mirror of
https://github.com/Q3Rally-Team/rallyunlimited-engine.git
synced 2024-11-25 05:31:16 +00:00
423 lines
10 KiB
C
423 lines
10 KiB
C
/*
|
|
===========================================================================
|
|
Copyright (C) 1999-2005 Id Software, Inc.
|
|
|
|
This file is part of Quake III Arena source code.
|
|
|
|
Quake III Arena source code is free software; you can redistribute it
|
|
and/or modify it under the terms of the GNU General Public License as
|
|
published by the Free Software Foundation; either version 2 of the License,
|
|
or (at your option) any later version.
|
|
|
|
Quake III Arena source code is distributed in the hope that it will be
|
|
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with Quake III Arena source code; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
===========================================================================
|
|
*/
|
|
|
|
/* This is based on the Adaptive Huffman algorithm described in Sayood's Data
|
|
* Compression book. The ranks are not actually stored, but implicitly defined
|
|
* by the location of a node within a doubly-linked list */
|
|
|
|
#include "q_shared.h"
|
|
#include "qcommon.h"
|
|
|
|
#define NYT HMAX /* NYT = Not Yet Transmitted */
|
|
#define INTERNAL_NODE (HMAX+1)
|
|
|
|
typedef struct nodetype {
|
|
struct nodetype *left, *right, *parent; /* tree structure */
|
|
struct nodetype *next, *prev; /* doubly-linked list */
|
|
struct nodetype **head; /* highest ranked node in block */
|
|
int weight;
|
|
int symbol;
|
|
} node_t;
|
|
|
|
#define HMAX 256 /* Maximum symbol */
|
|
|
|
typedef struct {
|
|
int blocNode;
|
|
int blocPtrs;
|
|
|
|
node_t* tree;
|
|
node_t* lhead;
|
|
node_t* ltail;
|
|
node_t* loc[HMAX+1];
|
|
node_t** freelist;
|
|
|
|
node_t nodeList[768];
|
|
node_t* nodePtrs[768];
|
|
} huff_t;
|
|
|
|
typedef struct {
|
|
huff_t compressor;
|
|
huff_t decompressor;
|
|
} huffman_t;
|
|
|
|
static int bloc = 0;
|
|
|
|
/* Add a bit to the output file (buffered) */
|
|
static void add_bit (char bit, byte *fout) {
|
|
if ((bloc&7) == 0) {
|
|
fout[(bloc>>3)] = 0;
|
|
}
|
|
fout[(bloc>>3)] |= bit << (bloc&7);
|
|
bloc++;
|
|
}
|
|
|
|
/* Receive one bit from the input file (buffered) */
|
|
static int get_bit (byte *fin) {
|
|
int t;
|
|
t = (fin[(bloc>>3)] >> (bloc&7)) & 0x1;
|
|
bloc++;
|
|
return t;
|
|
}
|
|
|
|
static node_t **get_ppnode(huff_t* huff) {
|
|
node_t **tppnode;
|
|
if (!huff->freelist) {
|
|
return &(huff->nodePtrs[huff->blocPtrs++]);
|
|
} else {
|
|
tppnode = huff->freelist;
|
|
huff->freelist = (node_t **)*tppnode;
|
|
return tppnode;
|
|
}
|
|
}
|
|
|
|
static void free_ppnode(huff_t* huff, node_t **ppnode) {
|
|
*ppnode = (node_t *)huff->freelist;
|
|
huff->freelist = ppnode;
|
|
}
|
|
|
|
/* Swap the location of these two nodes in the tree */
|
|
static void swap (huff_t* huff, node_t *node1, node_t *node2) {
|
|
node_t *par1, *par2;
|
|
|
|
par1 = node1->parent;
|
|
par2 = node2->parent;
|
|
|
|
if (par1) {
|
|
if (par1->left == node1) {
|
|
par1->left = node2;
|
|
} else {
|
|
par1->right = node2;
|
|
}
|
|
} else {
|
|
huff->tree = node2;
|
|
}
|
|
|
|
if (par2) {
|
|
if (par2->left == node2) {
|
|
par2->left = node1;
|
|
} else {
|
|
par2->right = node1;
|
|
}
|
|
} else {
|
|
huff->tree = node1;
|
|
}
|
|
|
|
node1->parent = par2;
|
|
node2->parent = par1;
|
|
}
|
|
|
|
/* Swap these two nodes in the linked list (update ranks) */
|
|
static void swaplist(node_t *node1, node_t *node2) {
|
|
node_t *par1;
|
|
|
|
par1 = node1->next;
|
|
node1->next = node2->next;
|
|
node2->next = par1;
|
|
|
|
par1 = node1->prev;
|
|
node1->prev = node2->prev;
|
|
node2->prev = par1;
|
|
|
|
if (node1->next == node1) {
|
|
node1->next = node2;
|
|
}
|
|
if (node2->next == node2) {
|
|
node2->next = node1;
|
|
}
|
|
if (node1->next) {
|
|
node1->next->prev = node1;
|
|
}
|
|
if (node2->next) {
|
|
node2->next->prev = node2;
|
|
}
|
|
if (node1->prev) {
|
|
node1->prev->next = node1;
|
|
}
|
|
if (node2->prev) {
|
|
node2->prev->next = node2;
|
|
}
|
|
}
|
|
|
|
/* Do the increments */
|
|
static void increment(huff_t* huff, node_t *node) {
|
|
node_t *lnode;
|
|
|
|
if (!node) {
|
|
return;
|
|
}
|
|
|
|
if (node->next != NULL && node->next->weight == node->weight) {
|
|
lnode = *node->head;
|
|
if (lnode != node->parent) {
|
|
swap(huff, lnode, node);
|
|
}
|
|
swaplist(lnode, node);
|
|
}
|
|
if (node->prev && node->prev->weight == node->weight) {
|
|
*node->head = node->prev;
|
|
} else {
|
|
*node->head = NULL;
|
|
free_ppnode(huff, node->head);
|
|
}
|
|
node->weight++;
|
|
if (node->next && node->next->weight == node->weight) {
|
|
node->head = node->next->head;
|
|
} else {
|
|
node->head = get_ppnode(huff);
|
|
*node->head = node;
|
|
}
|
|
if (node->parent) {
|
|
increment(huff, node->parent);
|
|
if (node->prev == node->parent) {
|
|
swaplist(node, node->parent);
|
|
if (*node->head == node) {
|
|
*node->head = node->parent;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static void Huff_addRef(huff_t* huff, byte ch) {
|
|
node_t *tnode, *tnode2;
|
|
if (huff->loc[ch] == NULL) { /* if this is the first transmission of this node */
|
|
tnode = &(huff->nodeList[huff->blocNode++]);
|
|
tnode2 = &(huff->nodeList[huff->blocNode++]);
|
|
|
|
tnode2->symbol = INTERNAL_NODE;
|
|
tnode2->weight = 1;
|
|
tnode2->next = huff->lhead->next;
|
|
if (huff->lhead->next) {
|
|
huff->lhead->next->prev = tnode2;
|
|
if (huff->lhead->next->weight == 1) {
|
|
tnode2->head = huff->lhead->next->head;
|
|
} else {
|
|
tnode2->head = get_ppnode(huff);
|
|
*tnode2->head = tnode2;
|
|
}
|
|
} else {
|
|
tnode2->head = get_ppnode(huff);
|
|
*tnode2->head = tnode2;
|
|
}
|
|
huff->lhead->next = tnode2;
|
|
tnode2->prev = huff->lhead;
|
|
|
|
tnode->symbol = ch;
|
|
tnode->weight = 1;
|
|
tnode->next = huff->lhead->next;
|
|
if (huff->lhead->next) {
|
|
huff->lhead->next->prev = tnode;
|
|
if (huff->lhead->next->weight == 1) {
|
|
tnode->head = huff->lhead->next->head;
|
|
} else {
|
|
/* this should never happen */
|
|
tnode->head = get_ppnode(huff);
|
|
*tnode->head = tnode2;
|
|
}
|
|
} else {
|
|
/* this should never happen */
|
|
tnode->head = get_ppnode(huff);
|
|
*tnode->head = tnode;
|
|
}
|
|
huff->lhead->next = tnode;
|
|
tnode->prev = huff->lhead;
|
|
tnode->left = tnode->right = NULL;
|
|
|
|
if (huff->lhead->parent) {
|
|
if (huff->lhead->parent->left == huff->lhead) { /* lhead is guaranteed to by the NYT */
|
|
huff->lhead->parent->left = tnode2;
|
|
} else {
|
|
huff->lhead->parent->right = tnode2;
|
|
}
|
|
} else {
|
|
huff->tree = tnode2;
|
|
}
|
|
|
|
tnode2->right = tnode;
|
|
tnode2->left = huff->lhead;
|
|
|
|
tnode2->parent = huff->lhead->parent;
|
|
huff->lhead->parent = tnode->parent = tnode2;
|
|
|
|
huff->loc[ch] = tnode;
|
|
|
|
increment(huff, tnode2->parent);
|
|
} else {
|
|
increment(huff, huff->loc[ch]);
|
|
}
|
|
}
|
|
|
|
/* Get a symbol */
|
|
static int Huff_Receive(node_t *node, int *ch, byte *fin) {
|
|
while (node && node->symbol == INTERNAL_NODE) {
|
|
if (get_bit(fin)) {
|
|
node = node->right;
|
|
} else {
|
|
node = node->left;
|
|
}
|
|
}
|
|
if (!node) {
|
|
return 0;
|
|
// Com_Error(ERR_DROP, "Illegal tree!");
|
|
}
|
|
return (*ch = node->symbol);
|
|
}
|
|
|
|
/* Send the prefix code for this node */
|
|
static void send(node_t *node, node_t *child, byte *fout) {
|
|
if (node->parent) {
|
|
send(node->parent, node, fout);
|
|
}
|
|
if (child) {
|
|
if (node->right == child) {
|
|
add_bit(1, fout);
|
|
} else {
|
|
add_bit(0, fout);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Send a symbol */
|
|
static void Huff_transmit( huff_t *huff, int ch, byte *fout ) {
|
|
int i;
|
|
if (huff->loc[ch] == NULL) {
|
|
/* node_t hasn't been transmitted, send a NYT, then the symbol */
|
|
Huff_transmit(huff, NYT, fout);
|
|
for (i = 7; i >= 0; i--) {
|
|
add_bit((char)((ch >> i) & 0x1), fout);
|
|
}
|
|
} else {
|
|
send(huff->loc[ch], NULL, fout);
|
|
}
|
|
}
|
|
|
|
void Huff_Decompress(msg_t *mbuf, int offset) {
|
|
int ch, cch, i, j, size;
|
|
byte seq[65536];
|
|
byte* buffer;
|
|
huff_t huff;
|
|
|
|
size = mbuf->cursize - offset;
|
|
buffer = mbuf->data + offset;
|
|
|
|
if ( size <= 0 ) {
|
|
return;
|
|
}
|
|
|
|
Com_Memset(&huff, 0, sizeof(huff_t));
|
|
// Initialize the tree & list with the NYT node
|
|
huff.tree = huff.lhead = huff.ltail = huff.loc[NYT] = &(huff.nodeList[huff.blocNode++]);
|
|
huff.tree->symbol = NYT;
|
|
huff.tree->weight = 0;
|
|
huff.lhead->next = huff.lhead->prev = NULL;
|
|
huff.tree->parent = huff.tree->left = huff.tree->right = NULL;
|
|
|
|
cch = buffer[0]*256 + buffer[1];
|
|
// don't overflow with bad messages
|
|
if ( cch > mbuf->maxsize - offset ) {
|
|
cch = mbuf->maxsize - offset;
|
|
}
|
|
bloc = 16;
|
|
|
|
for ( j = 0; j < cch; j++ ) {
|
|
ch = 0;
|
|
// don't overflow reading from the messages
|
|
// FIXME: would it be better to have an overflow check in get_bit ?
|
|
if ( (bloc >> 3) > size ) {
|
|
seq[j] = 0;
|
|
break;
|
|
}
|
|
Huff_Receive(huff.tree, &ch, buffer); /* Get a character */
|
|
if ( ch == NYT ) { /* We got a NYT, get the symbol associated with it */
|
|
ch = 0;
|
|
for ( i = 0; i < 8; i++ ) {
|
|
ch = (ch<<1) + get_bit(buffer);
|
|
}
|
|
}
|
|
|
|
seq[j] = ch; /* Write symbol */
|
|
|
|
Huff_addRef(&huff, (byte)ch); /* Increment node */
|
|
}
|
|
mbuf->cursize = cch + offset;
|
|
Com_Memcpy(mbuf->data + offset, seq, cch);
|
|
}
|
|
|
|
|
|
void Huff_Compress(msg_t *mbuf, int offset) {
|
|
int i, ch, size;
|
|
byte seq[65536];
|
|
byte* buffer;
|
|
huff_t huff;
|
|
|
|
size = mbuf->cursize - offset;
|
|
buffer = mbuf->data + offset;
|
|
|
|
if (size<=0) {
|
|
return;
|
|
}
|
|
|
|
Com_Memset(&huff, 0, sizeof(huff_t));
|
|
// Add the NYT (not yet transmitted) node into the tree/list */
|
|
huff.tree = huff.lhead = huff.loc[NYT] = &(huff.nodeList[huff.blocNode++]);
|
|
huff.tree->symbol = NYT;
|
|
huff.tree->weight = 0;
|
|
huff.lhead->next = huff.lhead->prev = NULL;
|
|
huff.tree->parent = huff.tree->left = huff.tree->right = NULL;
|
|
|
|
seq[0] = (size>>8);
|
|
seq[1] = size&0xff;
|
|
|
|
bloc = 16;
|
|
|
|
for (i=0; i<size; i++ ) {
|
|
ch = buffer[i];
|
|
Huff_transmit(&huff, ch, seq); /* Transmit symbol */
|
|
Huff_addRef(&huff, (byte)ch); /* Do update */
|
|
}
|
|
|
|
bloc += 8; // next byte
|
|
|
|
mbuf->cursize = (bloc>>3) + offset;
|
|
Com_Memcpy(mbuf->data+offset, seq, (bloc>>3));
|
|
}
|
|
|
|
#if 0
|
|
void Huff_Init(huffman_t *huff) {
|
|
|
|
Com_Memset(&huff->compressor, 0, sizeof(huff_t));
|
|
Com_Memset(&huff->decompressor, 0, sizeof(huff_t));
|
|
|
|
// Initialize the tree & list with the NYT node
|
|
huff->decompressor.tree = huff->decompressor.lhead = huff->decompressor.ltail = huff->decompressor.loc[NYT] = &(huff->decompressor.nodeList[huff->decompressor.blocNode++]);
|
|
huff->decompressor.tree->symbol = NYT;
|
|
huff->decompressor.tree->weight = 0;
|
|
huff->decompressor.lhead->next = huff->decompressor.lhead->prev = NULL;
|
|
huff->decompressor.tree->parent = huff->decompressor.tree->left = huff->decompressor.tree->right = NULL;
|
|
|
|
// Add the NYT (not yet transmitted) node into the tree/list */
|
|
huff->compressor.tree = huff->compressor.lhead = huff->compressor.loc[NYT] = &(huff->compressor.nodeList[huff->compressor.blocNode++]);
|
|
huff->compressor.tree->symbol = NYT;
|
|
huff->compressor.tree->weight = 0;
|
|
huff->compressor.lhead->next = huff->compressor.lhead->prev = NULL;
|
|
huff->compressor.tree->parent = huff->compressor.tree->left = huff->compressor.tree->right = NULL;
|
|
}
|
|
#endif
|