foo.cpp

#include <string.h>
#include <assert.h>

#include <hash_map>

// Here's how I'd structure the code to eliminate code duplication:

struct String_Hasher
{
    size_t operator()(const char *value) const
    {
        size_t hash = 0;
        while (*value)
            hash = (hash >> 7) + (hash << 25) + *value++;
        return hash + (hash >> 16);
    }

    bool operator()(const char *left, const char *right) const
    {
        return strcmp(left, right) < 0;
    }
};

#ifndef USE_STL_PORT
struct MSVC_String_Hasher : public stdext::hash_compare<const char*, std::less<const char*> >, public String_Hasher { };
#endif

#ifdef USE_STL_PORT
typedef stdext::hash_map<const char*, const char*, String_Hasher, String_Hasher> StringHashMap;
#else
typedef stdext::hash_map<const char*, const char*, MSVC_String_Hasher> StringHashMap;
#endif

int main()
{
	stdext::hash_map<const char*, int, MSVC_String_Hasher> m;
	m["foo"] = 42;
	m["bar"] = 24;
	assert(m["foo"] == 42);
	assert(m["bar"] == 24);
	return 0;
}