737 lines
16 KiB
C
737 lines
16 KiB
C
/* blib - Library of useful things to hack the Blinkenlights
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*
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* Copyright (c) 2001-2002 The Blinkenlights Crew
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* Sven Neumann <sven@gimp.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/* GIF savinging routines stripped out of the GIF saving filter for The GIMP.
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*
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* Modified for blinkentools in 2001 by Sven Neumann <sven@gimp.org>.
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* Included into blib in 2002 by Sven Neumann <sven@gimp.org>.
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*
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* GIMP plug-in written by Adam D. Moss <adam@gimp.org> <adam@foxbox.org>
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*
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* Based around original GIF code by David Koblas.
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*
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* This filter uses code taken from the "giftopnm" and "ppmtogif" programs
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* which are part of the "netpbm" package.
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*
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* "The Graphics Interchange Format(c) is the Copyright property of
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* CompuServe Incorporated. GIF(sm) is a Service Mark property of
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* CompuServe Incorporated."
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*/
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/* Copyright notice for GIF code from which this plugin was long ago *
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* derived (David Koblas has granted permission to relicense): *
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* +-------------------------------------------------------------------+ *
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* | Copyright 1990, 1991, 1993, David Koblas. (koblas@extra.com) | *
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* +-------------------------------------------------------------------+ */
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#include <stdio.h>
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#include <string.h>
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#include "gif-save.h"
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static int GIFNextPixel (void);
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/*
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* a code_int must be able to hold 2**BITS values of type int, and also -1
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*/
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typedef int code_int;
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typedef long int count_int;
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unsigned char *pixels;
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static void Putword (int, FILE *);
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static void compress (int, FILE *);
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static void output (code_int);
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static void cl_block (void);
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static void cl_hash (count_int);
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static void writeerr (void);
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static void char_init (void);
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static void char_out (int);
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static void flush_char (void);
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static long CountDown;
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/*
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* Return the next pixel from the image
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*/
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int
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GIFNextPixel (void)
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{
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if (CountDown == 0)
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return EOF;
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--CountDown;
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return *pixels++;
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}
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/* public */
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void
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GIFEncodeHeader (FILE *fp,
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int gif89,
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int Width,
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int Height,
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int Background,
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int BitsPerPixel,
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char *cmap)
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{
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int B;
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int Resolution;
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int ColorMapSize;
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int i;
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ColorMapSize = 1 << BitsPerPixel;
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Resolution = BitsPerPixel;
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/*
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* Write the Magic header
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*/
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fwrite (gif89 ? "GIF89a" : "GIF87a", 1, 6, fp);
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/*
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* Write out the screen width and height
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*/
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Putword (Width, fp);
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Putword (Height, fp);
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/*
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* Indicate that there is a global colour map
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*/
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B = 0x80; /* Yes, there is a color map */
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/*
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* OR in the resolution
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*/
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B |= (Resolution - 1) << 5;
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/*
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* OR in the Bits per Pixel
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*/
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B |= (BitsPerPixel - 1);
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/*
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* Write it out
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*/
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fputc (B, fp);
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/*
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* Write out the Background colour
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*/
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fputc (Background, fp);
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/*
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* Byte of 0's (future expansion)
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*/
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fputc (0, fp);
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/*
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* Write out the Global Colour Map
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*/
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for (i = 0; i < 3 * ColorMapSize; i++)
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fputc (cmap[i], fp);
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}
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void
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GIFEncodeGraphicControlExt (FILE *fp,
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GIFDisposeType Disposal,
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int Delay,
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int Animation,
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int Transparent)
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{
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Delay /= 10; /* the external API is ms */
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/*
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* Write out extension for transparent colour index, if necessary.
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*/
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if ( (Transparent >= 0) || (Animation) )
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{
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/* Extension Introducer - fixed. */
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fputc ('!', fp);
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/* Graphic Control Label - fixed. */
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fputc (0xf9, fp);
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/* Block Size - fixed. */
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fputc (4, fp);
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/* Packed Fields - XXXdddut (d=disposal, u=userInput, t=transFlag) */
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/* s8421 */
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fputc ( ((Transparent >= 0) ? 0x01 : 0x00) /* TRANSPARENCY */
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/* DISPOSAL */
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| (Animation ? (Disposal << 2) : 0x00),
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/* 0x03 or 0x01 build frames cumulatively */
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/* 0x02 clears frame before drawing */
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/* 0x00 'don't care' */
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fp);
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fputc (Delay & 255, fp);
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fputc ((Delay>>8) & 255, fp);
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fputc (Transparent, fp);
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fputc (0, fp);
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}
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}
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void
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GIFEncodeImageData (FILE *fp,
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int Width,
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int Height,
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int BitsPerPixel,
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int offset_x,
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int offset_y,
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char *data)
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{
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int Resolution;
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int ColorMapSize;
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int InitCodeSize;
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ColorMapSize = 1 << BitsPerPixel;
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Resolution = BitsPerPixel;
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/*
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* Calculate number of bits we are expecting
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*/
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CountDown = (long) Width * (long) Height;
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pixels = data;
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/*
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* The initial code size
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*/
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if (BitsPerPixel <= 1)
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InitCodeSize = 2;
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else
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InitCodeSize = BitsPerPixel;
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/*
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* Write an Image separator
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*/
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fputc (',', fp);
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/*
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* Write the Image header
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*/
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Putword (offset_x, fp);
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Putword (offset_y, fp);
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Putword (Width, fp);
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Putword (Height, fp);
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/* no interlacing */
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fputc (0x0, fp);
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/*
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* Write out the initial code size
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*/
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fputc (InitCodeSize, fp);
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/*
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* Go and actually compress the data
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*/
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compress (InitCodeSize + 1, fp);
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/*
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* Write out a Zero-length packet (to end the series)
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*/
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fputc (0x0, fp);
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}
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void
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GIFEncodeClose (FILE *fp)
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{
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/*
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* Write the GIF file terminator
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*/
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fputc (';', fp);
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/*
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* And close the file
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*/
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fclose (fp);
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}
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void
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GIFEncodeLoopExt (FILE *fp,
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int num_loops)
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{
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fputc(0x21,fp);
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fputc(0xff,fp);
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fputc(0x0b,fp);
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fputs("NETSCAPE2.0",fp);
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fputc(0x03,fp);
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fputc(0x01,fp);
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Putword(num_loops,fp);
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fputc(0x00,fp);
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/* NOTE: num_loops==0 means 'loop infinitely' */
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}
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void
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GIFEncodeCommentExt (FILE *fp,
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char *comment)
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{
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if (!comment || !*comment)
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return;
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if (strlen(comment)>240)
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{
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fprintf (stderr,
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"GIF: warning: comment too large - comment block not written.\n");
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return;
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}
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fputc(0x21,fp);
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fputc(0xfe,fp);
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fputc(strlen(comment),fp);
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fputs((const char *)comment,fp);
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fputc(0x00,fp);
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}
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/*
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* Write out a word to the GIF file
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*/
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static void
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Putword (int w,
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FILE *fp)
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{
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fputc (w & 0xff, fp);
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fputc ((w / 256) & 0xff, fp);
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}
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/***************************************************************************
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*
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* GIFCOMPR.C - GIF Image compression routines
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*
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* Lempel-Ziv compression based on 'compress'. GIF modifications by
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* David Rowley (mgardi@watdcsu.waterloo.edu)
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*
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***************************************************************************/
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/*
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* General DEFINEs
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*/
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#define GIF_BITS 12
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#define HSIZE 5003 /* 80% occupancy */
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#ifdef NO_UCHAR
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typedef char char_type;
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#else /*NO_UCHAR */
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typedef unsigned char char_type;
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#endif /*NO_UCHAR */
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/*
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* GIF Image compression - modified 'compress'
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*
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* Based on: compress.c - File compression ala IEEE Computer, June 1984.
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*
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* By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
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* Jim McKie (decvax!mcvax!jim)
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* Steve Davies (decvax!vax135!petsd!peora!srd)
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* Ken Turkowski (decvax!decwrl!turtlevax!ken)
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* James A. Woods (decvax!ihnp4!ames!jaw)
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* Joe Orost (decvax!vax135!petsd!joe)
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*
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*/
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#include <ctype.h>
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#define ARGVAL() (*++(*argv) || (--argc && *++argv))
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static int n_bits; /* number of bits/code */
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static int maxbits = GIF_BITS; /* user settable max # bits/code */
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static code_int maxcode; /* maximum code, given n_bits */
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static code_int maxmaxcode = (code_int) 1 << GIF_BITS; /* should NEVER generate this code */
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#ifdef COMPATIBLE /* But wrong! */
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#define MAXCODE(Mn_bits) ((code_int) 1 << (Mn_bits) - 1)
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#else /*COMPATIBLE */
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#define MAXCODE(Mn_bits) (((code_int) 1 << (Mn_bits)) - 1)
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#endif /*COMPATIBLE */
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static count_int htab[HSIZE];
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static unsigned short codetab[HSIZE];
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#define HashTabOf(i) htab[i]
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#define CodeTabOf(i) codetab[i]
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const code_int hsize = HSIZE; /* the original reason for this being
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variable was "for dynamic table sizing",
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but since it was never actually changed
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I made it const --Adam. */
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/*
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* To save much memory, we overlay the table used by compress() with those
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* used by decompress(). The tab_prefix table is the same size and type
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* as the codetab. The tab_suffix table needs 2**GIF_BITS characters. We
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* get this from the beginning of htab. The output stack uses the rest
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* of htab, and contains characters. There is plenty of room for any
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* possible stack (stack used to be 8000 characters).
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*/
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#define tab_prefixof(i) CodeTabOf(i)
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#define tab_suffixof(i) ((char_type*)(htab))[i]
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#define de_stack ((char_type*)&tab_suffixof((code_int)1<<GIF_BITS))
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static code_int free_ent = 0; /* first unused entry */
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/*
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* block compression parameters -- after all codes are used up,
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* and compression rate changes, start over.
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*/
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static int clear_flg = 0;
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static int offset;
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static long int in_count = 1; /* length of input */
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static long int out_count = 0; /* # of codes output (for debugging) */
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/*
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* compress stdin to stdout
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*
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* Algorithm: use open addressing double hashing (no chaining) on the
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* prefix code / next character combination. We do a variant of Knuth's
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* algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
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* secondary probe. Here, the modular division first probe is gives way
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* to a faster exclusive-or manipulation. Also do block compression with
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* an adaptive reset, whereby the code table is cleared when the compression
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* ratio decreases, but after the table fills. The variable-length output
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* codes are re-sized at this point, and a special CLEAR code is generated
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* for the decompressor. Late addition: construct the table according to
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* file size for noticeable speed improvement on small files. Please direct
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* questions about this implementation to ames!jaw.
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*/
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static int g_init_bits;
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static FILE *g_outfile;
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static int ClearCode;
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static int EOFCode;
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static unsigned long cur_accum;
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static int cur_bits;
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static unsigned long masks[] =
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{0x0000, 0x0001, 0x0003, 0x0007, 0x000F,
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0x001F, 0x003F, 0x007F, 0x00FF,
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0x01FF, 0x03FF, 0x07FF, 0x0FFF,
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0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF};
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static void
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compress (int init_bits,
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FILE *outfile)
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{
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register long fcode;
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register code_int i /* = 0 */ ;
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register int c;
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register code_int ent;
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register code_int disp;
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register code_int hsize_reg;
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register int hshift;
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/*
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* Set up the globals: g_init_bits - initial number of bits
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* g_outfile - pointer to output file
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*/
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g_init_bits = init_bits;
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g_outfile = outfile;
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cur_bits = 0;
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cur_accum = 0;
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/*
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* Set up the necessary values
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*/
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offset = 0;
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out_count = 0;
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clear_flg = 0;
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in_count = 1;
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ClearCode = (1 << (init_bits - 1));
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EOFCode = ClearCode + 1;
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free_ent = ClearCode + 2;
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/* Had some problems here... should be okay now. --Adam */
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n_bits = g_init_bits;
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maxcode = MAXCODE (n_bits);
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char_init ();
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ent = GIFNextPixel ();
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hshift = 0;
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for (fcode = (long) hsize; fcode < 65536L; fcode *= 2L)
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++hshift;
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hshift = 8 - hshift; /* set hash code range bound */
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hsize_reg = hsize;
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cl_hash ((count_int) hsize_reg); /* clear hash table */
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output ((code_int) ClearCode);
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while ((c = GIFNextPixel()) != EOF)
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{
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++in_count;
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fcode = (long) (((long) c << maxbits) + ent);
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i = (((code_int) c << hshift) ^ ent); /* xor hashing */
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if (HashTabOf (i) == fcode)
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{
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ent = CodeTabOf (i);
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continue;
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}
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else if ((long) HashTabOf (i) < 0) /* empty slot */
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goto nomatch;
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disp = hsize_reg - i; /* secondary hash (after G. Knott) */
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if (i == 0)
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disp = 1;
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probe:
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if ((i -= disp) < 0)
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i += hsize_reg;
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if (HashTabOf (i) == fcode)
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{
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ent = CodeTabOf (i);
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continue;
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}
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if ((long) HashTabOf (i) > 0)
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goto probe;
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nomatch:
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output ((code_int) ent);
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++out_count;
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ent = c;
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if (free_ent < maxmaxcode)
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{
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CodeTabOf (i) = free_ent++; /* code -> hashtable */
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HashTabOf (i) = fcode;
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}
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else
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cl_block ();
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}
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/*
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* Put out the final code.
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*/
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output ((code_int) ent);
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++out_count;
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output ((code_int) EOFCode);
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}
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/*****************************************************************
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* TAG( output )
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*
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* Output the given code.
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* Inputs:
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* code: A n_bits-bit integer. If == -1, then EOF. This assumes
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* that n_bits =< (long)wordsize - 1.
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* Outputs:
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* Outputs code to the file.
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* Assumptions:
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* Chars are 8 bits long.
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* Algorithm:
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* Maintain a GIF_BITS character long buffer (so that 8 codes will
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* fit in it exactly). Use the VAX insv instruction to insert each
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* code in turn. When the buffer fills up empty it and start over.
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*/
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static void
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output (code_int code)
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{
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cur_accum &= masks[cur_bits];
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if (cur_bits > 0)
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cur_accum |= ((long) code << cur_bits);
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else
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cur_accum = code;
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cur_bits += n_bits;
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while (cur_bits >= 8)
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{
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char_out ((unsigned int) (cur_accum & 0xff));
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cur_accum >>= 8;
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cur_bits -= 8;
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}
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/*
|
|
* 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 (register count_int hsize) /* reset code table */
|
|
{
|
|
|
|
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, "GIF: error writing output file\n");
|
|
return;
|
|
}
|
|
|
|
/******************************************************************************
|
|
*
|
|
* 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 (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 (void)
|
|
{
|
|
if (a_count > 0)
|
|
{
|
|
fputc (a_count, g_outfile);
|
|
fwrite (accum, 1, a_count, g_outfile);
|
|
a_count = 0;
|
|
}
|
|
}
|