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//===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the MemoryBuffer interface.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_MEMORYBUFFER_H
#define LLVM_SUPPORT_MEMORYBUFFER_H
#include "llvm-c/Support.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/CBindingWrapping.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/ErrorOr.h"
#include <memory>
#include <system_error>
namespace llvm {
/// MemoryBuffer - This interface provides simple read-only access to a block
/// of memory, and provides simple methods for reading files and standard input
/// into a memory buffer. In addition to basic access to the characters in the
/// file, this interface guarantees you can read one character past the end of
/// the file, and that this character will read as '\0'.
///
/// The '\0' guarantee is needed to support an optimization -- it's intended to
/// be more efficient for clients which are reading all the data to stop
/// reading when they encounter a '\0' than to continually check the file
/// position to see if it has reached the end of the file.
class MemoryBuffer {
const char *BufferStart; // Start of the buffer.
const char *BufferEnd; // End of the buffer.
MemoryBuffer(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
MemoryBuffer &operator=(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
protected:
MemoryBuffer() {}
void init(const char *BufStart, const char *BufEnd,
bool RequiresNullTerminator);
public:
virtual ~MemoryBuffer();
const char *getBufferStart() const { return BufferStart; }
const char *getBufferEnd() const { return BufferEnd; }
size_t getBufferSize() const { return BufferEnd-BufferStart; }
StringRef getBuffer() const {
return StringRef(BufferStart, getBufferSize());
}
/// getBufferIdentifier - Return an identifier for this buffer, typically the
/// filename it was read from.
virtual const char *getBufferIdentifier() const {
return "Unknown buffer";
}
/// Open the specified file as a MemoryBuffer, returning a new MemoryBuffer
/// if successful, otherwise returning null. If FileSize is specified, this
/// means that the client knows that the file exists and that it has the
/// specified size.
///
/// \param IsVolatileSize Set to true to indicate that the file size may be
/// changing, e.g. when libclang tries to parse while the user is
/// editing/updating the file.
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFile(Twine Filename, int64_t FileSize = -1,
bool RequiresNullTerminator = true, bool IsVolatileSize = false);
/// Given an already-open file descriptor, map some slice of it into a
/// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize.
/// Since this is in the middle of a file, the buffer is not null terminated.
///
/// \param IsVolatileSize Set to true to indicate that the file size may be
/// changing, e.g. when libclang tries to parse while the user is
/// editing/updating the file.
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getOpenFileSlice(int FD, const char *Filename, uint64_t MapSize,
int64_t Offset, bool IsVolatileSize = false);
/// Given an already-open file descriptor, read the file and return a
/// MemoryBuffer.
///
/// \param IsVolatileSize Set to true to indicate that the file size may be
/// changing, e.g. when libclang tries to parse while the user is
/// editing/updating the file.
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getOpenFile(int FD, const char *Filename, uint64_t FileSize,
bool RequiresNullTerminator = true, bool IsVolatileSize = false);
/// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
/// that InputData must be null terminated if RequiresNullTerminator is true.
static MemoryBuffer *getMemBuffer(StringRef InputData,
StringRef BufferName = "",
bool RequiresNullTerminator = true);
/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
/// copying the contents and taking ownership of it. InputData does not
/// have to be null terminated.
static MemoryBuffer *getMemBufferCopy(StringRef InputData,
StringRef BufferName = "");
/// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
/// is completely initialized to zeros. Note that the caller should
/// initialize the memory allocated by this method. The memory is owned by
/// the MemoryBuffer object.
static MemoryBuffer *getNewMemBuffer(size_t Size, StringRef BufferName = "");
/// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
/// that is not initialized. Note that the caller should initialize the
/// memory allocated by this method. The memory is owned by the MemoryBuffer
/// object.
static MemoryBuffer *getNewUninitMemBuffer(size_t Size,
StringRef BufferName = "");
/// Read all of stdin into a file buffer, and return it.
static ErrorOr<std::unique_ptr<MemoryBuffer>> getSTDIN();
/// Open the specified file as a MemoryBuffer, or open stdin if the Filename
/// is "-".
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFileOrSTDIN(StringRef Filename, int64_t FileSize = -1);
//===--------------------------------------------------------------------===//
// Provided for performance analysis.
//===--------------------------------------------------------------------===//
/// The kind of memory backing used to support the MemoryBuffer.
enum BufferKind {
MemoryBuffer_Malloc,
MemoryBuffer_MMap
};
/// Return information on the memory mechanism used to support the
/// MemoryBuffer.
virtual BufferKind getBufferKind() const = 0;
};
// Create wrappers for C Binding types (see CBindingWrapping.h).
DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef)
} // end namespace llvm
#endif
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