Choose memset procs once.

src/core/SkUtils.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkUtils.h"
+#include "SkOnce.h"
 
 #if 0
 #define assign_16_longs(dst, value)             \
     do {                                        \
         (dst)[0] = value;   (dst)[1] = value;   \
         (dst)[2] = value;   (dst)[3] = value;   \
         (dst)[4] = value;   (dst)[5] = value;   \
         (dst)[6] = value;   (dst)[7] = value;   \
         (dst)[8] = value;   (dst)[9] = value;   \
         (dst)[10] = value;  (dst)[11] = value;  \
         (dst)[12] = value;  (dst)[13] = value;  \
         (dst)[14] = value;  (dst)[15] = value;  \
     } while (0)
 #else
 #define assign_16_longs(dst, value)             \
     do {                                        \
         *(dst)++ = value;   *(dst)++ = value;   \
         *(dst)++ = value;   *(dst)++ = value;   \
         *(dst)++ = value;   *(dst)++ = value;   \
         *(dst)++ = value;   *(dst)++ = value;   \
         *(dst)++ = value;   *(dst)++ = value;   \
         *(dst)++ = value;   *(dst)++ = value;   \
         *(dst)++ = value;   *(dst)++ = value;   \
         *(dst)++ = value;   *(dst)++ = value;   \
     } while (0)
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void sk_memset16_portable(uint16_t dst[], uint16_t value, int count) {
+static void sk_memset16_portable(uint16_t dst[], uint16_t value, int count) {
     SkASSERT(dst != NULL && count >= 0);
 
     if (count <= 0) {
         return;
     }
 
     // not sure if this helps to short-circuit on small values of count
     if (count < 8) {
         do {
             *dst++ = (uint16_t)value;
@@ skipping 32 matching lines @@
             } while (--longs != 0);
         }
     }
 
     // cleanup a possible trailing short
     if (count & 1) {
         *dst = (uint16_t)value;
     }
 }
 
-void sk_memset32_portable(uint32_t dst[], uint32_t value, int count) {
+static void sk_memset32_portable(uint32_t dst[], uint32_t value, int count) {
     SkASSERT(dst != NULL && count >= 0);
 
     int sixteenlongs = count >> 4;
     if (sixteenlongs) {
         do {
             assign_16_longs(dst, value);
         } while (--sixteenlongs != 0);
         count &= 15;
     }
 
     if (count) {
         do {
             *dst++ = value;
         } while (--count != 0);
     }
 }
 
-static void sk_memset16_stub(uint16_t dst[], uint16_t value, int count) {
-    SkMemset16Proc proc = SkMemset16GetPlatformProc();
-    sk_memset16 = proc ? proc : sk_memset16_portable;
-    sk_memset16(dst, value, count);
+static void choose_memset16(SkMemset16Proc* proc) {
+    *proc = SkMemset16GetPlatformProc();
+    if (NULL == *proc) {
+        *proc = &sk_memset16_portable;
+    }
 }
 
-SkMemset16Proc sk_memset16 = sk_memset16_stub;
+void sk_memset16(uint16_t dst[], uint16_t value, int count) {
+    SK_DECLARE_STATIC_ONCE(once);
+    static SkMemset16Proc proc = NULL;
+    SkOnce(&once, choose_memset16, &proc);
+    SkASSERT(proc != NULL);
 
-static void sk_memset32_stub(uint32_t dst[], uint32_t value, int count) {
-    SkMemset32Proc proc = SkMemset32GetPlatformProc();
-    sk_memset32 = proc ? proc : sk_memset32_portable;
-    sk_memset32(dst, value, count);
+    return proc(dst, value, count);
 }
 
-SkMemset32Proc sk_memset32 = sk_memset32_stub;
+static void choose_memset32(SkMemset32Proc* proc) {
+    *proc = SkMemset32GetPlatformProc();
+    if (NULL == *proc) {
+        *proc = &sk_memset32_portable;
+    }
+}
+
+void sk_memset32(uint32_t dst[], uint32_t value, int count) {
+    SK_DECLARE_STATIC_ONCE(once);
+    static SkMemset32Proc proc = NULL;
+    SkOnce(&once, choose_memset32, &proc);
+    SkASSERT(proc != NULL);
+
+    return proc(dst, value, count);
+}
 
 ///////////////////////////////////////////////////////////////////////////////
 
 /*  0xxxxxxx    1 total
     10xxxxxx    // never a leading byte
     110xxxxx    2 total
     1110xxxx    3 total
     11110xxx    4 total
 
     11 10 01 01 xx xx xx xx 0...
@@ skipping 252 matching lines @@
         }
     } else {
         char* start = utf8;
         while (utf16 < stop) {
             utf8 += SkUTF8_FromUnichar(SkUTF16_NextUnichar(&utf16), utf8);
         }
         size = utf8 - start;
     }
     return size;
 }