include/llvm/Support/FormatCommon.h

   1 //===- FormatCommon.h - Formatters for common LLVM types --------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_SUPPORT_FORMATCOMMON_H
  10 #define LLVM_SUPPORT_FORMATCOMMON_H
  11
  12 #include "llvm/ADT/SmallString.h"
  13 #include "llvm/Support/FormatVariadicDetails.h"
  14 #include "llvm/Support/raw_ostream.h"
  15
  16 namespace llvm {
  17 enum class AlignStyle { Left, Center, Right };
  18
  19 struct FmtAlign {
  20   detail::format_adapter &Adapter;
  21   AlignStyle Where;
  22   size_t Amount;
  23   char Fill;
  24
  25   FmtAlign(detail::format_adapter &Adapter, AlignStyle Where, size_t Amount,
  26            char Fill = ' ')
  27       : Adapter(Adapter), Where(Where), Amount(Amount), Fill(Fill) {}
  28
  29   void format(raw_ostream &S, StringRef Options) {
  30     // If we don't need to align, we can format straight into the underlying
  31     // stream.  Otherwise we have to go through an intermediate stream first
  32     // in order to calculate how long the output is so we can align it.
  33     // TODO: Make the format method return the number of bytes written, that
  34     // way we can also skip the intermediate stream for left-aligned output.
  35     if (Amount == 0) {
  36       Adapter.format(S, Options);
  37       return;
  38     }
  39     SmallString<64> Item;
  40     raw_svector_ostream Stream(Item);
  41
  42     Adapter.format(Stream, Options);
  43     if (Amount <= Item.size()) {
  44       S << Item;
  45       return;
  46     }
  47
  48     size_t PadAmount = Amount - Item.size();
  49     switch (Where) {
  50     case AlignStyle::Left:
  51       S << Item;
  52       fill(S, PadAmount);
  53       break;
  54     case AlignStyle::Center: {
  55       size_t X = PadAmount / 2;
  56       fill(S, X);
  57       S << Item;
  58       fill(S, PadAmount - X);
  59       break;
  60     }
  61     default:
  62       fill(S, PadAmount);
  63       S << Item;
  64       break;
  65     }
  66   }
  67
  68 private:
  69   void fill(llvm::raw_ostream &S, uint32_t Count) {
  70     for (uint32_t I = 0; I < Count; ++I)
  71       S << Fill;
  72   }
  73 };
  74 }
  75
  76 #endif