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Diffstat (limited to 'Examples/GIFPlot/Lib/gif.c')
| -rw-r--r-- | Examples/GIFPlot/Lib/gif.c | 672 |
1 files changed, 672 insertions, 0 deletions
diff --git a/Examples/GIFPlot/Lib/gif.c b/Examples/GIFPlot/Lib/gif.c new file mode 100644 index 0000000..7953e5c --- /dev/null +++ b/Examples/GIFPlot/Lib/gif.c @@ -0,0 +1,672 @@ + +/********************************************************************** + * GIFPlot 0.0 + * + * Dave Beazley + * + * Department of Computer Science Theoretical Division (T-11) + * University of Utah Los Alamos National Laboratory + * Salt Lake City, Utah 84112 Los Alamos, New Mexico 87545 + * beazley@cs.utah.edu beazley@lanl.gov + * + * Copyright (c) 1996 + * The Regents of the University of California and the University of Utah + * All Rights Reserved + * + * Permission is hereby granted, without written agreement and without + * license or royalty fees, to use, copy, modify, and distribute this + * software and its documentation for any purpose, provided that + * (1) The above copyright notice and the following two paragraphs + * appear in all copies of the source code and (2) redistributions + * including binaries reproduces these notices in the supporting + * documentation. Substantial modifications to this software may be + * copyrighted by their authors and need not follow the licensing terms + * described here, provided that the new terms are clearly indicated in + * all files where they apply. + * + * IN NO EVENT SHALL THE AUTHOR, THE UNIVERSITY OF CALIFORNIA, THE + * UNIVERSITY OF UTAH OR DISTRIBUTORS OF THIS SOFTWARE BE LIABLE TO ANY + * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL + * DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, + * EVEN IF THE AUTHORS OR ANY OF THE ABOVE PARTIES HAVE BEEN ADVISED OF + * THE POSSIBILITY OF SUCH DAMAGE. + * + * THE AUTHOR, THE UNIVERSITY OF CALIFORNIA, AND THE UNIVERSITY OF UTAH + * SPECIFICALLY DISCLAIM ANY WARRANTIES,INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND + * THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE MAINTENANCE, + * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + * + **************************************************************************/ + +/******************************************************************* + * Creates a GIF format file. + * + * Dave Beazley (T-11) + * August 11, 1995 + * + * Rather than writing directly to files, this module fills out + * output buffer. + * + * Note : To save memory, this routine uses approximately 50K of the + * output buffer as temporary storage (for hash tables and compression codes). + * The remainder of the output buffer is used to store the final image. + * This feature allows GIF images to be created with no additional + * memory overhead. + * + * -- Revision History + * $Log$ + * Revision 1.2 2003/09/01 16:23:31 beazley + * Restored the 'mojo'. + * + * Revision 1.2 1996/09/25 22:39:30 dmb + * Fixed prototypes and use of void pointers for compatibility with the Cray T3D + * + * Revision 1.1 1996/09/10 17:44:00 dmb + * Initial revision + * + * Revision 1.2 1995/08/31 14:46:07 beazley + * Minor changes to support comments and a few bug fixes. + * + * + ******************************************************************/ + + +/* + * xvgifwr.c - handles writing of GIF files. based on flgife.c and + * flgifc.c from the FBM Library, by Michael Maudlin + * + * Contains: + * WriteGIF(fp, pic, ptype, w, h, rmap, gmap, bmap, numcols, colorstyle, + * comment) + * + * Note: slightly brain-damaged, in that it'll only write non-interlaced + * GIF files (in the interests of speed, or something) + * + */ + + + +/***************************************************************** + * Portions of this code Copyright (C) 1989 by Michael Mauldin. + * Permission is granted to use this file in whole or in + * part for any purpose, educational, recreational or commercial, + * provided that this copyright notice is retained unchanged. + * This software is available to all free of charge by anonymous + * FTP and in the UUNET archives. + * + * + * Authors: Michael Mauldin (mlm@cs.cmu.edu) + * David Rowley (mgardi@watdcsu.waterloo.edu) + * + * Based on: compress.c - File compression ala IEEE Computer, June 1984. + * + * Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas) + * Jim McKie (decvax!mcvax!jim) + * Steve Davies (decvax!vax135!petsd!peora!srd) + * Ken Turkowski (decvax!decwrl!turtlevax!ken) + * James A. Woods (decvax!ihnp4!ames!jaw) + * Joe Orost (decvax!vax135!petsd!joe) + *****************************************************************/ + +#include "gifplot.h" +#include <string.h> +typedef long int count_int; +typedef unsigned char byte; + +static int gif_error; +static unsigned char *op; +static int Width, Height; +static int curx, cury; +static int Interlace; + +static void putgifword(int); +static void compress(int, byte **, int); +static void output_GIF(int); +static void cl_block(void); +static void cl_hash(count_int); +static void char_init(void); +static void char_out(int); +static void flush_char(void); +static void *OutBuffer; +static int OutBufSize; +static FrameBuffer *GIF_frame; + +static unsigned char pc2nc[256],r1[256],g1[256],b1[256]; + +/*************************************************************/ +int FrameBuffer_makeGIF(FrameBuffer *f, ColorMap *c, void *outbuffer, unsigned int outbufsize) +{ + int RWidth, RHeight; + int LeftOfs, TopOfs; + int ColorMapSize, InitCodeSize, Background, BitsPerPixel; + int i,j,nc; + char *rmap, *gmap, *bmap; + char *cmap; + int count; + + Interlace = 0; + Background = 0; + OutBuffer = outbuffer; + OutBufSize = outbufsize; + GIF_frame = f; + cmap = (char *) c->cmap; + + op = (unsigned char *) outbuffer; + gif_error = 0; + for (i=0; i<256; i++) { pc2nc[i] = r1[i] = g1[i] = b1[i] = 0; } + + /* compute number of unique colors */ + nc = 0; + rmap = &cmap[0]; + gmap = &cmap[256]; + bmap = &cmap[512]; + + for (i=0; i<256; i++) { + /* see if color #i is already used */ + for (j=0; j<i; j++) { + if (rmap[i] == rmap[j] && gmap[i] == gmap[j] && + bmap[i] == bmap[j]) break; + } + + if (j==i) { /* wasn't found */ + pc2nc[i] = nc; + r1[nc] = rmap[i]; + g1[nc] = gmap[i]; + b1[nc] = bmap[i]; + nc++; + } + else pc2nc[i] = pc2nc[j]; + } + + /* figure out 'BitsPerPixel' */ + for (i=1; i<8; i++) + if ( (1<<i) >= nc) break; + + BitsPerPixel = i; + + ColorMapSize = 1 << BitsPerPixel; + + RWidth = Width = f->width; + RHeight = Height = f->height; + LeftOfs = TopOfs = 0; + + if (BitsPerPixel <= 1) InitCodeSize = 2; + else InitCodeSize = BitsPerPixel; + + curx = 0; + cury = f->height - 1; + + strcpy((char *) op,"GIF89a"); /* Put in GIF magic number */ + op+=6; + putgifword(RWidth); /* screen descriptor */ + putgifword(RHeight); + + i = 0x80; /* Yes, there is a color map */ + i |= (8-1)<<4; /* OR in the color resolution (hardwired 8) */ + i |= (BitsPerPixel - 1); /* OR in the # of bits per pixel */ + *(op++) = i; + *(op++) = Background; /* background color */ + *(op++) = 0; + for (i=0; i<ColorMapSize; i++) { /* write out Global colormap */ + *(op++) = r1[i]; + *(op++) = g1[i]; + *(op++) = b1[i]; + } + + *(op++) = ','; /* image separator */ + + /* Write the Image header */ + putgifword(LeftOfs); + putgifword(TopOfs); + putgifword(Width); + putgifword(Height); + *(op++) = 0; + *(op++) = InitCodeSize; + + compress(InitCodeSize+1, f->pixels, f->width*f->height); + + *(op++) = 0; + *(op++) = ';'; + + count = (op - (unsigned char *) OutBuffer); + if (gif_error) return -1; + else return count; +} + +/******************************/ +static void putgifword(w) +int w; +{ + /* writes a 16-bit integer in GIF order (LSB first) */ + *(op++) = w & 0xff; + *(op++) = (w>>8)&0xff; +} + +/***********************************************************************/ + + +static unsigned long cur_accum = 0; +static int cur_bits = 0; + + + + +#define GP_BITS 12 /* BITS was already defined on some systems */ + +#define HSIZE 5003 /* 80% occupancy */ + +typedef unsigned char char_type; + +static int n_bits; /* number of bits/code */ +static int maxbits = GP_BITS; /* user settable max # bits/code */ +static int maxcode; /* maximum code, given n_bits */ +static int maxmaxcode = 1 << GP_BITS; /* NEVER generate this */ + +#define MAXCODE(n_bits) ( (1 << (n_bits)) - 1) + +static count_int *htab; +static unsigned short *codetab; +static int GIFOutBufSize; + +/* static count_int htab [HSIZE]; +static unsigned short codetab [HSIZE]; */ + +#define HashTabOf(i) htab[i] +#define CodeTabOf(i) codetab[i] + +static int hsize = HSIZE; /* for dynamic table sizing */ + +/* + * To save much memory, we overlay the table used by compress() with those + * used by decompress(). The tab_prefix table is the same size and type + * as the codetab. The tab_suffix table needs 2**BITS characters. We + * get this from the beginning of htab. The output stack uses the rest + * of htab, and contains characters. There is plenty of room for any + * possible stack (stack used to be 8000 characters). + */ + +#define tab_prefixof(i) CodeTabOf(i) +#define tab_suffixof(i) ((char_type *)(htab))[i] +#define de_stack ((char_type *)&tab_suffixof(1<<GP_BITS)) + +static int free_ent = 0; /* first unused entry */ + +/* + * block compression parameters -- after all codes are used up, + * and compression rate changes, start over. + */ +static int clear_flg = 0; + +static long int out_count = 0; /* # of codes output (for debugging) */ + +/* + * compress stdin to stdout + * + * Algorithm: use open addressing double hashing (no chaining) on the + * prefix code / next character combination. We do a variant of Knuth's + * algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime + * secondary probe. Here, the modular division first probe is gives way + * to a faster exclusive-or manipulation. Also do block compression with + * an adaptive reset, whereby the code table is cleared when the compression + * ratio decreases, but after the table fills. The variable-length output + * codes are re-sized at this point, and a special CLEAR code is generated + * for the decompressor. Late addition: construct the table according to + * file size for noticeable speed improvement on small files. Please direct + * questions about this implementation to ames!jaw. + */ + +static int g_init_bits; + +static int ClearCode; +static int EOFCode; + + +/********************************************************/ +static void compress(init_bits, data, len) + int init_bits; + unsigned char **data; + int len; +{ + register long fcode; + register int i = 0; + register int c; + register int ent; + register int disp; + register int hsize_reg; + register int hshift; + int code_count = 0; + + /* Use the output buffer as temporary storage for GIF data */ + + if (OutBufSize < HSIZE*(sizeof(count_int) + sizeof(unsigned short))) { + gif_error =1; + return; + } + + /* Put htab and codetab arrays into the output buffer */ + + GIFOutBufSize = OutBufSize - HSIZE*(sizeof(count_int) + sizeof(unsigned short)) - 16; + GIFOutBufSize = GIFOutBufSize & (~0x3); /* Make sure it's double word alligned */ + + htab = (count_int *) ((char *) OutBuffer + GIFOutBufSize); + codetab = (unsigned short *) ((char *) OutBuffer + GIFOutBufSize + HSIZE*sizeof(count_int)); + + /* + * Set up the globals: g_init_bits - initial number of bits + * g_outfile - pointer to output file + */ + g_init_bits = init_bits; + + + /* initialize 'compress' globals */ + maxbits = GP_BITS; + maxmaxcode = 1<<GP_BITS; + memset(htab,0,sizeof(htab)); + memset(codetab,0,sizeof(codetab)); + hsize = HSIZE; + free_ent = 0; + clear_flg = 0; + out_count = 0; + cur_accum = 0; + cur_bits = 0; + + /* + * Set up the necessary values + */ + out_count = 0; + clear_flg = 0; + maxcode = MAXCODE(n_bits = g_init_bits); + + ClearCode = (1 << (init_bits - 1)); + EOFCode = ClearCode + 1; + free_ent = ClearCode + 2; + + char_init(); + ent = pc2nc[data[cury][curx]]; + curx++; + if (curx >= GIF_frame->width) { + curx = 0; + cury--; + } + len--; + + hshift = 0; + for ( fcode = (long) hsize; fcode < 65536L; fcode *= 2L ) + hshift++; + hshift = 8 - hshift; /* set hash code range bound */ + + hsize_reg = hsize; + cl_hash( (count_int) hsize_reg); /* clear hash table */ + + output_GIF(ClearCode); + while (len) { + c = pc2nc[data[cury][curx]]; + curx++; + if (curx >= GIF_frame->width) { + curx = 0; + cury--; + } + len--; + + fcode = (long) ( ( (long) c << maxbits) + ent); + i = (((int) c << hshift) ^ ent); /* xor hashing */ + + if ( HashTabOf (i) == fcode ) { + ent = CodeTabOf (i); + continue; + } + + if ( (long)HashTabOf (i) < 0 ) /* empty slot */ + goto nomatch; + + disp = hsize_reg - i; /* secondary hash (after G. Knott) */ + if ( i == 0 ) + disp = 1; + +probe: + if ( (i -= disp) < 0 ) + i += hsize_reg; + + if ( HashTabOf (i) == fcode ) { + ent = CodeTabOf (i); + continue; + } + + if ( (long)HashTabOf (i) >= 0 ) + goto probe; + +nomatch: + output_GIF(ent); + out_count++; + ent = c; + + if ( free_ent < maxmaxcode ) { + CodeTabOf (i) = free_ent++; /* code -> hashtable */ + HashTabOf (i) = fcode; + } + else + cl_block(); + + } + /* Put out the final code */ + output_GIF(ent); + output_GIF(EOFCode); +} + + +/***************************************************************** + * TAG( output_GIF ) + * + * Output the given code. + * Inputs: + * code: A n_bits-bit integer. If == -1, then EOF. This assumes + * that n_bits =< (long)wordsize - 1. + * Outputs: + * Outputs code to the file. + * Assumptions: + * Chars are 8 bits long. + * Algorithm: + * Maintain a BITS character long buffer (so that 8 codes will + * fit in it exactly). Use the VAX insv instruction to insert each + * code in turn. When the buffer fills up empty it and start over. + */ + +static +unsigned long masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F, + 0x001F, 0x003F, 0x007F, 0x00FF, + 0x01FF, 0x03FF, 0x07FF, 0x0FFF, + 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF }; + +static void output_GIF(code) +int code; +{ + cur_accum &= masks[cur_bits]; + + if (cur_bits > 0) + cur_accum |= ((long)code << cur_bits); + else + cur_accum = code; + + cur_bits += n_bits; + + while( cur_bits >= 8 ) { + char_out( (int) (cur_accum & 0xff) ); + cur_accum >>= 8; + cur_bits -= 8; + } + + /* + * If the next entry is going to be too big for the code size, + * then increase it, if possible. + */ + + if (free_ent > maxcode || clear_flg) { + + if( clear_flg ) { + maxcode = MAXCODE (n_bits = g_init_bits); + clear_flg = 0; + } + else { + n_bits++; + if ( n_bits == maxbits ) + maxcode = maxmaxcode; + else + maxcode = MAXCODE(n_bits); + } + } + + if( code == EOFCode ) { + /* At EOF, write the rest of the buffer */ + while( cur_bits > 0 ) { + char_out( (int)(cur_accum & 0xff) ); + cur_accum >>= 8; + cur_bits -= 8; + } + + flush_char(); + } +} + + +/********************************/ +static void cl_block () /* table clear for block compress */ +{ + /* Clear out the hash table */ + + cl_hash ( (count_int) hsize ); + free_ent = ClearCode + 2; + clear_flg = 1; + + output_GIF(ClearCode); +} + + +/********************************/ +static void cl_hash(hsize) /* reset code table */ +register count_int hsize; +{ + register count_int *htab_p = htab+hsize; + register long i; + register long m1 = -1; + + i = hsize - 16; + do { /* might use Sys V memset(3) here */ + *(htab_p-16) = m1; + *(htab_p-15) = m1; + *(htab_p-14) = m1; + *(htab_p-13) = m1; + *(htab_p-12) = m1; + *(htab_p-11) = m1; + *(htab_p-10) = m1; + *(htab_p-9) = m1; + *(htab_p-8) = m1; + *(htab_p-7) = m1; + *(htab_p-6) = m1; + *(htab_p-5) = m1; + *(htab_p-4) = m1; + *(htab_p-3) = m1; + *(htab_p-2) = m1; + *(htab_p-1) = m1; + htab_p -= 16; + } while ((i -= 16) >= 0); + + for ( i += 16; i > 0; i-- ) + *--htab_p = m1; +} + + +/****************************************************************************** + * + * GIF Specific routines + * + ******************************************************************************/ + +/* + * Number of characters so far in this 'packet' + */ +static int a_count; + +/* + * Set up the 'byte output' routine + */ +static void char_init() +{ + a_count = 0; +} + +/* + * Define the storage for the packet accumulator + */ +static char accum[ 256 ]; + +/* + * Add a character to the end of the current packet, and if it is 254 + * characters, flush the packet to disk. + */ +static void char_out(c) +int c; +{ + accum[ a_count++ ] = c; + if( a_count >= 254 ) + flush_char(); +} + +/* + * Flush the packet to disk, and reset the accumulator + */ +static void flush_char() +{ + if (gif_error) return; + if( a_count > 0 ) { + *(op++) = a_count; + memcpy(op,accum,a_count); + op+=a_count; + a_count = 0; + + if (op > (unsigned char *) ((char *) OutBuffer + (GIFOutBufSize - 2048))) { + gif_error = 1; + } + } +} + + +/* ---------------------------------------------------------------------- + int FrameBuffer_writeGIF(char *filename) + + Write a GIF file to filename + ----------------------------------------------------------------------- */ + +int FrameBuffer_writeGIF(FrameBuffer *f, ColorMap *c, char *filename) { + + FILE *file; + void *buffer; + int nbytes; + int bufsize; + + file = fopen(filename,"wb"); + if (file == NULL) return -1; + + bufsize = (f->width*f->height*3)/2; + buffer = (void *) malloc(bufsize); + nbytes = FrameBuffer_makeGIF(f,c,buffer,bufsize); + if (nbytes == -1) { + free(buffer); + fclose(file); + return -1; + } + if (fwrite(buffer,nbytes,1,file) != 1) { + free(buffer); + fclose(file); + return -1; + } + fclose(file); + free(buffer); + return 0; +} + + + + + |