llvm-6502/include/llvm/Support/Format.h
Douglas Gregor fbe67f85b2 Make a few headers standalone. Plus, add a missing "template" keyword
that Clang diagnoses but GCC does not.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86130 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-05 13:30:28 +00:00

150 lines
5.2 KiB
C++

//===- Format.h - Efficient printf-style formatting for streams -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the format() function, which can be used with other
// LLVM subsystems to provide printf-style formatting. This gives all the power
// and risk of printf. This can be used like this (with raw_ostreams as an
// example):
//
// OS << "mynumber: " << format("%4.5f", 1234.412) << '\n';
//
// Or if you prefer:
//
// OS << format("mynumber: %4.5f\n", 1234.412);
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_FORMAT_H
#define LLVM_SUPPORT_FORMAT_H
#include <cassert>
#include <cstdio>
#ifdef WIN32
#define snprintf _snprintf
#endif
namespace llvm {
/// format_object_base - This is a helper class used for handling formatted
/// output. It is the abstract base class of a templated derived class.
class format_object_base {
protected:
const char *Fmt;
virtual void home(); // Out of line virtual method.
/// snprint - Call snprintf() for this object, on the given buffer and size.
virtual int snprint(char *Buffer, unsigned BufferSize) const = 0;
public:
format_object_base(const char *fmt) : Fmt(fmt) {}
virtual ~format_object_base() {}
/// print - Format the object into the specified buffer. On success, this
/// returns the length of the formatted string. If the buffer is too small,
/// this returns a length to retry with, which will be larger than BufferSize.
unsigned print(char *Buffer, unsigned BufferSize) const {
assert(BufferSize && "Invalid buffer size!");
// Print the string, leaving room for the terminating null.
int N = snprint(Buffer, BufferSize);
// VC++ and old GlibC return negative on overflow, just double the size.
if (N < 0)
return BufferSize*2;
// Other impls yield number of bytes needed, not including the final '\0'.
if (unsigned(N) >= BufferSize)
return N+1;
// Otherwise N is the length of output (not including the final '\0').
return N;
}
};
/// format_object1 - This is a templated helper class used by the format
/// function that captures the object to be formated and the format string. When
/// actually printed, this synthesizes the string into a temporary buffer
/// provided and returns whether or not it is big enough.
template <typename T>
class format_object1 : public format_object_base {
T Val;
public:
format_object1(const char *fmt, const T &val)
: format_object_base(fmt), Val(val) {
}
virtual int snprint(char *Buffer, unsigned BufferSize) const {
return snprintf(Buffer, BufferSize, Fmt, Val);
}
};
/// format_object2 - This is a templated helper class used by the format
/// function that captures the object to be formated and the format string. When
/// actually printed, this synthesizes the string into a temporary buffer
/// provided and returns whether or not it is big enough.
template <typename T1, typename T2>
class format_object2 : public format_object_base {
T1 Val1;
T2 Val2;
public:
format_object2(const char *fmt, const T1 &val1, const T2 &val2)
: format_object_base(fmt), Val1(val1), Val2(val2) {
}
virtual int snprint(char *Buffer, unsigned BufferSize) const {
return snprintf(Buffer, BufferSize, Fmt, Val1, Val2);
}
};
/// format_object3 - This is a templated helper class used by the format
/// function that captures the object to be formated and the format string. When
/// actually printed, this synthesizes the string into a temporary buffer
/// provided and returns whether or not it is big enough.
template <typename T1, typename T2, typename T3>
class format_object3 : public format_object_base {
T1 Val1;
T2 Val2;
T3 Val3;
public:
format_object3(const char *fmt, const T1 &val1, const T2 &val2,const T3 &val3)
: format_object_base(fmt), Val1(val1), Val2(val2), Val3(val3) {
}
virtual int snprint(char *Buffer, unsigned BufferSize) const {
return snprintf(Buffer, BufferSize, Fmt, Val1, Val2, Val3);
}
};
/// format - This is a helper function that is used to produce formatted output.
/// This is typically used like: OS << format("%0.4f", myfloat) << '\n';
template <typename T>
inline format_object1<T> format(const char *Fmt, const T &Val) {
return format_object1<T>(Fmt, Val);
}
/// format - This is a helper function that is used to produce formatted output.
/// This is typically used like: OS << format("%0.4f", myfloat) << '\n';
template <typename T1, typename T2>
inline format_object2<T1, T2> format(const char *Fmt, const T1 &Val1,
const T2 &Val2) {
return format_object2<T1, T2>(Fmt, Val1, Val2);
}
/// format - This is a helper function that is used to produce formatted output.
/// This is typically used like: OS << format("%0.4f", myfloat) << '\n';
template <typename T1, typename T2, typename T3>
inline format_object3<T1, T2, T3> format(const char *Fmt, const T1 &Val1,
const T2 &Val2, const T3 &Val3) {
return format_object3<T1, T2, T3>(Fmt, Val1, Val2, Val3);
}
} // end namespace llvm
#endif