Ticket #8934: openfile.c

#include <stdio.h>
#include <stdlib.h>

static const wchar_t prefix[4] = {L'\\',L'\\',L'?',L'\\'};
static const size_t m = 32768;

static wchar_t* __cdecl c2w(const char *c)
{
        size_t l = mbstowcs(NULL,c,0);
        wchar_t *w = (wchar_t *)calloc(l+1,sizeof(wchar_t));

        if(w == NULL) return NULL;

        if( mbstowcs(w,c,l) == l) {
                return w;
        }else {
                free(w);
                return NULL;
        }
}

static wchar_t* __cdecl c2w_path(const char *c)
{
        wchar_t *w = c2w(c);
        int r = 0;

        if(w == NULL) return NULL;

        r = wcsncmp(w,prefix,4);

        if(0 != r) {
                wchar_t *ww = (wchar_t *)calloc(m + 4,sizeof(wchar_t));

                if(ww == NULL) {
                        free(w);
                        w = NULL;
                }else {

                        memcpy(ww,prefix,sizeof(prefix));

                        if(NULL == _wfullpath(ww+4,w,m)) {
                                free(ww);
                                ww = NULL;
                        }

                        free(w);
                        w = ww;
                }
        }

        return w;
}

FILE * __cdecl openfile(const char * path, const char *flags)
{

        wchar_t* fn = c2w_path(path);
        wchar_t* fg = NULL;
        FILE *fp = NULL;

        if(fn == NULL) return NULL;

        fg = c2w(flags);

        if(fg == NULL) {
                free(fn);
                return NULL;
        }

        fp = _wfopen(fn,fg);

        free(fg);
        free(fn);

        return fp;
}