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#ifndef WRITER_H
#define WRITER_H
#include <stdio.h>
#include <stdint.h>
#include <algorithm>
#ifndef LITTLE_ENDIAN
enum {
BIG_ENDIAN = 4321,
LITTLE_ENDIAN = 1234,
UNKNOWN_ENDIAN = 0x0000
};
#else
#define UNKNOWN_ENDIAN (0x0000)
#endif
int get_host_endian();
int parse_endian(const char* arg);
const char* endian2str(int endian);
// change the byte order of given variable
template <typename Type>
Type change_byte_order(const Type& v){
Type t = v;
const size_t size = sizeof(v);
uint8_t* first = (uint8_t *) (&t);
uint8_t* last = first + size - 1;
while (first < last) {
std::swap(*first++, *last--);
}
return t;
}
template <typename T>
class OtherEndian
{
public:
typedef T TargetType;
static TargetType create(const T& from){
return from;
}
};
#if WORDS_BIGENDIAN
#define DEFINE_OTHER_TYPE(__T__) typedef __T__ ## _BE TargetType
#else
#define DEFINE_OTHER_TYPE(__T__) typedef __T__ ## _LE TargetType
#endif
//
// we always defined a reversed layout of big-endian and little-endian
// bit-field struct, so such kind of struct need to be reverted if host
// arch is different from build arch.
//
template <typename T>
bool revert_write(const T& t, FILE *fp){
T reverted = change_byte_order(t);
typename OtherEndian<T>::TargetType o =
OtherEndian<T>::create(reverted);
return fwrite(&o, sizeof(o), 1, fp) == 1;
}
//
// if the struct has non-bit-field member(s), TTransUnit, among others,
// the order of members is the same as how they are defined.
//
class Writer
{
public:
Writer(FILE *fp, bool doRevert)
: m_fp(fp), m_doRevert(doRevert)
{}
template <typename T>
bool write(const T& t){
if (m_doRevert)
return revert_write(t, m_fp);
else
return fwrite(&t, sizeof(t), 1, m_fp) == 1;
}
template <typename T>
bool write(const T* t, size_t len){
for (unsigned i = 0; i < len; i++) {
if (!write(t[i]))
return false;
}
return true;
}
private:
FILE *m_fp;
const bool m_doRevert;
};
#endif // WRITER_H
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