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//===-- ReaderPrimitives.h - Bytecode file format reading prims -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This header defines some basic functions for reading basic primitive types
// from a bytecode stream.
//
//===----------------------------------------------------------------------===//
#ifndef READERPRIMITIVES_H
#define READERPRIMITIVES_H
#include "Support/DataTypes.h"
#include <string>
namespace llvm {
/// @brief Read an unsigned integer
static inline unsigned read(const unsigned char *&Buf,
const unsigned char *EndBuf) {
if (Buf+4 > EndBuf) throw std::string("Ran out of data!");
Buf += 4;
return Buf[-4] | (Buf[-3] << 8) | (Buf[-2] << 16) | (Buf[-1] << 24);
}
/// @brief Read an unsigned integer encoded in variable bitrate format.
static inline unsigned read_vbr_uint(const unsigned char *&Buf,
const unsigned char *EndBuf) {
unsigned Shift = 0;
unsigned Result = 0;
do {
if (Buf == EndBuf) throw std::string("Ran out of data!");
Result |= (unsigned)((*Buf++) & 0x7F) << Shift;
Shift += 7;
} while (Buf[-1] & 0x80);
return Result;
}
static inline uint64_t read_vbr_uint64(const unsigned char *&Buf,
const unsigned char *EndBuf) {
unsigned Shift = 0;
uint64_t Result = 0;
do {
if (Buf == EndBuf) throw std::string("Ran out of data!");
Result |= (uint64_t)((*Buf++) & 0x7F) << Shift;
Shift += 7;
} while (Buf[-1] & 0x80);
return Result;
}
static inline int64_t read_vbr_int64(const unsigned char *&Buf,
const unsigned char *EndBuf) {
uint64_t R = read_vbr_uint64(Buf, EndBuf);
if (R & 1) {
if (R != 1)
return -(int64_t)(R >> 1);
else // There is no such thing as -0 with integers. "-0" really means
// 0x8000000000000000.
return 1LL << 63;
} else
return (int64_t)(R >> 1);
}
// align32 - Round up to multiple of 32 bits...
static inline void align32(const unsigned char *&Buf,
const unsigned char *EndBuf) {
Buf = (const unsigned char *)((unsigned long)(Buf+3) & (~3UL));
if (Buf > EndBuf) throw std::string("Ran out of data!");
}
static inline std::string read_str(const unsigned char *&Buf,
const unsigned char *EndBuf) {
unsigned Size = read_vbr_uint(Buf, EndBuf);
const unsigned char *OldBuf = Buf;
Buf += Size;
if (Buf > EndBuf) // Size invalid?
throw std::string("Ran out of data reading a string!");
return std::string((char*)OldBuf, Size);
}
static inline void input_data(const unsigned char *&Buf,
const unsigned char *EndBuf,
void *Ptr, void *End) {
unsigned char *Start = (unsigned char *)Ptr;
unsigned Amount = (unsigned char *)End - Start;
if (Buf+Amount > EndBuf) throw std::string("Ran out of data!");
std::copy(Buf, Buf+Amount, Start);
Buf += Amount;
}
} // End llvm namespace
#endif
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