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/*************************************************************************
SampleDecoderLinear.cpp - decoder for all non-compressed linear formats
-------------------
begin : Sat Nov 01 2003
copyright : (C) 2003 by Thomas Eschenbacher
email : Thomas.Eschenbacher@gmx.de
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#include "config.h"
#include <QtGlobal>
#include "libkwave/Sample.h"
#include "libkwave/SampleFormat.h"
#include "libkwave/Utils.h"
#include "SampleDecoderLinear.h"
//***************************************************************************
static void decode_NULL(const quint8 *src, sample_t *dst, unsigned int count)
{
while (count--) {
qWarning("%02X ", Kwave::toUint(*src));
*(dst++) = count % (1 << (SAMPLE_BITS-1));
}
}
//***************************************************************************
// this little function is provided as inline code to avaid a compiler
// warning about negative shift value when included directly
static inline quint32 shl(const quint32 v, const int s)
{
if (!s)
return v;
else if (s > 0)
return (v << s);
else
return (v >> (-s));
}
//***************************************************************************
/**
* Template for decoding a buffer with linear samples. The tricky part is
* done in the compiler which optimizes away all unused parts of current
* variant and does nice loop optimizing!
* @param src array with raw data
* @param dst array that receives the samples in Kwave's format
* @param count the number of samples to be decoded
*/
template<const unsigned int bits, const bool is_signed,
const bool is_little_endian>
void decode_linear(const quint8 *src, sample_t *dst, unsigned int count)
{
const int shift = (SAMPLE_BITS - bits);
const quint32 sign = 1 << (SAMPLE_BITS-1);
const quint32 negative = ~(sign - 1);
const quint32 bytes = (bits+7) >> 3;
while (count) {
count--;
// read from source buffer
quint32 s = 0;
if (is_little_endian) {
// little endian
for (unsigned int byte = 0; byte < bytes; ++byte, ++src) {
s |= static_cast<quint8>(*src) << (byte << 3);
}
} else {
// big endian
for (int byte = bytes - 1; byte >= 0; --byte, ++src) {
s |= static_cast<quint8>(*src) << (byte << 3);
}
}
// convert to signed
if (!is_signed) s -= shl(1, bits-1)-1;
// shift up to Kwave's bit count
s = shl(s, shift);
// sign correcture for negative values
if (is_signed && (s & sign)) s |= negative;
// write to destination buffer
*(dst++) = static_cast<sample_t>(s);
}
}
//***************************************************************************
#define MAKE_DECODER(bits) \
if (sample_format != Kwave::SampleFormat::Unsigned) { \
if (endianness != Kwave::BigEndian) { \
m_decoder = decode_linear<bits, true, true>; \
} else { \
m_decoder = decode_linear<bits, true, false>; \
} \
} else { \
if (endianness != Kwave::BigEndian) { \
m_decoder = decode_linear<bits, false, true>; \
} else { \
m_decoder = decode_linear<bits, false, false>; \
} \
}
//***************************************************************************
Kwave::SampleDecoderLinear::SampleDecoderLinear(
Kwave::SampleFormat::Format sample_format,
unsigned int bits_per_sample,
Kwave::byte_order_t endianness
)
:Kwave::SampleDecoder(),
m_bytes_per_sample((bits_per_sample + 7) >> 3),
m_decoder(decode_NULL)
{
// sanity checks: we support only signed/unsigned and big/little endian
Q_ASSERT((sample_format == Kwave::SampleFormat::Signed) ||
(sample_format == Kwave::SampleFormat::Unsigned));
if ((sample_format != Kwave::SampleFormat::Signed) &&
(sample_format != Kwave::SampleFormat::Unsigned)) return;
// allow unknown endianness only with 8 bits
Q_ASSERT((endianness != Kwave::UnknownEndian) || (m_bytes_per_sample == 1));
if ((endianness == Kwave::UnknownEndian) &&
(m_bytes_per_sample != 1)) return;
// map cpu endianness to little or big
#if Q_BYTE_ORDER == Q_BIG_ENDIAN
if (endianness == Kwave::CpuEndian) endianness = Kwave::BigEndian;
#else
if (endianness == Kwave::CpuEndian) endianness = Kwave::LittleEndian;
#endif
switch (m_bytes_per_sample) {
case 1:
MAKE_DECODER(8)
break;
case 2:
MAKE_DECODER(16)
break;
case 3:
MAKE_DECODER(24)
break;
case 4:
MAKE_DECODER(32)
break;
DEFAULT_IMPOSSIBLE;
}
}
//***************************************************************************
Kwave::SampleDecoderLinear::~SampleDecoderLinear()
{
}
//***************************************************************************
void Kwave::SampleDecoderLinear::decode(QByteArray &raw_data,
Kwave::SampleArray &decoded)
{
Q_ASSERT(m_decoder);
if (!m_decoder) return;
unsigned int raw_size = static_cast<unsigned int>(raw_data.size());
unsigned int samples = raw_size / m_bytes_per_sample;
const quint8 *src = reinterpret_cast<const quint8 *>(raw_data.constData());
sample_t *dst = decoded.data();
m_decoder(src, dst, samples);
}
//***************************************************************************
unsigned int Kwave::SampleDecoderLinear::rawBytesPerSample()
{
return m_bytes_per_sample;
}
//***************************************************************************
//***************************************************************************
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