llvm-6502/include/llvm/Bytecode/Primitives.h
Misha Brukman 5560c9d49c Spell `necessary' correctly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7944 91177308-0d34-0410-b5e6-96231b3b80d8
2003-08-18 14:43:39 +00:00

272 lines
8.3 KiB
C++

//===-- llvm/Bytecode/Primitives.h - Bytecode file format prims --*- C++ -*--=//
//
// This header defines some basic functions for reading and writing basic
// primitive types to a bytecode stream.
//
// Using the routines defined in this file does not require linking to any
// libraries, as all of the services are small self contained units that are to
// be inlined as necessary.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_BYTECODE_PRIMITIVES_H
#define LLVM_BYTECODE_PRIMITIVES_H
#include "Support/DataTypes.h"
#include <string>
#include <deque>
//===----------------------------------------------------------------------===//
// Reading Primitives
//===----------------------------------------------------------------------===//
static inline bool read(const unsigned char *&Buf, const unsigned char *EndBuf,
unsigned &Result) {
if (Buf+4 > EndBuf) return true;
#ifdef ENDIAN_LITTLE
Result = *(unsigned*)Buf;
#else
Result = Buf[0] | (Buf[1] << 8) | (Buf[2] << 16) | (Buf[3] << 24);
#endif
Buf += 4;
return false;
}
static inline bool read(const unsigned char *&Buf, const unsigned char *EndBuf,
uint64_t &Result) {
if (Buf+8 > EndBuf) return true;
#ifdef ENDIAN_LITTLE
Result = *(uint64_t*)Buf;
#else
Result = Buf[0] | (Buf[1] << 8) | (Buf[2] << 16) | (Buf[3] << 24) |
((uint64_t)(Buf[4] | (Buf[5] << 8) | (Buf[6] << 16) | (Buf[7] << 24)) <<32);
#endif
Buf += 8;
return false;
}
static inline bool read(const unsigned char *&Buf, const unsigned char *EndBuf,
int &Result) {
return read(Buf, EndBuf, (unsigned &)Result);
}
static inline bool read(const unsigned char *&Buf, const unsigned char *EndBuf,
int64_t &Result) {
return read(Buf, EndBuf, (uint64_t &)Result);
}
// read_vbr - Read an unsigned integer encoded in variable bitrate format.
//
static inline bool read_vbr(const unsigned char *&Buf,
const unsigned char *EndBuf, unsigned &Result) {
unsigned Shift = Result = 0;
do {
Result |= (unsigned)((*Buf++) & 0x7F) << Shift;
Shift += 7;
} while (Buf[-1] & 0x80 && Buf < EndBuf);
return Buf > EndBuf;
}
static inline bool read_vbr(const unsigned char *&Buf,
const unsigned char *EndBuf, uint64_t &Result) {
unsigned Shift = 0; Result = 0;
do {
Result |= (uint64_t)((*Buf++) & 0x7F) << Shift;
Shift += 7;
} while (Buf[-1] & 0x80 && Buf < EndBuf);
return Buf > EndBuf;
}
// read_vbr (signed) - Read a signed number stored in sign-magnitude format
static inline bool read_vbr(const unsigned char *&Buf,
const unsigned char *EndBuf, int &Result) {
unsigned R;
if (read_vbr(Buf, EndBuf, R)) return true;
if (R & 1)
Result = -(int)(R >> 1);
else
Result = (int)(R >> 1);
return false;
}
static inline bool read_vbr(const unsigned char *&Buf,
const unsigned char *EndBuf, int64_t &Result) {
uint64_t R;
if (read_vbr(Buf, EndBuf, R)) return true;
if (R & 1)
Result = -(int64_t)(R >> 1);
else
Result = (int64_t)(R >> 1);
return false;
}
// align32 - Round up to multiple of 32 bits...
static inline bool align32(const unsigned char *&Buf,
const unsigned char *EndBuf) {
Buf = (const unsigned char *)((unsigned long)(Buf+3) & (~3UL));
return Buf > EndBuf;
}
static inline bool read(const unsigned char *&Buf, const unsigned char *EndBuf,
std::string &Result, bool Aligned = true) {
unsigned Size;
if (read_vbr(Buf, EndBuf, Size)) return true; // Failure reading size?
if (Buf+Size > EndBuf) return true; // Size invalid?
Result = std::string((char*)Buf, Size);
Buf += Size;
if (Aligned) // If we should stay aligned do so...
if (align32(Buf, EndBuf)) return true; // Failure aligning?
return false;
}
static inline bool input_data(const unsigned char *&Buf,
const unsigned char *EndBuf,
void *Ptr, void *End, bool Align = false) {
unsigned char *Start = (unsigned char *)Ptr;
unsigned Amount = (unsigned char *)End - Start;
if (Buf+Amount > EndBuf) return true;
#ifdef ENDIAN_LITTLE
std::copy(Buf, Buf+Amount, Start);
Buf += Amount;
#else
unsigned char *E = (unsigned char *)End;
while (Ptr != E)
*--E = *Buf++;
#endif
if (Align) return align32(Buf, EndBuf);
return false;
}
//===----------------------------------------------------------------------===//
// Writing Primitives
//===----------------------------------------------------------------------===//
// output - If a position is specified, it must be in the valid portion of the
// string... note that this should be inlined always so only the relevant IF
// body should be included...
//
static inline void output(unsigned i, std::deque<unsigned char> &Out,
int pos = -1) {
#ifdef ENDIAN_LITTLE
if (pos == -1)
Out.insert(Out.end(), (unsigned char*)&i, (unsigned char*)&i+4);
else
// This cannot use block copy because deques are not guaranteed contiguous!
std::copy((unsigned char*)&i, 4+(unsigned char*)&i, Out.begin()+pos);
#else
if (pos == -1) { // Be endian clean, little endian is our friend
Out.push_back((unsigned char)i);
Out.push_back((unsigned char)(i >> 8));
Out.push_back((unsigned char)(i >> 16));
Out.push_back((unsigned char)(i >> 24));
} else {
Out[pos ] = (unsigned char)i;
Out[pos+1] = (unsigned char)(i >> 8);
Out[pos+2] = (unsigned char)(i >> 16);
Out[pos+3] = (unsigned char)(i >> 24);
}
#endif
}
static inline void output(int i, std::deque<unsigned char> &Out) {
output((unsigned)i, Out);
}
// output_vbr - Output an unsigned value, by using the least number of bytes
// possible. This is useful because many of our "infinite" values are really
// very small most of the time... but can be large a few times...
//
// Data format used: If you read a byte with the night bit set, use the low
// seven bits as data and then read another byte...
//
// Note that using this may cause the output buffer to become unaligned...
//
static inline void output_vbr(uint64_t i, std::deque<unsigned char> &out) {
while (1) {
if (i < 0x80) { // done?
out.push_back((unsigned char)i); // We know the high bit is clear...
return;
}
// Nope, we are bigger than a character, output the next 7 bits and set the
// high bit to say that there is more coming...
out.push_back(0x80 | (i & 0x7F));
i >>= 7; // Shift out 7 bits now...
}
}
static inline void output_vbr(unsigned i, std::deque<unsigned char> &out) {
while (1) {
if (i < 0x80) { // done?
out.push_back((unsigned char)i); // We know the high bit is clear...
return;
}
// Nope, we are bigger than a character, output the next 7 bits and set the
// high bit to say that there is more coming...
out.push_back(0x80 | (i & 0x7F));
i >>= 7; // Shift out 7 bits now...
}
}
static inline void output_vbr(int64_t i, std::deque<unsigned char> &out) {
if (i < 0)
output_vbr(((uint64_t)(-i) << 1) | 1, out); // Set low order sign bit...
else
output_vbr((uint64_t)i << 1, out); // Low order bit is clear.
}
static inline void output_vbr(int i, std::deque<unsigned char> &out) {
if (i < 0)
output_vbr(((unsigned)(-i) << 1) | 1, out); // Set low order sign bit...
else
output_vbr((unsigned)i << 1, out); // Low order bit is clear.
}
// align32 - emit the minimal number of bytes that will bring us to 32 bit
// alignment...
//
static inline void align32(std::deque<unsigned char> &Out) {
int NumPads = (4-(Out.size() & 3)) & 3; // Bytes to get padding to 32 bits
while (NumPads--) Out.push_back((unsigned char)0xAB);
}
static inline void output(const std::string &s, std::deque<unsigned char> &Out,
bool Aligned = true) {
unsigned Len = s.length();
output_vbr(Len, Out); // Strings may have an arbitrary length...
Out.insert(Out.end(), s.begin(), s.end());
if (Aligned)
align32(Out); // Make sure we are now aligned...
}
static inline void output_data(void *Ptr, void *End,
std::deque<unsigned char> &Out,
bool Align = false) {
#ifdef ENDIAN_LITTLE
Out.insert(Out.end(), (unsigned char*)Ptr, (unsigned char*)End);
#else
unsigned char *E = (unsigned char *)End;
while (Ptr != E)
Out.push_back(*--E);
#endif
if (Align) align32(Out);
}
#endif