write_json.cpp
// for vasprintf() on Linux
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <vector>
#include <map>
#include <string>
#include "projection.hpp"
#include "geometry.hpp"
#include "mvt.hpp"
#include "write_json.hpp"
#include "milo/dtoa_milo.h"
void json_writer::json_adjust() {
if (state.size() == 0) {
state.push_back(JSON_WRITE_TOP);
} else if (state[state.size() - 1] == JSON_WRITE_TOP) {
addc('\n');
state[state.size() - 1] = JSON_WRITE_TOP;
} else if (state[state.size() - 1] == JSON_WRITE_HASH) {
if (!nospace) {
addc(' ');
}
nospace = false;
state[state.size() - 1] = JSON_WRITE_HASH_KEY;
} else if (state[state.size() - 1] == JSON_WRITE_HASH_KEY) {
adds(": ");
state[state.size() - 1] = JSON_WRITE_HASH_VALUE;
} else if (state[state.size() - 1] == JSON_WRITE_HASH_VALUE) {
if (wantnl) {
adds(",\n");
nospace = false;
} else if (nospace) {
addc(',');
nospace = false;
} else {
adds(", ");
}
wantnl = false;
state[state.size() - 1] = JSON_WRITE_HASH_KEY;
} else if (state[state.size() - 1] == JSON_WRITE_ARRAY) {
if (!nospace) {
addc(' ');
}
nospace = false;
state[state.size() - 1] = JSON_WRITE_ARRAY_ELEMENT;
} else if (state[state.size() - 1] == JSON_WRITE_ARRAY_ELEMENT) {
if (wantnl) {
adds(",\n");
nospace = false;
} else if (nospace) {
addc(',');
nospace = false;
} else {
adds(", ");
}
wantnl = false;
state[state.size() - 1] = JSON_WRITE_ARRAY_ELEMENT;
} else {
fprintf(stderr, "Impossible JSON state\n");
exit(EXIT_FAILURE);
}
}
void json_writer::json_write_array() {
json_adjust();
addc('[');
state.push_back(JSON_WRITE_ARRAY);
}
void json_writer::json_end_array() {
if (state.size() == 0) {
fprintf(stderr, "End JSON array at top level\n");
exit(EXIT_FAILURE);
}
json_write_tok tok = state[state.size() - 1];
state.pop_back();
if (tok == JSON_WRITE_ARRAY || tok == JSON_WRITE_ARRAY_ELEMENT) {
if (!nospace) {
addc(' ');
}
nospace = false;
addc(']');
} else {
fprintf(stderr, "End JSON array with unexpected state\n");
exit(EXIT_FAILURE);
}
}
void json_writer::json_write_hash() {
json_adjust();
addc('{');
state.push_back(JSON_WRITE_HASH);
}
void json_writer::json_end_hash() {
if (state.size() == 0) {
fprintf(stderr, "End JSON hash at top level\n");
exit(EXIT_FAILURE);
}
json_write_tok tok = state[state.size() - 1];
state.pop_back();
if (tok == JSON_WRITE_HASH) {
if (!nospace) {
adds(" "); // Preserve accidental extra space from before
}
nospace = false;
addc('}');
} else if (tok == JSON_WRITE_HASH_VALUE) {
if (!nospace) {
addc(' ');
}
nospace = false;
addc('}');
} else {
fprintf(stderr, "End JSON hash with unexpected state\n");
exit(EXIT_FAILURE);
}
}
void json_writer::json_write_string(std::string const &str) {
json_adjust();
addc('"');
for (size_t i = 0; i < str.size(); i++) {
if (str[i] == '\\' || str[i] == '"') {
aprintf("\\%c", str[i]);
} else if ((unsigned char) str[i] < ' ') {
aprintf("\\u%04x", str[i]);
} else {
addc(str[i]);
}
}
addc('"');
}
void json_writer::json_write_number(double d) {
json_adjust();
adds(milo::dtoa_milo(d).c_str());
}
// Just to avoid json_writer:: changing expected output format
void json_writer::json_write_float(double d) {
json_adjust();
aprintf("%f", d);
}
void json_writer::json_write_unsigned(unsigned long long v) {
json_adjust();
aprintf("%llu", v);
}
void json_writer::json_write_signed(long long v) {
json_adjust();
aprintf("%lld", v);
}
void json_writer::json_write_stringified(std::string const &str) {
json_adjust();
adds(str);
}
void json_writer::json_write_bool(bool b) {
json_adjust();
if (b) {
adds("true");
} else {
adds("false");
}
}
void json_writer::json_write_null() {
json_adjust();
adds("null");
}
void json_writer::json_write_newline() {
addc('\n');
nospace = true;
}
void json_writer::json_comma_newline() {
wantnl = true;
}
void json_writer::aprintf(const char *format, ...) {
va_list ap;
char *tmp;
va_start(ap, format);
if (vasprintf(&tmp, format, ap) < 0) {
fprintf(stderr, "memory allocation failure\n");
exit(EXIT_FAILURE);
}
va_end(ap);
adds(std::string(tmp, strlen(tmp)));
free(tmp);
}
void json_writer::addc(char c) {
if (f != NULL) {
putc(c, f);
} else if (s != NULL) {
s->push_back(c);
}
}
void json_writer::adds(std::string const &str) {
if (f != NULL) {
fputs(str.c_str(), f);
} else if (s != NULL) {
s->append(str);
}
}
struct lonlat {
int op;
double lon;
double lat;
long long x;
long long y;
lonlat(int nop, double nlon, double nlat, long long nx, long long ny)
: op(nop),
lon(nlon),
lat(nlat),
x(nx),
y(ny) {
}
};
void layer_to_geojson(mvt_layer const &layer, unsigned z, unsigned x, unsigned y, bool comma, bool name, bool zoom, bool dropped, unsigned long long index, long long sequence, long long extent, bool complain, json_writer &state) {
for (size_t f = 0; f < layer.features.size(); f++) {
mvt_feature const &feat = layer.features[f];
state.json_write_hash();
state.json_write_string("type");
state.json_write_string("Feature");
if (feat.has_id) {
state.json_write_string("id");
state.json_write_unsigned(feat.id);
}
if (name || zoom || index != 0 || sequence != 0 || extent != 0) {
state.json_write_string("tippecanoe");
state.json_write_hash();
if (name) {
state.json_write_string("layer");
state.json_write_string(layer.name);
}
if (zoom) {
state.json_write_string("minzoom");
state.json_write_unsigned(z);
state.json_write_string("maxzoom");
state.json_write_unsigned(z);
}
if (dropped) {
state.json_write_string("dropped");
state.json_write_bool(feat.dropped);
}
if (index != 0) {
state.json_write_string("index");
state.json_write_unsigned(index);
}
if (sequence != 0) {
state.json_write_string("sequence");
state.json_write_signed(sequence);
}
if (extent != 0) {
state.json_write_string("extent");
state.json_write_signed(extent);
}
state.json_end_hash();
}
state.json_write_string("properties");
state.json_write_hash();
for (size_t t = 0; t + 1 < feat.tags.size(); t += 2) {
if (feat.tags[t] >= layer.keys.size()) {
fprintf(stderr, "Error: out of bounds feature key (%u in %zu)\n", feat.tags[t], layer.keys.size());
exit(EXIT_FAILURE);
}
if (feat.tags[t + 1] >= layer.values.size()) {
fprintf(stderr, "Error: out of bounds feature value (%u in %zu)\n", feat.tags[t + 1], layer.values.size());
exit(EXIT_FAILURE);
}
const char *key = layer.keys[feat.tags[t]].c_str();
mvt_value const &val = layer.values[feat.tags[t + 1]];
if (val.type == mvt_string) {
state.json_write_string(key);
state.json_write_string(val.string_value);
} else if (val.type == mvt_int) {
state.json_write_string(key);
state.json_write_signed(val.numeric_value.int_value);
} else if (val.type == mvt_double) {
state.json_write_string(key);
state.json_write_number(val.numeric_value.double_value);
} else if (val.type == mvt_float) {
state.json_write_string(key);
state.json_write_number(val.numeric_value.float_value);
} else if (val.type == mvt_sint) {
state.json_write_string(key);
state.json_write_signed(val.numeric_value.sint_value);
} else if (val.type == mvt_uint) {
state.json_write_string(key);
state.json_write_unsigned(val.numeric_value.uint_value);
} else if (val.type == mvt_bool) {
state.json_write_string(key);
state.json_write_bool(val.numeric_value.bool_value);
} else if (val.type == mvt_null) {
state.json_write_string(key);
state.json_write_null();
} else {
fprintf(stderr, "Internal error: property with unknown type\n");
exit(EXIT_FAILURE);
}
}
state.json_end_hash();
state.json_write_string("geometry");
state.json_write_hash();
std::vector<lonlat> ops;
for (size_t g = 0; g < feat.geometry.size(); g++) {
int op = feat.geometry[g].op;
long long px = feat.geometry[g].x;
long long py = feat.geometry[g].y;
if (op == VT_MOVETO || op == VT_LINETO) {
long long scale = 1LL << (32 - z);
long long wx = scale * x + (scale / layer.extent) * px;
long long wy = scale * y + (scale / layer.extent) * py;
double lat, lon;
projection->unproject(wx, wy, 32, &lon, &lat);
ops.push_back(lonlat(op, lon, lat, px, py));
} else {
ops.push_back(lonlat(op, 0, 0, 0, 0));
}
}
if (feat.type == VT_POINT) {
if (ops.size() == 1) {
state.json_write_string("type");
state.json_write_string("Point");
state.json_write_string("coordinates");
state.json_write_array();
state.json_write_float(ops[0].lon);
state.json_write_float(ops[0].lat);
state.json_end_array();
} else {
state.json_write_string("type");
state.json_write_string("MultiPoint");
state.json_write_string("coordinates");
state.json_write_array();
for (size_t i = 0; i < ops.size(); i++) {
state.json_write_array();
state.json_write_float(ops[i].lon);
state.json_write_float(ops[i].lat);
state.json_end_array();
}
state.json_end_array();
}
} else if (feat.type == VT_LINE) {
int movetos = 0;
for (size_t i = 0; i < ops.size(); i++) {
if (ops[i].op == VT_MOVETO) {
movetos++;
}
}
if (movetos < 2) {
state.json_write_string("type");
state.json_write_string("LineString");
state.json_write_string("coordinates");
state.json_write_array();
for (size_t i = 0; i < ops.size(); i++) {
state.json_write_array();
state.json_write_float(ops[i].lon);
state.json_write_float(ops[i].lat);
state.json_end_array();
}
state.json_end_array();
} else {
state.json_write_string("type");
state.json_write_string("MultiLineString");
state.json_write_string("coordinates");
state.json_write_array();
state.json_write_array();
int sstate = 0;
for (size_t i = 0; i < ops.size(); i++) {
if (ops[i].op == VT_MOVETO) {
if (sstate == 0) {
state.json_write_array();
state.json_write_float(ops[i].lon);
state.json_write_float(ops[i].lat);
state.json_end_array();
sstate = 1;
} else {
state.json_end_array();
state.json_write_array();
state.json_write_array();
state.json_write_float(ops[i].lon);
state.json_write_float(ops[i].lat);
state.json_end_array();
sstate = 1;
}
} else {
state.json_write_array();
state.json_write_float(ops[i].lon);
state.json_write_float(ops[i].lat);
state.json_end_array();
}
}
state.json_end_array();
state.json_end_array();
}
} else if (feat.type == VT_POLYGON) {
std::vector<std::vector<lonlat> > rings;
std::vector<double> areas;
for (size_t i = 0; i < ops.size(); i++) {
if (ops[i].op == VT_MOVETO) {
rings.push_back(std::vector<lonlat>());
areas.push_back(0);
}
int n = rings.size() - 1;
if (n >= 0) {
if (ops[i].op == VT_CLOSEPATH) {
rings[n].push_back(rings[n][0]);
} else {
rings[n].push_back(ops[i]);
}
}
if (i + 1 >= ops.size() || ops[i + 1].op == VT_MOVETO) {
if (ops[i].op != VT_CLOSEPATH) {
static bool warned = false;
if (!warned) {
fprintf(stderr, "Ring does not end with closepath (ends with %d)\n", ops[i].op);
if (complain) {
exit(EXIT_FAILURE);
}
warned = true;
}
}
}
}
int outer = 0;
for (size_t i = 0; i < rings.size(); i++) {
long double area = 0;
for (size_t k = 0; k < rings[i].size(); k++) {
if (rings[i][k].op != VT_CLOSEPATH) {
area += (long double) rings[i][k].x * (long double) rings[i][(k + 1) % rings[i].size()].y;
area -= (long double) rings[i][k].y * (long double) rings[i][(k + 1) % rings[i].size()].x;
}
}
area /= 2;
areas[i] = area;
if (areas[i] >= 0 || i == 0) {
outer++;
}
// fprintf("\"area\": %Lf,", area);
}
if (outer > 1) {
state.json_write_string("type");
state.json_write_string("MultiPolygon");
state.json_write_string("coordinates");
state.json_write_array();
state.json_write_array();
state.json_write_array();
} else {
state.json_write_string("type");
state.json_write_string("Polygon");
state.json_write_string("coordinates");
state.json_write_array();
state.json_write_array();
}
int sstate = 0;
for (size_t i = 0; i < rings.size(); i++) {
if (i == 0 && areas[i] < 0) {
static bool warned = false;
if (!warned) {
fprintf(stderr, "Polygon begins with an inner ring\n");
if (complain) {
exit(EXIT_FAILURE);
}
warned = true;
}
}
if (areas[i] >= 0) {
if (sstate != 0) {
// new multipolygon
state.json_end_array();
state.json_end_array();
state.json_write_array();
state.json_write_array();
}
sstate = 1;
}
if (sstate == 2) {
// new ring in the same polygon
state.json_end_array();
state.json_write_array();
}
for (size_t j = 0; j < rings[i].size(); j++) {
if (rings[i][j].op != VT_CLOSEPATH) {
state.json_write_array();
state.json_write_float(rings[i][j].lon);
state.json_write_float(rings[i][j].lat);
state.json_end_array();
} else {
state.json_write_array();
state.json_write_float(rings[i][0].lon);
state.json_write_float(rings[i][0].lat);
state.json_end_array();
}
}
sstate = 2;
}
if (outer > 1) {
state.json_end_array();
state.json_end_array();
state.json_end_array();
} else {
state.json_end_array();
state.json_end_array();
}
}
state.json_end_hash();
state.json_end_hash();
if (comma) {
state.json_write_newline();
state.json_comma_newline();
}
}
}
void fprintq(FILE *fp, const char *s) {
fputc('"', fp);
for (; *s; s++) {
if (*s == '\\' || *s == '"') {
fprintf(fp, "\\%c", *s);
} else if (*s >= 0 && *s < ' ') {
fprintf(fp, "\\u%04x", *s);
} else {
fputc(*s, fp);
}
}
fputc('"', fp);
}