tippecanoe/geojson.c

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <string.h>
#include <fcntl.h>
#include <ctype.h>
#include "jsonpull.h"

#define GEOM_POINT 0                /* array of positions */
#define GEOM_MULTIPOINT 1           /* array of arrays of positions */
#define GEOM_LINESTRING 2           /* array of arrays of positions */
#define GEOM_MULTILINESTRING 3      /* array of arrays of arrays of positions */
#define GEOM_POLYGON 4              /* array of arrays of arrays of positions */
#define GEOM_MULTIPOLYGON 5         /* array of arrays of arrays of arrays of positions */

char *geometry_names[] = {
	"Point",
	"MultiPoint",
	"LineString",
	"MultiLineString",
	"Polygon",
	"MultiPolygon",
};

int geometry_depths[] = {
	1,
	2,
	2,
	3,
	3,
	4,
};

/* XXX */
#define META_STRING JSON_STRING
#define META_INTEGER JSON_NUMBER
int metabits = 32;

void read_json(FILE *f) {
	json_pull *jp = json_begin_file(f);

	while (1) {
		json_object *j = json_read(jp);

		if (j == NULL) {
			if (jp->error != NULL) {
				fprintf(stderr, "%d: %s\n", jp->line, jp->error);
			}

			json_free(jp->root);
			break;
		}

		json_object *type = json_hash_get(j, "type");
		if (type != NULL && type->type == JSON_STRING && strcmp(type->string, "Feature") == 0) {
			json_object *geometry = json_hash_get(j, "geometry");

			if (geometry != NULL) {
				json_object *geometry_type = json_hash_get(geometry, "type");
				if (geometry_type != NULL && geometry_type->type == JSON_STRING) {
					int t = -1;

					if (strcmp(geometry_type->string, "Point") == 0) {
						t = GEOM_POINT;
					} else if (strcmp(geometry_type->string, "LineString") == 0) {
						t = GEOM_LINESTRING;
					} else {
						fprintf(stderr, "%d: Can't handle geometry type %s\n", jp->line, geometry_type->string);
					}

					if (t != -1) {
						json_object *properties = json_hash_get(j, "properties");
						json_object *coordinates = json_hash_get(geometry, "coordinates");

						if (properties != NULL && properties->type == JSON_HASH) {
							int metasize[properties->length];
							char *metaname[properties->length];
							char *meta[properties->length];
							int metatype[properties->length];
							int m = 0;

							int i;
							for (i = 0; i < properties->length; i++) {
								if (properties->keys[i]->type == JSON_STRING) {
									metasize[m] = metabits;
									metaname[m] = properties->keys[i]->string;

									if (properties->values[i] != NULL && properties->values[i]->type == JSON_STRING) {
										metatype[m] = META_STRING;
										meta[m] = properties->values[i]->string;
										m++;
									} else if (properties->values[i] != NULL && properties->values[i]->type == JSON_NUMBER) {
										metatype[m] = META_INTEGER;
										meta[m] = properties->values[i]->string;
										m++;
									} else {
										fprintf(stderr, "%d: Unsupported meta type\n", jp->line);
									}
								}
							}

							if (coordinates != NULL && coordinates->type == JSON_ARRAY) {
								int n;

								if (t == GEOM_POINT) {
									n = 1;
								} else {
									n = coordinates->length;
								}

								double lon[n], lat[n];
								int ok = 1;

								if (t == GEOM_POINT) {
									if (coordinates->length >= 2) {
										lon[0] = coordinates->array[0]->number;
										lat[0] = coordinates->array[1]->number;
									} else {
										fprintf(stderr, "%d: not enough coordinates for a point\n", jp->line);
										ok = 0;
									}
								} else {
									for (i = 0; i < n; i++) {
										if (coordinates->array[i]->type == JSON_ARRAY &&
										    coordinates->array[i]->length >= 2) {
											lon[i] = coordinates->array[i]->array[0]->number;
											lat[i] = coordinates->array[i]->array[1]->number;
										} else {
											fprintf(stderr, "%d: not enough coordinates within the geometry\n", jp->line);
											ok = 0;
										}
									}
								}

								if (ok) {
									// XXX encode(destdir, files, maxn, extra, xoff, pool, n, lat, lon, m, metasize, metaname, meta, metatype);
								}
							} else {
								fprintf(stderr, "%d: feature geometry with no coordinates\n", jp->line);
							}
						} else {
							fprintf(stderr, "%d: feature with no properties\n", jp->line);
						}
					}
				}
			} else {
				fprintf(stderr, "%d: feature with no geometry\n", jp->line);
			}

			json_free(j);
		}
	}

	json_end(jp);
}