array.c

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/*!
   \file lib/vector/Vlib/array.c
 
   \brief Vector library - category array
 
   Higher level functions for reading/writing/manipulating vectors.
 
   (C) 2001-2009 by the GRASS Development Team
 
   This program is free software under the
   GNU General Public License (>=v2).
   Read the file COPYING that comes with GRASS
   for details.
 
   \author Radim Blazek
 */
 
#include <stdlib.h>
#include <grass/dbmi.h>
#include <grass/vector.h>
#include <grass/glocale.h>
 
/* function prototypes */
static int cmp(const void *pa, const void *pb);
static int in_array(int *cats, size_t ncats, int cat);
 
/*!
   \brief Create new struct varray and allocate space for given number of items.
 
   Space allocated is 'size + 1' so that lines are accessed by line id.
   Array values are set to 0.
 
   \param size size of array
 
   \return pointer to new struct varray
   \return NULL if failed
 */
struct varray *Vect_new_varray(int size)
{
    struct varray *p;
 
    p = (struct varray *)G_malloc(sizeof(struct varray));
 
    if (p == NULL)
        return NULL;
 
    p->size = size;
    p->c = (int *)G_calloc(sizeof(char) * size + 1, sizeof(int));
 
    if (p->c == NULL) {
        G_free(p);
        return NULL;
    }
 
    return p;
}
 
/*!
   \brief Set values in 'varray' to 'value' from category string.
 
   If category of object of given type is in <em>cstring</em> (string
   representing category list like: '1,3,5-7'). <em>type</em> may be
   either: GV_AREA or: GV_POINT | GV_LINE | GV_BOUNDARY | GV_CENTROID
 
   Array is not reset to zero before, but old values (if any > 0) are
   overwritten.  Array must be initialised by Vect_new_varray() call.
 
   \param Map vector map
   \param field layer number
   \param cstring pointer to string with categories
   \param type feature type
   \param value value to set up
   \param[out] varray varray structure to modify
 
   \return number of items set
   \return -1 on error
 */
int Vect_set_varray_from_cat_string(struct Map_info *Map, int field,
                                    const char *cstring, int type, int value,
                                    struct varray *varray)
{
    int ret;
    struct cat_list *Clist;
 
    G_debug(4, "Vect_set_varray_from_cat_string(): cstring = '%s'", cstring);
 
    Clist = Vect_new_cat_list();
 
    ret = Vect_str_to_cat_list(cstring, Clist);
 
    if (ret > 0)
        G_warning(_("%d errors in category string"), ret);
 
    G_debug(4, "  %d ranges in clist", Clist->n_ranges);
 
    ret = Vect_set_varray_from_cat_list(Map, field, Clist, type, value, varray);
 
    Vect_destroy_cat_list(Clist);
 
    return ret;
}
 
/*!
   \brief Set values in 'varray' to 'value' from category list
 
   If category of object of given type is in <em>clist</em> (category
   list).  <em>type</em> may be either: GV_AREA or: GV_POINT | GV_LINE
   | GV_BOUNDARY | GV_CENTROID
 
   Array is not reset to zero before, but old values (if any > 0) are
   overwritten.  Array must be initialised by Vect_new_varray() call.
 
   \param Map vector map
   \param field layer number
   \param clist list of categories
   \param type feature type
   \param value value to set up
   \param[out] varray varray structure to modify
 
   \return number of items set
   \return -1 on error
 */
int Vect_set_varray_from_cat_list(struct Map_info *Map, int field,
                                  struct cat_list *clist, int type, int value,
                                  struct varray *varray)
{
    int i, n, centr, cat;
    int ni = 0; /* number of items set */
    int ltype;  /* line type */
    struct line_cats *Cats;
 
    G_debug(4, "Vect_set_varray_from_cat_list(): field = %d", field);
 
    /* Check type */
    if ((type & GV_AREA) && (type & (GV_POINTS | GV_LINES))) {
        G_warning(_("Mixed area and other type requested for vector array"));
        return 0;
    }
 
    Cats = Vect_new_cats_struct();
 
    if (type & GV_AREA) { /* Areas */
        n = Vect_get_num_areas(Map);
 
        if (n > varray->size) { /* not enough space */
            G_warning(_("Not enough space in vector array"));
            Vect_destroy_cats_struct(Cats);
            return 0;
        }
 
        for (i = 1; i <= n; i++) {
            centr = Vect_get_area_centroid(Map, i);
            if (centr <= 0)
                continue; /* No centroid */
 
            Vect_read_line(Map, NULL, Cats, centr);
            if (!Vect_cat_get(Cats, field, &cat))
                continue; /* No such field */
 
            if (Vect_cat_in_cat_list(cat, clist)) { /* cat is in list */
                varray->c[i] = value;
                ni++;
            }
        }
    }
    else { /* Lines */
        n = Vect_get_num_lines(Map);
 
        if (n > varray->size) { /* not enough space */
            G_warning(_("Not enough space in vector array"));
            Vect_destroy_cats_struct(Cats);
            return 0;
        }
 
        for (i = 1; i <= n; i++) {
            ltype = Vect_read_line(Map, NULL, Cats, i);
 
            if (!(ltype & type))
                continue; /* is not specified type */
 
            if (!Vect_cat_get(Cats, field, &cat))
                continue; /* No such field */
 
            if (Vect_cat_in_cat_list(cat, clist)) { /* cat is in list */
                varray->c[i] = value;
                ni++;
            }
        }
    }
 
    Vect_destroy_cats_struct(Cats);
 
    return ni;
}
 
/* compare 2 integers in array */
static int cmp(const void *pa, const void *pb)
{
    int *p1 = (int *)pa;
    int *p2 = (int *)pb;
 
    if (*p1 < *p2)
        return -1;
    if (*p1 > *p2)
        return 1;
    return 0;
}
 
/* check if cat is in array */
static int in_array(int *cats, size_t ncats, int cat)
{
    int *p;
 
    p = (int *)bsearch((void *)&cat, cats, ncats, sizeof(int), cmp);
 
    if (p == NULL)
        return 0;
 
    return 1;
}
 
/*!
   \brief Set values in 'varray' to 'value' from DB (where statement)
 
   I category of object of given type is in categories selected from
   DB based on where statement (given without where). <em>type</em>
   may be either: GV_AREA or: GV_POINT | GV_LINE | GV_BOUNDARY |
   GV_CENTROID
 
   Array is not reset to zero before, but old values (if any > 0) are
   overwritten. Array must be initialised by Vect_new_varray() call.
 
   \param Map vector map
   \param field layer number
   \param where where statement
   \param type feature type
   \param value value to set up
   \param[out] varray varray structure to modify
 
   \return number of items set
   \return -1 on error
 */
int Vect_set_varray_from_db(struct Map_info *Map, int field, const char *where,
                            int type, int value, struct varray *varray)
{
    int i, n, c, centr, *cats;
    int ncats;
    int ni = 0; /* number of items set */
    int ltype;  /* line type */
    struct line_cats *Cats;
    struct field_info *Fi;
    dbDriver *driver;
 
    G_debug(4, "Vect_set_varray_from_db(): field = %d where = '%s'", field,
            where);
 
    /* Note: use category index once available */
 
    /* Check type */
    if ((type & GV_AREA) && (type & (GV_POINTS | GV_LINES))) {
        G_warning(_("Mixed area and other type requested for vector array"));
        return 0;
    }
 
    /* Select categories from DB to array */
    Fi = Vect_get_field(Map, field);
    if (Fi == NULL) {
        G_warning(_("Database connection not defined for layer %d"), field);
        return -1;
    }
 
    driver = db_start_driver_open_database(Fi->driver, Fi->database);
    if (driver == NULL) {
        G_warning(_("Unable to open database <%s> by driver <%s>"),
                  Fi->database, Fi->driver);
        Vect_destroy_field_info(Fi);
        return -1;
    }
 
    ncats = db_select_int(driver, Fi->table, Fi->key, where, &cats);
 
    db_close_database_shutdown_driver(driver);
 
    if (ncats == -1) {
        G_warning(
            _("Unable to select record from table <%s> (key %s, where %s)"),
            Fi->table, Fi->key, where);
        Vect_destroy_field_info(Fi);
        return -1;
    }
    Vect_destroy_field_info(Fi);
    Cats = Vect_new_cats_struct();
 
    if (type & GV_AREA) { /* Areas */
        n = Vect_get_num_areas(Map);
 
        /* IMHO varray should be allocated only when it's required AND only as
           large as required as WHERE will create a small subset of all vector
           features and thus on large datasets it's waste of memory to allocate
           it for all features. */
        if (n > varray->size) { /* not enough space */
            G_warning(_("Not enough space in vector array"));
            Vect_destroy_cats_struct(Cats);
            G_free(cats);
            return 0;
        }
 
        for (i = 1; i <= n; i++) {
            centr = Vect_get_area_centroid(Map, i);
            if (centr <= 0)
                continue; /* No centroid */
 
            Vect_read_line(Map, NULL, Cats, centr);
            /*if ( !Vect_cat_get(Cats, field, &cat) ) continue; No such field */
            for (c = 0; c < Cats->n_cats; c++) {
                if (Cats->field[c] == field &&
                    in_array(cats, ncats, Cats->cat[c])) {
                    varray->c[i] = value;
                    ni++;
                    break;
                }
            }
 
            /*
               if ( in_array ( cats, ncats, cat ) ) {
               varray->c[i] = value;
               ni++;
               }
             */
        }
    }
    else { /* Lines */
        n = Vect_get_num_lines(Map);
 
        if (n > varray->size) { /* not enough space */
            G_warning(_("Not enough space in vector array"));
            Vect_destroy_cats_struct(Cats);
            G_free(cats);
            return 0;
        }
 
        for (i = 1; i <= n; i++) {
            ltype = Vect_read_line(Map, NULL, Cats, i);
 
            if (!(ltype & type))
                continue; /* is not specified type */
 
            /* if ( !Vect_cat_get(Cats, field, &cat) ) continue;  No such field
             */
            for (c = 0; c < Cats->n_cats; c++) {
                if (Cats->field[c] == field &&
                    in_array(cats, ncats, Cats->cat[c])) {
                    varray->c[i] = value;
                    ni++;
                    break;
                }
            }
            /*
               if ( in_array ( cats, ncats, cat ) ) {
               varray->c[i] = value;
               ni++;
               }
             */
        }
    }
 
    G_free(cats);
    Vect_destroy_cats_struct(Cats);
 
    return ni;
}