////////////////////////////////////////////////////////////////////////////
// **** WAVPACK **** //
// Hybrid Lossless Wavefile Compressor //
// Copyright (c) 1998 - 2013 Conifer Software. //
// All Rights Reserved. //
// Distributed under the BSD Software License (see license.txt) //
////////////////////////////////////////////////////////////////////////////
// entropy_utils.c
// This module contains the functions that process metadata blocks that are
// specific to the entropy decoder; these would be called any time a WavPack
// block was parsed. Additionally, it contains tables and functions that are
// common to both entropy coding and decoding. These are in a module separate
// from the actual entropy encoder (write_words.c) and decoder (read_words.c)
// so that if applications that just do a subset of the full WavPack reading
// and writing can link with a subset of the library.
#include <stdlib.h>
#include <string.h>
#include "wavpack_local.h"
///////////////////////////// local table storage ////////////////////////////
const uint32_t bitset [] = {
1L << 0, 1L << 1, 1L << 2, 1L << 3,
1L << 4, 1L << 5, 1L << 6, 1L << 7,
1L << 8, 1L << 9, 1L << 10, 1L << 11,
1L << 12, 1L << 13, 1L << 14, 1L << 15,
1L << 16, 1L << 17, 1L << 18, 1L << 19,
1L << 20, 1L << 21, 1L << 22, 1L << 23,
1L << 24, 1L << 25, 1L << 26, 1L << 27,
1L << 28, 1L << 29, 1L << 30, 1L << 31
};
const uint32_t bitmask [] = {
(1L << 0) - 1, (1L << 1) - 1, (1L << 2) - 1, (1L << 3) - 1,
(1L << 4) - 1, (1L << 5) - 1, (1L << 6) - 1, (1L << 7) - 1,
(1L << 8) - 1, (1L << 9) - 1, (1L << 10) - 1, (1L << 11) - 1,
(1L << 12) - 1, (1L << 13) - 1, (1L << 14) - 1, (1L << 15) - 1,
(1L << 16) - 1, (1L << 17) - 1, (1L << 18) - 1, (1L << 19) - 1,
(1L << 20) - 1, (1L << 21) - 1, (1L << 22) - 1, (1L << 23) - 1,
(1L << 24) - 1, (1L << 25) - 1, (1L << 26) - 1, (1L << 27) - 1,
(1L << 28) - 1, (1L << 29) - 1, (1L << 30) - 1, 0x7fffffff
};
const char nbits_table [] = {
0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, // 0 - 15
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, // 16 - 31
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, // 32 - 47
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, // 48 - 63
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 64 - 79
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 80 - 95
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 96 - 111
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 112 - 127
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 128 - 143
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 144 - 159
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 160 - 175
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 176 - 191
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 192 - 207
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 208 - 223
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 224 - 239
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 // 240 - 255
};
static const unsigned char log2_table [] = {
0x00, 0x01, 0x03, 0x04, 0x06, 0x07, 0x09, 0x0a, 0x0b, 0x0d, 0x0e, 0x10, 0x11, 0x12, 0x14, 0x15,
0x16, 0x18, 0x19, 0x1a, 0x1c, 0x1d, 0x1e, 0x20, 0x21, 0x22, 0x24, 0x25, 0x26, 0x28, 0x29, 0x2a,
0x2c, 0x2d, 0x2e, 0x2f, 0x31, 0x32, 0x33, 0x34, 0x36, 0x37, 0x38, 0x39, 0x3b, 0x3c, 0x3d, 0x3e,
0x3f, 0x41, 0x42, 0x43, 0x44, 0x45, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4d, 0x4e, 0x4f, 0x50, 0x51,
0x52, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5c, 0x5d, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63,
0x64, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x74, 0x75,
0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85,
0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95,
0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4,
0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb0, 0xb1, 0xb2, 0xb2,
0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, 0xc0,
0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcb, 0xcc, 0xcd, 0xce,
0xcf, 0xd0, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd8, 0xd9, 0xda, 0xdb,
0xdc, 0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe4, 0xe5, 0xe6, 0xe7, 0xe7,
0xe8, 0xe9, 0xea, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xee, 0xef, 0xf0, 0xf1, 0xf1, 0xf2, 0xf3, 0xf4,
0xf4, 0xf5, 0xf6, 0xf7, 0xf7, 0xf8, 0xf9, 0xf9, 0xfa, 0xfb, 0xfc, 0xfc, 0xfd, 0xfe, 0xff, 0xff
};
static const unsigned char exp2_table [] = {
0x00, 0x01, 0x01, 0x02, 0x03, 0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x08, 0x09, 0x0a, 0x0b,
0x0b, 0x0c, 0x0d, 0x0e, 0x0e, 0x0f, 0x10, 0x10, 0x11, 0x12, 0x13, 0x13, 0x14, 0x15, 0x16, 0x16,
0x17, 0x18, 0x19, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1d, 0x1e, 0x1f, 0x20, 0x20, 0x21, 0x22, 0x23,
0x24, 0x24, 0x25, 0x26, 0x27, 0x28, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3a, 0x3b, 0x3c, 0x3d,
0x3e, 0x3f, 0x40, 0x41, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x48, 0x49, 0x4a, 0x4b,
0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a,
0x5b, 0x5c, 0x5d, 0x5e, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x87, 0x88, 0x89, 0x8a,
0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b,
0x9c, 0x9d, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad,
0xaf, 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0,
0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc8, 0xc9, 0xca, 0xcb, 0xcd, 0xce, 0xcf, 0xd0, 0xd2, 0xd3, 0xd4,
0xd6, 0xd7, 0xd8, 0xd9, 0xdb, 0xdc, 0xdd, 0xde, 0xe0, 0xe1, 0xe2, 0xe4, 0xe5, 0xe6, 0xe8, 0xe9,
0xea, 0xec, 0xed, 0xee, 0xf0, 0xf1, 0xf2, 0xf4, 0xf5, 0xf6, 0xf8, 0xf9, 0xfa, 0xfc, 0xfd, 0xff
};
///////////////////////////// executable code ////////////////////////////////
// Read the median log2 values from the specified metadata structure, convert
// them back to 32-bit unsigned values and store them. If length is not
// exactly correct then we flag and return an error.
int read_entropy_vars (WavpackStream *wps, WavpackMetadata *wpmd)
{
unsigned char *byteptr = (unsigned char *)wpmd->data;
if (wpmd->byte_length != ((wps->wphdr.flags & MONO_DATA) ? 6 : 12))
return FALSE;
wps->w.c [0].median [0] = wp_exp2s (byteptr [0] + (byteptr [1] << 8));
wps->w.c [0].median [1] = wp_exp2s (byteptr [2] + (byteptr [3] << 8));
wps->w.c [0].median [2] = wp_exp2s (byteptr [4] + (byteptr [5] << 8));
if (!(wps->wphdr.flags & MONO_DATA)) {
wps->w.c [1].median [0] = wp_exp2s (byteptr [6] + (byteptr [7] << 8));
wps->w.c [1].median [1] = wp_exp2s (byteptr [8] + (byteptr [9] << 8));
wps->w.c [1].median [2] = wp_exp2s (byteptr [10] + (byteptr [11] << 8));
}
return TRUE;
}
// Read the hybrid related values from the specified metadata structure, convert
// them back to their internal formats and store them. The extended profile
// stuff is not implemented yet, so return an error if we get more data than
// we know what to do with.
int read_hybrid_profile (WavpackStream *wps, WavpackMetadata *wpmd)
{
unsigned char *byteptr = (unsigned char *)wpmd->data;
unsigned char *endptr = byteptr + wpmd->byte_length;
if (wps->wphdr.flags & HYBRID_BITRATE) {
if (byteptr + (wps->wphdr.flags & MONO_DATA ? 2 : 4) > endptr)
return FALSE;
wps->w.c [0].slow_level = wp_exp2s (byteptr [0] + (byteptr [1] << 8));
byteptr += 2;
if (!(wps->wphdr.flags & MONO_DATA)) {
wps->w.c [1].slow_level = wp_exp2s (byteptr [0] + (byteptr [1] << 8));
byteptr += 2;
}
}
if (byteptr + (wps->wphdr.flags & MONO_DATA ? 2 : 4) > endptr)
return FALSE;
wps->w.bitrate_acc [0] = (int32_t)(byteptr [0] + (byteptr [1] << 8)) << 16;
byteptr += 2;
if (!(wps->wphdr.flags & MONO_DATA)) {
wps->w.bitrate_acc [1] = (int32_t)(byteptr [0] + (byteptr [1] << 8)) << 16;
byteptr += 2;
}
if (byteptr < endptr) {
if (byteptr + (wps->wphdr.flags & MONO_DATA ? 2 : 4) > endptr)
return FALSE;
wps->w.bitrate_delta [0] = wp_exp2s ((int16_t)(byteptr [0] + (byteptr [1] << 8)));
byteptr += 2;
if (!(wps->wphdr.flags & MONO_DATA)) {
wps->w.bitrate_delta [1] = wp_exp2s ((int16_t)(byteptr [0] + (byteptr [1] << 8)));
byteptr += 2;
}
if (byteptr < endptr)
return FALSE;
}
else
wps->w.bitrate_delta [0] = wps->w.bitrate_delta [1] = 0;
return TRUE;
}
// This function is called during both encoding and decoding of hybrid data to
// update the "error_limit" variable which determines the maximum sample error
// allowed in the main bitstream. In the HYBRID_BITRATE mode (which is the only
// currently implemented) this is calculated from the slow_level values and the
// bitrate accumulators. Note that the bitrate accumulators can be changing.
void update_error_limit (WavpackStream *wps)
{
int bitrate_0 = (wps->w.bitrate_acc [0] += wps->w.bitrate_delta [0]) >> 16;
if (wps->wphdr.flags & MONO_DATA) {
if (wps->wphdr.flags & HYBRID_BITRATE) {
int slow_log_0 = (wps->w.c [0].slow_level + SLO) >> SLS;
if (slow_log_0 - bitrate_0 > -0x100)
wps->w.c [0].error_limit = wp_exp2s (slow_log_0 - bitrate_0 + 0x100);
else
wps->w.c [0].error_limit = 0;
}
else
wps->w.c [0].error_limit = wp_exp2s (bitrate_0);
}
else {
int bitrate_1 = (wps->w.bitrate_acc [1] += wps->w.bitrate_delta [1]) >> 16;
if (wps->wphdr.flags & HYBRID_BITRATE) {
int slow_log_0 = (wps->w.c [0].slow_level + SLO) >> SLS;
int slow_log_1 = (wps->w.c [1].slow_level + SLO) >> SLS;
if (wps->wphdr.flags & HYBRID_BALANCE) {
int balance = (slow_log_1 - slow_log_0 + bitrate_1 + 1) >> 1;
if (balance > bitrate_0) {
bitrate_1 = bitrate_0 * 2;
bitrate_0 = 0;
}
else if (-balance > bitrate_0) {
bitrate_0 = bitrate_0 * 2;
bitrate_1 = 0;
}
else {
bitrate_1 = bitrate_0 + balance;
bitrate_0 = bitrate_0 - balance;
}
}
if (slow_log_0 - bitrate_0 > -0x100)
wps->w.c [0].error_limit = wp_exp2s (slow_log_0 - bitrate_0 + 0x100);
else
wps->w.c [0].error_limit = 0;
if (slow_log_1 - bitrate_1 > -0x100)
wps->w.c [1].error_limit = wp_exp2s (slow_log_1 - bitrate_1 + 0x100);
else
wps->w.c [1].error_limit = 0;
}
else {
wps->w.c [0].error_limit = wp_exp2s (bitrate_0);
wps->w.c [1].error_limit = wp_exp2s (bitrate_1);
}
}
}
// The concept of a base 2 logarithm is used in many parts of WavPack. It is
// a way of sufficiently accurately representing 32-bit signed and unsigned
// values storing only 16 bits (actually fewer). It is also used in the hybrid
// mode for quickly comparing the relative magnitude of large values (i.e.
// division) and providing smooth exponentials using only addition.
// These are not strict logarithms in that they become linear around zero and
// can therefore represent both zero and negative values. They have 8 bits
// of precision and in "roundtrip" conversions the total error never exceeds 1
// part in 225 except for the cases of +/-115 and +/-195 (which error by 1).
// This function returns the log2 for the specified 32-bit unsigned value.
// The maximum value allowed is about 0xff800000 and returns 8447.
int FASTCALL wp_log2 (uint32_t avalue)
{
int dbits;
if ((avalue += avalue >> 9) < (1 << 8)) {
dbits = nbits_table [avalue];
return (dbits << 8) + log2_table [(avalue << (9 - dbits)) & 0xff];
}
else {
if (avalue < (1L << 16))
dbits = nbits_table [avalue >> 8] + 8;
else if (avalue < (1L << 24))
dbits = nbits_table [avalue >> 16] + 16;
else
dbits = nbits_table [avalue >> 24] + 24;
return (dbits << 8) + log2_table [(avalue >> (dbits - 9)) & 0xff];
}
}
// This function scans a buffer of longs and accumulates the total log2 value
// of all the samples. This is useful for determining maximum compression
// because the bitstream storage required for entropy coding is proportional
// to the base 2 log of the samples. On some platforms there is an assembly
// version of this.
#if !defined(OPT_ASM_X86) && !defined(OPT_ASM_X64)
uint32_t log2buffer (int32_t *samples, uint32_t num_samples, int limit)
{
uint32_t result = 0, avalue;
int dbits;
while (num_samples--) {
avalue = abs (*samples++);
if ((avalue += avalue >> 9) < (1 << 8)) {
dbits = nbits_table [avalue];
result += (dbits << 8) + log2_table [(avalue << (9 - dbits)) & 0xff];
}
else {
if (avalue < (1L << 16))
dbits = nbits_table [avalue >> 8] + 8;
else if (avalue < (1L << 24))
dbits = nbits_table [avalue >> 16] + 16;
else
dbits = nbits_table [avalue >> 24] + 24;
result += dbits = (dbits << 8) + log2_table [(avalue >> (dbits - 9)) & 0xff];
if (limit && dbits >= limit)
return (uint32_t) -1;
}
}
return result;
}
#endif
// This function returns the log2 for the specified 32-bit signed value.
// All input values are valid and the return values are in the range of
// +/- 8192.
int wp_log2s (int32_t value)
{
return (value < 0) ? -wp_log2 (-value) : wp_log2 (value);
}
// This function returns the original integer represented by the supplied
// logarithm (at least within the provided accuracy). The log is signed,
// but since a full 32-bit value is returned this can be used for unsigned
// conversions as well (i.e. the input range is -8192 to +8447).
int32_t wp_exp2s (int log)
{
uint32_t value;
if (log < 0)
return -wp_exp2s (-log);
value = exp2_table [log & 0xff] | 0x100;
if ((log >>= 8) <= 9)
return value >> (9 - log);
else
return value << (log - 9);
}
// These two functions convert internal weights (which are normally +/-1024)
// to and from an 8-bit signed character version for storage in metadata. The
// weights are clipped here in the case that they are outside that range.
signed char store_weight (int weight)
{
if (weight > 1024)
weight = 1024;
else if (weight < -1024)
weight = -1024;
if (weight > 0)
weight -= (weight + 64) >> 7;
return (weight + 4) >> 3;
}
int restore_weight (signed char weight)
{
int result;
if ((result = (int) weight << 3) > 0)
result += (result + 64) >> 7;
return result;
}