0ad19c7262
in Rockbox standard S3.28 format git-svn-id: svn://svn.rockbox.org/rockbox/trunk@9272 a1c6a512-1295-4272-9138-f99709370657
83 lines
2.3 KiB
C
83 lines
2.3 KiB
C
////////////////////////////////////////////////////////////////////////////
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// **** WAVPACK **** //
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// Hybrid Lossless Wavefile Compressor //
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// Copyright (c) 1998 - 2004 Conifer Software. //
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// All Rights Reserved. //
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// Distributed under the BSD Software License (see license.txt) //
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////////////////////////////////////////////////////////////////////////////
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// float.c
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#include "wavpack.h"
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int read_float_info (WavpackStream *wps, WavpackMetadata *wpmd)
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{
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int bytecnt = wpmd->byte_length;
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char *byteptr = wpmd->data;
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if (bytecnt != 4)
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return FALSE;
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wps->float_flags = *byteptr++;
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wps->float_shift = *byteptr++;
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wps->float_max_exp = *byteptr++;
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wps->float_norm_exp = *byteptr;
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return TRUE;
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}
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void float_values (WavpackStream *wps, int32_t *values, int32_t num_values)
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{
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while (num_values--) {
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int shift_count = 0, exp = wps->float_max_exp;
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f32 outval = { 0, 0, 0 };
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if (*values) {
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*values <<= wps->float_shift;
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if (*values < 0) {
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*values = -*values;
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outval.sign = 1;
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}
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if (*values == 0x1000000)
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outval.exponent = 255;
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else {
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if (exp)
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while (!(*values & 0x800000) && --exp) {
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shift_count++;
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*values <<= 1;
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}
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if (shift_count && (wps->float_flags & FLOAT_SHIFT_ONES))
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*values |= ((1 << shift_count) - 1);
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outval.mantissa = *values;
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outval.exponent = exp;
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}
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}
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* (f32 *) values++ = outval;
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}
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}
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void float_normalize (int32_t *values, int32_t num_values, int delta_exp)
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{
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f32 *fvalues = (f32 *) values, fzero = { 0, 0, 0 };
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int exp;
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if (!delta_exp)
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return;
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while (num_values--) {
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if ((exp = fvalues->exponent) == 0 || exp + delta_exp <= 0)
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*fvalues = fzero;
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else if (exp == 255 || (exp += delta_exp) >= 255) {
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fvalues->exponent = 255;
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fvalues->mantissa = 0;
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}
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else
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fvalues->exponent = exp;
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fvalues++;
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}
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}
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