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image.cpp
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image.cpp
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#include "r-tech1/graphics/bitmap.h"
#include <string.h>
namespace Graphics{
static bool isPng(const unsigned char * data, int length){
return length > 3 &&
data[0] == 0x89 &&
data[1] == 'P' &&
data[2] == 'N' &&
data[3] == 'G';
}
static bool isBmp(const unsigned char * data, int length){
return length > 2 &&
data[0] == 'B' &&
data[1] == 'M';
}
static bool isJpg(const unsigned char * data, int length){
/* TODO */
return false;
#if 0
int start;
int is_JPG;
int in_scan;
Uint8 magic[4];
/* This detection code is by Steaphan Greene <stea@cs.binghamton.edu> */
/* Blame me, not Sam, if this doesn't work right. */
/* And don't forget to report the problem to the the sdl list too! */
if ( !src )
return 0;
start = SDL_RWtell(src);
is_JPG = 0;
in_scan = 0;
if ( SDL_RWread(src, magic, 2, 1) ) {
if ( (magic[0] == 0xFF) && (magic[1] == 0xD8) ) {
is_JPG = 1;
while (is_JPG == 1) {
if(SDL_RWread(src, magic, 1, 2) != 2) {
is_JPG = 0;
} else if( (magic[0] != 0xFF) && (in_scan == 0) ) {
is_JPG = 0;
} else if( (magic[0] != 0xFF) || (magic[1] == 0xFF) ) {
/* Extra padding in JPEG (legal) */
/* or this is data and we are scanning */
SDL_RWseek(src, -1, RW_SEEK_CUR);
} else if(magic[1] == 0xD9) {
/* Got to end of good JPEG */
break;
} else if( (in_scan == 1) && (magic[1] == 0x00) ) {
/* This is an encoded 0xFF within the data */
} else if( (magic[1] >= 0xD0) && (magic[1] < 0xD9) ) {
/* These have nothing else */
} else if(SDL_RWread(src, magic+2, 1, 2) != 2) {
is_JPG = 0;
} else {
/* Yes, it's big-endian */
Uint32 start;
Uint32 size;
Uint32 end;
start = SDL_RWtell(src);
size = (magic[2] << 8) + magic[3];
end = SDL_RWseek(src, size-2, RW_SEEK_CUR);
if ( end != start + size - 2 ) is_JPG = 0;
if ( magic[1] == 0xDA ) {
/* Now comes the actual JPEG meat */
#ifdef FAST_IS_JPEG
/* Ok, I'm convinced. It is a JPEG. */
break;
#else
/* I'm not convinced. Prove it! */
in_scan = 1;
#endif
}
}
}
}
}
SDL_RWseek(src, start, RW_SEEK_SET);
return(is_JPG);
#endif
}
static bool isPcx(const unsigned char * data, int length){
const int ZSoft_Manufacturer = 10;
const int PC_Paintbrush_Version = 5;
const int PCX_Uncompressed_Encoding = 0;
const int PCX_RunLength_Encoding = 1;
return length > 3 &&
data[0] == ZSoft_Manufacturer &&
data[1] == PC_Paintbrush_Version &&
(data[2] == PCX_RunLength_Encoding ||
data[2] == PCX_Uncompressed_Encoding);
}
static bool isTga(const unsigned char * data, int length){
/* No magic for tga files.. come up with some way to detect them */
return false;
}
static bool isTif(const unsigned char * data, int length){
return length > 4 &&
((data[0] == 'I' &&
data[1] == 'I' &&
data[2] == 0x2a &&
data[3] == 0x00) ||
(data[0] == 'M' &&
data[1] == 'M' &&
data[2] == 0x00 &&
data[3] == 0x2a));
}
static bool isXpm(const unsigned char * data, int length){
return strncmp((const char *) data, "/* XPM */", length) == 0;
}
static bool isGif(const unsigned char * data, int length){
return length > 7 &&
(strncmp((const char *) data, "GIF", 3) == 0) &&
(strncmp((const char *) data + 3, "87a", 3) == 0 ||
strncmp((const char *) data + 3, "89a", 3) == 0);
}
ImageFormat identifyImage(const unsigned char * data, int length){
if (isPng(data, length)){
return FormatPNG;
}
if (isBmp(data, length)){
return FormatBMP;
}
if (isJpg(data, length)){
return FormatJPG;
}
if (isPcx(data, length)){
return FormatPCX;
}
if (isTga(data, length)){
return FormatTGA;
}
if (isTif(data, length)){
return FormatTIF;
}
if (isXpm(data, length)){
return FormatXPM;
}
if (isGif(data, length)){
return FormatGIF;
}
return FormatUnknown;
}
}

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