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Stabilize feature order between the different reading methods

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This commit is contained in:
Eric Fischer 2016-01-12 14:12:56 -08:00
parent ca97c5ec6d
commit ecae14e2d4
1 changed files with 9 additions and 7 deletions
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16
geojson.c
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@ -274,7 +274,8 @@ struct index {
long long start;
long long end;
unsigned long long index;
int segment;
short segment;
unsigned long long seq : (64 - 16); // pack with segment to stay in 32 bytes
};
int indexcmp(const void *v1, const void *v2) {
@ -287,6 +288,12 @@ int indexcmp(const void *v1, const void *v2) {
return 1;
}
if (i1->seq < i2->seq) {
return -1;
} else if (i1->seq > i2->seq) {
return 1;
}
return 0;
}
@ -599,6 +606,7 @@ int serialize_geometry(json_object *geometry, json_object *properties, const cha
index.start = geomstart;
index.end = *geompos;
index.segment = segment;
index.seq = *layer_seq;
// Calculate the center even if off the edge of the plane,
// and then mask to bring it back into the addressable area
@ -1430,12 +1438,6 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
fprintf(stderr, "Sorting %lld features\n", (long long) indexpos / bytes);
}
// XXX On machines with different page sizes, doing the sorting
// in different-sized chunks can cause features with the same
// index (i.e., the same bbox) to appear in different orders
// because the sort is unstable. This doesn't seem worth spending
// more memory to fix, but could make tests unstable.
int page = sysconf(_SC_PAGESIZE);
long long unit = (50 * 1024 * 1024 / bytes) * bytes;
while (unit % page != 0) {