src/llvm/include/llvm/Support/Format.h

   1 //===- Format.h - Efficient printf-style formatting for streams -*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the format() function, which can be used with other
  11 // LLVM subsystems to provide printf-style formatting.  This gives all the power
  12 // and risk of printf.  This can be used like this (with raw_ostreams as an
  13 // example):
  14 //
  15 //    OS << "mynumber: " << format("%4.5f", 1234.412) << '\n';
  16 //
  17 // Or if you prefer:
  18 //
  19 //  OS << format("mynumber: %4.5f\n", 1234.412);
  20 //
  21 //===----------------------------------------------------------------------===//
  22
  23 #ifndef LLVM_SUPPORT_FORMAT_H
  24 #define LLVM_SUPPORT_FORMAT_H
  25
  26 #include "llvm/ADT/StringRef.h"
  27 #include "llvm/Support/DataTypes.h"
  28 #include <cassert>
  29 #include <cstdio>
  30 #ifdef _MSC_VER
  31 // FIXME: This define is wrong:
  32 //  - _snprintf does not guarantee that trailing null is always added - if
  33 //    there is no space for null, it does not report any error.
  34 //  - According to C++ standard, snprintf should be visible in the 'std'
  35 //    namespace - this define makes this impossible.
  36 #define snprintf _snprintf
  37 #endif
  38
  39 namespace llvm {
  40
  41 /// This is a helper class used for handling formatted output.  It is the
  42 /// abstract base class of a templated derived class.
  43 class format_object_base {
  44 protected:
  45   const char *Fmt;
  46   ~format_object_base() {} // Disallow polymorphic deletion.
  47   virtual void home(); // Out of line virtual method.
  48
  49   /// Call snprintf() for this object, on the given buffer and size.
  50   virtual int snprint(char *Buffer, unsigned BufferSize) const = 0;
  51
  52 public:
  53   format_object_base(const char *fmt) : Fmt(fmt) {}
  54
  55   /// Format the object into the specified buffer.  On success, this returns
  56   /// the length of the formatted string.  If the buffer is too small, this
  57   /// returns a length to retry with, which will be larger than BufferSize.
  58   unsigned print(char *Buffer, unsigned BufferSize) const {
  59     assert(BufferSize && "Invalid buffer size!");
  60
  61     // Print the string, leaving room for the terminating null.
  62     int N = snprint(Buffer, BufferSize);
  63
  64     // VC++ and old GlibC return negative on overflow, just double the size.
  65     if (N < 0)
  66       return BufferSize * 2;
  67
  68     // Other implementations yield number of bytes needed, not including the
  69     // final '\0'.
  70     if (unsigned(N) >= BufferSize)
  71       return N + 1;
  72
  73     // Otherwise N is the length of output (not including the final '\0').
  74     return N;
  75   }
  76 };
  77
  78 /// These are templated helper classes used by the format function that
  79 /// capture the object to be formated and the format string. When actually
  80 /// printed, this synthesizes the string into a temporary buffer provided and
  81 /// returns whether or not it is big enough.
  82
  83 template <typename T>
  84 class format_object1 final : public format_object_base {
  85   T Val;
  86 public:
  87   format_object1(const char *fmt, const T &val)
  88     : format_object_base(fmt), Val(val) {
  89   }
  90
  91   int snprint(char *Buffer, unsigned BufferSize) const override {
  92     return snprintf(Buffer, BufferSize, Fmt, Val);
  93   }
  94 };
  95
  96 template <typename T1, typename T2>
  97 class format_object2 final : public format_object_base {
  98   T1 Val1;
  99   T2 Val2;
 100 public:
 101   format_object2(const char *fmt, const T1 &val1, const T2 &val2)
 102   : format_object_base(fmt), Val1(val1), Val2(val2) {
 103   }
 104
 105   int snprint(char *Buffer, unsigned BufferSize) const override {
 106     return snprintf(Buffer, BufferSize, Fmt, Val1, Val2);
 107   }
 108 };
 109
 110 template <typename T1, typename T2, typename T3>
 111 class format_object3 final : public format_object_base {
 112   T1 Val1;
 113   T2 Val2;
 114   T3 Val3;
 115 public:
 116   format_object3(const char *fmt, const T1 &val1, const T2 &val2,const T3 &val3)
 117     : format_object_base(fmt), Val1(val1), Val2(val2), Val3(val3) {
 118   }
 119
 120   int snprint(char *Buffer, unsigned BufferSize) const override {
 121     return snprintf(Buffer, BufferSize, Fmt, Val1, Val2, Val3);
 122   }
 123 };
 124
 125 template <typename T1, typename T2, typename T3, typename T4>
 126 class format_object4 final : public format_object_base {
 127   T1 Val1;
 128   T2 Val2;
 129   T3 Val3;
 130   T4 Val4;
 131 public:
 132   format_object4(const char *fmt, const T1 &val1, const T2 &val2,
 133                  const T3 &val3, const T4 &val4)
 134     : format_object_base(fmt), Val1(val1), Val2(val2), Val3(val3), Val4(val4) {
 135   }
 136
 137   int snprint(char *Buffer, unsigned BufferSize) const override {
 138     return snprintf(Buffer, BufferSize, Fmt, Val1, Val2, Val3, Val4);
 139   }
 140 };
 141
 142 template <typename T1, typename T2, typename T3, typename T4, typename T5>
 143 class format_object5 final : public format_object_base {
 144   T1 Val1;
 145   T2 Val2;
 146   T3 Val3;
 147   T4 Val4;
 148   T5 Val5;
 149 public:
 150   format_object5(const char *fmt, const T1 &val1, const T2 &val2,
 151                  const T3 &val3, const T4 &val4, const T5 &val5)
 152     : format_object_base(fmt), Val1(val1), Val2(val2), Val3(val3), Val4(val4),
 153       Val5(val5) {
 154   }
 155
 156   int snprint(char *Buffer, unsigned BufferSize) const override {
 157     return snprintf(Buffer, BufferSize, Fmt, Val1, Val2, Val3, Val4, Val5);
 158   }
 159 };
 160
 161 template <typename T1, typename T2, typename T3, typename T4, typename T5,
 162           typename T6>
 163 class format_object6 final : public format_object_base {
 164   T1 Val1;
 165   T2 Val2;
 166   T3 Val3;
 167   T4 Val4;
 168   T5 Val5;
 169   T6 Val6;
 170 public:
 171   format_object6(const char *Fmt, const T1 &Val1, const T2 &Val2,
 172                  const T3 &Val3, const T4 &Val4, const T5 &Val5, const T6 &Val6)
 173     : format_object_base(Fmt), Val1(Val1), Val2(Val2), Val3(Val3), Val4(Val4),
 174       Val5(Val5), Val6(Val6) { }
 175
 176   int snprint(char *Buffer, unsigned BufferSize) const override {
 177     return snprintf(Buffer, BufferSize, Fmt, Val1, Val2, Val3, Val4, Val5, Val6);
 178   }
 179 };
 180
 181 /// These are helper functions used to produce formatted output.  They use
 182 /// template type deduction to construct the appropriate instance of the
 183 /// format_object class to simplify their construction.
 184 ///
 185 /// This is typically used like:
 186 /// \code
 187 ///   OS << format("%0.4f", myfloat) << '\n';
 188 /// \endcode
 189
 190 template <typename T>
 191 inline format_object1<T> format(const char *Fmt, const T &Val) {
 192   return format_object1<T>(Fmt, Val);
 193 }
 194
 195 template <typename T1, typename T2>
 196 inline format_object2<T1, T2> format(const char *Fmt, const T1 &Val1,
 197                                      const T2 &Val2) {
 198   return format_object2<T1, T2>(Fmt, Val1, Val2);
 199 }
 200
 201 template <typename T1, typename T2, typename T3>
 202   inline format_object3<T1, T2, T3> format(const char *Fmt, const T1 &Val1,
 203                                            const T2 &Val2, const T3 &Val3) {
 204   return format_object3<T1, T2, T3>(Fmt, Val1, Val2, Val3);
 205 }
 206
 207 template <typename T1, typename T2, typename T3, typename T4>
 208 inline format_object4<T1, T2, T3, T4> format(const char *Fmt, const T1 &Val1,
 209                                              const T2 &Val2, const T3 &Val3,
 210                                              const T4 &Val4) {
 211   return format_object4<T1, T2, T3, T4>(Fmt, Val1, Val2, Val3, Val4);
 212 }
 213
 214 template <typename T1, typename T2, typename T3, typename T4, typename T5>
 215 inline format_object5<T1, T2, T3, T4, T5> format(const char *Fmt,const T1 &Val1,
 216                                              const T2 &Val2, const T3 &Val3,
 217                                              const T4 &Val4, const T5 &Val5) {
 218   return format_object5<T1, T2, T3, T4, T5>(Fmt, Val1, Val2, Val3, Val4, Val5);
 219 }
 220
 221 template <typename T1, typename T2, typename T3, typename T4, typename T5,
 222           typename T6>
 223 inline format_object6<T1, T2, T3, T4, T5, T6>
 224 format(const char *Fmt, const T1 &Val1, const T2 &Val2, const T3 &Val3,
 225        const T4 &Val4, const T5 &Val5, const T6 &Val6) {
 226   return format_object6<T1, T2, T3, T4, T5, T6>(Fmt, Val1, Val2, Val3, Val4,
 227                                                 Val5, Val6);
 228 }
 229
 230 /// This is a helper class used for left_justify() and right_justify().
 231 class FormattedString {
 232   StringRef Str;
 233   unsigned Width;
 234   bool RightJustify;
 235   friend class raw_ostream;
 236 public:
 237     FormattedString(StringRef S, unsigned W, bool R)
 238       : Str(S), Width(W), RightJustify(R) { }
 239 };
 240
 241 /// left_justify - append spaces after string so total output is
 242 /// \p Width characters.  If \p Str is larger that \p Width, full string
 243 /// is written with no padding.
 244 inline FormattedString left_justify(StringRef Str, unsigned Width) {
 245   return FormattedString(Str, Width, false);
 246 }
 247
 248 /// right_justify - add spaces before string so total output is
 249 /// \p Width characters.  If \p Str is larger that \p Width, full string
 250 /// is written with no padding.
 251 inline FormattedString right_justify(StringRef Str, unsigned Width) {
 252   return FormattedString(Str, Width, true);
 253 }
 254
 255 /// This is a helper class used for format_hex() and format_decimal().
 256 class FormattedNumber {
 257   uint64_t HexValue;
 258   int64_t DecValue;
 259   unsigned Width;
 260   bool Hex;
 261   bool Upper;
 262   friend class raw_ostream;
 263 public:
 264     FormattedNumber(uint64_t HV, int64_t DV, unsigned W, bool H, bool U)
 265       : HexValue(HV), DecValue(DV), Width(W), Hex(H), Upper(U) { }
 266 };
 267
 268 /// format_hex - Output \p N as a fixed width hexadecimal. If number will not
 269 /// fit in width, full number is still printed.  Examples:
 270 ///   OS << format_hex(255, 4)        => 0xff
 271 ///   OS << format_hex(255, 4, true)  => 0xFF
 272 ///   OS << format_hex(255, 6)        => 0x00ff
 273 ///   OS << format_hex(255, 2)        => 0xff
 274 inline FormattedNumber format_hex(uint64_t N, unsigned Width, bool Upper=false) {
 275   assert(Width <= 18 && "hex width must be <= 18");
 276   return FormattedNumber(N, 0, Width, true, Upper);
 277 }
 278
 279 /// format_decimal - Output \p N as a right justified, fixed-width decimal. If
 280 /// number will not fit in width, full number is still printed.  Examples:
 281 ///   OS << format_decimal(0, 5)     => "    0"
 282 ///   OS << format_decimal(255, 5)   => "  255"
 283 ///   OS << format_decimal(-1, 3)    => " -1"
 284 ///   OS << format_decimal(12345, 3) => "12345"
 285 inline FormattedNumber format_decimal(int64_t N, unsigned Width) {
 286   return FormattedNumber(0, N, Width, false, false);
 287 }
 288
 289
 290 } // end namespace llvm
 291
 292 #endif