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1 //===- StreamWrite.cpp - Writes bytes and objects to a stream -------------===//
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/DebugInfo/CodeView/StreamWriter.h"
11 
12 #include "llvm/DebugInfo/CodeView/CodeViewError.h"
13 #include "llvm/DebugInfo/CodeView/StreamReader.h"
14 #include "llvm/DebugInfo/CodeView/StreamRef.h"
15 
16 using namespace llvm;
17 using namespace llvm::codeview;
18 
StreamWriter(StreamRef S)19 StreamWriter::StreamWriter(StreamRef S) : Stream(S), Offset(0) {}
20 
writeBytes(ArrayRef<uint8_t> Buffer)21 Error StreamWriter::writeBytes(ArrayRef<uint8_t> Buffer) {
22   if (auto EC = Stream.writeBytes(Offset, Buffer))
23     return EC;
24   Offset += Buffer.size();
25   return Error::success();
26 }
27 
writeInteger(uint16_t Int)28 Error StreamWriter::writeInteger(uint16_t Int) {
29   return writeObject(support::ulittle16_t(Int));
30 }
31 
writeInteger(uint32_t Int)32 Error StreamWriter::writeInteger(uint32_t Int) {
33   return writeObject(support::ulittle32_t(Int));
34 }
35 
writeZeroString(StringRef Str)36 Error StreamWriter::writeZeroString(StringRef Str) {
37   if (auto EC = writeFixedString(Str))
38     return EC;
39   if (auto EC = writeObject('\0'))
40     return EC;
41 
42   return Error::success();
43 }
44 
writeFixedString(StringRef Str)45 Error StreamWriter::writeFixedString(StringRef Str) {
46   ArrayRef<uint8_t> Bytes(Str.bytes_begin(), Str.bytes_end());
47   if (auto EC = Stream.writeBytes(Offset, Bytes))
48     return EC;
49 
50   Offset += Str.size();
51   return Error::success();
52 }
53 
writeStreamRef(StreamRef Ref)54 Error StreamWriter::writeStreamRef(StreamRef Ref) {
55   if (auto EC = writeStreamRef(Ref, Ref.getLength()))
56     return EC;
57   Offset += Ref.getLength();
58   return Error::success();
59 }
60 
writeStreamRef(StreamRef Ref,uint32_t Length)61 Error StreamWriter::writeStreamRef(StreamRef Ref, uint32_t Length) {
62   Ref = Ref.slice(0, Length);
63 
64   StreamReader SrcReader(Ref);
65   // This is a bit tricky.  If we just call readBytes, we are requiring that it
66   // return us the entire stream as a contiguous buffer.  For large streams this
67   // will allocate a huge amount of space from the pool.  Instead, iterate over
68   // each contiguous chunk until we've consumed the entire stream.
69   while (SrcReader.bytesRemaining() > 0) {
70     ArrayRef<uint8_t> Chunk;
71     if (auto EC = SrcReader.readLongestContiguousChunk(Chunk))
72       return EC;
73     if (auto EC = writeBytes(Chunk))
74       return EC;
75   }
76   return Error::success();
77 }
78