mirror of
https://github.com/bearstonem/openmohaa-vr.git
synced 2026-10-18 19:00:21 +02:00
440 lines
11 KiB
C++
440 lines
11 KiB
C++
/*
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===========================================================================
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Copyright (C) 2025 the OpenMoHAA team
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This file is part of OpenMoHAA source code.
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OpenMoHAA source code is free software; you can redistribute it
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and/or modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the License,
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or (at your option) any later version.
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OpenMoHAA source code is distributed in the hope that it will be
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useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with OpenMoHAA source code; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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===========================================================================
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*/
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// lz77.cpp: LZ77 Compression Algorithm
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#include "lz77.h"
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#include "../qcommon/q_shared.h"
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#include <cstdio>
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#include <cstring>
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cLZ77 g_lz77;
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unsigned int cLZ77::m_pDictionary[0xffff];
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static void copy_bytes(unsigned char *dest, unsigned char *from, size_t length)
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{
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size_t i;
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for (i = 0; i < length; i++) {
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dest[i] = from[i];
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}
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}
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cLZ77::cLZ77() {}
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unsigned int cLZ77::CompressData(unsigned char *in, size_t in_len, unsigned char *out, size_t *out_len)
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{
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this->in_end = &in[in_len];
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this->ip_end = &in[in_len - 13];
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this->op = out;
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this->ip = in;
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this->ii = this->ip;
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this->ip += 4;
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while (this->ip < this->ip_end) {
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bool match_found = false;
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while (this->ip < this->ip_end) {
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// Primary hash index
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this->dindex =
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((33 * (this->ip[0] ^ (32 * ((32 * ((this->ip[3] << 6) ^ this->ip[2])) ^ (unsigned int)this->ip[1]))))
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>> 5)
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& 0x3FFF;
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this->m_off = cLZ77::m_pDictionary[this->dindex];
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if (this->ip - in <= this->m_off) {
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cLZ77::m_pDictionary[this->dindex] = this->ip - in;
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this->ip++;
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continue;
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}
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this->m_off = this->ip - in - this->m_off;
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if (this->m_off > 0xBFFF) {
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cLZ77::m_pDictionary[this->dindex] = this->ip - in;
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this->ip++;
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continue;
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}
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this->m_pos = this->ip - this->m_off;
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if (this->m_off <= 0x800 || (this->m_pos[3] == this->ip[3])) {
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if (*this->m_pos == *this->ip && this->m_pos[1] == this->ip[1] && this->m_pos[2] == this->ip[2]) {
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match_found = true;
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break;
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}
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}
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// Fallback hash index
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this->dindex = (this->dindex & 0x7FF) ^ 0x201F;
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this->m_off = cLZ77::m_pDictionary[this->dindex];
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if (this->ip - in <= this->m_off) {
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cLZ77::m_pDictionary[this->dindex] = this->ip - in;
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this->ip++;
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continue;
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}
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this->m_off = this->ip - in - this->m_off;
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if (this->m_off > 0xBFFF) {
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cLZ77::m_pDictionary[this->dindex] = this->ip - in;
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this->ip++;
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continue;
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}
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this->m_pos = this->ip - this->m_off;
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if (this->m_off <= 0x800 || (this->m_pos[3] == this->ip[3])) {
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if (this->m_pos[0] == this->ip[0] && this->m_pos[1] == this->ip[1] && this->m_pos[2] == this->ip[2]) {
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match_found = true;
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break;
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}
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}
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cLZ77::m_pDictionary[this->dindex] = this->ip - in;
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this->ip++;
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}
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if (!match_found) {
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break;
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}
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cLZ77::m_pDictionary[this->dindex] = this->ip - in;
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unsigned int t = this->ip - this->ii;
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if (t > 0) {
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if (t <= 3) {
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*(this->op - 2) |= t;
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} else if (t <= 18) {
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*this->op++ = t - 3;
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} else {
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unsigned int tt = t - 18;
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*this->op++ = 0;
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while (tt > 255) {
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tt -= 255;
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*this->op++ = 0;
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}
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*this->op++ = tt;
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}
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copy_bytes(op, ii, t);
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ii += t;
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op += t;
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}
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this->ip += 3;
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for (t = 0; ip < in_end; t++, this->ip++) {
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if (this->m_pos[t + 3] != *this->ip) {
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break;
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}
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}
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this->m_len = this->ip - this->ii;
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if (this->m_off > 0x4000) {
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this->m_off -= 0x4000;
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if (this->m_len > 9) {
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this->m_len -= 9;
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*this->op++ = ((this->m_off & 0x4000) >> 11) | 0x10;
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while (this->m_len > 0xFF) {
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this->m_len -= 255;
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*this->op++ = 0;
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}
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*this->op++ = this->m_len;
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} else {
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*this->op++ = ((this->m_off & 0x4000) >> 11) | ((this->m_len & 0xFF) - 2) | 0x10;
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}
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} else {
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--this->m_off;
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if (this->m_len > 33) {
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this->m_len -= 33;
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*this->op++ = 32;
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while (this->m_len > 255) {
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this->m_len -= 255;
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*this->op++ = 0;
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}
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*this->op++ = this->m_len;
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} else {
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*this->op++ = ((this->m_len & 0xFF) - 2) | 0x20;
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}
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}
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*this->op++ = 4 * (this->m_off & 63);
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*this->op++ = this->m_off >> 6;
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this->ii = this->ip;
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}
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*out_len = this->op - out;
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return this->in_end - this->ii;
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}
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int cLZ77::Compress(unsigned char *in, size_t in_len, unsigned char *out, size_t *out_len)
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{
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byte *op = out;
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size_t t = 0;
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if (in_len == 0) {
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*out_len = 0;
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return 0;
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}
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if (in_len > 13) {
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t = CompressData(in, in_len, out, out_len);
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op = out + *out_len;
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} else {
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t = in_len;
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}
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if (t) {
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if (op == out && t <= 238) {
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*op++ = t + 17;
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} else if (t <= 3) {
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*(op - 2) |= t;
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} else if (t <= 18) {
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*op++ = t - 3;
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} else {
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unsigned int tt;
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*op++ = 0;
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tt = t - 18;
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while (tt > 255) {
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tt -= 255;
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*op++ = 0;
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}
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*op++ = tt;
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}
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copy_bytes(op, &in[in_len - t], t);
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op += t;
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}
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*op++ = 17;
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*op++ = 0;
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*op++ = 0;
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*out_len = op - out;
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return 0;
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}
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static unsigned int decode_length(unsigned int base, unsigned char *& ip)
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{
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unsigned int len = base;
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while (!*ip) {
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len += 255;
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++ip;
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}
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return len + *ip++;
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}
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int cLZ77::Decompress(unsigned char *in, size_t in_len, unsigned char *out, size_t *out_len)
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{
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unsigned int t;
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unsigned short s;
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ip_end = &in[in_len];
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ip = in;
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op = out;
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*out_len = 0;
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if (*ip > 17u) {
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t = *ip++ - 17;
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if (t <= 3) {
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copy_bytes(op, ip, t);
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op += t;
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ip += t;
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t = *ip++;
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} else {
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copy_bytes(op, ip, t);
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op += t;
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ip += t;
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t = *ip++;
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}
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} else {
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t = *ip++;
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}
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for (;;) {
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if (t <= 15) {
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if (t == 0) {
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t = decode_length(15, ip);
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}
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memcpy(op, ip, 4);
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op += 4;
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ip += 4;
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t--;
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if (t) {
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if (t <= 3) {
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copy_bytes(op, ip, t);
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op += t;
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ip += t;
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} else {
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while (t > 3) {
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memcpy(op, ip, 4);
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op += 4;
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ip += 4;
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t -= 4;
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}
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copy_bytes(op, ip, t);
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op += t;
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ip += t;
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}
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}
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t = *ip++;
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if (t <= 15) {
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m_pos = op - 2049 - (t >> 2) - 4 * *ip++;
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*op++ = *m_pos++;
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*op++ = *m_pos++;
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*op++ = *m_pos++;
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continue;
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}
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}
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while (true) {
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if (t > 63) {
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m_pos = op - 1 - ((t >> 2) & 7) - 8 * *ip++;
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t = (t >> 5) - 1;
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*op++ = *m_pos++;
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*op++ = *m_pos++;
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copy_bytes(op, m_pos, t);
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op += t;
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break;
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}
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if (t > 31) {
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t &= 31;
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if (t == 0) {
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t = decode_length(31, ip);
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}
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m_pos = op - 1;
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CopyLittleShort(&s, ip);
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ip += 2;
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m_pos -= (s >> 2);
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} else {
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if (t <= 15) {
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m_pos = op - 1 - (t >> 2) - 4 * *ip++;
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*op++ = *m_pos++;
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*op++ = *m_pos++;
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break;
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}
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m_pos = op - 2048 * (t & 8);
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t &= 7u;
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if (t == 0) {
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t = decode_length(7, ip);
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}
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CopyLittleShort(&s, ip);
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ip += 2;
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m_pos -= (s >> 2);
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if (m_pos == op) {
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*out_len = op - out;
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return 0;
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}
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m_pos -= 0x4000;
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}
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if (t <= 5 || static_cast<size_t>(op - m_pos) <= 3) {
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*op++ = *m_pos++;
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*op++ = *m_pos++;
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copy_bytes(op, m_pos, t);
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op += t;
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} else {
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memcpy(op, m_pos, 4);
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op += 4;
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m_pos += 4;
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t -= 2;
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while (t > 3) {
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memcpy(op, m_pos, 4);
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op += 4;
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m_pos += 4;
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t -= 4;
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}
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copy_bytes(op, m_pos, t);
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op += t;
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}
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break;
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}
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t = *(ip - 2) & 3;
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if (t == 0) {
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t = *ip++;
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continue;
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}
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copy_bytes(op, ip, t);
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op += t;
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ip += t;
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t = *ip++;
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}
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*out_len = op - out;
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if (ip == ip_end) {
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return 0;
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}
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return (ip < ip_end) ? -1 : -2;
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}
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static unsigned char in[0x40000];
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static unsigned char out[0x41013];
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static void test_compression()
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{
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size_t in_len;
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size_t out_len;
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size_t new_len;
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cLZ77 lz77;
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memset(&in, 0, 0x40000);
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if (lz77.Compress(in, sizeof(in), out, &out_len)) {
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puts("Compression Failed!");
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return;
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}
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printf("Compressed %i bytes into %zi bytes\n", 0x40000, out_len);
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if (lz77.Decompress(out, out_len, in, &in_len)) {
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new_len = in_len;
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} else {
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new_len = in_len;
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if (in_len == 0x40000) {
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printf("Decompressed %zi bytes into %i bytes\n", out_len, 0x40000);
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puts("Compression Test: Passed");
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return;
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}
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}
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printf("Decompression got FuBar'd... %i != %zi\n", 0x40000, new_len);
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}
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