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;
}
bool Bitmap::getImageSize(const io::Producer &file, size_t &width, size_t &height) {
StackBuffer<256> data;
if (file.seekAndRead(0, data, 30) < 30) {
return false;
}
if (isPng(data.data(), data.size()) && data.size() >= 24) {
auto reader = DataReader<ByteOrder::Network>(data.data() + 16, 8);
width = reader.readUnsigned32();
height = reader.readUnsigned32();
return true;
} else if(isJpg(data.data(), data.size())) {
size_t offset = 2;
uint16_t len = 0;
uint8_t marker = 0;
auto reader = DataReader<ByteOrder::Network>(data.data() + 2, data.size() - 2);
while (reader.is((uint8_t)0xFF)) {
++ reader;
}
marker = reader.readUnsigned();
len = reader.readUnsigned16();
while (marker < 0xC0 || marker > 0xCF) {
offset += 2 + len;
data.clear();
if (file.seekAndRead(offset, data, 12) != 12) {
return false;
}
if (data.size() >= 12) {
reader = data.get<DataReader<ByteOrder::Network>>();
while (reader.is((uint8_t)0xFF)) {
++ reader;
}
marker = reader.readUnsigned();
len = reader.readUnsigned16();
} else {
reader.clear();
break;
}
}
if (reader >= 5 && marker >= 0xC0 && marker <= 0xCF) {
++ reader;
height = reader.readUnsigned16();
width = reader.readUnsigned16();
return true;
}
return false;
} else if (isGif(data.data(), data.size())) {
auto reader = DataReader<ByteOrder::Little>(data.data() + 6, 4);
width = reader.readUnsigned16();
height = reader.readUnsigned16();
return true;
} else if (isWebp(data.data(), data.size())) {
auto reader = DataReader<ByteOrder::Little>(data.data() + 26, 4);
width = reader.readUnsigned16();
height = reader.readUnsigned16();
return true;
} else if (isTiff(data.data(), data.size())) {
if (memcmp(data.data(), "II", 2) == 0) {
if (Bitmap_getTiffImageSize<DataReader<ByteOrder::Little>>(data, file, width, height)) {
return true;
}
} else {
if (Bitmap_getTiffImageSize<DataReader<ByteOrder::Big>>(data, file, width, height)) {
return true;
}
}
}
return false;
}