{-# LANGUAGE BangPatterns , UnicodeSyntax #-} -- | WavPack internal functions module Codec.Audio.WavPack.Internal ( packWeight , unpackWeight , log2s , log2 , exp2s , exp2 , countBits , b2n ) where import Data.Int import Data.Word import Data.Bits import qualified Data.Vector.Unboxed as UV import Prelude.Unicode -- | Convert internal weights (which are normally +/-1024) to an 8-bit -- signed character version for storage in metadata. The weights are -- clipped here in the case they are outside that range. packWeight ∷ Int16 → Word8 {-# INLINEABLE packWeight #-} packWeight !w = let !w' | w > 1024 = 1024 | w < -1024 = -1024 | otherwise = w !w'' | w' > 0 = w' - ((w' + 64) `shiftR` 7) | otherwise = w' !w''' = (w'' + 4) `shiftR` 3 in fromIntegral w''' -- | Convert a packed weight to internal weight (+/-1024). Note that -- the following equation /might not hold/ because 'packWeight' is -- lossy. -- -- > unpackWeight . packWeight = id -- unpackWeight ∷ Word8 → Int16 {-# INLINEABLE unpackWeight #-} unpackWeight !w = let w' ∷ Int8 w' = fromIntegral w w'' ∷ Int16 w'' = (fromIntegral w') `shiftL` 3 !w''' | w'' > 0 = w'' + ((w'' + 64) `shiftR` 7) | otherwise = w'' in w''' -- | Return the 'log2' for the specified 32-bit signed integer. All -- input values are valid and the return values are in the range of -- +/-8192. log2s ∷ Int32 → Int16 {-# INLINE log2s #-} log2s !n | n < 0 = fromIntegral $ negate $ log2 $ fromIntegral $ negate n | otherwise = fromIntegral $ log2 $ fromIntegral n -- | The concept of a base 2 logarithm is used in many parts of -- WavPack. It is a way of sufficiently accurately representing 32-bit -- signed and unsigned values storing only 16 bits (actually -- fewer). It is also used in the hybrid mode for quickly comparing -- the relative magnitude of large values (i.e. division) and -- providing smooth exponentials using only addition. -- -- These are not strict logarithms in that they become linear around -- zero and can therefore represent both zero and negative -- values. They have 8 bits of precision and in \"roundtrip\" -- conversions the total error never exceeds 1 part in 225 except for -- the cases of +\/-115 and +\/-195 (which error by 1). -- -- This function returns the log2 for the specified 32-bit unsigned -- value. The maximum value allowed is about 0xff800000 and returns -- 8447. log2 ∷ Word32 → Word16 {-# INLINEABLE log2 #-} log2 !n | n' < (1 `shiftL` 8) = let dbits ∷ Word16 !dbits = getNBits $ fromIntegral n' !index = (n' `shiftL` fromIntegral (9 - dbits)) .&. 0xFF !log2n = getLog2 $ fromIntegral index in (dbits `shiftL` 8) + log2n | otherwise = let dbits ∷ Word16 !dbits | n' < (1 `shiftL` 16) = (getNBits $ fromIntegral $ n' `shiftR` 8) + 8 | n' < (1 `shiftL` 24) = (getNBits $ fromIntegral $ n' `shiftR` 16) + 16 | otherwise = (getNBits $ fromIntegral $ n' `shiftR` 24) + 24 !index = (n' `shiftR` fromIntegral (dbits - 9)) .&. 0xFF !log2n = getLog2 $ fromIntegral index in (dbits `shiftL` 8) + log2n where n' ∷ Word32 n' = n + (n `shiftR` 9) -- | Return the original integer represented by the supplied logarithm -- (at least within the provided accuracy). The log is signed, but -- since a full 32-bit value is returned this can be used for unsigned -- conversions as well (i.e. the input range is -8192 to +8447). exp2s ∷ Int16 → Int32 {-# INLINE exp2s #-} exp2s !l | l < 0 = fromIntegral $ negate $ exp2 $ fromIntegral $ negate l | otherwise = fromIntegral $ exp2 $ fromIntegral l -- | Return the original integer represented by the supplied logarithm -- (at least within the provided accuracy). exp2 ∷ Word16 → Word32 {-# INLINEABLE exp2 #-} exp2 !l = let exp2l ∷ Word32 exp2l = (getExp2 $ fromIntegral $ l .&. 0xFF) .|. 0x100 l' ∷ Word32 l' = fromIntegral $ l `shiftR` 8 in if l' ≤ 9 then exp2l `shiftR` fromIntegral (9 - l') else exp2l `shiftL` fromIntegral (l' - 9) -- | 'countBits' @av@ returns the number of bits that is required to -- represent @av@. countBits ∷ Num a ⇒ Word32 → a {-# INLINEABLE countBits #-} countBits av | av < (1 `shiftL` 8) = getNBits (fromIntegral av) | av < (1 `shiftL` 16) = getNBits (fromIntegral (av `shiftR` 8)) + 8 | av < (1 `shiftL` 24) = getNBits (fromIntegral (av `shiftR` 16)) + 16 | otherwise = getNBits (fromIntegral (av `shiftR` 24)) + 24 -- | Return 0 for 'False' and 1 for 'True'. b2n ∷ Num a ⇒ Bool → a {-# INLINE b2n #-} b2n True = 1 b2n False = 0 getNBits ∷ Num a ⇒ Word8 → a {-# INLINE getNBits #-} getNBits = fromIntegral ∘ UV.unsafeIndex nbitsTable ∘ fromIntegral where nbitsTable ∷ UV.Vector Word8 {-# NOINLINE nbitsTable #-} nbitsTable = UV.fromList [ 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4 -- 0 - 15 , 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 -- 16 - 31 , 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6 -- 32 - 47 , 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6 -- 48 - 63 , 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 -- 64 - 79 , 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 -- 80 - 95 , 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 -- 96 - 111 , 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 -- 112 - 127 , 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 -- 128 - 143 , 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 -- 144 - 159 , 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 -- 160 - 175 , 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 -- 176 - 191 , 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 -- 192 - 207 , 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 -- 208 - 223 , 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 -- 224 - 239 , 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 -- 240 - 255 ] getLog2 ∷ Num n ⇒ Word8 → n {-# INLINE getLog2 #-} getLog2 = fromIntegral ∘ UV.unsafeIndex log2Table ∘ fromIntegral where log2Table ∷ UV.Vector Word8 {-# NOINLINE log2Table #-} log2Table = UV.fromList [ 0x00, 0x01, 0x03, 0x04, 0x06, 0x07, 0x09, 0x0a, 0x0B, 0x0D, 0x0E, 0x10, 0x11, 0x12, 0x14, 0x15 , 0x16, 0x18, 0x19, 0x1a, 0x1C, 0x1D, 0x1E, 0x20, 0x21, 0x22, 0x24, 0x25, 0x26, 0x28, 0x29, 0x2a , 0x2C, 0x2D, 0x2E, 0x2F, 0x31, 0x32, 0x33, 0x34, 0x36, 0x37, 0x38, 0x39, 0x3B, 0x3C, 0x3D, 0x3E , 0x3F, 0x41, 0x42, 0x43, 0x44, 0x45, 0x47, 0x48, 0x49, 0x4a, 0x4B, 0x4D, 0x4E, 0x4F, 0x50, 0x51 , 0x52, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63 , 0x64, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72, 0x74, 0x75 , 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85 , 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95 , 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9B, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4 , 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xa9, 0xaa, 0xaB, 0xaC, 0xaD, 0xaE, 0xaF, 0xB0, 0xB1, 0xB2, 0xB2 , 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xB9, 0xBa, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF, 0xC0, 0xC0 , 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC6, 0xC7, 0xC8, 0xC9, 0xCa, 0xCB, 0xCB, 0xCC, 0xCD, 0xCE , 0xCF, 0xD0, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD8, 0xD9, 0xDa, 0xDB , 0xDC, 0xDC, 0xDD, 0xDE, 0xDF, 0xE0, 0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE4, 0xE5, 0xE6, 0xE7, 0xE7 , 0xE8, 0xE9, 0xEa, 0xEa, 0xEB, 0xEC, 0xED, 0xEE, 0xEE, 0xEF, 0xF0, 0xF1, 0xF1, 0xF2, 0xF3, 0xF4 , 0xF4, 0xF5, 0xF6, 0xF7, 0xF7, 0xF8, 0xF9, 0xF9, 0xFa, 0xFB, 0xFC, 0xFC, 0xFD, 0xFE, 0xFF, 0xFF ] getExp2 ∷ Num n ⇒ Word8 → n {-# INLINE getExp2 #-} getExp2 = fromIntegral ∘ UV.unsafeIndex exp2Table ∘ fromIntegral where exp2Table ∷ UV.Vector Word8 {-# NOINLINE exp2Table #-} exp2Table = UV.fromList [ 0x00, 0x01, 0x01, 0x02, 0x03, 0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x08, 0x09, 0x0a, 0x0B , 0x0B, 0x0C, 0x0D, 0x0E, 0x0E, 0x0F, 0x10, 0x10, 0x11, 0x12, 0x13, 0x13, 0x14, 0x15, 0x16, 0x16 , 0x17, 0x18, 0x19, 0x19, 0x1a, 0x1B, 0x1C, 0x1D, 0x1D, 0x1E, 0x1F, 0x20, 0x20, 0x21, 0x22, 0x23 , 0x24, 0x24, 0x25, 0x26, 0x27, 0x28, 0x28, 0x29, 0x2a, 0x2B, 0x2C, 0x2C, 0x2D, 0x2E, 0x2F, 0x30 , 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3a, 0x3B, 0x3C, 0x3D , 0x3E, 0x3F, 0x40, 0x41, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x48, 0x49, 0x4a, 0x4B , 0x4C, 0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a , 0x5B, 0x5C, 0x5D, 0x5E, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69 , 0x6a, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79 , 0x7a, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x87, 0x88, 0x89, 0x8a , 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92, 0x93, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9B , 0x9C, 0x9D, 0x9F, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa8, 0xa9, 0xaa, 0xaB, 0xaC, 0xaD , 0xaF, 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB6, 0xB7, 0xB8, 0xB9, 0xBa, 0xBC, 0xBD, 0xBE, 0xBF, 0xC0 , 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC8, 0xC9, 0xCa, 0xCB, 0xCD, 0xCE, 0xCF, 0xD0, 0xD2, 0xD3, 0xD4 , 0xD6, 0xD7, 0xD8, 0xD9, 0xDB, 0xDC, 0xDD, 0xDE, 0xE0, 0xE1, 0xE2, 0xE4, 0xE5, 0xE6, 0xE8, 0xE9 , 0xEa, 0xEC, 0xED, 0xEE, 0xF0, 0xF1, 0xF2, 0xF4, 0xF5, 0xF6, 0xF8, 0xF9, 0xFa, 0xFC, 0xFD, 0xFF ]