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// 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
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