Support IMA4 ADPCM as a mixing voice format

3 files changed, 30 insertions, 13 deletions

diff --git a/common/alnumeric.h b/common/alnumeric.h
index 13e61645..a426763f 100644
--- a/common/alnumeric.h
+++ b/common/alnumeric.h
@@ -12,6 +12,7 @@
 #include <xmmintrin.h>
 #endif
 
+#include "altraits.h"
 #include "opthelpers.h"
 
 
@@ -97,12 +98,20 @@ inline uint32_t NextPowerOf2(uint32_t value) noexcept
     return value+1;
 }
 
-/** Round up a value to the next multiple. */
-inline size_t RoundUp(size_t value, size_t r) noexcept
-{
-    value += r-1;
-    return value - (value%r);
-}
+/**
+ * If the value is not already a multiple of r, round down to the next
+ * multiple.
+ */
+template<typename T>
+constexpr T RoundDown(T value, al::type_identity_t<T> r) noexcept
+{ return value - (value%r); }
+
+/**
+ * If the value is not already a multiple of r, round up to the next multiple.
+ */
+template<typename T>
+constexpr T RoundUp(T value, al::type_identity_t<T> r) noexcept
+{ return RoundDown(value + r-1, r); }
 
 
 /**
diff --git a/common/alspan.h b/common/alspan.h
index 519f22e4..1d6cdfe5 100644
--- a/common/alspan.h
+++ b/common/alspan.h
@@ -8,6 +8,7 @@
 #include <type_traits>
 
 #include "almalloc.h"
+#include "altraits.h"
 
 namespace al {
 
@@ -37,13 +38,6 @@ constexpr const T* data(std::initializer_list<T> list) noexcept
 { return list.begin(); }
 
 
-template<typename T>
-struct type_identity { using type = T; };
-
-template<typename T>
-using type_identity_t = typename type_identity<T>::type;
-
-
 constexpr size_t dynamic_extent{static_cast<size_t>(-1)};
 
 template<typename T, size_t E=dynamic_extent>
diff --git a/common/altraits.h b/common/altraits.h
new file mode 100644
index 00000000..7ce0422e
--- /dev/null
+++ b/common/altraits.h
@@ -0,0 +1,14 @@
+#ifndef COMMON_ALTRAITS_H
+#define COMMON_ALTRAITS_H
+
+namespace al {
+
+template<typename T>
+struct type_identity { using type = T; };
+
+template<typename T>
+using type_identity_t = typename type_identity<T>::type;
+
+} // namespace al
+
+#endif /* COMMON_ALTRAITS_H */