gif2png.c

神龙卡开发原代码

/*
 * gif2png : convert a GIF to a PNGwith the same palette
 *
 * Fabrice Gautier (c) 2002 Sigma Desings, Inc.
 *
 */


/* 
 * Derived from Microwindows' devimage.c
 *
 * Copyright (c) 2000, 2001 Greg Haerr <[e-mail]>
 * Portions Copyright (c) 2000 Martin Jolicoeur <[e-mail]>
 * Portions Copyright (c) 2000 Alex Holden <[e-mail]>
 *
 */


#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
 
#include <png.h>


#define TRUE 1
#define FALSE 0


#define EPRINTF(x...) fprintf(stderr,x)
/*
 * Buffered input functions to replace stdio functions
 */

typedef struct {  /* structure for reading images from buffer   */
  void *start;    /* The pointer to the beginning of the buffer */
  int offset;     /* The current offset within the buffer       */
  int size;       /* The total size of the buffer               */
} buffer_t;

static void
binit(void *in, int size, buffer_t *dest)
{
	dest->start = in;
	dest->offset = 0;
	dest->size = size;
}
 
static int
bseek(buffer_t *buffer, int offset, int whence)
{
	int new;

	switch(whence) {
	case SEEK_SET:
		if (offset >= buffer->size || offset < 0)
			return(-1);
		buffer->offset = offset;
		return(0);

	case SEEK_CUR:
		new = buffer->offset + offset;
		if (new >= buffer->size || new < 0)
			return(-1);
		buffer->offset = new;
		return(0);

	case SEEK_END:
		if (offset >= buffer->size || offset > 0)
			return(-1);
		buffer->offset = (buffer->size - 1) - offset;
		return(0);

	default:
		return(-1);
	}
}
   
static int
bread(buffer_t *buffer, void *dest, int size)
{
	int copysize = size;

	if (buffer->offset == buffer->size)
		return(0);

	if (buffer->offset + size > buffer->size) 
		copysize = (buffer->size - buffer->offset);

	memcpy((void *)dest, (void *)(buffer->start + buffer->offset),copysize);

	buffer->offset += copysize;
	return(copysize);
}
 

/* Code for GIF decoding has been adapted from XPaint:                   */
/* +-------------------------------------------------------------------+ */
/* | Copyright 1990, 1991, 1993 David Koblas.			       | */
/* | Copyright 1996 Torsten Martinsen.				       | */
/* |   Permission to use, copy, modify, and distribute this software   | */
/* |   and its documentation for any purpose and without fee is hereby | */
/* |   granted, provided that the above copyright notice appear in all | */
/* |   copies and that both that copyright notice and this permission  | */
/* |   notice appear in supporting documentation.  This software is    | */
/* |   provided "as is" without express or implied warranty.	       | */
/* +-------------------------------------------------------------------+ */
/* Portions Copyright (C) 1999  Sam Lantinga*/
/* Adapted for use in SDL by Sam Lantinga -- 7/20/98 */
/*
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
/* GIF stuff*/
/*
 * GIF decoding routine
 */
#define	MAXCOLORMAPSIZE		256
#define	MAX_LWZ_BITS		12
#define INTERLACE		0x40
#define LOCALCOLORMAP		0x80

#define CM_RED		0
#define CM_GREEN	1
#define CM_BLUE		2

#define BitSet(byte, bit)	(((byte) & (bit)) == (bit))
#define	ReadOK(src,buffer,len)	bread(src, buffer, len)
#define LM_to_uint(a,b)		(((b)<<8)|(a))

struct {
    unsigned int Width;
    unsigned int Height;
    unsigned char ColorMap[3][MAXCOLORMAPSIZE];
    unsigned int BitPixel;
    unsigned int ColorResolution;
    unsigned int Background;
    unsigned int AspectRatio;
    int GrayScale;
} GifScreen;

static struct {
    int transparent;
    int delayTime;
    int inputFlag;
    int disposal;
} Gif89;

static int ReadColorMap(buffer_t *src, int number,
			unsigned char buffer[3][MAXCOLORMAPSIZE], int *flag);
static int DoExtension(buffer_t *src, int label);
static int GetDataBlock(buffer_t *src, unsigned char *buf);
static int GetCode(buffer_t *src, int code_size, int flag);
static int LWZReadByte(buffer_t *src, int flag, int input_code_size);

static int ReadImage(buffer_t* src, const char *png_filename, 
		     int len, int height, int cmapSize,
		     unsigned char cmap[3][MAXCOLORMAPSIZE],
		     int gray, int interlace, int ignore);

static int
LoadGIF(buffer_t *src, const char *png_filename)
{
    unsigned char buf[16];
    unsigned char c;
    unsigned char localColorMap[3][MAXCOLORMAPSIZE];
    int grayScale;
    int useGlobalColormap;
    int bitPixel;
    int imageCount = 0;
    char version[4];
    int imageNumber = 1;
    int ok = 0;

    bseek(src, 0, SEEK_SET);

//    pimage->imagebits = NULL;
//    pimage->palette = NULL;

    if (!ReadOK(src, buf, 6))
        return 0;		/* not gif image*/
    if (strncmp((char *) buf, "GIF", 3) != 0)
        return 0;
    strncpy(version, (char *) buf + 3, 3);
    version[3] = '\0';

    if (strcmp(version, "87a") != 0 && strcmp(version, "89a") != 0) {
	EPRINTF("LoadGIF: GIF version number not 87a or 89a\n");
        return 2;		/* image loading error*/
    }
    Gif89.transparent = -1;
    Gif89.delayTime = -1;
    Gif89.inputFlag = -1;
    Gif89.disposal = 0;

    if (!ReadOK(src, buf, 7)) {
	EPRINTF("LoadGIF: bad screen descriptor\n");
        return 2;		/* image loading error*/
    }
    GifScreen.Width = LM_to_uint(buf[0], buf[1]);
    GifScreen.Height = LM_to_uint(buf[2], buf[3]);
    GifScreen.BitPixel = 2 << (buf[4] & 0x07);
    GifScreen.ColorResolution = (((buf[4] & 0x70) >> 3) + 1);
    GifScreen.Background = buf[5];
    GifScreen.AspectRatio = buf[6];

    if (BitSet(buf[4], LOCALCOLORMAP)) {	/* Global Colormap */
	if (ReadColorMap(src, GifScreen.BitPixel, GifScreen.ColorMap,
			 &GifScreen.GrayScale)) {
	    EPRINTF("LoadGIF: bad global colormap\n");
            return 2;		/* image loading error*/
	}
    }

    do {
	if (!ReadOK(src, &c, 1)) {
	    EPRINTF("LoadGIF: EOF on image data\n");
            goto done;
	}
	if (c == ';') {		/* GIF terminator */
	    if (imageCount < imageNumber) {
		EPRINTF("LoadGIF: no image %d of %d\n", imageNumber,imageCount);
                goto done;
	    }
	}
	if (c == '!') {		/* Extension */
	    if (!ReadOK(src, &c, 1)) {
		EPRINTF("LoadGIF: EOF on extension function code\n");
                goto done;
	    }
	    DoExtension(src, c);
	    continue;
	}
	if (c != ',') {		/* Not a valid start character */
	    continue;
	}
	++imageCount;

	if (!ReadOK(src, buf, 9)) {
	    EPRINTF("LoadGIF: bad image size\n");
            goto done;
	}
	useGlobalColormap = !BitSet(buf[8], LOCALCOLORMAP);

	bitPixel = 1 << ((buf[8] & 0x07) + 1);

	if (!useGlobalColormap) {
	    if (ReadColorMap(src, bitPixel, localColorMap, &grayScale)) {
		EPRINTF("LoadGIF: bad local colormap\n");
                goto done;
	    }	    
	    printf("ReadImage :  localColorMap\n");
	    ok = ReadImage(src, png_filename, LM_to_uint(buf[4], buf[5]),
			      LM_to_uint(buf[6], buf[7]),
			      bitPixel, localColorMap, grayScale,
			      BitSet(buf[8], INTERLACE),
			      imageCount != imageNumber);
	} else {
	    printf("ReadImage :  globalColorMap\n");
	    ok = ReadImage(src, png_filename, LM_to_uint(buf[4], buf[5]),
			      LM_to_uint(buf[6], buf[7]),
			      GifScreen.BitPixel, GifScreen.ColorMap,
			      GifScreen.GrayScale, BitSet(buf[8], INTERLACE),
			      imageCount != imageNumber);
	}
    } while (ok == 0);


    if (ok)
	    return 1;		/* image load ok*/

done:
    return 2;			/* image load error*/
}

static int
ReadColorMap(buffer_t *src, int number, unsigned char buffer[3][MAXCOLORMAPSIZE],
    int *gray)
{
    int i;
    unsigned char rgb[3];
    int flag;

    flag = TRUE;

    for (i = 0; i < number; ++i) {
	if (!ReadOK(src, rgb, sizeof(rgb)))
	    return 1;
	buffer[CM_RED][i] = rgb[0];
	buffer[CM_GREEN][i] = rgb[1];
	buffer[CM_BLUE][i] = rgb[2];
	flag &= (rgb[0] == rgb[1] && rgb[1] == rgb[2]);
    }

#if 0
    if (flag)
	*gray = (number == 2) ? PBM_TYPE : PGM_TYPE;
    else
	*gray = PPM_TYPE;
#else
    *gray = 0;
#endif

    return FALSE;
}

static int
DoExtension(buffer_t *src, int label)
{
    static unsigned char buf[256];

    switch (label) {
    case 0x01:			/* Plain Text Extension */
	break;
    case 0xff:			/* Application Extension */
	break;
    case 0xfe:			/* Comment Extension */
	while (GetDataBlock(src, (unsigned char *) buf) != 0);
	return FALSE;
    case 0xf9:			/* Graphic Control Extension */
	GetDataBlock(src, (unsigned char *) buf);
	Gif89.disposal = (buf[0] >> 2) & 0x7;
	Gif89.inputFlag = (buf[0] >> 1) & 0x1;
	Gif89.delayTime = LM_to_uint(buf[1], buf[2]);
	if ((buf[0] & 0x1) != 0)
	    Gif89.transparent = buf[3];

	while (GetDataBlock(src, (unsigned char *) buf) != 0);
	return FALSE;
    default:
	break;
    }

    while (GetDataBlock(src, (unsigned char *) buf) != 0);

    return FALSE;
}

static int ZeroDataBlock = FALSE;

static int
GetDataBlock(buffer_t *src, unsigned char *buf)
{
    unsigned char count;

    if (!ReadOK(src, &count, 1))
	return -1;
    ZeroDataBlock = count == 0;

    if ((count != 0) && (!ReadOK(src, buf, count)))
	return -1;
    return count;
}

static int
GetCode(buffer_t *src, int code_size, int flag)
{
    static unsigned char buf[280];
    static int curbit, lastbit, done, last_byte;
    int i, j, ret;
    unsigned char count;

    if (flag) {
	curbit = 0;
	lastbit = 0;
	done = FALSE;