Add single sample push.

apu/apu.cpp

@@ -33,7 +33,7 @@ namespace SNES
 {
 #include "bapu/dsp/blargg_endian.h"
 CPU cpu;
-}
+} // namespace SNES
 
 namespace spc
 {
@@ -57,7 +57,7 @@ static uint32 ratio_numerator = APU_NUMERATOR_NTSC;
 static uint32 ratio_denominator = APU_DENOMINATOR_NTSC;
 
 static double dynamic_rate_multiplier = 1.0;
-}
+} // namespace spc
 
 namespace msu
 {
@@ -66,7 +66,7 @@ static const int buffer_size = MAX_SAMPLE_FRAMES * 6;
 static uint8 mixing_buffer[buffer_size];
 static Resampler *resampler = NULL;
 static std::vector<uint16> resample_buffer;
-}
+} // namespace msu
 
 static void UpdatePlaybackRate(void);
 static void SPCSnapshotCallback(void);

apu/resampler.h

@@ -95,12 +95,27 @@ struct Resampler
         return true;
     }
 
+    inline void push(int16_t l, int16_t r)
+    {
+        if (space_empty() >= 2)
+        {
+            int end = start + size;
+            if (end > buffer_size)
+                end -= buffer_size;
+            buffer[end] = l;
+            buffer[end + 1] = r;
+            size += 2;
+        }
+    }
+
     inline bool push(int16_t *src, int num_samples)
     {
         if (space_empty() < num_samples)
             return false;
 
-        int end = (start + size) % buffer_size;
+        int end = start + size;
+        if (end > buffer_size)
+            end -= buffer_size;
         int first_write_size = min(num_samples, buffer_size - end);
 
         memcpy(buffer + end, src, first_write_size * 2);