LLVM 18.0.0git
BinaryStreamReader.cpp
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1//===- BinaryStreamReader.cpp - Reads objects from a binary stream --------===//
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
10
13#include "llvm/Support/LEB128.h"
14
15using namespace llvm;
17
19
21
23 endianness Endian)
24 : Stream(Data, Endian) {}
25
27 : Stream(Data, Endian) {}
28
30 ArrayRef<uint8_t> &Buffer) {
31 if (auto EC = Stream.readLongestContiguousChunk(Offset, Buffer))
32 return EC;
33 Offset += Buffer.size();
34 return Error::success();
35}
36
38 if (auto EC = Stream.readBytes(Offset, Size, Buffer))
39 return EC;
40 Offset += Size;
41 return Error::success();
42}
43
45 SmallVector<uint8_t, 10> EncodedBytes;
46 ArrayRef<uint8_t> NextByte;
47
48 // Copy the encoded ULEB into the buffer.
49 do {
50 if (auto Err = readBytes(NextByte, 1))
51 return Err;
52 EncodedBytes.push_back(NextByte[0]);
53 } while (NextByte[0] & 0x80);
54
55 Dest = decodeULEB128(EncodedBytes.begin(), nullptr, EncodedBytes.end());
56 return Error::success();
57}
58
60 SmallVector<uint8_t, 10> EncodedBytes;
61 ArrayRef<uint8_t> NextByte;
62
63 // Copy the encoded ULEB into the buffer.
64 do {
65 if (auto Err = readBytes(NextByte, 1))
66 return Err;
67 EncodedBytes.push_back(NextByte[0]);
68 } while (NextByte[0] & 0x80);
69
70 Dest = decodeSLEB128(EncodedBytes.begin(), nullptr, EncodedBytes.end());
71 return Error::success();
72}
73
75 uint64_t OriginalOffset = getOffset();
76 uint64_t FoundOffset = 0;
77 while (true) {
78 uint64_t ThisOffset = getOffset();
79 ArrayRef<uint8_t> Buffer;
80 if (auto EC = readLongestContiguousChunk(Buffer))
81 return EC;
82 StringRef S(reinterpret_cast<const char *>(Buffer.begin()), Buffer.size());
83 size_t Pos = S.find_first_of('\0');
84 if (LLVM_LIKELY(Pos != StringRef::npos)) {
85 FoundOffset = Pos + ThisOffset;
86 break;
87 }
88 }
89 assert(FoundOffset >= OriginalOffset);
90
91 setOffset(OriginalOffset);
92 size_t Length = FoundOffset - OriginalOffset;
93
94 if (auto EC = readFixedString(Dest, Length))
95 return EC;
96
97 // Now set the offset back to after the null terminator.
98 setOffset(FoundOffset + 1);
99 return Error::success();
100}
101
103 uint64_t Length = 0;
104 uint64_t OriginalOffset = getOffset();
105 const UTF16 *C;
106 while (true) {
107 if (auto EC = readObject(C))
108 return EC;
109 if (*C == 0x0000)
110 break;
111 ++Length;
112 }
113 uint64_t NewOffset = getOffset();
114 setOffset(OriginalOffset);
115
116 if (auto EC = readArray(Dest, Length))
117 return EC;
118 setOffset(NewOffset);
119 return Error::success();
120}
121
123 ArrayRef<uint8_t> Bytes;
124 if (auto EC = readBytes(Bytes, Length))
125 return EC;
126 Dest = StringRef(reinterpret_cast<const char *>(Bytes.begin()), Bytes.size());
127 return Error::success();
128}
129
132}
133
135 if (bytesRemaining() < Length)
136 return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
137 Ref = Stream.slice(Offset, Length);
138 Offset += Length;
139 return Error::success();
140}
141
144 Ref.Offset = getOffset();
145 return readStreamRef(Ref.StreamData, Length);
146}
147
149 if (Amount > bytesRemaining())
150 return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
151 Offset += Amount;
152 return Error::success();
153}
154
156 uint32_t NewOffset = alignTo(Offset, Align);
157 return skip(NewOffset - Offset);
158}
159
161 ArrayRef<uint8_t> Buffer;
162 auto EC = Stream.readBytes(Offset, 1, Buffer);
163 assert(!EC && "Cannot peek an empty buffer!");
164 llvm::consumeError(std::move(EC));
165 return Buffer[0];
166}
167
168std::pair<BinaryStreamReader, BinaryStreamReader>
170 assert(getLength() >= Off);
171
172 BinaryStreamRef First = Stream.drop_front(Offset);
173
174 BinaryStreamRef Second = First.drop_front(Off);
175 First = First.keep_front(Off);
177 BinaryStreamReader W2{Second};
178 return std::make_pair(W1, W2);
179}
#define LLVM_LIKELY(EXPR)
Definition: Compiler.h:221
uint64_t Size
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
endianness Endian
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:165
iterator begin() const
Definition: ArrayRef.h:153
Provides read only access to a subclass of BinaryStream.
Error readStreamRef(BinaryStreamRef &Ref)
Read the entire remainder of the underlying stream into Ref.
Error readObject(const T *&Dest)
Get a pointer to an object of type T from the underlying stream, as if by memcpy, and store the resul...
Error readCString(StringRef &Dest)
Read a null terminated string from Dest.
Error readBytes(ArrayRef< uint8_t > &Buffer, uint32_t Size)
Read Size bytes from the underlying stream at the current offset and and set Buffer to the resulting ...
uint8_t peek() const
Examine the next byte of the underlying stream without advancing the stream's offset.
Error readWideString(ArrayRef< UTF16 > &Dest)
Similar to readCString, however read a null-terminated UTF16 string instead.
Error readSubstream(BinarySubstreamRef &Ref, uint32_t Length)
Read Length bytes from the underlying stream into Ref.
uint64_t bytesRemaining() const
Error readSLEB128(int64_t &Dest)
Read a signed LEB128 encoded value.
Error readLongestContiguousChunk(ArrayRef< uint8_t > &Buffer)
Read as much as possible from the underlying string at the current offset without invoking a copy,...
Error padToAlignment(uint32_t Align)
Error readFixedString(StringRef &Dest, uint32_t Length)
Read a Length byte string into Dest.
std::pair< BinaryStreamReader, BinaryStreamReader > split(uint64_t Offset) const
void setOffset(uint64_t Off)
Error readArray(ArrayRef< T > &Array, uint32_t NumElements)
Get a reference to a NumElements element array of objects of type T from the underlying stream as if ...
Error readULEB128(uint64_t &Dest)
Read an unsigned LEB128 encoded value.
Error skip(uint64_t Amount)
Advance the stream's offset by Amount bytes.
RefType drop_front(uint64_t N) const
Return a new BinaryStreamRef with the first N elements removed.
RefType slice(uint64_t Offset, uint64_t Len) const
Return a new BinaryStreamRef with the first Offset elements removed, and retaining exactly Len elemen...
BinaryStreamRef is to BinaryStream what ArrayRef is to an Array.
Error readLongestContiguousChunk(uint64_t Offset, ArrayRef< uint8_t > &Buffer) const
Given an Offset into this BinaryStreamRef, return a reference to the largest buffer the stream could ...
Error readBytes(uint64_t Offset, uint64_t Size, ArrayRef< uint8_t > &Buffer) const
Given an Offset into this StreamRef and a Size, return a reference to a buffer owned by the stream.
An interface for accessing data in a stream-like format, but which discourages copying.
Definition: BinaryStream.h:35
Lightweight error class with error context and mandatory checking.
Definition: Error.h:160
static ErrorSuccess success()
Create a success value.
Definition: Error.h:334
void push_back(const T &Elt)
Definition: SmallVector.h:416
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1200
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
size_t find_first_of(char C, size_t From=0) const
Find the first character in the string that is C, or npos if not found.
Definition: StringRef.h:381
static constexpr size_t npos
Definition: StringRef.h:52
@ C
The default llvm calling convention, compatible with C.
Definition: CallingConv.h:34
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
@ Length
Definition: DWP.cpp:440
unsigned short UTF16
Definition: ConvertUTF.h:129
uint64_t decodeULEB128(const uint8_t *p, unsigned *n=nullptr, const uint8_t *end=nullptr, const char **error=nullptr)
Utility function to decode a ULEB128 value.
Definition: LEB128.h:128
int64_t decodeSLEB128(const uint8_t *p, unsigned *n=nullptr, const uint8_t *end=nullptr, const char **error=nullptr)
Utility function to decode a SLEB128 value.
Definition: LEB128.h:161
@ Ref
The access may reference the value stored in memory.
@ First
Helpers to iterate all locations in the MemoryEffectsBase class.
uint64_t alignTo(uint64_t Size, Align A)
Returns a multiple of A needed to store Size bytes.
Definition: Alignment.h:155
void consumeError(Error Err)
Consume a Error without doing anything.
Definition: Error.h:1041
This struct is a compact representation of a valid (non-zero power of two) alignment.
Definition: Alignment.h:39