SkPDF: fix name escape code [cherry-pick from master]

src/pdf/SkPDFTypes.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 "SkPDFTypes.h"
 #include "SkPDFUtils.h"
@@ skipping 81 matching lines @@
     while (*n) {
         if (*n < '!' || *n > '~' || strchr(kControlChars, *n)) {
             return false;
         }
         ++n;
     }
     return true;
 }
 #endif  // SK_DEBUG
 
-// Given an arbitrary string, convert it to a valid name.
-static SkString escape_name(const char* name, size_t len) {
+// Given an arbitrary string, write it as a valid name (not including
+// leading slash).
+static void write_name_escaped(SkWStream* o, const char* name) {
     static const char kToEscape[] = "#/%()<>[]{}";
-    int count = 0;
-    const char* const end = &name[len];
-    for (const char* n = name; n != end; ++n) {
+    static const char kHex[] = "0123456789ABCDEF";
+    for (const uint8_t* n = reinterpret_cast<const uint8_t*>(name); *n; ++n) {
         if (*n < '!' || *n > '~' || strchr(kToEscape, *n)) {
-            count += 2;
-        }
-        ++count;
-    }
-    SkString result(count);
-    char* s = result.writable_str();
-    static const char kHex[] = "0123456789ABCDEF";
-    for (const char* n = name; n != end; ++n) {
-        if (*n < '!' || *n > '~' || strchr(kToEscape, *n)) {
-            *s++ = '#';
-            *s++ = kHex[(*n >> 4) & 0xF];
-            *s++ = kHex[*n & 0xF];
+            char buffer[3] = {'#', '\0', '\0'};
+            buffer[1] = kHex[(*n >> 4) & 0xF];
+            buffer[2] = kHex[*n & 0xF];
+            o->write(buffer, sizeof(buffer));
         } else {
-            *s++ = *n;
+            o->write(n, 1);
         }
     }
-    SkASSERT(&result.writable_str()[count] == s);  // don't over-write
-    return result;                                 // allocated space
-}
-
-static SkString escape_name(const SkString& name) {
-    return escape_name(name.c_str(), name.size());
 }
 
 static void write_string(SkWStream* o, const SkString& s) {
     o->write(s.c_str(), s.size());
 }
 
 static SkString format_string(const SkString& s) {
     return SkPDFUtils::FormatString(s.c_str(), s.size());
 }
 
@@ skipping 18 matching lines @@
             stream->writeText("/");
             SkASSERT(is_valid_name(fStaticString));
             stream->writeText(fStaticString);
             return;
         case Type::kString:
             SkASSERT(fStaticString);
             write_string(stream, format_string(fStaticString));
             return;
         case Type::kNameSkS:
             stream->writeText("/");
-            write_string(stream, escape_name(*pun(fSkString)));
+            write_name_escaped(stream, pun(fSkString)->c_str());
             return;
         case Type::kStringSkS:
             write_string(stream, format_string(*pun(fSkString)));
             return;
         case Type::kObjRef:
             stream->writeDecAsText(objNumMap.getObjectNumber(
                     substitutes.getSubstitute(fObject)));
             stream->writeText(" 0 R");  // Generation number is always 0.
             return;
         case Type::kObject:
@@ skipping 300 matching lines @@
     fObjects.push(obj);
     return true;
 }
 
 int32_t SkPDFObjNumMap::getObjectNumber(SkPDFObject* obj) const {
     int32_t* objectNumberFound = fObjectNumbers.find(obj);
     SkASSERT(objectNumberFound);
     return *objectNumberFound;
 }