281 lines
6.7 KiB
C
281 lines
6.7 KiB
C
#include "de_lzah.h"
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#include "macunpack.h"
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#ifdef SIT
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#define DELZAH
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#endif /* SIT */
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#ifdef LZH
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#define DELZAH
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#endif /* LZH */
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#ifdef DELZAH
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#include "globals.h"
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#include "../util/masks.h"
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#include "../fileio/wrfile.h"
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/* Note: compare with LZSS decoding in lharc! */
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#define N 314
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#define T (2*N-1)
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/* Huffman table used for first 6 bits of offset:
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#bits codes
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3 0x000
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4 0x040-0x080
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5 0x100-0x2c0
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6 0x300-0x5c0
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7 0x600-0xbc0
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8 0xc00-0xfc0
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*/
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static unsigned short HuffCode[] = {
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0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
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0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
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0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
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0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
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0x040, 0x040, 0x040, 0x040, 0x040, 0x040, 0x040, 0x040,
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0x040, 0x040, 0x040, 0x040, 0x040, 0x040, 0x040, 0x040,
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0x080, 0x080, 0x080, 0x080, 0x080, 0x080, 0x080, 0x080,
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0x080, 0x080, 0x080, 0x080, 0x080, 0x080, 0x080, 0x080,
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0x0c0, 0x0c0, 0x0c0, 0x0c0, 0x0c0, 0x0c0, 0x0c0, 0x0c0,
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0x0c0, 0x0c0, 0x0c0, 0x0c0, 0x0c0, 0x0c0, 0x0c0, 0x0c0,
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0x100, 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, 0x100,
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0x140, 0x140, 0x140, 0x140, 0x140, 0x140, 0x140, 0x140,
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0x180, 0x180, 0x180, 0x180, 0x180, 0x180, 0x180, 0x180,
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0x1c0, 0x1c0, 0x1c0, 0x1c0, 0x1c0, 0x1c0, 0x1c0, 0x1c0,
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0x200, 0x200, 0x200, 0x200, 0x200, 0x200, 0x200, 0x200,
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0x240, 0x240, 0x240, 0x240, 0x240, 0x240, 0x240, 0x240,
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0x280, 0x280, 0x280, 0x280, 0x280, 0x280, 0x280, 0x280,
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0x2c0, 0x2c0, 0x2c0, 0x2c0, 0x2c0, 0x2c0, 0x2c0, 0x2c0,
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0x300, 0x300, 0x300, 0x300, 0x340, 0x340, 0x340, 0x340,
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0x380, 0x380, 0x380, 0x380, 0x3c0, 0x3c0, 0x3c0, 0x3c0,
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0x400, 0x400, 0x400, 0x400, 0x440, 0x440, 0x440, 0x440,
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0x480, 0x480, 0x480, 0x480, 0x4c0, 0x4c0, 0x4c0, 0x4c0,
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0x500, 0x500, 0x500, 0x500, 0x540, 0x540, 0x540, 0x540,
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0x580, 0x580, 0x580, 0x580, 0x5c0, 0x5c0, 0x5c0, 0x5c0,
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0x600, 0x600, 0x640, 0x640, 0x680, 0x680, 0x6c0, 0x6c0,
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0x700, 0x700, 0x740, 0x740, 0x780, 0x780, 0x7c0, 0x7c0,
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0x800, 0x800, 0x840, 0x840, 0x880, 0x880, 0x8c0, 0x8c0,
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0x900, 0x900, 0x940, 0x940, 0x980, 0x980, 0x9c0, 0x9c0,
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0xa00, 0xa00, 0xa40, 0xa40, 0xa80, 0xa80, 0xac0, 0xac0,
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0xb00, 0xb00, 0xb40, 0xb40, 0xb80, 0xb80, 0xbc0, 0xbc0,
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0xc00, 0xc40, 0xc80, 0xcc0, 0xd00, 0xd40, 0xd80, 0xdc0,
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0xe00, 0xe40, 0xe80, 0xec0, 0xf00, 0xf40, 0xf80, 0xfc0};
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static short HuffLength[] = {
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3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
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3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
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4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
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4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
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4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
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5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
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5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
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5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
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5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
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6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
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6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
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6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
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8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8};
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unsigned char (*lzah_getbyte)(void);
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static void lzah_inithuf(void);
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static void lzah_reorder(void);
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static void lzah_move(int *p, int *q, int n);
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static void lzah_getbit(void);
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static void lzah_outchar(int ch);
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static char lzah_buf[4096];
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static int lzah_bufptr;
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static int lzah_bitsavail;
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static int lzah_bits;
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static int Frequ[1000];
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static int ForwTree[1000];
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static int BackTree[1000];
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void de_lzah(uint32_t obytes)
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{
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int i, i1, j, ch, byte, offs, skip;
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lzah_inithuf();
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lzah_bitsavail = 0;
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for(i = 0; i < 4036; i++) {
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lzah_buf[i] = ' ';
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}
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lzah_bufptr = 4036;
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while(obytes != 0) {
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ch = ForwTree[T - 1];
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while(ch < T) {
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lzah_getbit();
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if(lzah_bits & 0x80) {
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ch = ch + 1;
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}
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ch = ForwTree[ch];
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}
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ch -= T;
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if(Frequ[T - 1] >= 0x8000) {
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lzah_reorder();
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}
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i = BackTree[ch + T];
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do {
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j = ++Frequ[i];
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i1 = i + 1;
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if(Frequ[i1] < j) {
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while(Frequ[++i1] < j) ;
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i1--;
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Frequ[i] = Frequ[i1];
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Frequ[i1] = j;
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j = ForwTree[i];
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BackTree[j] = i1;
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if(j < T) {
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BackTree[j + 1] = i1;
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}
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ForwTree[i] = ForwTree[i1];
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ForwTree[i1] = j;
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j = ForwTree[i];
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BackTree[j] = i;
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if(j < T) {
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BackTree[j + 1] = i;
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}
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i = i1;
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}
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i = BackTree[i];
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} while(i != 0);
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if(ch < 256) {
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lzah_outchar((char)ch);
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obytes--;
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} else {
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if(lzah_bitsavail != 0) {
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byte = (lzah_bits << 1) & BYTEMASK;
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lzah_bits = (*lzah_getbyte)() & BYTEMASK;
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byte |= (lzah_bits >> lzah_bitsavail);
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lzah_bits = lzah_bits << (7 - lzah_bitsavail);
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} else {
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byte = (*lzah_getbyte)() & BYTEMASK;
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}
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offs = HuffCode[byte];
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skip = HuffLength[byte] - 2;
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while(skip-- != 0) {
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byte = byte + byte;
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lzah_getbit();
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if(lzah_bits & 0x80) {
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byte++;
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}
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}
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offs |= (byte & 0x3f);
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offs = ((lzah_bufptr - offs - 1) & 0xfff);
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ch = ch - 253;
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while(ch-- > 0) {
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lzah_outchar(lzah_buf[offs++ & 0xfff]);
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obytes--;
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if(obytes == 0) {
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break;
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}
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}
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}
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}
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}
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static void
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lzah_inithuf (void)
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{
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int i, j;
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for(i = 0; i < N; i++) {
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Frequ[i] = 1;
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ForwTree[i] = i + T;
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BackTree[i + T] = i;
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}
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for(i = 0, j = N; j < T; i += 2, j++) {
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Frequ[j] = Frequ[i] + Frequ[i + 1];
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ForwTree[j] = i;
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BackTree[i] = j;
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BackTree[i + 1] = j;
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}
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Frequ[T] = 0xffff;
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BackTree[T - 1] = 0;
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}
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static void
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lzah_reorder (void)
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{
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int i, j, k, l;
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j = 0;
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for(i = 0; i < T; i++) {
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if(ForwTree[i] >= T) {
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Frequ[j] = ((Frequ[i] + 1) >> 1);
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ForwTree[j] = ForwTree[i];
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j++;
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}
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}
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for(i = 0, j = N; i < T; i += 2, j++) {
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k = i + 1;
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l = Frequ[i] + Frequ[k];
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Frequ[j] = l;
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k = j - 1;
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while(l < Frequ[k]) {
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k--;
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}
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k = k + 1;
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lzah_move(Frequ + k, Frequ + k + 1, j - k);
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Frequ[k] = l;
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lzah_move(ForwTree + k, ForwTree + k + 1, j - k);
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ForwTree[k] = i;
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}
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for(i = 0; i < T; i++) {
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k = ForwTree[i];
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if(k >= T) {
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BackTree[k] = i;
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} else {
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BackTree[k] = i;
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BackTree[k + 1] = i;
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}
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}
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}
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static void lzah_move(int *p, int *q, int n)
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{
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if(p > q) {
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while(n-- > 0) {
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*q++ = *p++;
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}
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} else {
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p += n;
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q += n;
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while(n-- > 0) {
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*--q = *--p;
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}
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}
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}
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static void
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lzah_getbit (void)
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{
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if(lzah_bitsavail != 0) {
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lzah_bits = lzah_bits + lzah_bits;
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lzah_bitsavail--;
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} else {
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lzah_bits = (*lzah_getbyte)() & BYTEMASK;
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lzah_bitsavail = 7;
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}
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}
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static void
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lzah_outchar (int ch)
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{
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*out_ptr++ = ch;
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lzah_buf[lzah_bufptr++] = ch;
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lzah_bufptr &= 0xfff;
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}
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#else /* DELZAH */
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int delzah; /* keep lint and some compilers happy */
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#endif /* DELZAH */
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