llvm/lib/Support/BinaryStreamRef.cpp

   1 //===- BinaryStreamRef.cpp - ----------------------------------------------===//
   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 #include "llvm/Support/BinaryStreamRef.h"
  10 #include "llvm/Support/BinaryByteStream.h"
  11
  12 using namespace llvm;
  13
  14 namespace {
  15
  16 class ArrayRefImpl : public BinaryStream {
  17 public:
  18   ArrayRefImpl(ArrayRef<uint8_t> Data, endianness Endian) : BBS(Data, Endian) {}
  19
  20   llvm::endianness getEndian() const override { return BBS.getEndian(); }
  21   Error readBytes(uint64_t Offset, uint64_t Size,
  22                   ArrayRef<uint8_t> &Buffer) override {
  23     return BBS.readBytes(Offset, Size, Buffer);
  24   }
  25   Error readLongestContiguousChunk(uint64_t Offset,
  26                                    ArrayRef<uint8_t> &Buffer) override {
  27     return BBS.readLongestContiguousChunk(Offset, Buffer);
  28   }
  29   uint64_t getLength() override { return BBS.getLength(); }
  30
  31 private:
  32   BinaryByteStream BBS;
  33 };
  34
  35 class MutableArrayRefImpl : public WritableBinaryStream {
  36 public:
  37   MutableArrayRefImpl(MutableArrayRef<uint8_t> Data, endianness Endian)
  38       : BBS(Data, Endian) {}
  39
  40   // Inherited via WritableBinaryStream
  41   llvm::endianness getEndian() const override { return BBS.getEndian(); }
  42   Error readBytes(uint64_t Offset, uint64_t Size,
  43                   ArrayRef<uint8_t> &Buffer) override {
  44     return BBS.readBytes(Offset, Size, Buffer);
  45   }
  46   Error readLongestContiguousChunk(uint64_t Offset,
  47                                    ArrayRef<uint8_t> &Buffer) override {
  48     return BBS.readLongestContiguousChunk(Offset, Buffer);
  49   }
  50   uint64_t getLength() override { return BBS.getLength(); }
  51
  52   Error writeBytes(uint64_t Offset, ArrayRef<uint8_t> Data) override {
  53     return BBS.writeBytes(Offset, Data);
  54   }
  55   Error commit() override { return BBS.commit(); }
  56
  57 private:
  58   MutableBinaryByteStream BBS;
  59 };
  60 } // namespace
  61
  62 BinaryStreamRef::BinaryStreamRef(BinaryStream &Stream)
  63     : BinaryStreamRefBase(Stream) {}
  64 BinaryStreamRef::BinaryStreamRef(BinaryStream &Stream, uint64_t Offset,
  65                                  std::optional<uint64_t> Length)
  66     : BinaryStreamRefBase(Stream, Offset, Length) {}
  67 BinaryStreamRef::BinaryStreamRef(ArrayRef<uint8_t> Data, endianness Endian)
  68     : BinaryStreamRefBase(std::make_shared<ArrayRefImpl>(Data, Endian), 0,
  69                           Data.size()) {}
  70 BinaryStreamRef::BinaryStreamRef(StringRef Data, endianness Endian)
  71     : BinaryStreamRef(ArrayRef(Data.bytes_begin(), Data.bytes_end()), Endian) {}
  72
  73 Error BinaryStreamRef::readBytes(uint64_t Offset, uint64_t Size,
  74                                  ArrayRef<uint8_t> &Buffer) const {
  75   if (auto EC = checkOffsetForRead(Offset, Size))
  76     return EC;
  77   return BorrowedImpl->readBytes(ViewOffset + Offset, Size, Buffer);
  78 }
  79
  80 Error BinaryStreamRef::readLongestContiguousChunk(
  81     uint64_t Offset, ArrayRef<uint8_t> &Buffer) const {
  82   if (auto EC = checkOffsetForRead(Offset, 1))
  83     return EC;
  84
  85   if (auto EC =
  86           BorrowedImpl->readLongestContiguousChunk(ViewOffset + Offset, Buffer))
  87     return EC;
  88   // This StreamRef might refer to a smaller window over a larger stream.  In
  89   // that case we will have read out more bytes than we should return, because
  90   // we should not read past the end of the current view.
  91   uint64_t MaxLength = getLength() - Offset;
  92   if (Buffer.size() > MaxLength)
  93     Buffer = Buffer.slice(0, MaxLength);
  94   return Error::success();
  95 }
  96
  97 WritableBinaryStreamRef::WritableBinaryStreamRef(WritableBinaryStream &Stream)
  98     : BinaryStreamRefBase(Stream) {}
  99
 100 WritableBinaryStreamRef::WritableBinaryStreamRef(WritableBinaryStream &Stream,
 101                                                  uint64_t Offset,
 102                                                  std::optional<uint64_t> Length)
 103     : BinaryStreamRefBase(Stream, Offset, Length) {}
 104
 105 WritableBinaryStreamRef::WritableBinaryStreamRef(MutableArrayRef<uint8_t> Data,
 106                                                  endianness Endian)
 107     : BinaryStreamRefBase(std::make_shared<MutableArrayRefImpl>(Data, Endian),
 108                           0, Data.size()) {}
 109
 110 Error WritableBinaryStreamRef::writeBytes(uint64_t Offset,
 111                                           ArrayRef<uint8_t> Data) const {
 112   if (auto EC = checkOffsetForWrite(Offset, Data.size()))
 113     return EC;
 114
 115   return BorrowedImpl->writeBytes(ViewOffset + Offset, Data);
 116 }
 117
 118 WritableBinaryStreamRef::operator BinaryStreamRef() const {
 119   return BinaryStreamRef(*BorrowedImpl, ViewOffset, Length);
 120 }
 121
 122 /// For buffered streams, commits changes to the backing store.
 123 Error WritableBinaryStreamRef::commit() { return BorrowedImpl->commit(); }