core/fmt_traits.h

   1 #ifndef CORE_FMT_TRAITS_H
   2 #define CORE_FMT_TRAITS_H
   3
   4 #include <stddef.h>
   5 #include <stdint.h>
   6
   7 #include "albyte.h"
   8 #include "buffer_storage.h"
   9
  10
  11 namespace al {
  12
  13 extern const int16_t muLawDecompressionTable[256];
  14 extern const int16_t aLawDecompressionTable[256];
  15
  16
  17 template<FmtType T>
  18 struct FmtTypeTraits { };
  19
  20 template<>
  21 struct FmtTypeTraits<FmtUByte> {
  22     using Type = uint8_t;
  23
  24     template<typename OutT>
  25     static constexpr inline OutT to(const Type val) noexcept
  26     { return val*OutT{1.0/128.0} - OutT{1.0}; }
  27 };
  28 template<>
  29 struct FmtTypeTraits<FmtShort> {
  30     using Type = int16_t;
  31
  32     template<typename OutT>
  33     static constexpr inline OutT to(const Type val) noexcept { return val*OutT{1.0/32768.0}; }
  34 };
  35 template<>
  36 struct FmtTypeTraits<FmtFloat> {
  37     using Type = float;
  38
  39     template<typename OutT>
  40     static constexpr inline OutT to(const Type val) noexcept { return val; }
  41 };
  42 template<>
  43 struct FmtTypeTraits<FmtDouble> {
  44     using Type = double;
  45
  46     template<typename OutT>
  47     static constexpr inline OutT to(const Type val) noexcept { return static_cast<OutT>(val); }
  48 };
  49 template<>
  50 struct FmtTypeTraits<FmtMulaw> {
  51     using Type = uint8_t;
  52
  53     template<typename OutT>
  54     static constexpr inline OutT to(const Type val) noexcept
  55     { return muLawDecompressionTable[val] * OutT{1.0/32768.0}; }
  56 };
  57 template<>
  58 struct FmtTypeTraits<FmtAlaw> {
  59     using Type = uint8_t;
  60
  61     template<typename OutT>
  62     static constexpr inline OutT to(const Type val) noexcept
  63     { return aLawDecompressionTable[val] * OutT{1.0/32768.0}; }
  64 };
  65
  66
  67 template<FmtType SrcType, typename DstT>
  68 inline void LoadSampleArray(DstT *RESTRICT dst, const al::byte *src, const size_t srcstep,
  69     const size_t samples) noexcept
  70 {
  71     using TypeTraits = FmtTypeTraits<SrcType>;
  72     using SampleType = typename TypeTraits::Type;
  73
  74     const SampleType *RESTRICT ssrc{reinterpret_cast<const SampleType*>(src)};
  75     for(size_t i{0u};i < samples;i++)
  76         dst[i] = TypeTraits::template to<DstT>(ssrc[i*srcstep]);
  77 }
  78
  79 } // namespace al
  80
  81 #endif /* CORE_FMT_TRAITS_H */