SampleDecoderLinear.cpp File Reference

#include "config.h"
#include <stdio.h>
#include <QtGlobal>
#include "libkwave/Sample.h"
#include "libkwave/SampleFormat.h"
#include "libkwave/Utils.h"
#include "SampleDecoderLinear.h"

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Macros
#define	MAKE_DECODER(bits)

Functions
static void	decode_NULL (const quint8 *src, sample_t *dst, unsigned int count)
static quint32	shl (const quint32 v, const int s)
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)

Macro Definition Documentation

MAKE_DECODER

#define MAKE_DECODER

(

bits

)

Value:

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>; \
    }                                                  \
}

Definition at line 102 of file SampleDecoderLinear.cpp.

Referenced by Kwave::SampleDecoderLinear::SampleDecoderLinear().

Function Documentation

decode_linear()

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
	)

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!

Parameters

src	array with raw data
dst	array that receives the samples in Kwave's format
count	the number of samples to be decoded

Definition at line 63 of file SampleDecoderLinear.cpp.

References SAMPLE_BITS, and shl().

{
    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);
    }
}

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decode_NULL()

static void decode_NULL ( const quint8 *  src, sample_t *  dst, unsigned int  count  )

static

Definition at line 31 of file SampleDecoderLinear.cpp.

References SAMPLE_BITS, and Kwave::toInt().

{
    while (count--) {
        printf("%02X ", Kwave::toInt(*src));
        *(dst++) = count % (1 << (SAMPLE_BITS-1));
    }
}

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shl()

static quint32 shl ( const quint32  v, const int  s  )

inlinestatic

Definition at line 42 of file SampleDecoderLinear.cpp.

Referenced by decode_linear().

{
    if (!s)
        return v;
    else if (s > 0)
        return (v << s);
    else
        return (v >> (-s));
}

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