mirror of
https://github.com/sheumann/hush.git
synced 2024-08-15 02:29:00 +00:00
230 lines
5.6 KiB
C
230 lines
5.6 KiB
C
/*
|
|
* bzip2 is written by Julian Seward <jseward@bzip.org>.
|
|
* Adapted for busybox by Denys Vlasenko <vda.linux@googlemail.com>.
|
|
* See README and LICENSE files in this directory for more information.
|
|
*/
|
|
|
|
/*-------------------------------------------------------------*/
|
|
/*--- Huffman coding low-level stuff ---*/
|
|
/*--- huffman.c ---*/
|
|
/*-------------------------------------------------------------*/
|
|
|
|
/* ------------------------------------------------------------------
|
|
This file is part of bzip2/libbzip2, a program and library for
|
|
lossless, block-sorting data compression.
|
|
|
|
bzip2/libbzip2 version 1.0.4 of 20 December 2006
|
|
Copyright (C) 1996-2006 Julian Seward <jseward@bzip.org>
|
|
|
|
Please read the WARNING, DISCLAIMER and PATENTS sections in the
|
|
README file.
|
|
|
|
This program is released under the terms of the license contained
|
|
in the file LICENSE.
|
|
------------------------------------------------------------------ */
|
|
|
|
/* #include "bzlib_private.h" */
|
|
|
|
/*---------------------------------------------------*/
|
|
#define WEIGHTOF(zz0) ((zz0) & 0xffffff00)
|
|
#define DEPTHOF(zz1) ((zz1) & 0x000000ff)
|
|
#define MYMAX(zz2,zz3) ((zz2) > (zz3) ? (zz2) : (zz3))
|
|
|
|
#define ADDWEIGHTS(zw1,zw2) \
|
|
(WEIGHTOF(zw1)+WEIGHTOF(zw2)) | \
|
|
(1 + MYMAX(DEPTHOF(zw1),DEPTHOF(zw2)))
|
|
|
|
#define UPHEAP(z) \
|
|
{ \
|
|
int32_t zz, tmp; \
|
|
zz = z; \
|
|
tmp = heap[zz]; \
|
|
while (weight[tmp] < weight[heap[zz >> 1]]) { \
|
|
heap[zz] = heap[zz >> 1]; \
|
|
zz >>= 1; \
|
|
} \
|
|
heap[zz] = tmp; \
|
|
}
|
|
|
|
|
|
/* 90 bytes, 0.3% of overall compress speed */
|
|
#if CONFIG_BZIP2_FAST >= 1
|
|
|
|
/* macro works better than inline (gcc 4.2.1) */
|
|
#define DOWNHEAP1(heap, weight, Heap) \
|
|
{ \
|
|
int32_t zz, yy, tmp; \
|
|
zz = 1; \
|
|
tmp = heap[zz]; \
|
|
while (1) { \
|
|
yy = zz << 1; \
|
|
if (yy > nHeap) \
|
|
break; \
|
|
if (yy < nHeap \
|
|
&& weight[heap[yy+1]] < weight[heap[yy]]) \
|
|
yy++; \
|
|
if (weight[tmp] < weight[heap[yy]]) \
|
|
break; \
|
|
heap[zz] = heap[yy]; \
|
|
zz = yy; \
|
|
} \
|
|
heap[zz] = tmp; \
|
|
}
|
|
|
|
#else
|
|
|
|
static
|
|
void DOWNHEAP1(int32_t *heap, int32_t *weight, int32_t nHeap)
|
|
{
|
|
int32_t zz, yy, tmp;
|
|
zz = 1;
|
|
tmp = heap[zz];
|
|
while (1) {
|
|
yy = zz << 1;
|
|
if (yy > nHeap)
|
|
break;
|
|
if (yy < nHeap
|
|
&& weight[heap[yy + 1]] < weight[heap[yy]])
|
|
yy++;
|
|
if (weight[tmp] < weight[heap[yy]])
|
|
break;
|
|
heap[zz] = heap[yy];
|
|
zz = yy;
|
|
}
|
|
heap[zz] = tmp;
|
|
}
|
|
|
|
#endif
|
|
|
|
/*---------------------------------------------------*/
|
|
static
|
|
void BZ2_hbMakeCodeLengths(EState *s,
|
|
uint8_t *len,
|
|
int32_t *freq,
|
|
int32_t alphaSize,
|
|
int32_t maxLen)
|
|
{
|
|
/*
|
|
* Nodes and heap entries run from 1. Entry 0
|
|
* for both the heap and nodes is a sentinel.
|
|
*/
|
|
int32_t nNodes, nHeap, n1, n2, i, j, k;
|
|
Bool tooLong;
|
|
|
|
/* bbox: moved to EState to save stack
|
|
int32_t heap [BZ_MAX_ALPHA_SIZE + 2];
|
|
int32_t weight[BZ_MAX_ALPHA_SIZE * 2];
|
|
int32_t parent[BZ_MAX_ALPHA_SIZE * 2];
|
|
*/
|
|
#define heap (s->BZ2_hbMakeCodeLengths__heap)
|
|
#define weight (s->BZ2_hbMakeCodeLengths__weight)
|
|
#define parent (s->BZ2_hbMakeCodeLengths__parent)
|
|
|
|
for (i = 0; i < alphaSize; i++)
|
|
weight[i+1] = (freq[i] == 0 ? 1 : freq[i]) << 8;
|
|
|
|
while (1) {
|
|
nNodes = alphaSize;
|
|
nHeap = 0;
|
|
|
|
heap[0] = 0;
|
|
weight[0] = 0;
|
|
parent[0] = -2;
|
|
|
|
for (i = 1; i <= alphaSize; i++) {
|
|
parent[i] = -1;
|
|
nHeap++;
|
|
heap[nHeap] = i;
|
|
UPHEAP(nHeap);
|
|
}
|
|
|
|
AssertH(nHeap < (BZ_MAX_ALPHA_SIZE+2), 2001);
|
|
|
|
while (nHeap > 1) {
|
|
n1 = heap[1]; heap[1] = heap[nHeap]; nHeap--; DOWNHEAP1(heap, weight, nHeap);
|
|
n2 = heap[1]; heap[1] = heap[nHeap]; nHeap--; DOWNHEAP1(heap, weight, nHeap);
|
|
nNodes++;
|
|
parent[n1] = parent[n2] = nNodes;
|
|
weight[nNodes] = ADDWEIGHTS(weight[n1], weight[n2]);
|
|
parent[nNodes] = -1;
|
|
nHeap++;
|
|
heap[nHeap] = nNodes;
|
|
UPHEAP(nHeap);
|
|
}
|
|
|
|
AssertH(nNodes < (BZ_MAX_ALPHA_SIZE * 2), 2002);
|
|
|
|
tooLong = False;
|
|
for (i = 1; i <= alphaSize; i++) {
|
|
j = 0;
|
|
k = i;
|
|
while (parent[k] >= 0) {
|
|
k = parent[k];
|
|
j++;
|
|
}
|
|
len[i-1] = j;
|
|
if (j > maxLen)
|
|
tooLong = True;
|
|
}
|
|
|
|
if (!tooLong)
|
|
break;
|
|
|
|
/* 17 Oct 04: keep-going condition for the following loop used
|
|
to be 'i < alphaSize', which missed the last element,
|
|
theoretically leading to the possibility of the compressor
|
|
looping. However, this count-scaling step is only needed if
|
|
one of the generated Huffman code words is longer than
|
|
maxLen, which up to and including version 1.0.2 was 20 bits,
|
|
which is extremely unlikely. In version 1.0.3 maxLen was
|
|
changed to 17 bits, which has minimal effect on compression
|
|
ratio, but does mean this scaling step is used from time to
|
|
time, enough to verify that it works.
|
|
|
|
This means that bzip2-1.0.3 and later will only produce
|
|
Huffman codes with a maximum length of 17 bits. However, in
|
|
order to preserve backwards compatibility with bitstreams
|
|
produced by versions pre-1.0.3, the decompressor must still
|
|
handle lengths of up to 20. */
|
|
|
|
for (i = 1; i <= alphaSize; i++) {
|
|
j = weight[i] >> 8;
|
|
/* bbox: yes, it is a signed division.
|
|
* don't replace with shift! */
|
|
j = 1 + (j / 2);
|
|
weight[i] = j << 8;
|
|
}
|
|
}
|
|
#undef heap
|
|
#undef weight
|
|
#undef parent
|
|
}
|
|
|
|
|
|
/*---------------------------------------------------*/
|
|
static
|
|
void BZ2_hbAssignCodes(int32_t *code,
|
|
uint8_t *length,
|
|
int32_t minLen,
|
|
int32_t maxLen,
|
|
int32_t alphaSize)
|
|
{
|
|
int32_t n, vec, i;
|
|
|
|
vec = 0;
|
|
for (n = minLen; n <= maxLen; n++) {
|
|
for (i = 0; i < alphaSize; i++) {
|
|
if (length[i] == n) {
|
|
code[i] = vec;
|
|
vec++;
|
|
};
|
|
}
|
|
vec <<= 1;
|
|
}
|
|
}
|
|
|
|
|
|
/*-------------------------------------------------------------*/
|
|
/*--- end huffman.c ---*/
|
|
/*-------------------------------------------------------------*/
|