some improvements of ATRAC3 implementation:atrac3

- simple (ATRAC1 like) psychoacoustic added
- possibility to encode tonal components
- simple tonal component extractor
- refactoring

1 files changed, 30 insertions, 0 deletions

diff --git a/src/util.h b/src/util.h
index e167655..9ba9d1d 100644
--- a/src/util.h
+++ b/src/util.h
@@ -1,6 +1,9 @@
 #pragma once
 #include <cstdint>
+#include <vector>
+#include <algorithm>
 
+#include "config.h"
 
 template<class T>
 inline void SwapArray(T* p, const size_t len) {
@@ -10,3 +13,30 @@ inline void SwapArray(T* p, const size_t len) {
         p[j] = tmp;
     }
 }
+
+inline uint16_t GetFirstSetBit(uint32_t x) {
+    static const uint16_t multiplyDeBruijnBitPosition[32] = {
+        0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30,
+        8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31
+    };
+    x |= x >> 1;
+    x |= x >> 2;
+    x |= x >> 4;
+    x |= x >> 8;
+    x |= x >> 16;
+    return multiplyDeBruijnBitPosition[(uint32_t)(x * 0x07C4ACDDU) >> 27];
+}
+
+template<class T>
+inline uint16_t Log2FloatToIdx(T x, uint16_t shift) {
+    T t = x * shift;
+    return GetFirstSetBit(t);
+}
+
+template<class T>
+inline T CalcMedian(T* in, uint32_t len) {
+    std::vector<T> tmp(in, in+len);
+    std::sort(tmp.begin(), tmp.end());
+    uint32_t pos = (len - 1) / 2;
+    return tmp[pos];
+}