#include #include #include #include #include static byte *inbuf; static byte *outbuf; static int inputsize,outputsize; static int input_ptr; static int output_ptr; #define N 4096 /* buffer size */ #define F 60 /* lookahead buffer size */ #define THRESHOLD 2 #define NIL N /* leaf of tree */ static byte *text_buf; /* Huffman coding */ #define N_CHAR (256 - THRESHOLD + F) /* kinds of characters (character code = 0..N_CHAR-1) */ #define T (N_CHAR * 2 - 1) /* size of table */ #define R (T - 1) /* position of root */ #define MAX_FREQ 0x8000 /* updates tree when the */ /* table for encoding and decoding the upper 6 bits of position */ /* for decoding */ static byte d_code[256] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0C, 0x0C, 0x0C, 0x0C, 0x0D, 0x0D, 0x0D, 0x0D, 0x0E, 0x0E, 0x0E, 0x0E, 0x0F, 0x0F, 0x0F, 0x0F, 0x10, 0x10, 0x10, 0x10, 0x11, 0x11, 0x11, 0x11, 0x12, 0x12, 0x12, 0x12, 0x13, 0x13, 0x13, 0x13, 0x14, 0x14, 0x14, 0x14, 0x15, 0x15, 0x15, 0x15, 0x16, 0x16, 0x16, 0x16, 0x17, 0x17, 0x17, 0x17, 0x18, 0x18, 0x19, 0x19, 0x1A, 0x1A, 0x1B, 0x1B, 0x1C, 0x1C, 0x1D, 0x1D, 0x1E, 0x1E, 0x1F, 0x1F, 0x20, 0x20, 0x21, 0x21, 0x22, 0x22, 0x23, 0x23, 0x24, 0x24, 0x25, 0x25, 0x26, 0x26, 0x27, 0x27, 0x28, 0x28, 0x29, 0x29, 0x2A, 0x2A, 0x2B, 0x2B, 0x2C, 0x2C, 0x2D, 0x2D, 0x2E, 0x2E, 0x2F, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F, }; static byte d_len[256] = { 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, }; static word freq[T + 1]; /* frequency table */ static int prnt[T + N_CHAR]; /* pointers to parent nodes, except for the */ /* elements [T..T + N_CHAR - 1] which are used to get */ /* the positions of leaves corresponding to the codes. */ static int son[T]; /* pointers to child nodes (son[], son[] + 1) */ static word getbuf; static byte getlen; static int GetBit(void) /* get one bit */ { word i; while (getlen <= 8) { if(input_ptr >= inputsize) { i = 0; } else { i = inbuf[input_ptr++]; } getbuf |= i << (8 - getlen); getlen += 8; } i = getbuf; getbuf <<= 1; getlen--; return (int)((i & 0x8000) >> 15); } static int GetByte(void) /* get one byte */ { word i; while (getlen <= 8) { if(input_ptr >= inputsize) { i = 0; } else { i = inbuf[input_ptr++]; } getbuf |= i << (8 - getlen); getlen += 8; } i = getbuf; getbuf <<= 8; getlen -= 8; return (int)((i & 0xff00) >> 8); } /* initialization of tree */ static void StartHuff(void) { int i, j; for (i = 0; i < N_CHAR; i++) { freq[i] = 1; son[i] = i + T; prnt[i + T] = i; } i = 0; j = N_CHAR; while (j <= R) { freq[j] = freq[i] + freq[i + 1]; son[j] = i; prnt[i] = prnt[i + 1] = j; i += 2; j++; } freq[T] = 0xffff; prnt[R] = 0; } /* reconstruction of tree */ static void reconst(void) { int i, j, k; word f, l; /* collect leaf nodes in the first half of the table */ /* and replace the freq by (freq + 1) / 2. */ j = 0; for (i = 0; i < T; i++) { if (son[i] >= T) { freq[j] = (freq[i] + 1) / 2; son[j] = son[i]; j++; } } /* begin constructing tree by connecting sons */ for (i = 0, j = N_CHAR; j < T; i += 2, j++) { k = i + 1; f = freq[j] = freq[i] + freq[k]; for (k = j - 1; f < freq[k]; k--); k++; l = (j - k) * 2; memmove(&freq[k + 1], &freq[k], l); freq[k] = f; memmove(&son[k + 1], &son[k], l); son[k] = i; } /* connect prnt */ for (i = 0; i < T; i++) { if ((k = son[i]) >= T) { prnt[k] = i; } else { prnt[k] = prnt[k + 1] = i; } } } /* increment frequency of given code by one, and update tree */ static void update(int c) { int i, j, k, l; if (freq[R] == MAX_FREQ) { reconst(); } c = prnt[c + T]; do { k = ++freq[c]; /* if the order is disturbed, exchange nodes */ if ((word)k > freq[l = c + 1]) { while ((word)k > freq[++l]); l--; freq[c] = freq[l]; freq[l] = k; i = son[c]; prnt[i] = l; if (i < T) prnt[i + 1] = l; j = son[l]; son[l] = i; prnt[j] = c; if (j < T) prnt[j + 1] = c; son[c] = j; c = l; } } while ((c = prnt[c]) != 0); /* repeat up to root */ } static int DecodeChar(void) { word c; c = son[R]; /* travel from root to leaf, */ /* choosing the smaller child node (son[]) if the read bit is 0, */ /* the bigger (son[]+1} if 1 */ while (c < T) { c += GetBit(); c = son[c]; } c -= T; update(c); return (int)c; } static int DecodePosition(void) { word i, j, c; /* recover upper 6 bits from table */ i = GetByte(); c = (word)d_code[i] << 6; j = d_len[i]; /* read lower 6 bits verbatim */ j -= 2; while (j--) { i = (i << 1) + GetBit(); } return (int)(c | (i & 0x3f)); } static void Decode(void) /* recover */ { int i, j, k, r, c; int count; StartHuff(); for (i = 0; i < N - F; i++) text_buf[i] = 0x20; r = N - F; for (count = 0; count < outputsize; ) { c = DecodeChar(); if (c < 256) { outbuf[output_ptr++] = c; text_buf[r++] = (byte)c; r &= (N - 1); count++; } else { i = (r - DecodePosition() - 1) & (N - 1); j = c - 255 + THRESHOLD; for (k = 0; k < j; k++) { c = text_buf[(i + k) & (N - 1)]; outbuf[output_ptr++] = c; text_buf[r++] = (byte)c; r &= (N - 1); count++; } } } } void decompress_data(byte *input,byte *output,int insize,int outsize) { text_buf = new byte[N + F - 1]; inputsize = insize; outputsize = outsize; inbuf = input; outbuf = output; input_ptr = 0; output_ptr = 0; getbuf = 0; getlen = 0; Decode(); delete [] text_buf; }