lib/Support/BinaryStreamRef.cpp

   1 //===- BinaryStreamRef.cpp - ----------------------------------------------===//
   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/BinaryStreamRef.h"
  11 #include "llvm/Support/BinaryByteStream.h"
  12
  13 using namespace llvm;
  14 using namespace llvm::support;
  15
  16 namespace {
  17
  18 class ArrayRefImpl : public BinaryStream {
  19 public:
  20   ArrayRefImpl(ArrayRef<uint8_t> Data, endianness Endian) : BBS(Data, Endian) {}
  21
  22   llvm::support::endianness getEndian() const override {
  23     return BBS.getEndian();
  24   }
  25   Error readBytes(uint32_t Offset, uint32_t Size,
  26                   ArrayRef<uint8_t> &Buffer) override {
  27     return BBS.readBytes(Offset, Size, Buffer);
  28   }
  29   Error readLongestContiguousChunk(uint32_t Offset,
  30                                    ArrayRef<uint8_t> &Buffer) override {
  31     return BBS.readLongestContiguousChunk(Offset, Buffer);
  32   }
  33   uint32_t getLength() override { return BBS.getLength(); }
  34
  35 private:
  36   BinaryByteStream BBS;
  37 };
  38
  39 class MutableArrayRefImpl : public WritableBinaryStream {
  40 public:
  41   MutableArrayRefImpl(MutableArrayRef<uint8_t> Data, endianness Endian)
  42       : BBS(Data, Endian) {}
  43
  44   // Inherited via WritableBinaryStream
  45   llvm::support::endianness getEndian() const override {
  46     return BBS.getEndian();
  47   }
  48   Error readBytes(uint32_t Offset, uint32_t Size,
  49                   ArrayRef<uint8_t> &Buffer) override {
  50     return BBS.readBytes(Offset, Size, Buffer);
  51   }
  52   Error readLongestContiguousChunk(uint32_t Offset,
  53                                    ArrayRef<uint8_t> &Buffer) override {
  54     return BBS.readLongestContiguousChunk(Offset, Buffer);
  55   }
  56   uint32_t getLength() override { return BBS.getLength(); }
  57
  58   Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Data) override {
  59     return BBS.writeBytes(Offset, Data);
  60   }
  61   Error commit() override { return BBS.commit(); }
  62
  63 private:
  64   MutableBinaryByteStream BBS;
  65 };
  66 }
  67
  68 BinaryStreamRef::BinaryStreamRef(BinaryStream &Stream)
  69     : BinaryStreamRefBase(Stream) {}
  70 BinaryStreamRef::BinaryStreamRef(BinaryStream &Stream, uint32_t Offset,
  71                                  Optional<uint32_t> Length)
  72     : BinaryStreamRefBase(Stream, Offset, Length) {}
  73 BinaryStreamRef::BinaryStreamRef(ArrayRef<uint8_t> Data, endianness Endian)
  74     : BinaryStreamRefBase(std::make_shared<ArrayRefImpl>(Data, Endian), 0,
  75                           Data.size()) {}
  76 BinaryStreamRef::BinaryStreamRef(StringRef Data, endianness Endian)
  77     : BinaryStreamRef(makeArrayRef(Data.bytes_begin(), Data.bytes_end()),
  78                       Endian) {}
  79
  80 Error BinaryStreamRef::readBytes(uint32_t Offset, uint32_t Size,
  81                                  ArrayRef<uint8_t> &Buffer) const {
  82   if (auto EC = checkOffsetForRead(Offset, Size))
  83     return EC;
  84   return BorrowedImpl->readBytes(ViewOffset + Offset, Size, Buffer);
  85 }
  86
  87 Error BinaryStreamRef::readLongestContiguousChunk(
  88     uint32_t Offset, ArrayRef<uint8_t> &Buffer) const {
  89   if (auto EC = checkOffsetForRead(Offset, 1))
  90     return EC;
  91
  92   if (auto EC =
  93           BorrowedImpl->readLongestContiguousChunk(ViewOffset + Offset, Buffer))
  94     return EC;
  95   // This StreamRef might refer to a smaller window over a larger stream.  In
  96   // that case we will have read out more bytes than we should return, because
  97   // we should not read past the end of the current view.
  98   uint32_t MaxLength = getLength() - Offset;
  99   if (Buffer.size() > MaxLength)
 100     Buffer = Buffer.slice(0, MaxLength);
 101   return Error::success();
 102 }
 103
 104 WritableBinaryStreamRef::WritableBinaryStreamRef(WritableBinaryStream &Stream)
 105     : BinaryStreamRefBase(Stream) {}
 106
 107 WritableBinaryStreamRef::WritableBinaryStreamRef(WritableBinaryStream &Stream,
 108                                                  uint32_t Offset,
 109                                                  Optional<uint32_t> Length)
 110     : BinaryStreamRefBase(Stream, Offset, Length) {}
 111
 112 WritableBinaryStreamRef::WritableBinaryStreamRef(MutableArrayRef<uint8_t> Data,
 113                                                  endianness Endian)
 114     : BinaryStreamRefBase(std::make_shared<MutableArrayRefImpl>(Data, Endian),
 115                           0, Data.size()) {}
 116
 117
 118 Error WritableBinaryStreamRef::writeBytes(uint32_t Offset,
 119                                           ArrayRef<uint8_t> Data) const {
 120   if (auto EC = checkOffsetForWrite(Offset, Data.size()))
 121     return EC;
 122
 123   return BorrowedImpl->writeBytes(ViewOffset + Offset, Data);
 124 }
 125
 126 WritableBinaryStreamRef::operator BinaryStreamRef() const {
 127   return BinaryStreamRef(*BorrowedImpl, ViewOffset, Length);
 128 }
 129
 130 /// For buffered streams, commits changes to the backing store.
 131 Error WritableBinaryStreamRef::commit() { return BorrowedImpl->commit(); }