usbloadergx/source/SoundOperations/Mp3Decoder.cpp

/***************************************************************************
 * Copyright (C) 2010
 * by Dimok
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event will the authors be held liable for any
 * damages arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any
 * purpose, including commercial applications, and to alter it and
 * redistribute it freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you
 * must not claim that you wrote the original software. If you use
 * this software in a product, an acknowledgment in the product
 * documentation would be appreciated but is not required.
 *
 * 2. Altered source versions must be plainly marked as such, and
 * must not be misrepresented as being the original software.
 *
 * 3. This notice may not be removed or altered from any source
 * distribution.
 *
 * for WiiXplorer 2010
 ***************************************************************************/
#include <string>
#include <string.h>
#include <limits.h>
#include <unistd.h>
#include <malloc.h>
#include <math.h>
#include "Mp3Decoder.hpp"

Mp3Decoder::Mp3Decoder(const char * filepath)
    : SoundDecoder(filepath)
{
    SoundType = SOUND_MP3;
	ReadBuffer = NULL;
    mad_timer_reset(&Timer);
	mad_stream_init(&Stream);
	mad_frame_init(&Frame);
	mad_synth_init(&Synth);

	if(!file_fd)
        return;

    OpenFile();
}

Mp3Decoder::Mp3Decoder(const u8 * snd, int len)
    : SoundDecoder(snd, len)
{
    SoundType = SOUND_MP3;
	ReadBuffer = NULL;
    mad_timer_reset(&Timer);
	mad_stream_init(&Stream);
	mad_frame_init(&Frame);
	mad_synth_init(&Synth);

	if(!file_fd)
        return;

    OpenFile();
}

Mp3Decoder::~Mp3Decoder()
{
    ExitRequested = true;
    while(Decoding)
        usleep(100);

    mad_synth_finish(&Synth);
    mad_frame_finish(&Frame);
    mad_stream_finish(&Stream);

    if(ReadBuffer)
        free(ReadBuffer);
    ReadBuffer = NULL;
}

void Mp3Decoder::OpenFile()
{
    GuardPtr = NULL;
    ReadBuffer = (u8 *) memalign(32, SoundBlockSize*SoundBlocks);
    if(!ReadBuffer)
    {
        if(file_fd)
            delete file_fd;
        file_fd = NULL;
        return;
    }

    u8 dummybuff[4096];
    int ret = Read((u8 *) &dummybuff, 4096, 0);
    if(ret <= 0)
    {
        if(file_fd)
            delete file_fd;
        file_fd = NULL;
        return;
    }

    SampleRate = (u32) Frame.header.samplerate;
    Format = ((MAD_NCHANNELS(&Frame.header) == 2) ? VOICE_STEREO_16BIT : VOICE_MONO_16BIT);
    Rewind();
    Decode();
}

int Mp3Decoder::Rewind()
{
    mad_synth_finish(&Synth);
    mad_frame_finish(&Frame);
    mad_stream_finish(&Stream);
    mad_timer_reset(&Timer);
	mad_stream_init(&Stream);
	mad_frame_init(&Frame);
	mad_synth_init(&Synth);
    SynthPos = 0;
    GuardPtr = NULL;

	if(!file_fd)
        return -1;

    return SoundDecoder::Rewind();
}

static inline s16 FixedToShort(mad_fixed_t Fixed)
{
	/* Clipping */
	if(Fixed>=MAD_F_ONE)
		return(SHRT_MAX);
	if(Fixed<=-MAD_F_ONE)
		return(-SHRT_MAX);

	Fixed=Fixed>>(MAD_F_FRACBITS-15);
	return((s16)Fixed);
}

int Mp3Decoder::Read(u8 * buffer, int buffer_size, int pos)
{
    if(!file_fd)
        return -1;

    if(Format == VOICE_STEREO_16BIT)
        buffer_size &= ~0x0003;
    else
        buffer_size &= ~0x0001;

    u8 * write_pos = buffer;
    u8 * write_end = buffer+buffer_size;

    while(1)
    {
        while(SynthPos < Synth.pcm.length)
        {
            if(write_pos >= write_end)
                return write_pos-buffer;

            *((s16 *) write_pos) = FixedToShort(Synth.pcm.samples[0][SynthPos]);
            write_pos += 2;

            if(MAD_NCHANNELS(&Frame.header) == 2)
            {
                *((s16 *) write_pos) = FixedToShort(Synth.pcm.samples[1][SynthPos]);
                write_pos += 2;
            }
            SynthPos++;
        }

        if(Stream.buffer == NULL || Stream.error == MAD_ERROR_BUFLEN)
        {
			u8 * ReadStart = ReadBuffer;
			int ReadSize = SoundBlockSize*SoundBlocks;
			int Remaining = 0;

			if(Stream.next_frame != NULL)
			{
				Remaining = Stream.bufend - Stream.next_frame;
				memmove(ReadBuffer, Stream.next_frame, Remaining);
				ReadStart += Remaining;
				ReadSize -= Remaining;
			}

			ReadSize = file_fd->read(ReadStart, ReadSize);
            if(ReadSize <= 0)
            {
				GuardPtr = ReadStart;
				memset(GuardPtr, 0, MAD_BUFFER_GUARD);
				ReadSize = MAD_BUFFER_GUARD;
            }

            CurPos += ReadSize;
			mad_stream_buffer(&Stream, ReadBuffer, Remaining+ReadSize);
		}

		if(mad_frame_decode(&Frame,&Stream))
		{
			if(MAD_RECOVERABLE(Stream.error))
			{
			  if(Stream.error != MAD_ERROR_LOSTSYNC || !GuardPtr)
                continue;
			}
			else
			{
				if(Stream.error != MAD_ERROR_BUFLEN)
                    return -1;
                else if(Stream.error == MAD_ERROR_BUFLEN && GuardPtr)
                    return -1;
			}
		}

        mad_timer_add(&Timer,Frame.header.duration);
        mad_synth_frame(&Synth,&Frame);
        SynthPos = 0;
    }
}