wave_writer.c

/* http://www.slack.net/~ant/ */

#include "wave_writer.h"

#include <stdlib.h>
#include <stdio.h>

/* Copyright (C) 2003-2009 Shay Green. This module is free software; you
can redistribute it and/or modify it under the terms of the GNU Lesser
General Public License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version. This
module is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
details. You should have received a copy of the GNU Lesser General Public
License along with this module; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */

enum { sample_size = 2 };

static FILE* file;
static int   sample_count;
static int   sample_rate;
static int   chan_count;

static void write_header( void );

#if defined(_MSC_VER) || defined(__MINGW32__)

#include <windows.h>

static wchar_t* str2wstr(const char *str) {
  int len = strlen(str) + 1;
  wchar_t* wstr = malloc(len * sizeof(wchar_t));
  MultiByteToWideChar(CP_UTF8, 0, str, len * sizeof(char), wstr, len);
  return wstr;
}

static FILE *ww_fopen(const char *filename, const char *mode)
{
  wchar_t* wFilename = str2wstr(filename);
  wchar_t* wMode = str2wstr(mode);
  FILE *pFile = _wfopen(wFilename, wMode);
  free(wFilename);
  free(wMode);

  return pFile;
}

#else
#define ww_fopen fopen
#endif

int wave_open( int new_sample_rate, char const filename [] )
{
	wave_close();
	
	file = ww_fopen( filename, "wb" );
	if (file )
	{
		sample_rate = new_sample_rate;
		write_header();		
	}

	return file != NULL;
}

int wave_close( void )
{
	if ( file )
	{
		if (!fflush(file))
		{
			rewind( file );
			write_header();
			
			if(!fclose(file))
				file = NULL;
		}	
	}
	
	sample_count = 0;
	chan_count   = 1;

	return file != NULL;
}

static int write_data( void const* in, unsigned size )
{
	return !fwrite( in, size, 1, file );
}

static void set_le32( unsigned char p [4], unsigned n )
{
	p [0] = (unsigned char) (n      );
	p [1] = (unsigned char) (n >>  8);
	p [2] = (unsigned char) (n >> 16);
	p [3] = (unsigned char) (n >> 24);
}

static void write_header( void )
{
	int data_size  = sample_size * sample_count;
	int frame_size = sample_size * chan_count;
	unsigned char h [0x2C] =
	{
		'R','I','F','F',
		0,0,0,0,        /* length of rest of file */
		'W','A','V','E',
		'f','m','t',' ',
		16,0,0,0,       /* size of fmt chunk */
		1,0,            /* uncompressed format */
		0,0,            /* channel count */
		0,0,0,0,        /* sample rate */
		0,0,0,0,        /* bytes per second */
		0,0,            /* bytes per sample frame */
		sample_size*8,0,/* bits per sample */
		'd','a','t','a',
		0,0,0,0         /* size of sample data */
		/* ... */       /* sample data */
	};
	
	set_le32( h + 0x04, sizeof h - 8 + data_size );
	h [0x16] = chan_count;
	set_le32( h + 0x18, sample_rate );
	set_le32( h + 0x1C, sample_rate * frame_size );
	h [0x20] = frame_size;
	set_le32( h + 0x28, data_size );
	
	write_data( h, sizeof h );
}

void wave_enable_stereo( void )
{
	chan_count = 2;
}

void wave_write( short const in [], int remain )
{
	sample_count += remain;
	
	while ( remain )
	{
		unsigned char buf [4096];
		
		int n = sizeof buf / sample_size;
		if ( n > remain )
			n = remain;
		remain -= n;
		
		/* Convert to little-endian */
		{
			unsigned char* out = buf;
			short const* end = in + n;
			do
			{
				unsigned s = *in++;
				out [0] = (unsigned char) (s     );
				out [1] = (unsigned char) (s >> 8);
				out += sample_size;
			}
			while ( in != end );
			
			write_data( buf, out - buf );
		}
	}
}

int wave_sample_count( void )
{
	return sample_count;
}