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7969dc2bec
returning error codes. Because they don't return an error code, they can return the value read, which simplifies the code and makes the reader more efficient (yaay!). Also eliminate the special case code for little endian machines. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10871 91177308-0d34-0410-b5e6-96231b3b80d8
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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