1 //===- StreamReader.cpp - Reads bytes and objects from 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/StreamReader.h"
11
12 #include "llvm/DebugInfo/CodeView/CodeViewError.h"
13 #include "llvm/DebugInfo/CodeView/StreamRef.h"
14
15 using namespace llvm;
16 using namespace llvm::codeview;
17
StreamReader(StreamRef S)18 StreamReader::StreamReader(StreamRef S) : Stream(S), Offset(0) {}
19
readLongestContiguousChunk(ArrayRef<uint8_t> & Buffer)20 Error StreamReader::readLongestContiguousChunk(ArrayRef<uint8_t> &Buffer) {
21 if (auto EC = Stream.readLongestContiguousChunk(Offset, Buffer))
22 return EC;
23 Offset += Buffer.size();
24 return Error::success();
25 }
26
readBytes(ArrayRef<uint8_t> & Buffer,uint32_t Size)27 Error StreamReader::readBytes(ArrayRef<uint8_t> &Buffer, uint32_t Size) {
28 if (auto EC = Stream.readBytes(Offset, Size, Buffer))
29 return EC;
30 Offset += Size;
31 return Error::success();
32 }
33
readInteger(uint16_t & Dest)34 Error StreamReader::readInteger(uint16_t &Dest) {
35 const support::ulittle16_t *P;
36 if (auto EC = readObject(P))
37 return EC;
38 Dest = *P;
39 return Error::success();
40 }
41
readInteger(uint32_t & Dest)42 Error StreamReader::readInteger(uint32_t &Dest) {
43 const support::ulittle32_t *P;
44 if (auto EC = readObject(P))
45 return EC;
46 Dest = *P;
47 return Error::success();
48 }
49
readZeroString(StringRef & Dest)50 Error StreamReader::readZeroString(StringRef &Dest) {
51 uint32_t Length = 0;
52 // First compute the length of the string by reading 1 byte at a time.
53 uint32_t OriginalOffset = getOffset();
54 const char *C;
55 do {
56 if (auto EC = readObject(C))
57 return EC;
58 if (*C != '\0')
59 ++Length;
60 } while (*C != '\0');
61 // Now go back and request a reference for that many bytes.
62 uint32_t NewOffset = getOffset();
63 setOffset(OriginalOffset);
64
65 ArrayRef<uint8_t> Data;
66 if (auto EC = readBytes(Data, Length))
67 return EC;
68 Dest = StringRef(reinterpret_cast<const char *>(Data.begin()), Data.size());
69
70 // Now set the offset back to where it was after we calculated the length.
71 setOffset(NewOffset);
72 return Error::success();
73 }
74
readFixedString(StringRef & Dest,uint32_t Length)75 Error StreamReader::readFixedString(StringRef &Dest, uint32_t Length) {
76 ArrayRef<uint8_t> Bytes;
77 if (auto EC = readBytes(Bytes, Length))
78 return EC;
79 Dest = StringRef(reinterpret_cast<const char *>(Bytes.begin()), Bytes.size());
80 return Error::success();
81 }
82
readStreamRef(StreamRef & Ref)83 Error StreamReader::readStreamRef(StreamRef &Ref) {
84 return readStreamRef(Ref, bytesRemaining());
85 }
86
readStreamRef(StreamRef & Ref,uint32_t Length)87 Error StreamReader::readStreamRef(StreamRef &Ref, uint32_t Length) {
88 if (bytesRemaining() < Length)
89 return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
90 Ref = Stream.slice(Offset, Length);
91 Offset += Length;
92 return Error::success();
93 }
94