Change String::WriteUtf8() to return characters written.

test/cctest/test-strings.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 
 // Check that we can traverse very deep stacks of ConsStrings using
 // StringInputBuffer.  Check that Get(int) works on very deep stacks
 // of ConsStrings.  These operations may not be very fast, but they
 // should be possible without getting errors due to too deep recursion.
 
 #include <stdlib.h>
 
 #include "v8.h"
@@ skipping 305 matching lines @@
   // U+0064 -> 64
   // U+12E4 -> E1 8B A4
   // U+0030 -> 30
   // U+3045 -> E3 81 85
   const uint16_t mixed_string[] = {0x02E4, 0x0064, 0x12E4, 0x0030, 0x3045};
   // The characters we expect to be output
   const unsigned char as_utf8[11] = {0xCB, 0xA4, 0x64, 0xE1, 0x8B, 0xA4, 0x30,
       0xE3, 0x81, 0x85, 0x00};
   // The number of bytes expected to be written for each length
   const int lengths[12] = {0, 0, 2, 3, 3, 3, 6, 7, 7, 7, 10, 11};
+  const int char_lengths[12] = {0, 0, 1, 2, 2, 2, 3, 4, 4, 4, 5, 5};
   v8::Handle<v8::String> mixed = v8::String::New(mixed_string, 5);
   CHECK_EQ(10, mixed->Utf8Length());
   // Try encoding the string with all capacities
   char buffer[11];
   const char kNoChar = static_cast<char>(-1);
   for (int i = 0; i <= 11; i++) {
     // Clear the buffer before reusing it
     for (int j = 0; j < 11; j++)
       buffer[j] = kNoChar;
-    int written = mixed->WriteUtf8(buffer, i);
+    int chars_written;
+    int written = mixed->WriteUtf8(buffer, i, &chars_written);
     CHECK_EQ(lengths[i], written);
+    CHECK_EQ(char_lengths[i], chars_written);
     // Check that the contents are correct
     for (int j = 0; j < lengths[i]; j++)
       CHECK_EQ(as_utf8[j], static_cast<unsigned char>(buffer[j]));
     // Check that the rest of the buffer hasn't been touched
     for (int j = lengths[i]; j < 11; j++)
       CHECK_EQ(kNoChar, buffer[j]);
   }
 }
 
 
@@ skipping 76 matching lines @@
     "      if (non_ascii[i] !="
     "          (non_ascii[j] + external_non_ascii[i - j])) return 12;"
     "    }"
     "  }"
     "  return 0;"
     "};"
     "test()";
   CHECK_EQ(0,
            v8::Script::Compile(v8::String::New(source))->Run()->Int32Value());
 }