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January 13, 2013 19:00
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fractal worldmap generator; from here: http://www.lysator.liu.se/~johol/fwmg/fwmg.html
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| /* | |
| * Copyright (C) 1999 John Olsson | |
| * | |
| * This program is free software; you can redistribute it and/or modify | |
| * it under the terms of the GNU General Public License as published by | |
| * the Free Software Foundation; either version 2 of the License, or | |
| * (at your option) any later version. | |
| * | |
| * This program is distributed in the hope that it will be useful, | |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| * GNU General Public License for more details. | |
| * | |
| * You should have received a copy of the GNU General Public License | |
| * along with this program; if not, write to the Free Software | |
| * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
| */ | |
| /* Fractal Worldmap Generator Version 2.2 | |
| * | |
| * Creator: John Olsson | |
| * Thanks to Carl Burke for interesting discussions and suggestions of | |
| * how to speed up the generation! :) | |
| * | |
| * This program is provided as is, and it's basically a "hack". So if you | |
| * want a better userinterface, you will have to provide it by yourself! | |
| * | |
| * For ideas about how to implement different projections, you can always | |
| * look in WorldMapGenerator.c (the CGI program that generates the gifs | |
| * on my www-page (http://www.lysator.liu.se/~johol/fwmg/fwmg.html). | |
| * | |
| * Please visit my WWW-pages located at: http://www.lysator.liu.se/~johol/ | |
| * You can send E-Mail to this adress: johol@lysator.liu.se | |
| * | |
| * I compile this program with: gcc -O3 worldgen.c -lm -o gengif | |
| * | |
| * This program will write the GIF-file to a file which you are | |
| * prompted to specify. | |
| * | |
| * To change size of the generated picture, change the default values | |
| * of the variables XRange och YRange. | |
| * | |
| * You use this program at your own risk! :) | |
| * | |
| * | |
| * When you run the program you are prompted to input three values: | |
| * | |
| * Seed: This the "seed" used to initialize the random number | |
| * generator. So if you use the same seed, you'll get the | |
| * same sequence of random numbers... | |
| * | |
| * Number of faults: This is how many iterations the program will do. | |
| * If you want to know how it works, just enter 1, 2, 3,... | |
| * etc. number of iterations and compare the different | |
| * GIF-files. | |
| * | |
| * PercentWater: This should be a value between 0 and 100 (you can | |
| * input 1000 also, but I don't know what the program | |
| * is up to then! :) The number tells the "ratio" | |
| * between water and land. If you want a world with | |
| * just a few islands, input a large value (EG. 80 or | |
| * above), if you want a world with nearly no oceans, | |
| * a value near 0 would do that. | |
| * | |
| */ | |
| #include <limits.h> | |
| #include <stdio.h> | |
| #include <stdlib.h> | |
| #include <unistd.h> | |
| #include <time.h> | |
| #include <string.h> | |
| #include <math.h> | |
| /* These define:s are for the GIF-saver... */ | |
| /* a code_int must be able to hold 2**BITS values of type int, and also -1 */ | |
| typedef int code_int; | |
| #ifdef SIGNED_COMPARE_SLOW | |
| typedef unsigned long int count_int; | |
| typedef unsigned short int count_short; | |
| #else /*SIGNED_COMPARE_SLOW*/ | |
| typedef long int count_int; | |
| #endif /*SIGNED_COMPARE_SLOW*/ | |
| static void BumpPixel ( void ); | |
| static int GIFNextPixel ( void ); | |
| static void GIFEncode (FILE* fp, int GWidth, int GHeight, int GInterlace, int Background, int BitsPerPixel, int Red[], int Green[], int Blue[]); | |
| static void Putword ( int w, FILE* fp ); | |
| static void compress ( int init_bits, FILE* outfile ); | |
| static void output ( code_int code ); | |
| static void cl_block ( void ); | |
| static void cl_hash ( count_int hsize ); | |
| static void writeerr ( void ); | |
| static void char_init ( void ); | |
| static void char_out ( int c ); | |
| static void flush_char ( void ); | |
| /* My own definitions */ | |
| #ifndef PI | |
| #define PI 3.141593 | |
| #endif | |
| /* This value holds the maximum value rand() can generate | |
| * | |
| * RAND_MAX *might* be defined in stdlib.h, if it's not | |
| * you *might* have to change the definition of MAX_RAND... | |
| */ | |
| #ifdef RAND_MAX | |
| #define MAX_RAND RAND_MAX | |
| #else | |
| #define MAX_RAND 0x7FFFFFFF | |
| #endif | |
| /* Function that generates the worldmap */ | |
| void GenerateWorldMap(); | |
| /* 4-connective floodfill algorithm which I use for constructing | |
| * the ice-caps.*/ | |
| void FloodFill4(int x, int y, int OldColor); | |
| int *WorldMapArray; | |
| int XRange = 320; | |
| int YRange = 160; | |
| int Histogram[256]; | |
| int FilledPixels; | |
| int Red[49] = {0,0,0,0,0,0,0,0,34,68,102,119,136,153,170,187, | |
| 0,34,34,119,187,255,238,221,204,187,170,153, | |
| 136,119,85,68, | |
| 255,250,245,240,235,230,225,220,215,210,205,200, | |
| 195,190,185,180,175}; | |
| int Green[49] = {0,0,17,51,85,119,153,204,221,238,255,255,255, | |
| 255,255,255,68,102,136,170,221,187,170,136, | |
| 136,102,85,85,68,51,51,34, | |
| 255,250,245,240,235,230,225,220,215,210,205,200, | |
| 195,190,185,180,175}; | |
| int Blue[49] = {0,68,102,136,170,187,221,255,255,255,255,255, | |
| 255,255,255,255,0,0,0,0,0,34,34,34,34,34,34, | |
| 34,34,34,17,0, | |
| 255,250,245,240,235,230,225,220,215,210,205,200, | |
| 195,190,185,180,175}; | |
| float YRangeDiv2, YRangeDivPI; | |
| float *SinIterPhi; | |
| void main(int argc, char **argv) | |
| { | |
| int NumberOfFaults=0, a, j, i, Color, MaxZ=1, MinZ=-1; | |
| int row, TwoColorMode=0; | |
| int index2; | |
| unsigned Seed=0; | |
| int Threshold, Count; | |
| int PercentWater, PercentIce, Cur; | |
| char SaveName[256]; /* 255 character filenames should be enough? */ | |
| char SaveFile[256]; /* SaveName + .gif */ | |
| FILE * Save; | |
| WorldMapArray = (int *) malloc(XRange*YRange*sizeof(int)); | |
| if (WorldMapArray == NULL) | |
| { | |
| fprintf(stderr, "I can't allocate enough memory!\n"); | |
| } | |
| SinIterPhi = (float *) malloc(2*XRange*sizeof(float)); | |
| if (SinIterPhi == NULL) | |
| { | |
| fprintf(stderr, "I can't allocate enough memory!\n"); | |
| } | |
| for (i=0; i<XRange; i++) | |
| { | |
| SinIterPhi[i] = SinIterPhi[i+XRange] = (float)sin(i*2*PI/XRange); | |
| } | |
| fprintf(stderr, "Seed: "); | |
| scanf("%d", &Seed); | |
| fprintf(stderr, "Number of faults: "); | |
| scanf("%d", &NumberOfFaults); | |
| fprintf(stderr, "Percent water: "); | |
| scanf("%d", &PercentWater); | |
| fprintf(stderr, "Percent ice: "); | |
| scanf("%d", &PercentIce); | |
| fprintf(stderr, "Save as (.GIF will be appended): "); | |
| scanf("%8s", SaveName); | |
| srand(Seed); | |
| for (j=0, row=0; j<XRange; j++) | |
| { | |
| WorldMapArray[row] = 0; | |
| for (i=1; i<YRange; i++) WorldMapArray[i+row] = INT_MIN; | |
| row += YRange; | |
| } | |
| /* Define some "constants" which we use frequently */ | |
| YRangeDiv2 = YRange/2; | |
| YRangeDivPI = YRange/PI; | |
| /* Generate the map! */ | |
| for (a=0; a<NumberOfFaults; a++) | |
| { | |
| GenerateWorldMap(); | |
| } | |
| /* Copy data (I have only calculated faults for 1/2 the image. | |
| * I can do this due to symmetry... :) */ | |
| index2 = (XRange/2)*YRange; | |
| for (j=0, row=0; j<XRange/2; j++) | |
| { | |
| for (i=0; i<YRange; i++) | |
| { | |
| WorldMapArray[row+index2+YRange-i] = WorldMapArray[row+i]; | |
| } | |
| row += YRange; | |
| } | |
| /* Reconstruct the real WorldMap from the WorldMapArray and FaultArray */ | |
| for (j=0, row=0; j<XRange; j++) | |
| { | |
| /* We have to start somewhere, and the top row was initialized to 0, | |
| * but it might have changed during the iterations... */ | |
| Color = WorldMapArray[row]; | |
| for (i=1; i<YRange; i++) | |
| { | |
| /* We "fill" all positions with values != INT_MIN with Color */ | |
| Cur = WorldMapArray[row+i]; | |
| if (Cur != INT_MIN) | |
| { | |
| Color += Cur; | |
| } | |
| WorldMapArray[row+i] = Color; | |
| } | |
| row += YRange; | |
| } | |
| /* Compute MAX and MIN values in WorldMapArray */ | |
| for (j=0; j<XRange*YRange; j++) | |
| { | |
| Color = WorldMapArray[j]; | |
| if (Color > MaxZ) MaxZ = Color; | |
| if (Color < MinZ) MinZ = Color; | |
| } | |
| /* Compute color-histogram of WorldMapArray. | |
| * This histogram is a very crude aproximation, since all pixels are | |
| * considered of the same size... I will try to change this in a | |
| * later version of this program. */ | |
| for (j=0, row=0; j<XRange; j++) | |
| { | |
| for (i=0; i<YRange; i++) | |
| { | |
| Color = WorldMapArray[row+i]; | |
| Color = (int)(((float)(Color - MinZ + 1) / (float)(MaxZ-MinZ+1))*30)+1; | |
| Histogram[Color]++; | |
| } | |
| row += YRange; | |
| } | |
| /* Threshold now holds how many pixels PercentWater means */ | |
| Threshold = PercentWater*XRange*YRange/100; | |
| /* "Integrate" the histogram to decide where to put sea-level */ | |
| for (j=0, Count=0;j<256;j++) | |
| { | |
| Count += Histogram[j]; | |
| if (Count > Threshold) break; | |
| } | |
| /* Threshold now holds where sea-level is */ | |
| Threshold = j*(MaxZ - MinZ + 1)/30 + MinZ; | |
| if (TwoColorMode) | |
| { | |
| for (j=0, row=0; j<XRange; j++) | |
| { | |
| for (i=0; i<YRange; i++) | |
| { | |
| Color = WorldMapArray[row+i]; | |
| if (Color < Threshold) | |
| WorldMapArray[row+i] = 3; | |
| else | |
| WorldMapArray[row+i] = 20; | |
| } | |
| row += YRange; | |
| } | |
| } | |
| else | |
| { | |
| /* Scale WorldMapArray to colorrange in a way that gives you | |
| * a certain Ocean/Land ratio */ | |
| for (j=0, row=0; j<XRange; j++) | |
| { | |
| for (i=0; i<YRange; i++) | |
| { | |
| Color = WorldMapArray[row+i]; | |
| if (Color < Threshold) | |
| Color = (int)(((float)(Color - MinZ) / (float)(Threshold - MinZ))*15)+1; | |
| else | |
| Color = (int)(((float)(Color - Threshold) / (float)(MaxZ - Threshold))*15)+16; | |
| /* Just in case... I DON't want the GIF-saver to flip out! :) */ | |
| if (Color < 1) Color=1; | |
| if (Color > 255) Color=31; | |
| WorldMapArray[row+i] = Color; | |
| } | |
| row += YRange; | |
| } | |
| /* "Recycle" Threshold variable, and, eh, the variable still has something | |
| * like the same meaning... :) */ | |
| Threshold = PercentIce*XRange*YRange/100; | |
| if ((Threshold <= 0) || (Threshold > XRange*YRange)) goto Finished; | |
| FilledPixels = 0; | |
| /* i==y, j==x */ | |
| for (i=0; i<YRange; i++) | |
| { | |
| for (j=0, row=0; j<XRange; j++) | |
| { | |
| Color = WorldMapArray[row+i]; | |
| if (Color < 32) FloodFill4(j,i,Color); | |
| /* FilledPixels is a global variable which FloodFill4 modifies... | |
| * I know it's ugly, but as it is now, this is a hack! :) | |
| */ | |
| if (FilledPixels > Threshold) goto NorthPoleFinished; | |
| row += YRange; | |
| } | |
| } | |
| NorthPoleFinished: | |
| FilledPixels=0; | |
| /* i==y, j==x */ | |
| for (i=YRange; i>0; i--) | |
| { | |
| for (j=0, row=0; j<XRange; j++) | |
| { | |
| Color = WorldMapArray[row+i]; | |
| if (Color < 32) FloodFill4(j,i,Color); | |
| /* FilledPixels is a global variable which FloodFill4 modifies... | |
| * I know it's ugly, but as it is now, this is a hack! :) | |
| */ | |
| if (FilledPixels > Threshold) goto Finished; | |
| row += YRange; | |
| } | |
| } | |
| Finished: | |
| } | |
| /* append .gif to SaveFile */ | |
| sprintf(SaveFile, "%s.gif", SaveName); | |
| /* open binary SaveFile */ | |
| Save = fopen(SaveFile, "wb"); | |
| /* Write GIF to savefile */ | |
| GIFEncode(Save, XRange, YRange, 1, 0, 8, Red, Green, Blue); | |
| fprintf(stderr, "Map created, saved as %s.\n", SaveFile); | |
| free(WorldMapArray); | |
| exit(0); | |
| } | |
| void FloodFill4(int x, int y, int OldColor) | |
| { | |
| if (WorldMapArray[x*YRange+y] == OldColor) | |
| { | |
| if (WorldMapArray[x*YRange+y] < 16) | |
| WorldMapArray[x*YRange+y] = 32; | |
| else | |
| WorldMapArray[x*YRange+y] += 17; | |
| FilledPixels++; | |
| if (y-1 > 0) FloodFill4( x, y-1, OldColor); | |
| if (y+1 < YRange) FloodFill4( x, y+1, OldColor); | |
| if (x-1 < 0) | |
| FloodFill4(XRange, y, OldColor); | |
| else | |
| FloodFill4( x-1, y, OldColor); | |
| if (x+1 > XRange) | |
| FloodFill4( 0, y, OldColor); | |
| else | |
| FloodFill4( x+1, y, OldColor); | |
| } | |
| } | |
| void GenerateWorldMap() | |
| { | |
| float Alpha, Beta; | |
| float TanB; | |
| float Result, Delta; | |
| int i, row, N2; | |
| int Theta, Phi, Xsi; | |
| unsigned int flag1; | |
| /* I have to do this because of a bug in rand() in Solaris 1... | |
| * Here's what the man-page says: | |
| * | |
| * "The low bits of the numbers generated are not very random; | |
| * use the middle bits. In particular the lowest bit alter- | |
| * nates between 0 and 1." | |
| * | |
| * So I can't optimize this, but you might if you don't have the | |
| * same bug... */ | |
| flag1 = rand() & 1; /*(int)((((float) rand())/MAX_RAND) + 0.5);*/ | |
| /* Create a random greatcircle... | |
| * Start with an equator and rotate it */ | |
| Alpha = (((float) rand())/MAX_RAND-0.5)*PI; /* Rotate around x-axis */ | |
| Beta = (((float) rand())/MAX_RAND-0.5)*PI; /* Rotate around y-axis */ | |
| TanB = tan(acos(cos(Alpha)*cos(Beta))); | |
| row = 0; | |
| Xsi = (int)(XRange/2-(XRange/PI)*Beta); | |
| for (Phi=0; Phi<XRange/2; Phi++) | |
| { | |
| Theta = (int)(YRangeDivPI*atan(*(SinIterPhi+Xsi-Phi+XRange)*TanB))+YRangeDiv2; | |
| if (flag1) | |
| { | |
| /* Rise northen hemisphere <=> lower southern */ | |
| if (WorldMapArray[row+Theta] != INT_MIN) | |
| WorldMapArray[row+Theta]--; | |
| else | |
| WorldMapArray[row+Theta] = -1; | |
| } | |
| else | |
| { | |
| /* Rise southern hemisphere */ | |
| if (WorldMapArray[row+Theta] != INT_MIN) | |
| WorldMapArray[row+Theta]++; | |
| else | |
| WorldMapArray[row+Theta] = 1; | |
| } | |
| row += YRange; | |
| } | |
| } | |
| /***************************************************************************** | |
| * | |
| * GIFENCODE.C - GIF Image compression interface | |
| * | |
| * GIFEncode( FName, GHeight, GWidth, GInterlace, Background, | |
| * BitsPerPixel, Red, Green, Blue, GetPixel ) | |
| * | |
| *****************************************************************************/ | |
| #define TRUE 1 | |
| #define FALSE 0 | |
| static int Width, Height; | |
| static int curx, cury; | |
| static long CountDown; | |
| static int Pass = 0; | |
| static int Interlace; | |
| /* | |
| * Bump the 'curx' and 'cury' to point to the next pixel | |
| */ | |
| static void | |
| BumpPixel() | |
| { | |
| /* | |
| * Bump the current X position | |
| */ | |
| ++curx; | |
| /* | |
| * If we are at the end of a scan line, set curx back to the beginning | |
| * If we are interlaced, bump the cury to the appropriate spot, | |
| * otherwise, just increment it. | |
| */ | |
| if( curx == Width ) { | |
| curx = 0; | |
| if( !Interlace ) | |
| ++cury; | |
| else { | |
| switch( Pass ) { | |
| case 0: | |
| cury += 8; | |
| if( cury >= Height ) { | |
| ++Pass; | |
| cury = 4; | |
| } | |
| break; | |
| case 1: | |
| cury += 8; | |
| if( cury >= Height ) { | |
| ++Pass; | |
| cury = 2; | |
| } | |
| break; | |
| case 2: | |
| cury += 4; | |
| if( cury >= Height ) { | |
| ++Pass; | |
| cury = 1; | |
| } | |
| break; | |
| case 3: | |
| cury += 2; | |
| break; | |
| } | |
| } | |
| } | |
| } | |
| /* | |
| * Return the next pixel from the image | |
| */ | |
| static int | |
| GIFNextPixel( void ) | |
| { | |
| int r; | |
| if( CountDown == 0 ) | |
| return EOF; | |
| --CountDown; | |
| r = WorldMapArray[ curx*YRange+cury ]; | |
| BumpPixel(); | |
| return r; | |
| } | |
| /* public */ | |
| static void | |
| GIFEncode( fp, GWidth, GHeight, GInterlace, Background, | |
| BitsPerPixel, Red, Green, Blue) | |
| FILE* fp; | |
| int GWidth, GHeight; | |
| int GInterlace; | |
| int Background; | |
| int BitsPerPixel; | |
| int Red[], Green[], Blue[]; | |
| { | |
| int B; | |
| int RWidth, RHeight; | |
| int LeftOfs, TopOfs; | |
| int Resolution; | |
| int ColorMapSize; | |
| int InitCodeSize; | |
| int i; | |
| Interlace = GInterlace; | |
| ColorMapSize = 1 << BitsPerPixel; | |
| RWidth = Width = GWidth; | |
| RHeight = Height = GHeight; | |
| LeftOfs = TopOfs = 0; | |
| Resolution = BitsPerPixel; | |
| /* | |
| * Calculate number of bits we are expecting | |
| */ | |
| CountDown = (long)Width * (long)Height; | |
| /* | |
| * Indicate which pass we are on (if interlace) | |
| */ | |
| Pass = 0; | |
| /* | |
| * The initial code size | |
| */ | |
| if( BitsPerPixel <= 1 ) | |
| InitCodeSize = 2; | |
| else | |
| InitCodeSize = BitsPerPixel; | |
| /* | |
| * Set up the current x and y position | |
| */ | |
| curx = cury = 0; | |
| /* | |
| * Write the Magic header | |
| */ | |
| fwrite( "GIF87a", 1, 6, fp ); | |
| /* | |
| * Write out the screen width and height | |
| */ | |
| Putword( RWidth, fp ); | |
| Putword( RHeight, fp ); | |
| /* | |
| * Indicate that there is a global colour map | |
| */ | |
| B = 0x80; /* Yes, there is a color map */ | |
| /* | |
| * OR in the resolution | |
| */ | |
| B |= (Resolution - 1) << 5; | |
| /* | |
| * OR in the Bits per Pixel | |
| */ | |
| B |= (BitsPerPixel - 1); | |
| /* | |
| * Write it out | |
| */ | |
| fputc( B, fp ); | |
| /* | |
| * Write out the Background colour | |
| */ | |
| fputc( Background, fp ); | |
| /* | |
| * Byte of 0's (future expansion) | |
| */ | |
| fputc( 0, fp ); | |
| /* | |
| * Write out the Global Colour Map | |
| */ | |
| for( i=0; i<ColorMapSize; ++i ) { | |
| fputc( Red[i], fp ); | |
| fputc( Green[i], fp ); | |
| fputc( Blue[i], fp ); | |
| } | |
| /* | |
| * Write an Image separator | |
| */ | |
| fputc( ',', fp ); | |
| /* | |
| * Write the Image header | |
| */ | |
| Putword( LeftOfs, fp ); | |
| Putword( TopOfs, fp ); | |
| Putword( Width, fp ); | |
| Putword( Height, fp ); | |
| /* | |
| * Write out whether or not the image is interlaced | |
| */ | |
| if( Interlace ) | |
| fputc( 0x40, fp ); | |
| else | |
| fputc( 0x00, fp ); | |
| /* | |
| * Write out the initial code size | |
| */ | |
| fputc( InitCodeSize, fp ); | |
| /* | |
| * Go and actually compress the data | |
| */ | |
| compress( InitCodeSize+1, fp); | |
| /* | |
| * Write out a Zero-length packet (to end the series) | |
| */ | |
| fputc( 0, fp ); | |
| /* | |
| * Write the GIF file terminator | |
| */ | |
| fputc( ';', fp ); | |
| /* | |
| * And close the file | |
| */ | |
| fclose( fp ); | |
| } | |
| /* | |
| * Write out a word to the GIF file | |
| */ | |
| static void | |
| Putword( w, fp ) | |
| int w; | |
| FILE* fp; | |
| { | |
| fputc( w & 0xff, fp ); | |
| fputc( (w / 256) & 0xff, fp ); | |
| } | |
| /*************************************************************************** | |
| * | |
| * GIFCOMPR.C - GIF Image compression routines | |
| * | |
| * Lempel-Ziv compression based on 'compress'. GIF modifications by | |
| * David Rowley (mgardi@watdcsu.waterloo.edu) | |
| * | |
| ***************************************************************************/ | |
| /* | |
| * General DEFINEs | |
| */ | |
| #define BITS 12 | |
| #define HSIZE 5003 /* 80% occupancy */ | |
| #ifdef NO_UCHAR | |
| typedef char char_type; | |
| #else /*NO_UCHAR*/ | |
| typedef unsigned char char_type; | |
| #endif /*NO_UCHAR*/ | |
| /* | |
| * | |
| * GIF Image compression - modified 'compress' | |
| * | |
| * Based on: compress.c - File compression ala IEEE Computer, June 1984. | |
| * | |
| * By Authors: 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 <ctype.h> | |
| #define ARGVAL() (*++(*argv) || (--argc && *++argv)) | |
| static int n_bits; /* number of bits/code */ | |
| static int maxbits = BITS; /* user settable max # bits/code */ | |
| static code_int maxcode; /* maximum code, given n_bits */ | |
| static code_int maxmaxcode = (code_int)1 << BITS; /* should NEVER generate this code */ | |
| #ifdef COMPATIBLE /* But wrong! */ | |
| # define MAXCODE(n_bits) ((code_int) 1 << (n_bits) - 1) | |
| #else /*COMPATIBLE*/ | |
| # define MAXCODE(n_bits) (((code_int) 1 << (n_bits)) - 1) | |
| #endif /*COMPATIBLE*/ | |
| static count_int htab [HSIZE]; | |
| static unsigned short codetab [HSIZE]; | |
| #define HashTabOf(i) htab[i] | |
| #define CodeTabOf(i) codetab[i] | |
| static code_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((code_int)1<<BITS)) | |
| static code_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 int offset; | |
| static long int in_count = 1; /* length of input */ | |
| 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 FILE* g_outfile; | |
| static int ClearCode; | |
| static int EOFCode; | |
| static void | |
| compress( init_bits, outfile) | |
| int init_bits; | |
| FILE* outfile; | |
| { | |
| register long fcode; | |
| register code_int i /* = 0 */; | |
| register int c; | |
| register code_int ent; | |
| register code_int disp; | |
| register code_int hsize_reg; | |
| register int hshift; | |
| /* | |
| * Set up the globals: g_init_bits - initial number of bits | |
| * g_outfile - pointer to output file | |
| */ | |
| g_init_bits = init_bits; | |
| g_outfile = outfile; | |
| /* | |
| * Set up the necessary values | |
| */ | |
| offset = 0; | |
| out_count = 0; | |
| clear_flg = 0; | |
| in_count = 1; | |
| maxcode = MAXCODE(n_bits = g_init_bits); | |
| ClearCode = (1 << (init_bits - 1)); | |
| EOFCode = ClearCode + 1; | |
| free_ent = ClearCode + 2; | |
| char_init(); | |
| ent = GIFNextPixel( ); | |
| 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( (code_int)ClearCode ); | |
| #ifdef SIGNED_COMPARE_SLOW | |
| while ( (c = GIFNextPixel( )) != (unsigned) EOF ) { | |
| #else /*SIGNED_COMPARE_SLOW*/ | |
| while ( (c = GIFNextPixel( )) != EOF ) { /* } */ | |
| #endif /*SIGNED_COMPARE_SLOW*/ | |
| ++in_count; | |
| fcode = (long) (((long) c << maxbits) + ent); | |
| i = (((code_int)c << hshift) ^ ent); /* xor hashing */ | |
| if ( HashTabOf (i) == fcode ) { | |
| ent = CodeTabOf (i); | |
| continue; | |
| } else 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 ( (code_int) ent ); | |
| ++out_count; | |
| ent = c; | |
| #ifdef SIGNED_COMPARE_SLOW | |
| if ( (unsigned) free_ent < (unsigned) maxmaxcode) { | |
| #else /*SIGNED_COMPARE_SLOW*/ | |
| if ( free_ent < maxmaxcode ) { /* } */ | |
| #endif /*SIGNED_COMPARE_SLOW*/ | |
| CodeTabOf (i) = free_ent++; /* code -> hashtable */ | |
| HashTabOf (i) = fcode; | |
| } else | |
| cl_block(); | |
| } | |
| /* | |
| * Put out the final code. | |
| */ | |
| output( (code_int)ent ); | |
| ++out_count; | |
| output( (code_int) EOFCode ); | |
| } | |
| /***************************************************************** | |
| * TAG( output ) | |
| * | |
| * 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 cur_accum = 0; | |
| static int cur_bits = 0; | |
| static unsigned long masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F, | |
| 0x001F, 0x003F, 0x007F, 0x00FF, | |
| 0x01FF, 0x03FF, 0x07FF, 0x0FFF, | |
| 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF }; | |
| static void | |
| output( code ) | |
| 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( (unsigned 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( (unsigned int)(cur_accum & 0xff) ); | |
| cur_accum >>= 8; | |
| cur_bits -= 8; | |
| } | |
| flush_char(); | |
| fflush( g_outfile ); | |
| if( ferror( g_outfile ) ) | |
| writeerr(); | |
| } | |
| } | |
| /* | |
| * Clear out the hash table | |
| */ | |
| static void | |
| cl_block () /* table clear for block compress */ | |
| { | |
| cl_hash ( (count_int) hsize ); | |
| free_ent = ClearCode + 2; | |
| clear_flg = 1; | |
| output( (code_int)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; | |
| } | |
| static void | |
| writeerr() | |
| { | |
| fprintf(stderr, "error writing output file" ); | |
| } | |
| /****************************************************************************** | |
| * | |
| * 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( a_count > 0 ) { | |
| fputc( a_count, g_outfile ); | |
| fwrite( accum, 1, a_count, g_outfile ); | |
| a_count = 0; | |
| } | |
| } | |
| /* The End */ |
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