detect.cpp

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#include <haio_codec.hpp>
#include <haio_util.hpp>
 
namespace {
 
constexpr std::array<uint8_t, 6> signature87a = {
    'G', 'I', 'F', '8', '7', 'a'
};
 
constexpr std::array<uint8_t, 6> signature89a = {
    'G', 'I', 'F', '8', '9', 'a'
};
 
bool headerSays(Haio::Bytes data) {
    return Haio::Util::matches(data, signature87a)
        || Haio::Util::matches(data, signature89a);
}
 
}
 
namespace Haio::Codecs {
 
/** what a gif holds when nobody asks for something else */
template <> struct DefaultColor<Format::GIF> { static constexpr Color value = Color::RGBA8888; };
 
/**
 * @addtogroup detect
 * @{
 */
template <>
bool Detect<Format::GIF, Color::RGBA8888>(Bytes data) {
    return headerSays(data);
}
/** @} */
 
/**
 * @addtogroup detect
 * @{
 */
/**
 * GIF has a palette rather than an RGB colour type, but the decoder expands
 * it directly to RGB888.
 */
template <>
bool Detect<Format::GIF, Color::RGB888>(Bytes data) {
    return headerSays(data);
}
/** @} */
 
}