98 lines
3.2 KiB
C++
98 lines
3.2 KiB
C++
//===-- ReaderPrimitives.h - Bytecode file format reading prims -*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This header defines some basic functions for reading basic primitive types
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// from a bytecode stream.
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//
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//===----------------------------------------------------------------------===//
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#ifndef READERPRIMITIVES_H
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#define READERPRIMITIVES_H
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#include "Support/DataTypes.h"
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#include <string>
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namespace llvm {
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static inline unsigned read(const unsigned char *&Buf,
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const unsigned char *EndBuf) {
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if (Buf+4 > EndBuf) throw std::string("Ran out of data!");
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Buf += 4;
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return Buf[-4] | (Buf[-3] << 8) | (Buf[-2] << 16) | (Buf[-1] << 24);
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}
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// read_vbr - Read an unsigned integer encoded in variable bitrate format.
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//
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static inline unsigned read_vbr_uint(const unsigned char *&Buf,
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const unsigned char *EndBuf) {
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unsigned Shift = 0;
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unsigned Result = 0;
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do {
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if (Buf == EndBuf) throw std::string("Ran out of data!");
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Result |= (unsigned)((*Buf++) & 0x7F) << Shift;
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Shift += 7;
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} while (Buf[-1] & 0x80);
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return Result;
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}
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static inline uint64_t read_vbr_uint64(const unsigned char *&Buf,
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const unsigned char *EndBuf) {
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unsigned Shift = 0;
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uint64_t Result = 0;
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do {
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if (Buf == EndBuf) throw std::string("Ran out of data!");
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Result |= (uint64_t)((*Buf++) & 0x7F) << Shift;
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Shift += 7;
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} while (Buf[-1] & 0x80);
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return Result;
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}
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static inline int64_t read_vbr_int64(const unsigned char *&Buf,
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const unsigned char *EndBuf) {
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uint64_t R = read_vbr_uint64(Buf, EndBuf);
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if (R & 1)
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return -(int64_t)(R >> 1);
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else
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return (int64_t)(R >> 1);
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}
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// align32 - Round up to multiple of 32 bits...
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static inline void align32(const unsigned char *&Buf,
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const unsigned char *EndBuf) {
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Buf = (const unsigned char *)((unsigned long)(Buf+3) & (~3UL));
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if (Buf > EndBuf) throw std::string("Ran out of data!");
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}
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static inline std::string read_str(const unsigned char *&Buf,
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const unsigned char *EndBuf) {
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unsigned Size = read_vbr_uint(Buf, EndBuf);
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const unsigned char *OldBuf = Buf;
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Buf += Size;
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if (Buf > EndBuf) // Size invalid?
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throw std::string("Ran out of data reading a string!");
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return std::string((char*)OldBuf, Size);
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}
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static inline void input_data(const unsigned char *&Buf,
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const unsigned char *EndBuf,
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void *Ptr, void *End) {
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unsigned char *Start = (unsigned char *)Ptr;
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unsigned Amount = (unsigned char *)End - Start;
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if (Buf+Amount > EndBuf) throw std::string("Ran out of data!");
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std::copy(Buf, Buf+Amount, Start);
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Buf += Amount;
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}
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} // End llvm namespace
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#endif
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