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//===- MSFCommon.h - Common types and functions for MSF files ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_DEBUGINFO_MSF_MSFCOMMON_H
#define LLVM_DEBUGINFO_MSF_MSFCOMMON_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/MathExtras.h"
#include <cstdint>
#include <vector>
namespace llvm {
namespace msf {
static const char Magic[] = {'M', 'i', 'c', 'r', 'o', 's', 'o', 'f',
't', ' ', 'C', '/', 'C', '+', '+', ' ',
'M', 'S', 'F', ' ', '7', '.', '0', '0',
'\r', '\n', '\x1a', 'D', 'S', '\0', '\0', '\0'};
// The superblock is overlaid at the beginning of the file (offset 0).
// It starts with a magic header and is followed by information which
// describes the layout of the file system.
struct SuperBlock {
char MagicBytes[sizeof(Magic)];
// The file system is split into a variable number of fixed size elements.
// These elements are referred to as blocks. The size of a block may vary
// from system to system.
support::ulittle32_t BlockSize;
// The index of the free block map.
support::ulittle32_t FreeBlockMapBlock;
// This contains the number of blocks resident in the file system. In
// practice, NumBlocks * BlockSize is equivalent to the size of the MSF
// file.
support::ulittle32_t NumBlocks;
// This contains the number of bytes which make up the directory.
support::ulittle32_t NumDirectoryBytes;
// This field's purpose is not yet known.
support::ulittle32_t Unknown1;
// This contains the block # of the block map.
support::ulittle32_t BlockMapAddr;
};
struct MSFLayout {
MSFLayout() = default;
const SuperBlock *SB = nullptr;
BitVector FreePageMap;
ArrayRef<support::ulittle32_t> DirectoryBlocks;
ArrayRef<support::ulittle32_t> StreamSizes;
std::vector<ArrayRef<support::ulittle32_t>> StreamMap;
};
/// \brief Describes the layout of a stream in an MSF layout. A "stream" here
/// is defined as any logical unit of data which may be arranged inside the MSF
/// file as a sequence of (possibly discontiguous) blocks. When we want to read
/// from a particular MSF Stream, we fill out a stream layout structure and the
/// reader uses it to determine which blocks in the underlying MSF file contain
/// the data, so that it can be pieced together in the right order.
class MSFStreamLayout {
public:
uint32_t Length;
std::vector<support::ulittle32_t> Blocks;
};
/// \brief Determine the layout of the FPM stream, given the MSF layout. An FPM
/// stream spans 1 or more blocks, each at equally spaced intervals throughout
/// the file.
MSFStreamLayout getFpmStreamLayout(const MSFLayout &Msf,
bool IncludeUnusedFpmData = false,
bool AltFpm = false);
inline bool isValidBlockSize(uint32_t Size) {
switch (Size) {
case 512:
case 1024:
case 2048:
case 4096:
return true;
}
return false;
}
// Super Block, Fpm0, Fpm1, and Block Map
inline uint32_t getMinimumBlockCount() { return 4; }
// Super Block, Fpm0, and Fpm1 are reserved. The Block Map, although required
// need not be at block 3.
inline uint32_t getFirstUnreservedBlock() { return 3; }
inline uint64_t bytesToBlocks(uint64_t NumBytes, uint64_t BlockSize) {
return divideCeil(NumBytes, BlockSize);
}
inline uint64_t blockToOffset(uint64_t BlockNumber, uint64_t BlockSize) {
return BlockNumber * BlockSize;
}
inline uint32_t getFpmIntervalLength(const MSFLayout &L) {
return L.SB->BlockSize;
}
inline uint32_t getNumFpmIntervals(const MSFLayout &L,
bool IncludeUnusedFpmData = false) {
if (IncludeUnusedFpmData)
return divideCeil(L.SB->NumBlocks, L.SB->BlockSize);
// We want the minimum number of intervals required, where each interval can
// represent BlockSize * 8 blocks.
return divideCeil(L.SB->NumBlocks, 8 * L.SB->BlockSize);
}
Error validateSuperBlock(const SuperBlock &SB);
} // end namespace msf
} // end namespace llvm
#endif // LLVM_DEBUGINFO_MSF_MSFCOMMON_H
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