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ximagif.cpp
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ximagif.cpp
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/*
* File: ximagif.cpp
* Purpose: Platform Independent GIF Image Class Loader and Writer
* 07/Aug/2001 Davide Pizzolato - www.xdp.it
* CxImage version 7.0.1 07/Jan/2011
*/
#include "ximagif.h"
#if CXIMAGE_SUPPORT_GIF
#include "ximaiter.h"
#if defined (_WIN32_WCE)
#define assert(s)
#else
#include <assert.h>
#endif
////////////////////////////////////////////////////////////////////////////////
CxImageGIF::CxImageGIF(): CxImage(CXIMAGE_FORMAT_GIF)
{
buf = new uint8_t [GIFBUFTAM + 1];
stack = new uint8_t [MAX_CODES + 1];
suffix = new uint8_t [MAX_CODES + 1];
prefix = new uint16_t [MAX_CODES + 1];
htab = new int32_t [HSIZE];
codetab = new uint16_t [HSIZE];
byte_buff = new uint8_t [257];
accum = new char [256];
m_comment = new char [256];
m_loops=0;
info.dispmeth=0;
m_comment[0]='\0';
}
////////////////////////////////////////////////////////////////////////////////
CxImageGIF::~CxImageGIF()
{
delete [] buf;
delete [] stack;
delete [] suffix;
delete [] prefix;
delete [] htab;
delete [] codetab;
delete [] byte_buff;
delete [] accum;
delete [] m_comment;
}
////////////////////////////////////////////////////////////////////////////////
#if CXIMAGE_SUPPORT_DECODE
////////////////////////////////////////////////////////////////////////////////
bool CxImageGIF::Decode(CxFile *fp)
{
/* AD - for transparency */
struct_dscgif dscgif;
struct_image image;
struct_TabCol TabCol;
if (fp == NULL) return false;
fp->Read(&dscgif,/*sizeof(dscgif)*/13,1);
//if (strncmp(dscgif.header,"GIF8",3)!=0) {
if (strncmp(dscgif.header,"GIF8",4)!=0) return FALSE;
// Avoid Byte order problem with Mac <AMSN>
dscgif.scrheight = m_ntohs(dscgif.scrheight);
dscgif.scrwidth = m_ntohs(dscgif.scrwidth);
if (info.nEscape == -1) {
// Return output dimensions only
head.biWidth = dscgif.scrwidth;
head.biHeight = dscgif.scrheight;
info.dwType = CXIMAGE_FORMAT_GIF;
return true;
}
/* AD - for interlace */
TabCol.sogct = (int16_t)(1 << ((dscgif.pflds & 0x07)+1));
TabCol.colres = (int16_t)(((dscgif.pflds & 0x70) >> 4) + 1);
// assume that the image is a truecolor-gif if
// 1) no global color map found
// 2) (image.w, image.h) of the 1st image != (dscgif.scrwidth, dscgif.scrheight)
int32_t bTrueColor=0;
CxImage* imaRGB=NULL;
// Global colour map?
if (dscgif.pflds & 0x80)
fp->Read(TabCol.paleta,sizeof(struct rgb_color)*TabCol.sogct,1);
else
bTrueColor++; //first chance for a truecolor gif
int32_t first_transparent_index = 0;
int32_t iImage = 0;
info.nNumFrames=get_num_frames(fp,&TabCol,&dscgif);
if ((info.nFrame<0)||(info.nFrame>=info.nNumFrames)) return false;
//it cannot be a true color GIF with only one frame
if (info.nNumFrames == 1)
bTrueColor=0;
char ch;
bool bPreviousWasNull = true;
int32_t prevdispmeth = 0;
CxImage *previousFrame = NULL;
for (BOOL bContinue = TRUE; bContinue; )
{
if (fp->Read(&ch, sizeof(ch), 1) != 1) {break;}
if (info.nEscape > 0) return false; // <vho> - cancel decoding
if (bPreviousWasNull || ch==0)
{
switch (ch)
{
case '!': // extension
{
bContinue = DecodeExtension(fp);
break;
}
case ',': // image
{
assert(sizeof(image) == 9);
fp->Read(&image,sizeof(image),1);
//avoid byte order problems with Solaris <candan> <AMSN>
image.l = m_ntohs(image.l);
image.t = m_ntohs(image.t);
image.w = m_ntohs(image.w);
image.h = m_ntohs(image.h);
if (((image.l + image.w) > dscgif.scrwidth)||((image.t + image.h) > dscgif.scrheight))
break;
// check if it could be a truecolor gif
if ((iImage==0) && (image.w != dscgif.scrwidth) && (image.h != dscgif.scrheight))
bTrueColor++;
rgb_color locpal[256]; //Local Palette
rgb_color* pcurpal = TabCol.paleta; //Current Palette
int16_t palcount = TabCol.sogct; //Current Palette color count
// Local colour map?
if (image.pf & 0x80) {
palcount = (int16_t)(1 << ((image.pf & 0x07) +1));
assert(3 == sizeof(struct rgb_color));
fp->Read(locpal,sizeof(struct rgb_color)*palcount,1);
pcurpal = locpal;
}
int32_t bpp; //<DP> select the correct bit per pixel value
if (palcount <= 2) bpp = 1;
else if (palcount <= 16) bpp = 4;
else bpp = 8;
CxImageGIF backimage;
backimage.CopyInfo(*this);
if (iImage==0){
//first frame: build image background
backimage.Create(dscgif.scrwidth, dscgif.scrheight, bpp, CXIMAGE_FORMAT_GIF);
first_transparent_index = info.nBkgndIndex;
backimage.Clear((uint8_t)gifgce.transpcolindex);
previousFrame = new CxImage(backimage);
previousFrame->SetRetreiveAllFrames(false);
} else {
//generic frame: handle disposal method from previous one
/*Values : 0 - No disposal specified. The decoder is
not required to take any action.
1 - Do not dispose. The graphic is to be left
in place.
2 - Restore to background color. The area used by the
graphic must be restored to the background color.
3 - Restore to previous. The decoder is required to
restore the area overwritten by the graphic with
what was there prior to rendering the graphic.
*/
/* backimage.Copy(*this);
if (prevdispmeth==2){
backimage.Clear((uint8_t)first_transparent_index);
}*/
if (prevdispmeth==2){
backimage.Copy(*this,false,false,false);
backimage.Clear((uint8_t)first_transparent_index);
} else if (prevdispmeth==3) {
backimage.Copy(*this,false,false,false);
backimage.Create(previousFrame->GetWidth(),
previousFrame->GetHeight(),
previousFrame->GetBpp(),CXIMAGE_FORMAT_GIF);
memcpy(backimage.GetDIB(),previousFrame->GetDIB(),
backimage.GetSize());
//backimage.AlphaSet(*previousFrame);
} else {
backimage.Copy(*this);
}
}
//active frame
Create(image.w, image.h, bpp, CXIMAGE_FORMAT_GIF);
if ((image.pf & 0x80) || (dscgif.pflds & 0x80)) {
uint8_t r[256], g[256], b[256];
int32_t i, has_white = 0;
for (i=0; i < palcount; i++) {
r[i] = pcurpal[i].r;
g[i] = pcurpal[i].g;
b[i] = pcurpal[i].b;
if (RGB(r[i],g[i],b[i]) == 0xFFFFFF) has_white = 1;
}
// Force transparency colour white...
//if (0) if (info.nBkgndIndex >= 0)
// r[info.nBkgndIndex] = g[info.nBkgndIndex] = b[info.nBkgndIndex] = 255;
// Fill in with white // AD
if (info.nBkgndIndex >= 0) {
while (i < 256) {
has_white = 1;
r[i] = g[i] = b[i] = 255;
i++;
}
}
// Force last colour to white... // AD
//if ((info.nBkgndIndex >= 0) && !has_white) {
// r[255] = g[255] = b[255] = 255;
//}
SetPalette((info.nBkgndIndex >= 0 ? 256 : palcount), r, g, b);
}
CImageIterator* iter = new CImageIterator(this);
iter->Upset();
int32_t badcode=0;
ibf = GIFBUFTAM+1;
interlaced = image.pf & 0x40;
iheight = image.h;
istep = 8;
iypos = 0;
ipass = 0;
int32_t pos_start = fp->Tell();
//if (interlaced) log << "Interlaced" << endl;
decoder(fp, iter, image.w, badcode);
delete iter;
if (info.nEscape) return false; // <vho> - cancel decoding
if (bTrueColor<2 ){ //standard GIF: mix frame with background
backimage.IncreaseBpp(bpp);
backimage.GifMix(*this,image);
backimage.SetTransIndex(first_transparent_index);
backimage.SetPalette(GetPalette());
Transfer(backimage,false);
} else { //it's a truecolor gif!
//force full image decoding
info.nFrame=info.nNumFrames-1;
//build the RGB image
if (imaRGB==NULL) imaRGB = new CxImage(dscgif.scrwidth,dscgif.scrheight,24,CXIMAGE_FORMAT_GIF);
//copy the partial image into the full RGB image
for(int32_t y=0;y<image.h;y++){
for (int32_t x=0;x<image.w;x++){
imaRGB->SetPixelColor(x+image.l,dscgif.scrheight-1-image.t-y,GetPixelColor(x,image.h-y-1));
}
}
}
prevdispmeth = (gifgce.flags >> 2) & 0x7;
//restore the correct position in the file for the next image
if (badcode){
seek_next_image(fp,pos_start);
} else {
fp->Seek(-(ibfmax - ibf - 1), SEEK_CUR);
}
if (info.bGetAllFrames && imaRGB == NULL) {
if (iImage == 0) {
DestroyFrames();
ppFrames = new CxImage*[info.nNumFrames];
for(int32_t frameIdx = 0; frameIdx < info.nNumFrames; frameIdx++){
ppFrames[frameIdx] = NULL;
}
}
ppFrames[iImage] = new CxImage(*this);
ppFrames[iImage]->SetRetreiveAllFrames(false);
}
if (prevdispmeth <= 1) {
delete previousFrame;
previousFrame = new CxImage(*this);
previousFrame->SetRetreiveAllFrames(false);
}
if ((info.nFrame==iImage) && (info.bGetAllFrames==false)) bContinue=false; else iImage++;
break;
}
case ';': //terminator
bContinue=false;
break;
default:
bPreviousWasNull = (ch==0);
break;
}
}
}
if (bTrueColor>=2 && imaRGB){
if (gifgce.flags & 0x1){
imaRGB->SetTransColor(GetPaletteColor((uint8_t)info.nBkgndIndex));
imaRGB->SetTransIndex(0);
}
Transfer(*imaRGB);
}
delete imaRGB;
delete previousFrame;
return true;
}
////////////////////////////////////////////////////////////////////////////////
bool CxImageGIF::DecodeExtension(CxFile *fp)
{
bool bContinue;
uint8_t count;
uint8_t fc;
bContinue = (1 == fp->Read(&fc, sizeof(fc), 1));
if (bContinue) {
/* AD - for transparency */
if (fc == 0xF9) {
bContinue = (1 == fp->Read(&count, sizeof(count), 1));
if (bContinue) {
assert(sizeof(gifgce) == 4);
bContinue = (count == fp->Read(&gifgce, 1, sizeof(gifgce)));
gifgce.delaytime = m_ntohs(gifgce.delaytime); // Avoid Byte order problem with Mac <AMSN>
if (bContinue) {
info.nBkgndIndex = (gifgce.flags & 0x1) ? gifgce.transpcolindex : -1;
info.dwFrameDelay = gifgce.delaytime;
SetDisposalMethod((gifgce.flags >> 2) & 0x7);
} } }
if (fc == 0xFE) { //<DP> Comment block
bContinue = (1 == fp->Read(&count, sizeof(count), 1));
if (bContinue) {
bContinue = (1 == fp->Read(m_comment, count, 1));
m_comment[count]='\0';
} }
if (fc == 0xFF) { //<DP> Application Extension block
bContinue = (1 == fp->Read(&count, sizeof(count), 1));
if (bContinue) {
bContinue = (count==11);
if (bContinue){
char AppID[11];
bContinue = (1 == fp->Read(AppID, count, 1));
if (bContinue) {
bContinue = (1 == fp->Read(&count, sizeof(count), 1));
if (bContinue) {
uint8_t* dati = (uint8_t*)malloc(count);
bContinue = (dati!=NULL);
if (bContinue){
bContinue = (1 == fp->Read(dati, count, 1));
if (count>2){
m_loops = dati[1]+256*dati[2];
}
}
free(dati);
} } } } }
while (bContinue && fp->Read(&count, sizeof(count), 1) && count) {
//log << "Skipping " << count << " bytes" << endl;
fp->Seek(count, SEEK_CUR);
}
}
return bContinue;
}
////////////////////////////////////////////////////////////////////////////////
#endif //CXIMAGE_SUPPORT_DECODE
////////////////////////////////////////////////////////////////////////////////
// - This external (machine specific) function is expected to return
// either the next uint8_t from the GIF file, or a negative error number.
int32_t CxImageGIF::get_byte(CxFile* file)
{
if (ibf>=GIFBUFTAM){
// FW 06/02/98 >>>
ibfmax = (int32_t)file->Read( buf , 1 , GIFBUFTAM) ;
if( ibfmax < GIFBUFTAM ) buf[ ibfmax ] = 255 ;
// FW 06/02/98 <<<
ibf = 0;
}
if (ibf>=ibfmax) return -1; //<DP> avoid overflows
return buf[ibf++];
}
////////////////////////////////////////////////////////////////////////////////
/* - This function takes a full line of pixels (one uint8_t per pixel) and
* displays them (or does whatever your program wants with them...). It
* should return zero, or negative if an error or some other event occurs
* which would require aborting the decode process... Note that the length
* passed will almost always be equal to the line length passed to the
* decoder function, with the sole exception occurring when an ending code
* occurs in an odd place in the GIF file... In any case, linelen will be
* equal to the number of pixels passed...
*/
int32_t CxImageGIF::out_line(CImageIterator* iter, uint8_t *pixels, int32_t linelen)
{
if (iter == NULL || pixels == NULL)
return -1;
//<DP> for 1 & 4 bpp images, the pixels are compressed
if (head.biBitCount < 8){
for(int32_t x=0;x<head.biWidth;x++){
uint8_t pos;
uint8_t* iDst= pixels + (x*head.biBitCount >> 3);
if (head.biBitCount==4){
pos = (uint8_t)(4*(1-x%2));
*iDst &= ~(0x0F<<pos);
*iDst |= ((pixels[x] & 0x0F)<<pos);
} else if (head.biBitCount==1){
pos = (uint8_t)(7-x%8);
*iDst &= ~(0x01<<pos);
*iDst |= ((pixels[x] & 0x01)<<pos);
}
}
}
/* AD - for interlace */
if (interlaced) {
iter->SetY(iheight-iypos-1);
iter->SetRow(pixels, linelen);
if ((iypos += istep) >= iheight) {
do {
if (ipass++ > 0) istep /= 2;
iypos = istep / 2;
}
while (iypos > iheight);
}
return 0;
} else {
if (iter->ItOK()) {
iter->SetRow(pixels, linelen);
(void)iter->PrevRow();
return 0;
} else {
// puts("chafeo");
return -1;
}
}
}
////////////////////////////////////////////////////////////////////////////////
#if CXIMAGE_SUPPORT_ENCODE
////////////////////////////////////////////////////////////////////////////////
// SaveFile - writes GIF87a gif file
// Randy Spann 6/15/97
bool CxImageGIF::Encode(CxFile * fp)
{
if (EncodeSafeCheck(fp)) return false;
if(head.biBitCount > 8) {
//strcpy(info.szLastError,"GIF Images must be 8 bit or less");
//return FALSE;
return EncodeRGB(fp);
}
if ( GetNumFrames()>1 && ppFrames ) {
return Encode(fp, ppFrames, GetNumFrames() );
}
EncodeHeader(fp);
EncodeExtension(fp);
EncodeComment(fp);
EncodeBody(fp);
fp->PutC(';'); // Write the GIF file terminator
return true; // done!
}
////////////////////////////////////////////////////////////////////////////////
bool CxImageGIF::Encode(CxFile * fp, CxImage ** pImages, int32_t pagecount, bool bLocalColorMap, bool bLocalDispMeth)
{
cx_try {
if (fp==NULL) cx_throw("invalid file pointer");
if (pImages==NULL || pagecount<=0 || pImages[0]==NULL) cx_throw("multipage GIF, no images!");
int32_t i;
for (i=0; i<pagecount; i++){
if (pImages[i]==NULL)
cx_throw("Bad image pointer");
if (!(pImages[i]->IsValid()))
cx_throw("Empty image");
if (pImages[i]->GetNumColors()==0)
cx_throw("CxImageGIF::Encode cannot create animated GIFs with a true color frame. Use DecreaseBpp before");
}
CxImageGIF ghost;
//write the first image
ghost.Ghost(pImages[0]);
ghost.EncodeHeader(fp);
if (m_loops!=1){
ghost.SetLoops(max(0,m_loops-1));
ghost.EncodeLoopExtension(fp);
}
if (bLocalDispMeth) {
ghost.EncodeExtension(fp);
} else {
uint8_t dm = ghost.GetDisposalMethod();
ghost.SetDisposalMethod(GetDisposalMethod());
ghost.EncodeExtension(fp);
ghost.SetDisposalMethod(dm);
}
EncodeComment(fp);
ghost.EncodeBody(fp);
for (i=1; i<pagecount; i++){
ghost.Ghost(pImages[i]);
if (bLocalDispMeth) {
ghost.EncodeExtension(fp);
} else {
uint8_t dm = ghost.GetDisposalMethod();
ghost.SetDisposalMethod(GetDisposalMethod());
ghost.EncodeExtension(fp);
ghost.SetDisposalMethod(dm);
}
ghost.EncodeBody(fp,bLocalColorMap);
}
fp->PutC(';'); // Write the GIF file terminator
} cx_catch {
if (strcmp(message,"")) strncpy(info.szLastError,message,255);
return false;
}
return true;
}
////////////////////////////////////////////////////////////////////////////////
void CxImageGIF::EncodeHeader(CxFile *fp)
{
fp->Write("GIF89a",1,6); //GIF Header
Putword(head.biWidth,fp); //Logical screen descriptor
Putword(head.biHeight,fp);
uint8_t Flags;
if (head.biClrUsed==0){
Flags=0x11;
} else {
Flags = 0x80;
Flags |=(head.biBitCount - 1) << 5;
Flags |=(head.biBitCount - 1);
}
fp->PutC(Flags); //GIF "packed fields"
fp->PutC(0); //GIF "BackGround"
fp->PutC(0); //GIF "pixel aspect ratio"
if (head.biClrUsed!=0){
RGBQUAD* pPal = GetPalette();
for(uint32_t i=0; i<head.biClrUsed; ++i)
{
fp->PutC(pPal[i].rgbRed);
fp->PutC(pPal[i].rgbGreen);
fp->PutC(pPal[i].rgbBlue);
}
}
}
////////////////////////////////////////////////////////////////////////////////
void CxImageGIF::EncodeExtension(CxFile *fp)
{
// TRK BEGIN : transparency
fp->PutC('!');
fp->PutC(TRANSPARENCY_CODE);
gifgce.flags = 0;
gifgce.flags |= ((info.nBkgndIndex != -1) ? 1 : 0);
gifgce.flags |= ((GetDisposalMethod() & 0x7) << 2);
gifgce.delaytime = (uint16_t)info.dwFrameDelay;
gifgce.transpcolindex = (uint8_t)info.nBkgndIndex;
//Invert byte order in case we use a byte order arch, then set it back <AMSN>
gifgce.delaytime = m_ntohs(gifgce.delaytime);
fp->PutC(sizeof(gifgce));
fp->Write(&gifgce, sizeof(gifgce), 1);
gifgce.delaytime = m_ntohs(gifgce.delaytime);
fp->PutC(0);
// TRK END
}
////////////////////////////////////////////////////////////////////////////////
void CxImageGIF::EncodeLoopExtension(CxFile *fp)
{
fp->PutC('!'); //byte 1 : 33 (hex 0x21) GIF Extension code
fp->PutC(255); //byte 2 : 255 (hex 0xFF) Application Extension Label
fp->PutC(11); //byte 3 : 11 (hex (0x0B) Length of Application Block (eleven bytes of data to follow)
fp->Write("NETSCAPE2.0",11,1);
fp->PutC(3); //byte 15 : 3 (hex 0x03) Length of Data Sub-Block (three bytes of data to follow)
fp->PutC(1); //byte 16 : 1 (hex 0x01)
Putword(m_loops,fp); //bytes 17 to 18 : 0 to 65535, an unsigned integer in lo-hi byte format.
//This indicate the number of iterations the loop should be executed.
fp->PutC(0); //bytes 19 : 0 (hex 0x00) a Data Sub-block Terminator.
}
////////////////////////////////////////////////////////////////////////////////
void CxImageGIF::EncodeBody(CxFile *fp, bool bLocalColorMap)
{
curx = 0;
cury = head.biHeight - 1; //because we read the image bottom to top
CountDown = (int32_t)head.biWidth * (int32_t)head.biHeight;
fp->PutC(',');
Putword(info.xOffset,fp);
Putword(info.yOffset,fp);
Putword(head.biWidth,fp);
Putword(head.biHeight,fp);
uint8_t Flags=0x00; //non-interlaced (0x40 = interlaced) (0x80 = LocalColorMap)
if (bLocalColorMap) { Flags|=0x80; Flags|=head.biBitCount-1; }
fp->PutC(Flags);
if (bLocalColorMap){
Flags|=0x87;
RGBQUAD* pPal = GetPalette();
for(uint32_t i=0; i<head.biClrUsed; ++i)
{
fp->PutC(pPal[i].rgbRed);
fp->PutC(pPal[i].rgbGreen);
fp->PutC(pPal[i].rgbBlue);
}
}
int32_t InitCodeSize = head.biBitCount <=1 ? 2 : head.biBitCount;
// Write out the initial code size
fp->PutC((uint8_t)InitCodeSize);
// Go and actually compress the data
switch (GetCodecOption(CXIMAGE_FORMAT_GIF))
{
case 1: //uncompressed
compressNONE(InitCodeSize+1, fp);
break;
case 2: //RLE
compressRLE(InitCodeSize+1, fp);
break;
default: //LZW
compressLZW(InitCodeSize+1, fp);
}
// Write out a Zero-length packet (to end the series)
fp->PutC(0);
}
////////////////////////////////////////////////////////////////////////////////
void CxImageGIF::EncodeComment(CxFile *fp)
{
uint32_t n = (uint32_t) strlen(m_comment);
if (n>255) n=255;
if (n) {
fp->PutC('!'); //extension code:
fp->PutC(254); //comment extension
fp->PutC((uint8_t)n); //size of comment
fp->Write(m_comment,n,1);
fp->PutC(0); //block terminator
}
}
////////////////////////////////////////////////////////////////////////////////
bool CxImageGIF::EncodeRGB(CxFile *fp)
{
EncodeHeader(fp);
// EncodeLoopExtension(fp);
EncodeComment(fp);
uint32_t w,h;
w=h=0;
const int32_t cellw = 17;
const int32_t cellh = 15;
CxImageGIF tmp;
for (int32_t y=0;y<head.biHeight;y+=cellh){
for (int32_t x=0;x<head.biWidth;x+=cellw){
if ((head.biWidth -x)<cellw) w=head.biWidth -x; else w=cellw;
if ((head.biHeight-y)<cellh) h=head.biHeight-y; else h=cellh;
if (w!=tmp.GetWidth() || h!=tmp.GetHeight()) tmp.Create(w,h,8);
if (IsTransparent()){
tmp.SetTransIndex(0);
tmp.SetPaletteColor(0,GetTransColor());
}
uint8_t i;
for (uint32_t j=0;j<h;j++){
for (uint32_t k=0;k<w;k++){
i=(uint8_t)(1+k+cellw*j);
tmp.SetPaletteColor(i,GetPixelColor(x+k,head.biHeight-y-h+j));
tmp.SetPixelIndex(k,j,tmp.GetNearestIndex(tmp.GetPaletteColor(i)));
}
}
tmp.SetOffset(x,y);
tmp.EncodeExtension(fp);
tmp.EncodeBody(fp,true);
}
}
fp->PutC(';'); // Write the GIF file terminator
return true; // done!
}
////////////////////////////////////////////////////////////////////////////////
#endif // CXIMAGE_SUPPORT_ENCODE
////////////////////////////////////////////////////////////////////////////////
// Return the next pixel from the image
// <DP> fix for 1 & 4 bpp images
int32_t CxImageGIF::GifNextPixel( )
{
if( CountDown == 0 ) return EOF;
--CountDown;
int32_t r = GetPixelIndex(curx,cury);
// Bump the current X position
++curx;
if( curx == head.biWidth ){
curx = 0;
cury--; //bottom to top
}
return r;
}
////////////////////////////////////////////////////////////////////////////////
void CxImageGIF::Putword(int32_t w, CxFile *fp )
{
fp->PutC((uint8_t)(w & 0xff));
fp->PutC((uint8_t)((w >> 8) & 0xff));
}
////////////////////////////////////////////////////////////////////////////////
void CxImageGIF::compressNONE( int32_t init_bits, CxFile* outfile)
{
register int32_t c;
register int32_t ent;
// 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
cur_accum = cur_bits = clear_flg = 0;
maxcode = (int16_t)MAXCODE(n_bits = g_init_bits);
code_int maxmaxcode = (code_int)1 << MAXBITSCODES;
ClearCode = (1 << (init_bits - 1));
EOFCode = ClearCode + 1;
free_ent = (int16_t)(ClearCode + 2);
a_count=0;
ent = GifNextPixel( );
output( (code_int)ClearCode );
while ( ent != EOF ) {
c = GifNextPixel();
output ( (code_int) ent );
ent = c;
if ( free_ent < maxmaxcode ) {
free_ent++;
} else {
free_ent=(int16_t)(ClearCode+2);
clear_flg=1;
output((code_int)ClearCode);
}
}
// Put out the final code.
output( (code_int) EOFCode );
}
////////////////////////////////////////////////////////////////////////////////
/***************************************************************************
*
* GIFCOMPR.C - LZW GIF Image compression routines
*
***************************************************************************/
void CxImageGIF::compressLZW( int32_t init_bits, CxFile* outfile)
{
register int32_t fcode;
register int32_t c;
register int32_t ent;
register int32_t hshift;
register int32_t disp;
register int32_t i;
// 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
cur_accum = cur_bits = clear_flg = 0;
maxcode = (int16_t)MAXCODE(n_bits = g_init_bits);
code_int maxmaxcode = (code_int)1 << MAXBITSCODES;
ClearCode = (1 << (init_bits - 1));
EOFCode = ClearCode + 1;
free_ent = (int16_t)(ClearCode + 2);
a_count=0;
ent = GifNextPixel( );
hshift = 0;
for ( fcode = (int32_t) HSIZE; fcode < 65536L; fcode *= 2L ) ++hshift;
hshift = 8 - hshift; /* set hash code range bound */
cl_hash((int32_t)HSIZE); /* clear hash table */
output( (code_int)ClearCode );
while ( (c = GifNextPixel( )) != EOF ) {
fcode = (int32_t) (((int32_t) c << MAXBITSCODES) + ent);
i = (((code_int)c << hshift) ^ ent); /* xor hashing */
if ( HashTabOf (i) == fcode ) {
ent = CodeTabOf (i);
continue;
} else if ( (int32_t)HashTabOf (i) < 0 ) /* empty slot */
goto nomatch;
disp = HSIZE - i; /* secondary hash (after G. Knott) */
if ( i == 0 ) disp = 1;
probe:
if ( (i -= disp) < 0 ) i += HSIZE;
if ( HashTabOf (i) == fcode ) { ent = CodeTabOf (i); continue; }
if ( (int32_t)HashTabOf (i) > 0 ) goto probe;
nomatch:
output ( (code_int) ent );
ent = c;
if ( free_ent < maxmaxcode ) {
CodeTabOf (i) = free_ent++; /* code -> hashtable */
HashTabOf (i) = fcode;
} else {
cl_hash((int32_t)HSIZE);
free_ent=(int16_t)(ClearCode+2);
clear_flg=1;
output((code_int)ClearCode);
}
}
// Put out the final code.
output( (code_int)ent );
output( (code_int) EOFCode );
}
////////////////////////////////////////////////////////////////////////////////
static const uint32_t code_mask[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F,
0x001F, 0x003F, 0x007F, 0x00FF,
0x01FF, 0x03FF, 0x07FF, 0x0FFF,
0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF };
////////////////////////////////////////////////////////////////////////////////
void CxImageGIF::output( code_int code)
{
cur_accum &= code_mask[ cur_bits ];
if( cur_bits > 0 )
cur_accum |= ((int32_t)code << cur_bits);
else
cur_accum = code;
cur_bits += n_bits;
while( cur_bits >= 8 ) {
char_out( (uint32_t)(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 = (int16_t)MAXCODE(n_bits = g_init_bits);
clear_flg = 0;
} else {
++n_bits;
if ( n_bits == MAXBITSCODES )
maxcode = (code_int)1 << MAXBITSCODES; /* should NEVER generate this code */
else
maxcode = (int16_t)MAXCODE(n_bits);
}
}
if( code == EOFCode ) {
// At EOF, write the rest of the buffer.
while( cur_bits > 0 ) {
char_out( (uint32_t)(cur_accum & 0xff) );
cur_accum >>= 8;
cur_bits -= 8;
}
flush_char();
g_outfile->Flush();
if(g_outfile->Error()) strcpy(info.szLastError,"Write Error in GIF file");
}
}
////////////////////////////////////////////////////////////////////////////////
void CxImageGIF::cl_hash(int32_t hsize)
{
register int32_t *htab_p = htab+hsize;
register int32_t i;
register int32_t m1 = -1L;
i = hsize - 16;
do {
*(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
*******************************************************************************/
void CxImageGIF::char_out(int32_t c)
{
accum[a_count++]=(char)c;
if (a_count >=254)
flush_char();
}
void CxImageGIF::flush_char()
{
if (a_count > 0) {
g_outfile->PutC((uint8_t)a_count);
g_outfile->Write(accum,1,a_count);
a_count=0;
}
}
/*******************************************************************************
* GIF decoder
*******************************************************************************/
/* DECODE.C - An LZW decoder for GIF
* Copyright (C) 1987, by Steven A. Bennett
* Copyright (C) 1994, C++ version by Alejandro Aguilar Sierra
*
* Permission is given by the author to freely redistribute and include
* this code in any program as int32_t as this credit is given where due.
*
* In accordance with the above, I want to credit Steve Wilhite who wrote
* the code which this is heavily inspired by...
*
* GIF and 'Graphics Interchange Format' are trademarks (tm) of
* Compuserve, Incorporated, an H&R Block Company.
*
* Release Notes: This file contains a decoder routine for GIF images