StreamOps.h
Go to the documentation of this file.
//
// Copyright (C) 2002-2008 Greg Landrum and Rational Discovery LLC
//
// @@ All Rights Reserved @@
// This file is part of the RDKit.
// The contents are covered by the terms of the BSD license
// which is included in the file license.txt, found at the root
// of the RDKit source tree.
//
//
#ifndef _RD_STREAMOPS_H
#define _RD_STREAMOPS_H
#include "types.h"
#include <string>
#include <sstream>
#include <iostream>
#include <boost/cstdint.hpp>
#include <boost/detail/endian.hpp>
namespace RDKit{
// this code block for handling endian problems is from :
// http://stackoverflow.com/questions/105252/how-do-i-convert-between-big-endian-and-little-endian-values-in-c
enum EEndian
{
LITTLE_ENDIAN_ORDER,
BIG_ENDIAN_ORDER,
#if defined(BOOST_LITTLE_ENDIAN)
HOST_ENDIAN_ORDER = LITTLE_ENDIAN_ORDER
#elif defined(BOOST_BIG_ENDIAN)
HOST_ENDIAN_ORDER = BIG_ENDIAN_ORDER
#else
#error "Failed to determine the system endian value"
#endif
};
// this function swap the bytes of values given it's size as a template
// parameter (could sizeof be used?).
template <class T, unsigned int size>
inline T SwapBytes(T value)
{
union
{
T value;
char bytes[size];
} in, out;
in.value = value;
for (unsigned int i = 0; i < size / 2; ++i)
{
out.bytes[i] = in.bytes[size - 1 - i];
out.bytes[size - 1 - i] = in.bytes[i];
}
return out.value;
}
// Here is the function you will use. Again there is two compile-time assertion
// that use the boost librarie. You could probably comment them out, but if you
// do be cautious not to use this function for anything else than integers
// types. This function need to be calles like this :
//
// int x = someValue;
// int i = EndianSwapBytes<HOST_ENDIAN_ORDER, BIG_ENDIAN_ORDER>(x);
//
template<EEndian from, EEndian to, class T>
inline T EndianSwapBytes(T value)
{
// A : La donnée à swapper à une taille de 2, 4 ou 8 octets
BOOST_STATIC_ASSERT(sizeof(T)==1 || sizeof(T) == 2 || sizeof(T) == 4 || sizeof(T) == 8);
if(sizeof(T)==1) return value;
// A : La donnée à swapper est d'un type arithmetic
//BOOST_STATIC_ASSERT(boost::is_arithmetic<T>::value);
// Si from et to sont du même type on ne swap pas.
if (from == to)
return value;
return SwapBytes<T, sizeof(T)>(value);
}
template<EEndian from, EEndian to>
inline char EndianSwapBytes(char value)
{
return value;
}
template<EEndian from, EEndian to>
inline unsigned char EndianSwapBytes(unsigned char value)
{
return value;
}
template<EEndian from, EEndian to>
inline signed char EndianSwapBytes(signed char value)
{
return value;
}
// --------------------------------------
//! Packs an integer and outputs it to a stream
inline void appendPackedIntToStream(std::stringstream &ss, boost::uint32_t num) {
int nbytes, bix;
unsigned int val, res;
char tc;
CHECK_INVARIANT(num >= 0, "");
res=num;
while (1) {
if (res < (1<<7)) {
val = (res<<1);
nbytes = 1;
break;
}
res -= (1<<7);
if (res < (1<<14)) {
val = ((res<<2) | 1);
nbytes = 2;
break;
}
res -= (1<<14);
if (res < (1<<21)) {
val = ((res<<3) | 3);
nbytes = 3;
break;
}
res -= (1<<21);
if ( res < (1<<29)) {
val = ((res<<3) | 7);
nbytes = 4;
break;
}
else {
CHECK_INVARIANT(0, "ERROR: Integer too big to pack\n");
}
}
//val = EndianSwapBytes<HOST_ENDIAN_ORDER,LITTLE_ENDIAN_ORDER>(val);
for (bix = 0; bix < nbytes; bix++) {
tc = (char) (val & 255);
ss.write(&tc, 1);
val >>= 8;
}
}
//! Reads an integer from a stream in packed format and returns the result.
inline boost::uint32_t readPackedIntFromStream(std::stringstream &ss) {
boost::uint32_t val, num;
int shift, offset;
char tmp;
ss.read(&tmp, sizeof(tmp));
val = UCHAR(tmp);
offset = 0;
if ((val&1) == 0) {
shift = 1;
}
else if ((val&3) == 1) {
ss.read((char *)&tmp, sizeof(tmp));
val |= (UCHAR(tmp) << 8);
shift = 2;
offset = (1<<7);
}
else if ((val&7) == 3) {
ss.read((char *)&tmp, sizeof(tmp));
val |= (UCHAR(tmp) << 8);
ss.read((char *)&tmp, sizeof(tmp));
val |= (UCHAR(tmp) << 16);
shift = 3;
offset = (1<<7) + (1<<14);
}
else {
ss.read((char *)&tmp, sizeof(tmp));
val |= (UCHAR(tmp) << 8);
ss.read((char *)&tmp, sizeof(tmp));
val |= (UCHAR(tmp) << 16);
ss.read((char *)&tmp, sizeof(tmp));
val |= (UCHAR(tmp) << 24);
shift = 3;
offset = (1<<7) + (1<<14) + (1<<21);
}
num = (val >> shift) + offset;
//num = EndianSwapBytes<LITTLE_ENDIAN_ORDER,HOST_ENDIAN_ORDER>(num);
return num;
}
//! Reads an integer from a char * in packed format and returns the result.
//! The argument is advanced
inline boost::uint32_t pullPackedIntFromString(const char *&text) {
boost::uint32_t val, num;
int shift, offset;
char tmp;
tmp = *text;
text++;
val = UCHAR(tmp);
offset = 0;
if ((val&1) == 0) {
shift = 1;
}
else if ((val&3) == 1) {
tmp = *text;
text++;
val |= (UCHAR(tmp) << 8);
shift = 2;
offset = (1<<7);
}
else if ((val&7) == 3) {
tmp = *text;
text++;
val |= (UCHAR(tmp) << 8);
tmp = *text;
text++;
val |= (UCHAR(tmp) << 16);
shift = 3;
offset = (1<<7) + (1<<14);
}
else {
tmp = *text;
text++;
val |= (UCHAR(tmp) << 8);
tmp = *text;
text++;
val |= (UCHAR(tmp) << 16);
tmp = *text;
text++;
val |= (UCHAR(tmp) << 24);
shift = 3;
offset = (1<<7) + (1<<14) + (1<<21);
}
num = (val >> shift) + offset;
//num = EndianSwapBytes<LITTLE_ENDIAN_ORDER,HOST_ENDIAN_ORDER>(num);
return num;
}
//! does a binary write of an object to a stream
template <typename T>
void streamWrite(std::ostream &ss,const T &val){
T tval=EndianSwapBytes<HOST_ENDIAN_ORDER,LITTLE_ENDIAN_ORDER>(val);
ss.write((const char *)&tval,sizeof(T));
}
//! does a binary read of an object from a stream
template <typename T>
void streamRead(std::istream &ss,T &loc){
T tloc;
ss.read((char *)&tloc,sizeof(T));
loc = EndianSwapBytes<LITTLE_ENDIAN_ORDER,HOST_ENDIAN_ORDER>(tloc);
}
//! grabs the next line from an instream and returns it.
inline std::string getLine(std::istream *inStream) {
std::string res;
std::getline(*inStream,res);
if ((res.length() > 0) && (res[res.length()-1]=='\r')){
res.erase(res.length()-1);
}
return res;
}
//! grabs the next line from an instream and returns it.
inline std::string getLine(std::istream &inStream) {
return getLine(&inStream);
}
}
#endif
types.h
RDKit::BIG_ENDIAN_ORDER
Definition: StreamOps.h:27
RDKit::EndianSwapBytes
T EndianSwapBytes(T value)
Definition: StreamOps.h:68
CHECK_INVARIANT
#define CHECK_INVARIANT(expr, mess)
Definition: Invariant.h:114
RDKit::UCHAR
unsigned char UCHAR
Definition: types.h:144
RDKit::EEndian
EEndian
Definition: StreamOps.h:24
RDKit::streamRead
void streamRead(std::istream &ss, T &loc)
does a binary read of an object from a stream
Definition: StreamOps.h:241
RDKit::readPackedIntFromStream
boost::uint32_t readPackedIntFromStream(std::stringstream &ss)
Reads an integer from a stream in packed format and returns the result.
Definition: StreamOps.h:146
RDKit::pullPackedIntFromString
boost::uint32_t pullPackedIntFromString(const char *&text)
Definition: StreamOps.h:187
RDKit::SwapBytes
T SwapBytes(T value)
Definition: StreamOps.h:40
RDKit
Includes a bunch of functionality for handling Atom and Bond queries.
Definition: Atom.h:28
RDKit::LITTLE_ENDIAN_ORDER
Definition: StreamOps.h:26
RDKit::streamWrite
void streamWrite(std::ostream &ss, const T &val)
does a binary write of an object to a stream
Definition: StreamOps.h:235
RDKit::getLine
std::string getLine(std::istream *inStream)
grabs the next line from an instream and returns it.
Definition: StreamOps.h:248
RDKit::appendPackedIntToStream
void appendPackedIntToStream(std::stringstream &ss, boost::uint32_t num)
Packs an integer and outputs it to a stream.
Definition: StreamOps.h:101