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raze-gles/source/common/filesystem/ancientzip.cpp

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/*
** ancientzip.cpp
**
**---------------------------------------------------------------------------
** Copyright 2010-2011 Randy Heit
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in the
** documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
** derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
** Based in information from
**
gunzip.c by Pasi Ojala, a1bert@iki.fi
http://www.iki.fi/a1bert/
A hopefully easier to understand guide to GZip
(deflate) decompression routine than the GZip
source code.
*/
/*----------------------------------------------------------------------*/
#include <stdlib.h>
#include "ancientzip.h"
/****************************************************************
Bit-I/O variables and routines/macros
These routines work in the bit level because the target
environment does not have a barrel shifter. Trying to
handle several bits at once would've only made the code
slower.
If the environment supports multi-bit shifts, you should
write these routines again (see e.g. the GZIP sources).
[RH] Since the target environment is not a C64, I did as
suggested and rewrote these using zlib as a reference.
****************************************************************/
#define READBYTE(c) \
do { \
c = 0; \
if (InLeft) { \
InLeft--; \
if (bs < be) \
c = ReadBuf[bs++]; \
else { \
be = (decltype(be))In->Read(&ReadBuf, sizeof(ReadBuf)); \
c = ReadBuf[0]; \
bs = 1; \
} \
} \
} while (0)
/* Get a byte of input into the bit accumulator. */
#define PULLBYTE() \
do { \
unsigned char next; \
READBYTE(next); \
Hold += (unsigned int)(next) << Bits; \
Bits += 8; \
} while (0)
/* Assure that there are at least n bits in the bit accumulator. */
#define NEEDBITS(n) \
do { \
while (Bits < (unsigned)(n)) \
PULLBYTE(); \
} while (0)
/* Return the low n bits of the bit accumulator (n < 16) */
#define BITS(n) \
((unsigned)Hold & ((1U << (n)) - 1))
/* Remove n bits from the bit accumulator */
#define DROPBITS(n) \
do { \
Hold >>= (n); \
Bits -= (unsigned)(n); \
} while (0)
#define READBITS(c, a) \
do { \
NEEDBITS(a); \
c = BITS(a); \
DROPBITS(a); \
} while (0)
/****************************************************************
Shannon-Fano tree routines
****************************************************************/
static const unsigned char BitReverse4[] = {
0x00, 0x08, 0x04, 0x0c, 0x02, 0x0a, 0x06, 0x0e,
0x01, 0x09, 0x05, 0x0d, 0x03, 0x0b, 0x07, 0x0f
};
#define FIRST_BIT_LEN 8
#define REST_BIT_LEN 4
void FZipExploder::InsertCode(TArray<HuffNode> &decoder, unsigned int pos, int bits, unsigned short code, int len, unsigned char value)
{
assert(len > 0);
unsigned int node = pos + (code & ((1 << bits) - 1));
if (len > bits)
{ // This code uses more bits than this level has room for. Store the bottom bits
// in this table, then proceed to the next one.
unsigned int child = decoder[node].ChildTable;
if (child == 0)
{ // Need to create child table.
child = InitTable(decoder, 1 << REST_BIT_LEN);
decoder[node].ChildTable = child;
decoder[node].Length = bits;
decoder[node].Value = 0;
}
else
{
assert(decoder[node].Length == bits);
assert(decoder[node].Value == 0);
}
InsertCode(decoder, child, REST_BIT_LEN, code >> bits, len - bits, value);
}
else
{ // If this code uses fewer bits than this level of the table, it is
// inserted repeatedly for each value that matches it at its lower
// bits.
for (int i = 1 << (bits - len); --i >= 0; node += 1 << len)
{
decoder[node].Length = len;
decoder[node].Value = value;
assert(decoder[node].ChildTable == 0);
}
}
}
unsigned int FZipExploder::InitTable(TArray<HuffNode> &decoder, int numspots)
{
unsigned int start = decoder.Size();
decoder.Reserve(numspots);
memset(&decoder[start], 0, sizeof(HuffNode)*numspots);
return start;
}
int FZipExploder::buildercmp(const void *a, const void *b)
{
const TableBuilder *v1 = (const TableBuilder *)a;
const TableBuilder *v2 = (const TableBuilder *)b;
int d = v1->Length - v2->Length;
if (d == 0) {
d = v1->Value - v2->Value;
}
return d;
}
int FZipExploder::BuildDecoder(TArray<HuffNode> &decoder, TableBuilder *values, int numvals)
{
int i;
qsort(values, numvals, sizeof(*values), buildercmp);
// Generate the Shannon-Fano tree:
unsigned short code = 0;
unsigned short code_increment = 0;
unsigned short last_bit_length = 0;
for (i = numvals - 1; i >= 0; --i)
{
code += code_increment;
if (values[i].Length != last_bit_length)
{
last_bit_length = values[i].Length;
code_increment = 1 << (16 - last_bit_length);
}
// Reverse the order of the bits in the code before storing it.
values[i].Code = BitReverse4[code >> 12] |
(BitReverse4[(code >> 8) & 0xf] << 4) |
(BitReverse4[(code >> 4) & 0xf] << 8) |
(BitReverse4[code & 0xf] << 12);
}
// Insert each code into the hierarchical table. The top level is FIRST_BIT_LEN bits,
// and the other levels are REST_BIT_LEN bits. If a code does not completely fill
// a level, every permutation for the remaining bits is filled in to
// match this one.
InitTable(decoder, 1 << FIRST_BIT_LEN); // Set up the top level.
for (i = 0; i < numvals; ++i)
{
InsertCode(decoder, 0, FIRST_BIT_LEN, values[i].Code, values[i].Length, values[i].Value);
}
return 0;
}
int FZipExploder::DecodeSFValue(const TArray<HuffNode> &decoder)
{
unsigned int bits = FIRST_BIT_LEN, table = 0, code;
const HuffNode *pos;
do
{
NEEDBITS(bits);
code = BITS(bits);
bits = REST_BIT_LEN;
pos = &decoder[table + code];
DROPBITS(pos->Length);
table = pos->ChildTable;
}
while (table != 0);
return pos->Value;
}
int FZipExploder::DecodeSF(TArray<HuffNode> &decoder, int numvals)
{
TableBuilder builder[256];
unsigned char a, c;
int i, n, v = 0;
READBYTE(c);
n = c + 1;
for (i = 0; i < n; i++) {
int nv, bl;
READBYTE(a);
nv = ((a >> 4) & 15) + 1;
bl = (a & 15) + 1;
while (nv--) {
builder[v].Length = bl;
builder[v].Value = v;
v++;
}
}
if (v != numvals)
return 1; /* bad table */
return BuildDecoder(decoder, builder, v);
}
int FZipExploder::Explode(unsigned char *out, unsigned int outsize,
FileReader &in, unsigned int insize,
int flags)
{
int c, i, minMatchLen = 3, len, dist;
int lowDistanceBits;
unsigned int bIdx = 0;
Hold = 0;
Bits = 0;
In = &in;
InLeft = insize;
bs = be = 0;
if ((flags & 4)) {
/* 3 trees: literals, lengths, distance top 6 */
minMatchLen = 3;
if (DecodeSF(LiteralDecoder, 256))
return 1;
} else {
/* 2 trees: lengths, distance top 6 */
minMatchLen = 2;
}
if (DecodeSF(LengthDecoder, 64))
return 1;
if (DecodeSF(DistanceDecoder, 64))
return 1;
lowDistanceBits = (flags & 2) ? /* 8k dictionary */ 7 : /* 4k dictionary */ 6;
while (bIdx < outsize)
{
READBITS(c, 1);
if (c) {
/* literal data */
if ((flags & 4)) {
c = DecodeSFValue(LiteralDecoder);
} else {
READBITS(c, 8);
}
out[bIdx++] = c;
} else {
READBITS(dist, lowDistanceBits);
c = DecodeSFValue(DistanceDecoder);
dist |= (c << lowDistanceBits);
len = DecodeSFValue(LengthDecoder);
if (len == 63) {
READBITS(c, 8);
len += c;
}
len += minMatchLen;
dist++;
if (bIdx + len > outsize) {
throw CExplosionError("Not enough output space");
}
if ((unsigned int)dist > bIdx) {
/* Anything before the first input byte is zero. */
int zeros = dist - bIdx;
if (len < zeros)
zeros = len;
for(i = zeros; i; i--)
out[bIdx++] = 0;
len -= zeros;
}
for(i = len; i; i--, bIdx++) {
out[bIdx] = out[bIdx - dist];
}
}
}
return 0;
}
/* HSIZE is defined as 2^13 (8192) in unzip.h */
#define HSIZE 8192
#define BOGUSCODE 256
#define CODE_MASK (HSIZE - 1) /* 0x1fff (lower bits are parent's index) */
#define FREE_CODE HSIZE /* 0x2000 (code is unused or was cleared) */
#define HAS_CHILD (HSIZE << 1) /* 0x4000 (code has a child--do not clear) */
int ShrinkLoop(unsigned char *out, unsigned int outsize, FileReader &_In, unsigned int InLeft)
{
FileReader *In = &_In;
unsigned char ReadBuf[256];
unsigned short Parent[HSIZE];
unsigned char Value[HSIZE], Stack[HSIZE];
unsigned char *newstr;
int len;
int KwKwK, codesize = 9; /* start at 9 bits/code */
int code, oldcode, freecode, curcode;
unsigned int Bits = 0, Hold = 0;
unsigned int size = 0;
unsigned int bs = 0, be = 0;
freecode = BOGUSCODE;
for (code = 0; code < BOGUSCODE; code++)
{
Value[code] = code;
Parent[code] = BOGUSCODE;
}
for (code = BOGUSCODE+1; code < HSIZE; code++)
Parent[code] = FREE_CODE;
READBITS(oldcode, codesize);
if (size < outsize) {
out[size++] = oldcode;
}
while (size < outsize)
{
READBITS(code, codesize);
if (code == BOGUSCODE) { /* possible to have consecutive escapes? */
READBITS(code, codesize);
if (code == 1) {
codesize++;
} else if (code == 2) {
/* clear leafs (nodes with no children) */
/* first loop: mark each parent as such */
for (code = BOGUSCODE+1; code < HSIZE; ++code) {
curcode = (Parent[code] & CODE_MASK);
if (curcode > BOGUSCODE)
Parent[curcode] |= HAS_CHILD; /* set parent's child-bit */
}
/* second loop: clear all nodes *not* marked as parents; reset flag bits */
for (code = BOGUSCODE+1; code < HSIZE; ++code) {
if (Parent[code] & HAS_CHILD) { /* just clear child-bit */
Parent[code] &= ~HAS_CHILD;
} else { /* leaf: lose it */
Parent[code] = FREE_CODE;
}
}
freecode = BOGUSCODE;
}
continue;
}
newstr = &Stack[HSIZE-1];
curcode = code;
if (Parent[curcode] == FREE_CODE) {
KwKwK = 1;
newstr--; /* last character will be same as first character */
curcode = oldcode;
len = 1;
} else {
KwKwK = 0;
len = 0;
}
do {
*newstr-- = Value[curcode];
len++;
curcode = (Parent[curcode] & CODE_MASK);
} while (curcode != BOGUSCODE);
newstr++;
if (KwKwK) {
Stack[HSIZE-1] = *newstr;
}
do {
freecode++;
} while (Parent[freecode] != FREE_CODE);
Parent[freecode] = oldcode;
Value[freecode] = *newstr;
oldcode = code;
while (len--) {
out[size++] = *newstr++;
}
}
return 0;
}
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