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#include "tensorflow/core/lib/strings/stringprintf.h"
#include <errno.h>
#include <stdarg.h> // For va_list and related operations
#include <stdio.h> // MSVC requires this for _vsnprintf
#include <vector>
namespace tensorflow {
namespace strings {
#ifdef COMPILER_MSVC
enum { IS_COMPILER_MSVC = 1 };
#else
enum { IS_COMPILER_MSVC = 0 };
#endif
void Appendv(string* dst, const char* format, va_list ap) {
// First try with a small fixed size buffer
static const int kSpaceLength = 1024;
char space[kSpaceLength];
// 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, kSpaceLength, format, backup_ap);
va_end(backup_ap);
if (result < kSpaceLength) {
if (result >= 0) {
// Normal case -- everything fit.
dst->append(space, result);
return;
}
if (IS_COMPILER_MSVC) {
// Error or MSVC running out of space. MSVC 8.0 and higher
// can be asked about space needed with the special idiom below:
va_copy(backup_ap, ap);
result = vsnprintf(NULL, 0, format, backup_ap);
va_end(backup_ap);
}
if (result < 0) {
// Just an error.
return;
}
}
// Increase the buffer size to the size requested by vsnprintf,
// plus one for the closing \0.
int 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;
}
string Printf(const char* format, ...) {
va_list ap;
va_start(ap, format);
string result;
Appendv(&result, format, ap);
va_end(ap);
return result;
}
void Appendf(string* dst, const char* format, ...) {
va_list ap;
va_start(ap, format);
Appendv(dst, format, ap);
va_end(ap);
}
} // namespace strings
} // namespace tensorflow
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