etc1_bool etc1_pkm_is_valid(const etc1_byte* pHeader)
{
if (memcmp(pHeader, kMagic, sizeof(kMagic)))
{
return false;
}
etc1_uint32 format = readBEUint16(pHeader + ETC1_PKM_FORMAT_OFFSET);
etc1_uint32 encodedWidth = readBEUint16(pHeader + ETC1_PKM_ENCODED_WIDTH_OFFSET);
etc1_uint32 encodedHeight = readBEUint16(pHeader + ETC1_PKM_ENCODED_HEIGHT_OFFSET);
etc1_uint32 width = readBEUint16(pHeader + ETC1_PKM_WIDTH_OFFSET);
etc1_uint32 height = readBEUint16(pHeader + ETC1_PKM_HEIGHT_OFFSET);
return format == ETC1_RGB_NO_MIPMAPS && encodedWidth >= width && encodedWidth - width < 4 && encodedHeight >= height && encodedHeight - height < 4;
}
static int
etc1_pkm_is_valid(const unsigned char* pHeader, unsigned* pencodedWidth,
unsigned* pencodedHeight)
{
if (memcmp(pHeader, kMagic, sizeof(kMagic))) {
return 0;
}
unsigned format = readBEUint16(pHeader + ETC1_PKM_FORMAT_OFFSET);
unsigned encodedWidth = readBEUint16(pHeader + ETC1_PKM_ENCODED_WIDTH_OFFSET);
unsigned encodedHeight =
readBEUint16(pHeader + ETC1_PKM_ENCODED_HEIGHT_OFFSET);
unsigned width = readBEUint16(pHeader + ETC1_PKM_WIDTH_OFFSET);
unsigned height = readBEUint16(pHeader + ETC1_PKM_HEIGHT_OFFSET);
*pencodedWidth = encodedWidth;
*pencodedHeight = encodedHeight;
return format == ETC1_RGB_NO_MIPMAPS && encodedWidth >= width &&
encodedWidth - width < 4 && encodedHeight >= height &&
encodedHeight - height < 4;
}
etc1_uint32 etc1_pkm_get_height(const etc1_byte* pHeader)
{
return readBEUint16(pHeader + ETC1_PKM_HEIGHT_OFFSET);
}
etc1_uint32 etc1_pkm_get_width(const etc1_byte* pHeader)
{
return readBEUint16(pHeader + ETC1_PKM_WIDTH_OFFSET);
}
