commit 22667a650cc3adbd00fe2173ff9631582498e8e6
author Andy Hung <hunga@google.com> Fri Nov 17 15:54:27 2017 -0800
committer Andy Hung <hunga@google.com> Fri Nov 17 16:18:15 2017 -0800
tree 7ef8163a97201cc3d4fdfb794f425e85b45010fa
parent 1307aa7fda6be97c4a64864e0c85724f1662c32f

Allow in-place audio primitive operations.

Difference in performance is negligible ~ 2% loss going reverse.

Test: primitives_tests
Bug: 69478507
Change-Id: I39522f45d81956e1108276161ce4a92fc0ab3fba

audio_utils/primitives.c

diff --git a/audio_utils/primitives.c b/audio_utils/primitives.c
index fc8a467..5bf5908 100644
--- a/audio_utils/primitives.c
+++ b/audio_utils/primitives.c
@@ -74,23 +74,29 @@
 
 void memcpy_to_float_from_i16(float *dst, const int16_t *src, size_t count)
 {
+    dst += count;
+    src += count;
     for (; count > 0; --count) {
-        *dst++ = float_from_i16(*src++);
+        *--dst = float_from_i16(*--src);
     }
 }
 
 void memcpy_to_float_from_u8(float *dst, const uint8_t *src, size_t count)
 {
+    dst += count;
+    src += count;
     for (; count > 0; --count) {
-        *dst++ = float_from_u8(*src++);
+        *--dst = float_from_u8(*--src);
     }
 }
 
 void memcpy_to_float_from_p24(float *dst, const uint8_t *src, size_t count)
 {
+    dst += count;
+    src += count * 3;
     for (; count > 0; --count) {
-        *dst++ = float_from_p24(src);
-        src += 3;
+        src -= 3;
+        *--dst = float_from_p24(src);
     }
 }
 
@@ -108,27 +114,32 @@
 
 void memcpy_to_i32_from_p24(int32_t *dst, const uint8_t *src, size_t count)
 {
+    dst += count;
+    src += count * 3;
     for (; count > 0; --count) {
+        src -= 3;
 #if HAVE_BIG_ENDIAN
-        *dst++ = (src[2] << 8) | (src[1] << 16) | (src[0] << 24);
+        *--dst = (src[2] << 8) | (src[1] << 16) | (src[0] << 24);
 #else
-        *dst++ = (src[0] << 8) | (src[1] << 16) | (src[2] << 24);
+        *--dst = (src[0] << 8) | (src[1] << 16) | (src[2] << 24);
 #endif
-        src += 3;
     }
 }
 
 void memcpy_to_p24_from_i16(uint8_t *dst, const int16_t *src, size_t count)
 {
+    dst += count * 3;
+    src += count;
     for (; count > 0; --count) {
+        dst -= 3;
 #if HAVE_BIG_ENDIAN
-        *dst++ = *src >> 8;
-        *dst++ = *src++;
-        *dst++ = 0;
+        dst[0] = *--src >> 8;
+        dst[1] = *src;
+        dst[2] = 0;
 #else
-        *dst++ = 0;
-        *dst++ = *src;
-        *dst++ = *src++ >> 8;
+        dst[0] = 0;
+        dst[1] = *--src;
+        dst[2] = *src >> 8;
 #endif
     }
 }
@@ -186,8 +197,10 @@
 
 void memcpy_to_q8_23_from_i16(int32_t *dst, const int16_t *src, size_t count)
 {
+    dst += count;
+    src += count;
     for (; count > 0; --count) {
-        *dst++ = (int32_t)*src++ << 8;
+        *--dst = (int32_t)*--src << 8;
     }
 }
 
@@ -200,13 +213,15 @@
 
 void memcpy_to_q8_23_from_p24(int32_t *dst, const uint8_t *src, size_t count)
 {
+    dst += count;
+    src += count * 3;
     for (; count > 0; --count) {
+        src -= 3;
 #if HAVE_BIG_ENDIAN
-        *dst++ = (int8_t)src[0] << 16 | src[1] << 8 | src[2];
+        *--dst = (int8_t)src[0] << 16 | src[1] << 8 | src[2];
 #else
-        *dst++ = (int8_t)src[2] << 16 | src[1] << 8 | src[0];
+        *--dst = (int8_t)src[2] << 16 | src[1] << 8 | src[0];
 #endif
-        src += 3;
     }
 }
 
@@ -233,8 +248,10 @@
 
 void memcpy_to_i32_from_i16(int32_t *dst, const int16_t *src, size_t count)
 {
+    dst += count;
+    src += count;
     for (; count > 0; --count) {
-        *dst++ = (int32_t)*src++ << 16;
+        *--dst = (int32_t)*--src << 16;
     }
 }
 
@@ -274,11 +291,13 @@
 
 void upmix_to_stereo_i16_from_mono_i16(int16_t *dst, const int16_t *src, size_t count)
 {
+    dst += count * 2;
+    src += count;
     for (; count > 0; --count) {
-        int32_t temp = *src++;
+        const int32_t temp = *--src;
+        dst -= 2;
         dst[0] = temp;
         dst[1] = temp;
-        dst += 2;
     }
 }
 
@@ -292,11 +311,13 @@
 
 void upmix_to_stereo_float_from_mono_float(float *dst, const float *src, size_t frames)
 {
+    dst += frames * 2;
+    src += frames;
     for (; frames > 0; --frames) {
-        float temp = *src++;
+        const float temp = *--src;
+        dst -= 2;
         dst[0] = temp;
         dst[1] = temp;
-        dst += 2;
     }
 }