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
77