ExternalVendorCode/tippecanoe
1
0
Fork 0
mirror of https://github.com/mapbox/tippecanoe.git synced 2025-04-04 17:49:06 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Start indexing; sanity check that the file positions are right

Browse Source
This commit is contained in:
Eric Fischer 2014-09-16 17:54:23 -07:00
parent 449da18c63
commit ee8c23b010
1 changed files with 74 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
geojson.c
View File

@ -70,6 +70,62 @@ void latlon2tile(double lat, double lon, int zoom, unsigned int *x, unsigned int
*y = n * (1 - (log(tan(lat_rad) + 1/cos(lat_rad)) / M_PI)) / 2;
}
#define MAX_ZOOM 28
#define ZOOM_BITS 5
int get_bbox_zoom(unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2) {
int z;
for (z = 0; z < MAX_ZOOM; z++) {
int mask = 1 << (32 - (z + 1));
if (((x1 & mask) != (x2 & mask)) ||
((y1 & mask) != (y2 & mask))) {
return z;
}
}
return MAX_ZOOM;
}
void get_bbox_tile(unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2, int *z, unsigned int *x, unsigned int *y) {
*z = get_bbox_zoom(x1, y1, x2, y2);
if (*z == 0) {
*x = *y = 0;
} else {
*x = x1 >> (32 - *z);
*y = y1 >> (32 - *z);
}
}
/*
* 5 bits for zoom (<< 59)
* 56 bits for interspersed yx (<< 3)
* 3 bits for tags (<< 0)
*/
unsigned long long encode_bbox(unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2, int tags) {
int z = get_bbox_zoom(x1, y1, x2, y2);
long long out = ((long long) z) << (64 - ZOOM_BITS);
int i;
for (i = 0; i < MAX_ZOOM; i++) {
long long v = ((y1 >> (32 - (i + 1))) & 1) << 1;
v |= (x1 >> (32 - (i + 1))) & 1;
v = v << (64 - ZOOM_BITS - 2 * (i + 1));
out |= v;
}
return out;
}
struct index {
unsigned long long index;
long long fpos;
struct index *next;
};
void serialize_int(FILE *out, int n, long long *fpos) {
fwrite(&n, sizeof(int), 1, out);
*fpos += sizeof(int);
@ -160,12 +216,16 @@ void deserialize_string(FILE *f) {
printf("%s", s);
}
void check() {
void check(struct index *ix) {
FILE *f = fopen("meta.out", "rb");
int m;
for (; ix != NULL; ix = ix->next) {
off_t pos = ix->fpos;
fseeko(f, pos, SEEK_SET);
int m;
deserialize_int(f, &m);
while (deserialize_int(f, &m)) {
int i;
for (i = 0; i < m; i++) {
int t;
@ -204,6 +264,7 @@ void check() {
void read_json(FILE *f) {
json_pull *jp = json_begin_file(f);
struct index *index = NULL;
FILE *out = fopen("meta.out", "wb");
long long fpos = 0;
@ -260,6 +321,8 @@ void read_json(FILE *f) {
/* scope for variable-length arrays */
{
long long start = fpos;
char *metakey[properties->length];
char *metaval[properties->length];
int metatype[properties->length];
@ -303,6 +366,13 @@ void read_json(FILE *f) {
serialize_int(out, VT_END, &fpos);
// printf("bbox %x %x %x %x\n", bbox[0], bbox[1], bbox[2], bbox[3]);
struct index *ix = malloc(sizeof(struct index));
ix->index = encode_bbox(bbox[0], bbox[1], bbox[2], bbox[3], 0);
ix->fpos = start;
ix->next = index;
index = ix;
}
next_feature:
@ -314,7 +384,7 @@ next_feature:
json_end(jp);
fclose(out);
check();
check(index);
}
int main(int argc, char **argv) {