Templetized SkWriter32 readTAt() & overwriteTAt()

src/core/SkWriter32.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkReader32.h"
 #include "SkString.h"
 #include "SkWriter32.h"
@@ skipping 26 matching lines @@
 }
 
 void SkWriter32::writeString(const char str[], size_t len) {
     if (NULL == str) {
         str = "";
         len = 0;
     }
     if ((long)len < 0) {
         len = strlen(str);
     }
-    this->write32(len);
-    // add 1 since we also write a terminating 0
-    size_t alignedLen = SkAlign4(len + 1);
-    char* ptr = (char*)this->reserve(alignedLen);
-    {
-        // Write the terminating 0 and fill in the rest with zeroes
-        uint32_t* padding = (uint32_t*)(ptr + (alignedLen - 4));
-        *padding = 0;
-    }
-    // Copy the string itself.
-    memcpy(ptr, str, len);
+
+    // [ 4 byte len ] [ str ... ] [1 - 4 \0s]
+    uint32_t* ptr = this->reservePad(sizeof(uint32_t) + len + 1);
+    *ptr = len;
+    char* chars = (char*)(ptr + 1);
+    memcpy(chars, str, len);
+    chars[len] = '\0';
 }
 
 size_t SkWriter32::WriteStringSize(const char* str, size_t len) {
     if ((long)len < 0) {
         SkASSERT(str);
         len = strlen(str);
     }
     const size_t lenBytes = 4;    // we use 4 bytes to record the length
     // add 1 since we also write a terminating 0
     return SkAlign4(lenBytes + len + 1);
 }
 
 const size_t kMinBufferBytes = 4096;
 
 void SkWriter32::growToAtLeast(size_t size) {
     const bool wasExternal = (fExternal != NULL) && (fData == fExternal);
     const size_t minCapacity = kMinBufferBytes +
         SkTMax(size, fCapacity + (fCapacity >> 1));
 
     // cause the buffer to grow
     fInternal.setCountExact(minCapacity);
     fData = fInternal.begin();
     fCapacity = fInternal.reserved();
     if (wasExternal) {
         // we were external, so copy in the data
         memcpy(fData, fExternal, fUsed);
     }
 }