Include RE2 library

third_party/re2/util/stringprintf.cc

+// Copyright 2002 The RE2 Authors.  All Rights Reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "util/util.h"
+
+#ifndef va_copy
+#define va_copy(d,s) ((d) = (s)) //KLUGE: for MS compilers
+#endif
+
+namespace re2 { 
+
+static void StringAppendV(string* dst, const char* format, va_list ap) {
+  // First try with a small fixed size buffer
+  char space[1024];
+
+  // It's possible for methods that use a va_list to invalidate
+  // the data in it upon use.  The fix is to make a copy
+  // of the structure before using it and use that copy instead.
+  va_list backup_ap;
+  va_copy(backup_ap, ap);
+  int result = vsnprintf(space, sizeof(space), format, backup_ap);
+  va_end(backup_ap);
+
+  if ((result >= 0) && (result < sizeof(space))) {
+    // It fit
+    dst->append(space, result);
+    return;
+  }
+
+  // Repeatedly increase buffer size until it fits
+  int length = sizeof(space);
+  while (true) {
+    if (result < 0) {
+      // Older behavior: just try doubling the buffer size
+      length *= 2;
+    } else {
+      // We need exactly "result+1" characters
+      length = result+1;
+    }
+    char* buf = new char[length];
+
+    // Restore the va_list before we use it again
+    va_copy(backup_ap, ap);
+    result = vsnprintf(buf, length, format, backup_ap);
+    va_end(backup_ap);
+
+    if ((result >= 0) && (result < length)) {
+      // It fit
+      dst->append(buf, result);
+      delete[] buf;
+      return;
+    }
+    delete[] buf;
+  }
+}
+
+string StringPrintf(const char* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  string result;
+  StringAppendV(&result, format, ap);
+  va_end(ap);
+  return result;
+}
+
+void SStringPrintf(string* dst, const char* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  dst->clear();
+  StringAppendV(dst, format, ap);
+  va_end(ap);
+}
+
+void StringAppendF(string* dst, const char* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  StringAppendV(dst, format, ap);
+  va_end(ap);
+}
+
+}  // namespace re2