608 lines
12 KiB
C
608 lines
12 KiB
C
//=======================================================================
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// Copyright XashXT Group 2007 ©
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// net_huff.c - Huffman compression routines for network bitstream
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//=======================================================================
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#include "common.h"
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#include "netchan.h"
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#define VALUE(a) ((int )(a))
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#define NODE(a) ((void *)(a))
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#define NODE_START NODE( 1)
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#define NODE_NONE NODE(256)
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#define NODE_NEXT NODE(257)
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#define NOT_REFERENCED 256
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#define HUFF_TREE_SIZE 7175
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typedef void *tree_t[HUFF_TREE_SIZE];
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//
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// pre-defined frequency counts for all bytes [0..255]
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//
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static const int huff_tree[256] =
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{
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0x3D1CB, 0x0A0E9, 0x01894, 0x01BC2, 0x00E92, 0x00EA6, 0x017DE, 0x05AF3,
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0x08225, 0x01B26, 0x01E9E, 0x025F2, 0x02429, 0x0436B, 0x00F6D, 0x006F2,
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0x02060, 0x00644, 0x00636, 0x0067F, 0x0044C, 0x004BD, 0x004D6, 0x0046E,
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0x006D5, 0x00423, 0x004DE, 0x0047D, 0x004F9, 0x01186, 0x00AF5, 0x00D90,
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0x0553B, 0x00487, 0x00686, 0x0042A, 0x00413, 0x003F4, 0x0041D, 0x0042E,
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0x006BE, 0x00378, 0x0049C, 0x00352, 0x003C0, 0x0030C, 0x006D8, 0x00CE0,
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0x02986, 0x011A2, 0x016F9, 0x00A7D, 0x0122A, 0x00EFD, 0x0082D, 0x0074B,
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0x00A18, 0x0079D, 0x007B4, 0x003AC, 0x0046E, 0x006FC, 0x00686, 0x004B6,
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0x01657, 0x017F0, 0x01C36, 0x019FE, 0x00E7E, 0x00ED3, 0x005D4, 0x005F4,
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0x008A7, 0x00474, 0x0054B, 0x003CB, 0x00884, 0x004E0, 0x00530, 0x004AB,
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0x006EA, 0x00436, 0x004F0, 0x004F2, 0x00490, 0x003C5, 0x00483, 0x004A2,
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0x00543, 0x004CC, 0x005F9, 0x00640, 0x00A39, 0x00800, 0x009F2, 0x00CCB,
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0x0096A, 0x00E01, 0x009C8, 0x00AF0, 0x00A73, 0x01802, 0x00E4F, 0x00B18,
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0x037AD, 0x00C5C, 0x008AD, 0x00697, 0x00C88, 0x00AB3, 0x00DB8, 0x012BC,
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0x00FFB, 0x00DBB, 0x014A8, 0x00FB0, 0x01F01, 0x0178F, 0x014F0, 0x00F54,
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0x0131C, 0x00E9F, 0x011D6, 0x012C7, 0x016DC, 0x01900, 0x01851, 0x02063,
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0x05ACB, 0x01E9E, 0x01BA1, 0x022E7, 0x0153D, 0x01183, 0x00E39, 0x01488,
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0x014C0, 0x014D0, 0x014FA, 0x00DA4, 0x0099A, 0x0069E, 0x0071D, 0x00849,
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0x0077C, 0x0047D, 0x005EC, 0x00557, 0x004D4, 0x00405, 0x004EA, 0x00450,
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0x004DD, 0x003EE, 0x0047D, 0x00401, 0x004D9, 0x003B8, 0x00507, 0x003E5,
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0x006B1, 0x003F1, 0x004A3, 0x0036F, 0x0044B, 0x003A1, 0x00436, 0x003B7,
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0x00678, 0x003A2, 0x00481, 0x00406, 0x004EE, 0x00426, 0x004BE, 0x00424,
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0x00655, 0x003A2, 0x00452, 0x00390, 0x0040A, 0x0037C, 0x00486, 0x003DE,
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0x00497, 0x00352, 0x00461, 0x00387, 0x0043F, 0x00398, 0x00478, 0x00420,
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0x00D86, 0x008C0, 0x0112D, 0x02F68, 0x01E4E, 0x00541, 0x0051B, 0x00CCE,
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0x0079E, 0x00376, 0x003FF, 0x00458, 0x00435, 0x00412, 0x00425, 0x0042F,
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0x005CC, 0x003E9, 0x00448, 0x00393, 0x0041C, 0x003E3, 0x0042E, 0x0036C,
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0x00457, 0x00353, 0x00423, 0x00325, 0x00458, 0x0039B, 0x0044F, 0x00331,
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0x0076B, 0x00750, 0x003D0, 0x00349, 0x00467, 0x003BC, 0x00487, 0x003B6,
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0x01E6F, 0x003BA, 0x00509, 0x003A5, 0x00467, 0x00C87, 0x003FC, 0x0039F,
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0x0054B, 0x00300, 0x00410, 0x002E9, 0x003B8, 0x00325, 0x00431, 0x002E4,
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0x003F5, 0x00325, 0x003F0, 0x0031C, 0x003E4, 0x00421, 0x02CC1, 0x034C0
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};
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// static Huffman tree
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static tree_t huffTree;
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// received from MSG_* code
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static int huffBitPos;
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static qboolean huffInit = false;
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/*
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=======================================================================================
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HUFFMAN TREE CONSTRUCTION
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=======================================================================================
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*/
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/*
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============
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Huff_PrepareTree
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============
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*/
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static _inline void Huff_PrepareTree( tree_t tree )
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{
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void **node;
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memset( tree, 0, sizeof( tree_t ));
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// create first node
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node = &tree[263];
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VALUE( tree[0] )++;
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node[7] = NODE_NONE;
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tree[2] = node;
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tree[3] = node;
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tree[4] = node;
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tree[261] = node;
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}
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/*
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============
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Huff_GetNode
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============
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*/
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static _inline void **Huff_GetNode( void **tree )
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{
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void **node;
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int value;
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node = tree[262];
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if( !node )
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{
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value = VALUE( tree[1] )++;
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node = &tree[value + 6407];
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return node;
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}
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tree[262] = node[0];
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return node;
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}
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/*
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============
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Huff_Swap
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============
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*/
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static _inline void Huff_Swap( void **tree1, void **tree2, void **tree3 )
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{
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void **a, **b;
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a = tree2[2];
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if( a )
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{
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if( a[0] == tree2 )
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a[0] = tree3;
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else a[1] = tree3;
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}
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else tree1[2] = tree3;
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b = tree3[2];
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if( b )
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{
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if( b[0] == tree3 )
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{
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b[0] = tree2;
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tree2[2] = b;
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tree3[2] = a;
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return;
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}
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b[1] = tree2;
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tree2[2] = b;
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tree3[2] = a;
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return;
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}
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tree1[2] = tree2;
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tree2[2] = NULL;
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tree3[2] = a;
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}
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/*
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============
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Huff_SwapTrees
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============
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*/
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static _inline void Huff_SwapTrees( void **tree1, void **tree2 )
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{
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void **temp;
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temp = tree1[3];
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tree1[3] = tree2[3];
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tree2[3] = temp;
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temp = tree1[4];
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tree1[4] = tree2[4];
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tree2[4] = temp;
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if( tree1[3] == tree1 )
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tree1[3] = tree2;
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if( tree2[3] == tree2 )
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tree2[3] = tree1;
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temp = tree1[3];
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if( temp ) temp[4] = tree1;
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temp = tree2[3];
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if( temp ) temp[4] = tree2;
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temp = tree1[4];
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if( temp ) temp[3] = tree1;
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temp = tree2[4];
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if( temp ) temp[3] = tree2;
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}
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/*
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============
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Huff_DeleteNode
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============
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*/
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static _inline void Huff_DeleteNode( void **tree1, void **tree2 )
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{
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tree2[0] = tree1[262];
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tree1[262] = tree2;
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}
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/*
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============
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Huff_IncrementFreq_r
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============
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*/
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static void Huff_IncrementFreq_r( void **tree1, void **tree2 )
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{
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void **a, **b;
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if( !tree2 ) return;
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a = tree2[3];
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if( a )
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{
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a = a[6];
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if( a == tree2[6] )
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{
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b = tree2[5];
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if( b[0] != tree2[2] )
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Huff_Swap( tree1, b[0], tree2 );
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Huff_SwapTrees( b[0], tree2 );
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}
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}
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a = tree2[4];
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if( a && a[6] == tree2[6] )
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{
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b = tree2[5];
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b[0] = a;
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}
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else
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{
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a = tree2[5];
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a[0] = 0;
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Huff_DeleteNode( tree1, tree2[5] );
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}
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VALUE( tree2[6] )++;
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a = tree2[3];
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if( a && a[6] == tree2[6] )
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{
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tree2[5] = a[5];
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}
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else
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{
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a = Huff_GetNode( tree1 );
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tree2[5] = a;
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a[0] = tree2;
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}
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if( tree2[2] )
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{
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Huff_IncrementFreq_r( tree1, tree2[2] );
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if( tree2[4] == tree2[2] )
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{
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Huff_SwapTrees( tree2, tree2[2] );
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a = tree2[5];
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if( a[0] == tree2 ) a[0] = tree2[2];
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}
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}
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}
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/*
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============
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Huff_AddReference
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Insert 'ch' into the tree or increment it's frequency
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============
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*/
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static void Huff_AddReference( void **tree, int ch )
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{
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void **a, **b, **c, **d;
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int value;
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ch &= 255;
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if( tree[ch + 5] )
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{
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Huff_IncrementFreq_r( tree, tree[ch + 5] );
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return; // already added
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}
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value = VALUE( tree[0] )++;
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b = &tree[value * 8 + 263];
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value = VALUE( tree[0] )++;
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a = &tree[value * 8 + 263];
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a[7] = NODE_NEXT;
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a[6] = NODE_START;
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d = tree[3];
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a[3] = d[3];
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if( a[3] )
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{
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d = a[3];
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d[4] = a;
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d = a[3];
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if( d[6] == NODE_START )
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{
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a[5] = d[5];
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}
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else
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{
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d = Huff_GetNode( tree );
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a[5] = d;
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d[0] = a;
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}
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}
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else
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{
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d = Huff_GetNode( tree );
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a[5] = d;
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d[0] = a;
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}
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d = tree[3];
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d[3] = a;
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a[4] = tree[3];
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b[7] = NODE( ch );
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b[6] = NODE_START;
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d = tree[3];
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b[3] = d[3];
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if( b[3] )
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{
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d = b[3];
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d[4] = b;
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if( d[6] == NODE_START )
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{
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b[5] = d[5];
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}
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else
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{
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d = Huff_GetNode( tree );
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b[5] = d;
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d[0] = a;
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}
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}
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else
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{
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d = Huff_GetNode( tree );
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b[5] = d;
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d[0] = b;
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}
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d = tree[3];
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d[3] = b;
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b[4] = tree[3];
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b[1] = NULL;
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b[0] = NULL;
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d = tree[3];
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c = d[2];
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if( c )
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{
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if( c[0] == tree[3] )
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c[0] = a;
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else c[1] = a;
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}
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else tree[2] = a;
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a[1] = b;
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d = tree[3];
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a[0] = d;
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a[2] = d[2];
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b[2] = a;
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d = tree[3];
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d[2] = a;
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tree[ch + 5] = b;
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Huff_IncrementFreq_r( tree, a[2] );
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}
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/*
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=======================================================================================
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BITSTREAM I/O
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=======================================================================================
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*/
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/*
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============
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Huff_EmitBit
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Put one bit into buffer
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============
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*/
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static _inline void Huff_EmitBit( int bit, byte *buffer )
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{
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if(!(huffBitPos & 7)) buffer[huffBitPos >> 3] = 0;
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buffer[huffBitPos >> 3] |= bit << (huffBitPos & 7);
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huffBitPos++;
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}
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/*
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============
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Huff_GetBit
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Read one bit from buffer
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============
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*/
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static _inline int Huff_GetBit( byte *buffer )
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{
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int bit = buffer[huffBitPos >> 3] >> (huffBitPos & 7);
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huffBitPos++;
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return (bit & 1);
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}
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/*
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============
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Huff_EmitPathToByte
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============
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*/
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static _inline void Huff_EmitPathToByte( void **tree, void **subtree, byte *buffer )
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{
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if( tree[2] ) Huff_EmitPathToByte( tree[2], tree, buffer );
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if( !subtree ) return;
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// emit tree walking control bits
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if( tree[1] == subtree )
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Huff_EmitBit( 1, buffer );
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else Huff_EmitBit( 0, buffer );
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}
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/*
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============
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Huff_GetByteFromTree
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Get one byte using dynamic or static tree
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============
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*/
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static _inline int Huff_GetByteFromTree( void **tree, byte *buffer )
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{
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if( !tree ) return 0;
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// walk through the tree until we get a value
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while( tree[7] == NODE_NEXT )
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{
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if( !Huff_GetBit( buffer ))
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tree = tree[0];
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else tree = tree[1];
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if( !tree ) return 0;
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}
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return VALUE( tree[7] );
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}
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/*
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============
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Huff_EmitByteDynamic
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Emit one byte using dynamic tree
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============
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*/
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static void Huff_EmitByteDynamic( void **tree, int value, byte *buffer )
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{
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void **subtree;
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int i;
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// if byte was already referenced, emit path to it
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subtree = tree[value + 5];
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if( subtree )
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{
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if( subtree[2] )
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Huff_EmitPathToByte( subtree[2], subtree, buffer );
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return;
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}
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// byte was not referenced, just emit 8 bits
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Huff_EmitByteDynamic( tree, NOT_REFERENCED, buffer );
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for( i = 7; i >= 0; i-- )
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{
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Huff_EmitBit( (value >> i) & 1, buffer );
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}
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}
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/*
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=======================================================================================
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PUBLIC INTERFACE
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=======================================================================================
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*/
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/*
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============
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Huff_CompressPacket
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Compress message using dynamic Huffman tree,
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beginning from specified offset
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============
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*/
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void Huff_CompressPacket( sizebuf_t *msg, int offset )
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{
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tree_t tree;
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byte buffer[MAX_MSGLEN];
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byte *data;
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int outLen;
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int i, inLen;
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data = BF_GetData( msg ) + offset;
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inLen = BF_GetNumBytesWritten( msg ) - offset;
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if( inLen <= 0 || inLen >= MAX_MSGLEN )
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return;
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Huff_PrepareTree( tree );
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buffer[0] = inLen >> 8;
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buffer[1] = inLen & 0xFF;
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huffBitPos = 16;
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for( i = 0; i < inLen; i++ )
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{
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Huff_EmitByteDynamic( tree, data[i], buffer );
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Huff_AddReference( tree, data[i] );
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}
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outLen = (huffBitPos >> 3) + 1;
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msg->iCurBit = (offset + outLen) << 3;
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Mem_Copy( data, buffer, outLen );
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}
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/*
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============
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Huff_DecompressPacket
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Decompress message using dynamic Huffman tree,
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beginning from specified offset
|
|
============
|
|
*/
|
|
void Huff_DecompressPacket( sizebuf_t *msg, int offset )
|
|
{
|
|
tree_t tree;
|
|
byte buffer[MAX_MSGLEN];
|
|
byte *data;
|
|
int outLen;
|
|
int inLen;
|
|
int ch, i, j;
|
|
|
|
data = BF_GetData( msg ) + offset;
|
|
inLen = BF_GetMaxBytes( msg ) - offset;
|
|
if( inLen <= 0 ) return;
|
|
|
|
Huff_PrepareTree( tree );
|
|
|
|
outLen = ( data[0] << 8 ) + data[1];
|
|
huffBitPos = 16;
|
|
|
|
if( outLen > MAX_MSGLEN - offset )
|
|
outLen = MAX_MSGLEN - offset;
|
|
|
|
for( i = 0; i < outLen; i++ )
|
|
{
|
|
if(( huffBitPos >> 3 ) > inLen )
|
|
{
|
|
buffer[i] = 0;
|
|
break;
|
|
}
|
|
|
|
ch = Huff_GetByteFromTree( tree[2], data );
|
|
|
|
if( ch == NOT_REFERENCED )
|
|
{
|
|
ch = 0; // just read 8 bits
|
|
for( j = 0; j < 8; j++ )
|
|
{
|
|
ch <<= 1;
|
|
ch |= Huff_GetBit( data );
|
|
}
|
|
}
|
|
buffer[i] = ch;
|
|
Huff_AddReference( tree, ch );
|
|
}
|
|
|
|
msg->nDataBits = ( offset + outLen ) << 3;
|
|
Mem_Copy( data, buffer, outLen );
|
|
}
|
|
|
|
/*
|
|
============
|
|
Huff_Init
|
|
============
|
|
*/
|
|
void Huff_Init( void )
|
|
{
|
|
int i, j;
|
|
|
|
if( huffInit ) return;
|
|
|
|
// build empty tree
|
|
Huff_PrepareTree( huffTree );
|
|
|
|
// add all pre-defined byte references
|
|
for( i = 0; i < 256; i++ )
|
|
for( j = 0; j < huff_tree[i]; j++ )
|
|
Huff_AddReference( huffTree, i );
|
|
huffInit = true;
|
|
} |