gis/open.c

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#include <grass/config.h>
#include <string.h>

#include <unistd.h>
#include <fcntl.h>

#include <grass/gis.h>
#include <grass/glocale.h>

static int G__open(const char *element,
                   const char *name, const char *mapset, int mode)
{
    char path[GPATH_MAX];
    char xname[GNAME_MAX], xmapset[GMAPSET_MAX];


    G__check_gisinit();

    /* READ */
    if (mode == 0) {
        if (G__name_is_fully_qualified(name, xname, xmapset)) {
            if (*mapset && strcmp(xmapset, mapset) != 0) {
                G_warning(_("G__open(read): mapset <%s> doesn't match xmapset <%s>"),
                          mapset, xmapset);
                return -1;
            }
            name = xname;
            mapset = xmapset;
        }
        else if (!mapset || !*mapset)
            mapset = G_find_file2(element, name, mapset);

        if (!mapset)
            return -1;

        G__file_name(path, element, name, mapset);

        return open(path, 0);
    }
    /* WRITE */
    if (mode == 1 || mode == 2) {
        mapset = G_mapset();
        if (G__name_is_fully_qualified(name, xname, xmapset)) {
            if (strcmp(xmapset, mapset) != 0) {
                G_warning(_("G__open(write): xmapset <%s> != G_mapset() <%s>"),
                          xmapset, mapset);
                return -1;
            }
            name = xname;
        }

        if (G_legal_filename(name) == -1)
            return -1;

        G__file_name(path, element, name, mapset);

        if (mode == 1 || access(path, 0) != 0) {
            G__make_mapset_element(element);
            close(open(path, O_WRONLY | O_CREAT | O_TRUNC, 0666));
        }

        return open(path, mode);
    }
    return -1;
}

int G_open_new(const char *element, const char *name)
{
    return G__open(element, name, G_mapset(), 1);
}


int G_open_old(const char *element, const char *name, const char *mapset)
{
    return G__open(element, name, mapset, 0);
}

int G_open_update(const char *element, const char *name)
{
    int fd;

    fd = G__open(element, name, G_mapset(), 2);
    if (fd >= 0)
        lseek(fd, 0L, SEEK_END);

    return fd;
}


FILE *G_fopen_new(const char *element, const char *name)
{
    int fd;

    fd = G__open(element, name, G_mapset(), 1);
    if (fd < 0)
        return (FILE *) 0;

    return fdopen(fd, "w");
}


FILE *G_fopen_old(const char *element, const char *name, const char *mapset)
{
    int fd;

    fd = G__open(element, name, mapset, 0);
    if (fd < 0)
        return (FILE *) 0;

    return fdopen(fd, "r");
}

FILE *G_fopen_append(const char *element, const char *name)
{
    int fd;

    fd = G__open(element, name, G_mapset(), 2);
    if (fd < 0)
        return (FILE *) 0;
    lseek(fd, 0L, SEEK_END);

    return fdopen(fd, "a");
}

FILE *G_fopen_modify(const char *element, const char *name)
{
    int fd;

    fd = G__open(element, name, G_mapset(), 2);
    if (fd < 0)
        return (FILE *) 0;
    lseek(fd, 0L, SEEK_END);

    return fdopen(fd, "r+");
}