1 //===- EndianStream.h - Stream ops with endian specific data ----*- 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 // This file defines utilities for operating on streams that have endian
10 // specific data.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_SUPPORT_ENDIANSTREAM_H
15 #define LLVM_SUPPORT_ENDIANSTREAM_H
16 
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/SmallVector.h"
19 #include "llvm/Support/Endian.h"
20 #include "llvm/Support/raw_ostream.h"
21 
22 namespace llvm {
23 namespace support {
24 
25 namespace endian {
26 
27 template <typename value_type>
28 inline void write_array(raw_ostream &os, ArrayRef<value_type> values,
29                         endianness endian) {
30   for (const auto orig : values) {
31     value_type value = byte_swap<value_type>(orig, endian);
32     os.write((const char *)&value, sizeof(value_type));
33   }
34 }
35 
36 template <typename value_type>
37 inline void write(raw_ostream &os, value_type value, endianness endian) {
38   value = byte_swap<value_type>(value, endian);
39   os.write((const char *)&value, sizeof(value_type));
40 }
41 
42 template <>
43 inline void write<float>(raw_ostream &os, float value, endianness endian) {
44   write(os, llvm::bit_cast<uint32_t>(value), endian);
45 }
46 
47 template <>
48 inline void write<double>(raw_ostream &os, double value,
49                           endianness endian) {
50   write(os, llvm::bit_cast<uint64_t>(value), endian);
51 }
52 
53 template <typename value_type>
54 inline void write(raw_ostream &os, ArrayRef<value_type> vals,
55                   endianness endian) {
56   for (value_type v : vals)
57     write(os, v, endian);
58 }
59 
60 template <typename value_type>
61 inline void write(SmallVectorImpl<char> &Out, value_type V, endianness E) {
62   V = byte_swap<value_type>(V, E);
63   Out.append((const char *)&V, (const char *)&V + sizeof(value_type));
64 }
65 
66 /// Adapter to write values to a stream in a particular byte order.
67 struct Writer {
68   raw_ostream &OS;
69   endianness Endian;
70   Writer(raw_ostream &OS, endianness Endian) : OS(OS), Endian(Endian) {}
71   template <typename value_type> void write(ArrayRef<value_type> Val) {
72     endian::write(OS, Val, Endian);
73   }
74   template <typename value_type> void write(value_type Val) {
75     endian::write(OS, Val, Endian);
76   }
77 };
78 
79 } // end namespace endian
80 
81 } // end namespace support
82 } // end namespace llvm
83 
84 #endif
85