1 // Copyright 2002 The RE2 Authors. All Rights Reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
8 #define va_copy(d,s) ((d) = (s)) //KLUGE: for MS compilers
13 static void StringAppendV(string* dst, const char* format, va_list ap) {
14 // First try with a small fixed size buffer
17 // It's possible for methods that use a va_list to invalidate
18 // the data in it upon use. The fix is to make a copy
19 // of the structure before using it and use that copy instead.
21 va_copy(backup_ap, ap);
22 int result = vsnprintf(space, sizeof(space), format, backup_ap);
25 if ((result >= 0) && (result < sizeof(space))) {
27 dst->append(space, result);
31 // Repeatedly increase buffer size until it fits
32 int length = sizeof(space);
35 // Older behavior: just try doubling the buffer size
38 // We need exactly "result+1" characters
41 char* buf = new char[length];
43 // Restore the va_list before we use it again
44 va_copy(backup_ap, ap);
45 result = vsnprintf(buf, length, format, backup_ap);
48 if ((result >= 0) && (result < length)) {
50 dst->append(buf, result);
58 string StringPrintf(const char* format, ...) {
62 StringAppendV(&result, format, ap);
67 void SStringPrintf(string* dst, const char* format, ...) {
71 StringAppendV(dst, format, ap);
75 void StringAppendF(string* dst, const char* format, ...) {
78 StringAppendV(dst, format, ap);