/* $XConsortium: decompress.c,v 1.5 94/04/17 20:26:57 dpw Exp $ */ /* Copyright (c) 1990 X Consortium Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. Except as contained in this notice, the name of the X Consortium shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from the X Consortium. */ /* * decompress - cat a compressed file */ #include #ifdef TEST #define xalloc(s) malloc(s) #define xfree(s) free(s) typedef char *FID; #include #include #include #else #include "Xos.h" #include "misc.h" #endif #define BITS 16 /* * a code_int must be able to hold 2**BITS values of type int, and also -1 */ #if BITS > 15 typedef long int code_int; #else typedef int code_int; #endif typedef long int count_int; #ifdef NO_UCHAR typedef char char_type; #else typedef unsigned char char_type; #endif /* UCHAR */ static char_type magic_header[] = { "\037\235" }; /* 1F 9D */ /* Defines for third byte of header */ #define BIT_MASK 0x1f #define BLOCK_MASK 0x80 /* Masks 0x40 and 0x20 are free. I think 0x20 should mean that there is a fourth header byte (for expansion). */ #define INIT_BITS 9 /* initial number of bits/code */ #ifdef COMPATIBLE /* But wrong! */ # define MAXCODE(n_bits) (1 << (n_bits) - 1) #else # define MAXCODE(n_bits) ((1 << (n_bits)) - 1) #endif /* COMPATIBLE */ static code_int getcode(); /* * the next two codes should not be changed lightly, as they must not * lie within the contiguous general code space. */ #define FIRST 257 /* first free entry */ #define CLEAR 256 /* table clear output code */ #define STACK_SIZE 8192 typedef struct _compressedFILE { FILE *file; char_type *stackp; code_int oldcode; char_type finchar; int block_compress; int maxbits; code_int maxcode, maxmaxcode; code_int free_ent; int clear_flg; int n_bits; /* bit buffer */ int offset, size; char_type buf[BITS]; char_type de_stack[STACK_SIZE]; char_type *tab_suffix; unsigned short *tab_prefix; } CompressedFile; static int hsize_table[] = { 5003, /* 12 bits - 80% occupancy */ 9001, /* 13 bits - 91% occupancy */ 18013, /* 14 bits - 91% occupancy */ 35023, /* 15 bits - 94% occupancy */ 69001 /* 16 bits - 95% occupancy */ }; FID CompressedFontFileInit (f) FILE *f; { int code; int maxbits; int hsize; CompressedFile *file; int extra; if ((getc(f) != (magic_header[0] & 0xFF)) || (getc(f) != (magic_header[1] & 0xFF))) { return 0; } code = getc (f); maxbits = code & BIT_MASK; if (maxbits > BITS || maxbits < 12) return 0; hsize = hsize_table[maxbits - 12]; extra = (1 << maxbits) * sizeof (char_type) + hsize * sizeof (unsigned short); file = (CompressedFile *) xalloc (sizeof (CompressedFile) + extra); if (!file) return 0; file->file = f; file->maxbits = maxbits; file->block_compress = code & BLOCK_MASK; file->maxmaxcode = 1 << file->maxbits; file->tab_suffix = (char_type *) &file[1]; file->tab_prefix = (unsigned short *) (file->tab_suffix + file->maxmaxcode); /* * As above, initialize the first 256 entries in the table. */ file->maxcode = MAXCODE(file->n_bits = INIT_BITS); for ( code = 255; code >= 0; code-- ) { file->tab_prefix[code] = 0; file->tab_suffix[code] = (char_type) code; } file->free_ent = ((file->block_compress) ? FIRST : 256 ); file->clear_flg = 0; file->offset = 0; file->size = 0; file->stackp = file->de_stack; file->finchar = file->oldcode = getcode (file); if (file->oldcode != -1) *file->stackp++ = file->finchar; return (FID) file; } FILE * CompressedFontFileDone (fid) FID fid; { CompressedFile *file; FILE *f; file = (CompressedFile *) fid; f = file->file; xfree (file); return f; } #define getdcchar(file) ((file)->stackp > (file)->de_stack ? (*--((file)->stackp)) : _filldcbuf (file)) _filldcbuf (file) CompressedFile *file; { register char_type *stackp; register code_int code, incode; if (file->stackp > file->de_stack) return *--file->stackp; if (file->oldcode == -1) return EOF; stackp = file->stackp; code = getcode (file); if (code == -1) return EOF; if ( (code == CLEAR) && file->block_compress ) { for ( code = 255; code >= 0; code-- ) file->tab_prefix[code] = 0; file->clear_flg = 1; file->free_ent = FIRST - 1; if ( (code = getcode (file)) == -1 ) /* O, untimely death! */ return EOF; } incode = code; /* * Special case for KwKwK string. */ if ( code >= file->free_ent ) { *stackp++ = file->finchar; code = file->oldcode; } /* * Generate output characters in reverse order */ while ( code >= 256 ) { *stackp++ = file->tab_suffix[code]; code = file->tab_prefix[code]; } file->finchar = file->tab_suffix[code]; /* * Generate the new entry. */ if ( (code=file->free_ent) < file->maxmaxcode ) { file->tab_prefix[code] = (unsigned short)file->oldcode; file->tab_suffix[code] = file->finchar; file->free_ent = code+1; } /* * Remember previous code. */ file->oldcode = incode; file->stackp = stackp; return file->finchar; } /***************************************************************** * TAG( getcode ) * * Read one code from the standard input. If EOF, return -1. * Inputs: * stdin * Outputs: * code or -1 is returned. */ static char_type rmask[9] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff}; static code_int getcode(file) CompressedFile *file; { register code_int code; register int r_off, bits; register char_type *bp = file->buf; register FILE *fp; if ( file->clear_flg > 0 || file->offset >= file->size || file->free_ent > file->maxcode ) { /* * If the next entry will be too big for the current code * size, then we must increase the size. This implies reading * a new buffer full, too. */ if ( file->free_ent > file->maxcode ) { file->n_bits++; if ( file->n_bits == file->maxbits ) file->maxcode = file->maxmaxcode; /* won't get any bigger now */ else file->maxcode = MAXCODE(file->n_bits); } if ( file->clear_flg > 0) { file->maxcode = MAXCODE (file->n_bits = INIT_BITS); file->clear_flg = 0; } bits = file->n_bits; fp = file->file; while (bits > 0 && (code = getc (fp)) != EOF) { *bp++ = code; --bits; } bp = file->buf; if (bits == file->n_bits) return -1; /* end of file */ file->size = file->n_bits - bits; file->offset = 0; /* Round size down to integral number of codes */ file->size = (file->size << 3) - (file->n_bits - 1); } r_off = file->offset; bits = file->n_bits; /* * Get to the first byte. */ bp += (r_off >> 3); r_off &= 7; /* Get first part (low order bits) */ #ifdef NO_UCHAR code = ((*bp++ >> r_off) & rmask[8 - r_off]) & 0xff; #else code = (*bp++ >> r_off); #endif /* NO_UCHAR */ bits -= (8 - r_off); r_off = 8 - r_off; /* now, offset into code word */ /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */ if ( bits >= 8 ) { #ifdef NO_UCHAR code |= (*bp++ & 0xff) << r_off; #else code |= *bp++ << r_off; #endif /* NO_UCHAR */ r_off += 8; bits -= 8; } /* high order bits. */ code |= (*bp & rmask[bits]) << r_off; file->offset += file->n_bits; return code; } CompressedFontFileRead (buf, itemsize, nitems, fid) char *buf; unsigned itemsize; unsigned nitems; FID fid; { CompressedFile *file; int c; int nbytes; file = (CompressedFile *) fid; nbytes = nitems * itemsize; while (nbytes) { if ((c = getdcchar (file)) == EOF) break; *buf++ = c; --nbytes; } return nitems - nbytes / itemsize; } CompressedFontFileSkip (bytes, fid) unsigned bytes; FID fid; { int c; while (bytes-- && ((c = getdcchar((CompressedFile *)fid)) != EOF)) ; return c; } #ifdef TEST main () { CompressedFile *input; int c; input = (CompressedFile *) CompressedFontFileInit (stdin); while ((c = getdcchar (input)) != -1) putchar (c); } #endif