add replace_char() method to SkString API (skbug.com/2651)

src/core/SkString.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 "SkString.h"
@@ skipping 537 matching lines @@
     SkASSERT(p >= buffer);
     this->insert(offset, p, buffer + sizeof(buffer) - p);
 }
 
 void SkString::insertScalar(size_t offset, SkScalar value) {
     char    buffer[SkStrAppendScalar_MaxSize];
     char*   stop = SkStrAppendScalar(buffer, value);
     this->insert(offset, buffer, stop - buffer);
 }
 
+void SkString::replace_char(const char oldChar, const char newChar) {
+    if (this->isEmpty()) {
+        return;
+    }
+    for (size_t i = 0; i < this->size(); ++i) {
+        if (oldChar == this->operator[](i)) {

[epoger, 2014/06/11 11:01:33]

Instead of going through the [] operator, I suspect it would be more efficient
to do something like this:

size_t len = this->size();
if (len > 0) {
  char* writable = this->writable_str();
  for (size_t i = len - 1; i >= 0; --i) {
    if (oldChar == writable[i]) {
      writable[i] = newChar;
    }
  }
}

[rs.prinja, 2014/06/11 12:08:03]

Done, although since unsigned always compares as >= 0 I ran the loop from 0 to
len-1 instead.

+            fRec->data()[i] = newChar;
+        }
+    }
+}
+
 void SkString::printf(const char format[], ...) {
     char    buffer[kBufferSize];
     ARGS_TO_BUFFER(format, buffer, kBufferSize);
 
     this->set(buffer, strlen(buffer));
 }
 
 void SkString::appendf(const char format[], ...) {
     char    buffer[kBufferSize];
     ARGS_TO_BUFFER(format, buffer, kBufferSize);
@@ skipping 73 matching lines @@
         const size_t len = strcspn(str, delimiters);
         out->push_back().set(str, len);
         str += len;
         // Skip any delimiters.
         str += strspn(str, delimiters);
     }
 }
 
 #undef VSNPRINTF
 #undef SNPRINTF