core/fmt_traits.h

   1 #ifndef CORE_FMT_TRAITS_H
   2 #define CORE_FMT_TRAITS_H
   3
   4 #include <array>
   5 #include <cstdint>
   6
   7 #include "storage_formats.h"
   8
   9
  10 namespace al {
  11
  12 extern const std::array<std::int16_t,256> muLawDecompressionTable;
  13 extern const std::array<std::int16_t,256> aLawDecompressionTable;
  14
  15
  16 template<FmtType T>
  17 struct FmtTypeTraits { };
  18
  19 template<>
  20 struct FmtTypeTraits<FmtUByte> {
  21     using Type = std::uint8_t;
  22
  23     constexpr float operator()(const Type val) const noexcept
  24     { return float(val)*(1.0f/128.0f) - 1.0f; }
  25 };
  26 template<>
  27 struct FmtTypeTraits<FmtShort> {
  28     using Type = std::int16_t;
  29
  30     constexpr float operator()(const Type val) const noexcept
  31     { return float(val) * (1.0f/32768.0f); }
  32 };
  33 template<>
  34 struct FmtTypeTraits<FmtInt> {
  35     using Type = std::int32_t;
  36
  37     constexpr float operator()(const Type val) const noexcept
  38     { return static_cast<float>(val)*(1.0f/2147483648.0f); }
  39 };
  40 template<>
  41 struct FmtTypeTraits<FmtFloat> {
  42     using Type = float;
  43
  44     constexpr float operator()(const Type val) const noexcept { return val; }
  45 };
  46 template<>
  47 struct FmtTypeTraits<FmtDouble> {
  48     using Type = double;
  49
  50     constexpr float operator()(const Type val) const noexcept { return static_cast<float>(val); }
  51 };
  52 template<>
  53 struct FmtTypeTraits<FmtMulaw> {
  54     using Type = std::uint8_t;
  55
  56     constexpr float operator()(const Type val) const noexcept
  57     { return float(muLawDecompressionTable[val]) * (1.0f/32768.0f); }
  58 };
  59 template<>
  60 struct FmtTypeTraits<FmtAlaw> {
  61     using Type = std::uint8_t;
  62
  63     constexpr float operator()(const Type val) const noexcept
  64     { return float(aLawDecompressionTable[val]) * (1.0f/32768.0f); }
  65 };
  66
  67 } // namespace al
  68
  69 #endif /* CORE_FMT_TRAITS_H */