Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Tree: a753edb386
Fetching contributors…

Cannot retrieve contributors at this time

99 lines (86 sloc) 2.582 kB
// Copyright 2010 Google
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "base/stringprintf.h"
#include <cstdarg>
#include <cstdio>
#include <string>
void StringAppendV(std::string* const dst,
const char* const 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;
#if defined(_MSC_VER)
backup_ap = ap;
#else
va_copy(backup_ap, ap);
#endif
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* const buf = new char[length];
// Restore the va_list before we use it again
#if defined(_MSC_VER)
backup_ap = ap;
#else
va_copy(backup_ap, ap);
#endif
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;
}
}
std::string StringPrintf(const char* const format, ...) {
va_list ap;
va_start(ap, format);
std::string result;
StringAppendV(&result, format, ap);
va_end(ap);
return result;
}
void SStringPrintf(std::string* const dst, const char* const format, ...) {
va_list ap;
va_start(ap, format);
dst->clear();
StringAppendV(dst, format, ap);
va_end(ap);
}
void StringAppendF(std::string* const dst, const char* const format, ...) {
va_list ap;
va_start(ap, format);
StringAppendV(dst, format, ap);
va_end(ap);
}
Jump to Line
Something went wrong with that request. Please try again.