_RWops *rw;
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} LMM_MREADER;
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BOOL LMM_Seek(struct MREADER *mr,long to,int dir)
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{
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	LMM_MREADER* lmmmr = (LMM_MREADER*)mr;
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	if ( dir == SEEK_SET ) {
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		to += lmmmr->offset;
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	}
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	return (SDL_RWseek(lmmmr->rw, to, dir) < lmmmr->offset);
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}
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long LMM_Tell(struct MREADER *mr)
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{
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	LMM_MREADER* lmmmr = (LMM_MREADER*)mr;
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	return SDL_RWtell(lmmmr->rw) - lmmmr->offset;
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}
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BOOL LMM_Read(struct MREADER *mr,void *buf,size_t sz)
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{
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	LMM_MREADER* lmmmr = (LMM_MREADER*)mr;
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	return SDL_RWread(lmmmr->rw, buf, sz, 1);
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}
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int LMM_Get(struct MREADER *mr)
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{
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	unsigned char c;
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	LMM_MREADER* lmmmr = (LMM_MREADER*)mr;
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	if ( SDL_RWread(lmmmr->rw, &c, 1, 1) ) {
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		return c;
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	}
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	return EOF;
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}
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BOOL LMM_Eof(struct MREADER *mr)
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{
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	long offset;
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	LMM_MREADER* lmmmr = (LMM_MREADER*)mr;
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	offset = LMM_Tell(mr);
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	return offset >= lmmmr->eof;
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}
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MODULE *MikMod_LoadSongRW(SDL_RWops *rw, int maxchan)
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{
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	LMM_MREADER lmmmr = {
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		{ LMM_Seek, LMM_Tell, LMM_Read, LMM_Get, LMM_Eof },
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		0,
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		0,
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		0
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	};
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	lmmmr.offset = SDL_RWtell(rw);
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	SDL_RWseek(rw, 0, RW_SEEK_END);
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	lmmmr.eof = SDL_RWtell(rw);
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	SDL_RWseek(rw, lmmmr.offset, RW_SEEK_SET);
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        lmmmr.rw = rw;
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	return mikmod.Player_LoadGeneric((MREADER*)&lmmmr, maxchan, 0);
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}
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/* Load a MOD stream from an SDL_RWops object */
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MODULE *MOD_new_RW(SDL_RWops *rw)
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{
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	MODULE *module;
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	/* Make sure the mikmod library is loaded */
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	if ( !Mix_Init(MIX_INIT_MOD) ) {
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		return NULL;
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	}
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	module = MikMod_LoadSongRW(rw,64);
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	if (!module) {
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		Mix_SetError("%s", mikmod.MikMod_strerror(*mikmod.MikMod_errno));
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		return NULL;
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	}
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	/* Stop implicit looping, fade out and other flags. */
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	module->extspd  = 1;
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	module->panflag = 1;
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	module->wrap    = 0;
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	module->loop    = 0;
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#if 0 /* Don't set fade out by default - unfortunately there's no real way
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to query the status of the song or set trigger actions.  Hum. */
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	module->fadeout = 1;
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#endif
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	return module;
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}
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/* Start playback of a given MOD stream */
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void MOD_play(MODULE *music)
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{
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	mikmod.Player_Start(music);
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}
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/* Return non-zero if a stream is currently playing */
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int MOD_playing(MODULE *music)
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{
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	return mikmod.Player_Active();
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}
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/* Play some of a stream previously started with MOD_play() */
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int MOD_playAudio(MODULE *music, Uint8 *stream, int len)
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{
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	if (current_output_channels > 2) {
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		int small_len = 2 * len / current_output_channels;
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		int i;
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		Uint8 *src, *dst;
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		mikmod.VC_WriteBytes((SBYTE *)stream, small_len);
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		/* and extend to len by copying channels */
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		src = stream + small_len;
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		dst = stream + len;
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		switch (current_output_format & 0xFF) {
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			case 8:
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				for ( i=small_len/2; i; --i ) {
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					src -= 2;
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					dst -= current_output_channels;
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					dst[0] = src[0];
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					dst[1] = src[1];
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					dst[2] = src[0];
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					dst[3] = src[1];
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					if (current_output_channels == 6) {
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						dst[4] = src[0];
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						dst[5] = src[1];
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					}
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				}
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				break;
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			case 16:
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				for ( i=small_len/4; i; --i ) {
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					src -= 4;
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					dst -= 2 * current_output_channels;
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					dst[0] = src[0];
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					dst[1] = src[1];
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					dst[2] = src[2];
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					dst[3] = src[3];
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					dst[4] = src[0];
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					dst[5] = src[1];
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					dst[6] = src[2];
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					dst[7] = src[3];
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					if (current_output_channels == 6) {
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						dst[8] = src[0];
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						dst[9] = src[1];
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						dst[10] = src[2];
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						dst[11] = src[3];
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					}
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				}
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				break;
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		}
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	} else {
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		mikmod.VC_WriteBytes((SBYTE *)stream, len);
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	}
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	if ( music_swap8 ) {
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		Uint8 *dst;
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		int i;
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		dst = stream;
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		for ( i=len; i; --i ) {
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			*dst++ ^= 0x80;
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		}
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	} else
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	if ( music_swap16 ) {
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		Uint8 *dst, tmp;
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		int i;
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		dst = stream;
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		for ( i=(len/2); i; --i ) {
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			tmp = dst[0];
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			dst[0] = dst[1];
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			dst[1] = tmp;
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			dst += 2;
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		}
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	}
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	return 0;
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}
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/* Stop playback of a stream previously started with MOD_play() */
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void MOD_stop(MODULE *music)
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{
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	mikmod.Player_Stop();
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}
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/* Close the given MOD stream */
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void MOD_delete(MODULE *music)
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{
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	mikmod.Player_Free(music);
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}
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/* Jump (seek) to a given position (time is in seconds) */
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void MOD_jump_to_time(MODULE *music, double time)
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{
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	mikmod.Player_SetPosition((UWORD)time);
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}
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#endif /* MOD_MUSIC */