reference/hash__seed_8h_source.html

#ifndef GINAC_HASH_SEED_H

#define GINAC_HASH_SEED_H


#include <typeinfo>

#include <cstring>

#include "utils.h"

#ifdef _WIN32

#define GINAC_HASH_USE_MANGLED_NAME 1

#endif


#ifdef GINAC_HASH_USE_MANGLED_NAME

#include "crc32.h"

#endif


namespace GiNaC

{

#ifndef GINAC_HASH_USE_MANGLED_NAME

static inline unsigned make_hash_seed(const std::type_info& tinfo)

{

    // This pointer is the same for all objects of the same type.

    // Hence we can use it.

    const void* mangled_name_ptr = (const void*)tinfo.name();

    unsigned v = golden_ratio_hash((uintptr_t)mangled_name_ptr);

    return v;

}

#else

static unsigned make_hash_seed(const std::type_info& tinfo)

{

    const char* mangled_name = tinfo.name();

    return crc32(mangled_name, std::strlen(mangled_name), 0);

}

#endif

} // namespace GiNaC

#endif /* GINAC_HASH_SEED_H */


crc32.h
CRC32 hash function.

GiNaC
Definition: add.cpp:38

GiNaC::golden_ratio_hash
unsigned golden_ratio_hash(uintptr_t n)
Truncated multiplication with golden ratio, for computing hash values.
Definition: utils.h:68

GiNaC::make_hash_seed
static unsigned make_hash_seed(const std::type_info &tinfo)
We need a hash function which gives different values for objects of different types.
Definition: hash_seed.h:36

GiNaC::crc32
static unsigned crc32(const char *c, const unsigned len, const unsigned crcinit)
Definition: crc32.h:66

utils.h
Interface to several small and furry utilities needed within GiNaC but not of any interest to the use...