llvm-project/lldb/source/Utility/VASprintf.cpp

57 lines
1.6 KiB
C++

//===-- VASPrintf.cpp -------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lldb/Utility/VASPrintf.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h" // for SmallVectorImpl
#include "llvm/ADT/StringRef.h" // for StringRef
#include <assert.h> // for assert
#include <stdarg.h> // for va_end, va_list, va_copy
#include <stdio.h> // for vsnprintf, size_t
bool lldb_private::VASprintf(llvm::SmallVectorImpl<char> &buf, const char *fmt,
va_list args) {
llvm::SmallString<16> error("<Encoding error>");
bool result = true;
// Copy in case our first call to vsnprintf doesn't fit into our buffer
va_list copy_args;
va_copy(copy_args, args);
buf.resize(buf.capacity());
// Write up to `capacity` bytes, ignoring the current size.
int length = ::vsnprintf(buf.data(), buf.size(), fmt, args);
if (length < 0) {
buf = error;
result = false;
goto finish;
}
if (size_t(length) >= buf.size()) {
// The error formatted string didn't fit into our buffer, resize it to the
// exact needed size, and retry
buf.resize(length + 1);
length = ::vsnprintf(buf.data(), buf.size(), fmt, copy_args);
if (length < 0) {
buf = error;
result = false;
goto finish;
}
assert(size_t(length) < buf.size());
}
buf.resize(length);
finish:
va_end(args);
va_end(copy_args);
return result;
}