1 //===- BinaryStreamWriter.cpp - Writes objects to a BinaryStream ----------===//
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 #include "llvm/Support/BinaryStreamWriter.h"
11
12 #include "llvm/Support/BinaryStreamError.h"
13 #include "llvm/Support/BinaryStreamReader.h"
14 #include "llvm/Support/BinaryStreamRef.h"
15
16 using namespace llvm;
17
BinaryStreamWriter(WritableBinaryStreamRef Ref)18 BinaryStreamWriter::BinaryStreamWriter(WritableBinaryStreamRef Ref)
19 : Stream(Ref) {}
20
BinaryStreamWriter(WritableBinaryStream & Stream)21 BinaryStreamWriter::BinaryStreamWriter(WritableBinaryStream &Stream)
22 : Stream(Stream) {}
23
BinaryStreamWriter(MutableArrayRef<uint8_t> Data,llvm::support::endianness Endian)24 BinaryStreamWriter::BinaryStreamWriter(MutableArrayRef<uint8_t> Data,
25 llvm::support::endianness Endian)
26 : Stream(Data, Endian) {}
27
writeBytes(ArrayRef<uint8_t> Buffer)28 Error BinaryStreamWriter::writeBytes(ArrayRef<uint8_t> Buffer) {
29 if (auto EC = Stream.writeBytes(Offset, Buffer))
30 return EC;
31 Offset += Buffer.size();
32 return Error::success();
33 }
34
writeCString(StringRef Str)35 Error BinaryStreamWriter::writeCString(StringRef Str) {
36 if (auto EC = writeFixedString(Str))
37 return EC;
38 if (auto EC = writeObject('\0'))
39 return EC;
40
41 return Error::success();
42 }
43
writeFixedString(StringRef Str)44 Error BinaryStreamWriter::writeFixedString(StringRef Str) {
45
46 return writeBytes(arrayRefFromStringRef(Str));
47 }
48
writeStreamRef(BinaryStreamRef Ref)49 Error BinaryStreamWriter::writeStreamRef(BinaryStreamRef Ref) {
50 return writeStreamRef(Ref, Ref.getLength());
51 }
52
writeStreamRef(BinaryStreamRef Ref,uint32_t Length)53 Error BinaryStreamWriter::writeStreamRef(BinaryStreamRef Ref, uint32_t Length) {
54 BinaryStreamReader SrcReader(Ref.slice(0, Length));
55 // This is a bit tricky. If we just call readBytes, we are requiring that it
56 // return us the entire stream as a contiguous buffer. There is no guarantee
57 // this can be satisfied by returning a reference straight from the buffer, as
58 // an implementation may not store all data in a single contiguous buffer. So
59 // we iterate over each contiguous chunk, writing each one in succession.
60 while (SrcReader.bytesRemaining() > 0) {
61 ArrayRef<uint8_t> Chunk;
62 if (auto EC = SrcReader.readLongestContiguousChunk(Chunk))
63 return EC;
64 if (auto EC = writeBytes(Chunk))
65 return EC;
66 }
67 return Error::success();
68 }
69
70 std::pair<BinaryStreamWriter, BinaryStreamWriter>
split(uint32_t Off) const71 BinaryStreamWriter::split(uint32_t Off) const {
72 assert(getLength() >= Off);
73
74 WritableBinaryStreamRef First = Stream.drop_front(Offset);
75
76 WritableBinaryStreamRef Second = First.drop_front(Off);
77 First = First.keep_front(Off);
78 BinaryStreamWriter W1{First};
79 BinaryStreamWriter W2{Second};
80 return std::make_pair(W1, W2);
81 }
82
padToAlignment(uint32_t Align)83 Error BinaryStreamWriter::padToAlignment(uint32_t Align) {
84 uint32_t NewOffset = alignTo(Offset, Align);
85 if (NewOffset > getLength())
86 return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
87 while (Offset < NewOffset)
88 if (auto EC = writeInteger('\0'))
89 return EC;
90 return Error::success();
91 }
92