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Initial import of libwavpack

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@6056 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Christian Gmeiner 2005-02-25 17:05:30 +00:00
parent 234489a449
commit e449d88b3e
12 changed files with 2190 additions and 0 deletions
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83
apps/codecs/libwavpack/float.c Normal file
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////////////////////////////////////////////////////////////////////////////
// **** WAVPACK **** //
// Hybrid Lossless Wavefile Compressor //
// Copyright (c) 1998 - 2004 Conifer Software. //
// All Rights Reserved. //
// Distributed under the BSD Software License (see license.txt) //
////////////////////////////////////////////////////////////////////////////
// float.c
#include "wavpack.h"
int read_float_info (WavpackStream *wps, WavpackMetadata *wpmd)
{
int bytecnt = wpmd->byte_length;
char *byteptr = wpmd->data;
if (bytecnt != 4)
return FALSE;
wps->float_flags = *byteptr++;
wps->float_shift = *byteptr++;
wps->float_max_exp = *byteptr++;
wps->float_norm_exp = *byteptr;
return TRUE;
}
void float_values (WavpackStream *wps, long *values, long num_values)
{
while (num_values--) {
int shift_count = 0, exp = wps->float_max_exp;
f32 outval = { 0, 0, 0 };
if (*values) {
*values <<= wps->float_shift;
if (*values < 0) {
*values = -*values;
outval.sign = 1;
}
if (*values == 0x1000000)
outval.exponent = 255;
else {
if (exp)
while (!(*values & 0x800000) && --exp) {
shift_count++;
*values <<= 1;
}
if (shift_count && (wps->float_flags & FLOAT_SHIFT_ONES))
*values |= ((1 << shift_count) - 1);
outval.mantissa = *values;
outval.exponent = exp;
}
}
* (f32 *) values++ = outval;
}
}
void float_normalize (long *values, long num_values, int delta_exp)
{
f32 *fvalues = (f32 *) values, fzero = { 0, 0, 0 };
int exp;
if (!delta_exp)
return;
while (num_values--) {
if ((exp = fvalues->exponent) == 0 || exp + delta_exp <= 0)
*fvalues = fzero;
else if (exp == 255 || (exp += delta_exp) >= 255) {
fvalues->exponent = 255;
fvalues->mantissa = 0;
}
else
fvalues->exponent = exp;
fvalues++;
}
}