From 46100c34dfd6c3bc71be9f131d94ea305cccf543 Mon Sep 17 00:00:00 2001
From: Eric Fischer <enf@pobox.com>
Date: Fri, 24 Oct 2014 17:22:14 -0700
Subject: [PATCH] Move projection and tile arithmetic to its own file

---
 Makefile     |  4 ++--
 decode.cc    | 12 ++++------
 enumerate.c  |  2 +-
 geojson.c    | 67 +--------------------------------------------------
 geometry.cc  |  1 +
 projection.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 projection.h |  4 ++++
 tile.cc      |  1 +
 tile.h       |  2 --
 9 files changed, 82 insertions(+), 79 deletions(-)
 create mode 100644 projection.c
 create mode 100644 projection.h

diff --git a/Makefile b/Makefile
index 11567adb..40c3a5d0 100644
--- a/Makefile
+++ b/Makefile
@@ -10,13 +10,13 @@ vector_tile.pb.cc vector_tile.pb.h: vector_tile.proto
 
 PG=
 
-tippecanoe: geojson.o jsonpull.o vector_tile.pb.o tile.o clip.o pool.o mbtiles.o geometry.o
+tippecanoe: geojson.o jsonpull.o vector_tile.pb.o tile.o clip.o pool.o mbtiles.o geometry.o projection.o
 	g++ $(PG) -O3 -g -Wall -o $@ $^ -lm -lz -lprotobuf-lite -lsqlite3
 
 enumerate: enumerate.o
 	gcc $(PG) -O3 -g -Wall -o $@ $^ -lsqlite3
 
-decode: decode.o vector_tile.pb.o
+decode: decode.o vector_tile.pb.o projection.o
 	g++ $(PG) -O3 -g -Wall -o $@ $^ -lm -lz -lprotobuf-lite -lsqlite3
 
 libjsonpull.a: jsonpull.o
diff --git a/decode.cc b/decode.cc
index 9d39b8f2..5fc539d7 100644
--- a/decode.cc
+++ b/decode.cc
@@ -7,6 +7,10 @@
 #include <math.h>
 #include "vector_tile.pb.h"
 
+extern "C" {
+	#include "projection.h"
+}
+
 // https://github.com/mapbox/mapnik-vector-tile/blob/master/src/vector_tile_compression.hpp
 inline bool is_compressed(std::string const& data) {
 	return data.size() > 2 && (uint8_t)data[0] == 0x78 && (uint8_t)data[1] == 0x9C;
@@ -44,14 +48,6 @@ int dezig(unsigned n) {
 	return (n >> 1) ^ (-(n & 1));
 }
 
-// http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
-void tile2latlon(unsigned int x, unsigned int y, int zoom, double *lat, double *lon) {
-        unsigned long long n = 1LL << zoom;
-        *lon = 360.0 * x / n - 180.0;
-        double lat_rad = atan(sinh(M_PI * (1 - 2.0 * y / n)));
-        *lat = lat_rad * 180 / M_PI;
-}
-
 void handle(std::string message, int z, unsigned x, unsigned y) {
 	GOOGLE_PROTOBUF_VERIFY_VERSION;
 
diff --git a/enumerate.c b/enumerate.c
index c2c319a4..6d4cfdfb 100644
--- a/enumerate.c
+++ b/enumerate.c
@@ -43,7 +43,7 @@ void usage(char **argv) {
 
 int main(int argc, char **argv) {
 	extern int optind;
-	extern char *optarg;
+	//extern char *optarg;
 	int i;
 
 	while ((i = getopt(argc, argv, "")) != -1) {
diff --git a/geojson.c b/geojson.c
index 0424f99f..1c094f82 100644
--- a/geojson.c
+++ b/geojson.c
@@ -17,6 +17,7 @@
 #include "tile.h"
 #include "pool.h"
 #include "mbtiles.h"
+#include "projection.h"
 
 int low_detail = 10;
 int full_detail = 12;
@@ -56,72 +57,6 @@ int mb_geometry[GEOM_TYPES] = {
 	VT_POLYGON,
 };
 
-// http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
-void latlon2tile(double lat, double lon, int zoom, unsigned int *x, unsigned int *y) {
-	double lat_rad = lat * M_PI / 180;
-	unsigned long long n = 1LL << zoom;
-
-	long long llx = n * ((lon + 180) / 360);
-	long long lly = n * (1 - (log(tan(lat_rad) + 1/cos(lat_rad)) / M_PI)) / 2;
-
-	if (lat >= 85.0511) {
-		lly = 0;
-	}
-	if (lat <= -85.0511) {
-		lly = n - 1;
-	}
-
-	if (llx < 0) {
-		llx = 0;
-	}
-	if (lly < 0) {
-		lly = 0;
-	}
-	if (llx >= n) {
-		llx = n - 1;
-	}
-	if (lly >= n) {
-		lly = n - 1;
-	}
-
-	*x = llx;
-	*y = lly;
-}
-
-// http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
-void tile2latlon(unsigned int x, unsigned int y, int zoom, double *lat, double *lon) {
-	unsigned long long n = 1LL << zoom;
-	*lon = 360.0 * x / n - 180.0;
-	float lat_rad = atan(sinh(M_PI * (1 - 2.0 * y / n)));
-	*lat = lat_rad * 180 / M_PI;
-}
-
-unsigned long long encode(unsigned int wx, unsigned int wy) {
-	long long out = 0;
-
-	int i;
-	for (i = 0; i < 32; i++) {
-		long long v = ((wx >> (32 - (i + 1))) & 1) << 1;
-		v |= (wy >> (32 - (i + 1))) & 1;
-		v = v << (64 - 2 * (i + 1));
-
-		out |= v;
-	}
-
-
-	return out;
-}
-
-void decode(unsigned long long index, unsigned *wx, unsigned *wy) {
-	*wx = *wy = 0;
-
-	int i;
-	for (i = 0; i < 32; i++) {
-		*wx |= ((index >> (64 - 2 * (i + 1) + 1)) & 1) << (32 - (i + 1));
-		*wy |= ((index >> (64 - 2 * (i + 1) + 0)) & 1) << (32 - (i + 1));
-	}
-}
-
 int indexcmp(const void *v1, const void *v2) {
 	const struct index *i1 = v1;
 	const struct index *i2 = v2;
diff --git a/geometry.cc b/geometry.cc
index 6e3818c8..a5405656 100644
--- a/geometry.cc
+++ b/geometry.cc
@@ -13,6 +13,7 @@
 extern "C" {
 	#include "tile.h"
 	#include "clip.h"
+	#include "projection.h"
 }
 
 drawvec decode_geometry(char **meta, int z, unsigned tx, unsigned ty, int detail) {
diff --git a/projection.c b/projection.c
new file mode 100644
index 00000000..a66a856d
--- /dev/null
+++ b/projection.c
@@ -0,0 +1,68 @@
+#include <math.h>
+#include "projection.h"
+
+// http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
+void latlon2tile(double lat, double lon, int zoom, unsigned int *x, unsigned int *y) {
+	double lat_rad = lat * M_PI / 180;
+	unsigned long long n = 1LL << zoom;
+
+	long long llx = n * ((lon + 180) / 360);
+	long long lly = n * (1 - (log(tan(lat_rad) + 1/cos(lat_rad)) / M_PI)) / 2;
+
+	if (lat >= 85.0511) {
+		lly = 0;
+	}
+	if (lat <= -85.0511) {
+		lly = n - 1;
+	}
+
+	if (llx < 0) {
+		llx = 0;
+	}
+	if (lly < 0) {
+		lly = 0;
+	}
+	if (llx >= n) {
+		llx = n - 1;
+	}
+	if (lly >= n) {
+		lly = n - 1;
+	}
+
+	*x = llx;
+	*y = lly;
+}
+
+// http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
+void tile2latlon(unsigned int x, unsigned int y, int zoom, double *lat, double *lon) {
+	unsigned long long n = 1LL << zoom;
+	*lon = 360.0 * x / n - 180.0;
+	float lat_rad = atan(sinh(M_PI * (1 - 2.0 * y / n)));
+	*lat = lat_rad * 180 / M_PI;
+}
+
+unsigned long long encode(unsigned int wx, unsigned int wy) {
+	long long out = 0;
+
+	int i;
+	for (i = 0; i < 32; i++) {
+		long long v = ((wx >> (32 - (i + 1))) & 1) << 1;
+		v |= (wy >> (32 - (i + 1))) & 1;
+		v = v << (64 - 2 * (i + 1));
+
+		out |= v;
+	}
+
+
+	return out;
+}
+
+void decode(unsigned long long index, unsigned *wx, unsigned *wy) {
+	*wx = *wy = 0;
+
+	int i;
+	for (i = 0; i < 32; i++) {
+		*wx |= ((index >> (64 - 2 * (i + 1) + 1)) & 1) << (32 - (i + 1));
+		*wy |= ((index >> (64 - 2 * (i + 1) + 0)) & 1) << (32 - (i + 1));
+	}
+}
diff --git a/projection.h b/projection.h
new file mode 100644
index 00000000..af7002ef
--- /dev/null
+++ b/projection.h
@@ -0,0 +1,4 @@
+void latlon2tile(double lat, double lon, int zoom, unsigned int *x, unsigned int *y);
+void tile2latlon(unsigned int x, unsigned int y, int zoom, double *lat, double *lon);
+unsigned long long encode(unsigned int wx, unsigned int wy);
+void decode(unsigned long long index, unsigned *wx, unsigned *wy);
diff --git a/tile.cc b/tile.cc
index 3f052544..a84622e7 100644
--- a/tile.cc
+++ b/tile.cc
@@ -19,6 +19,7 @@ extern "C" {
 	#include "pool.h"
 	#include "clip.h"
 	#include "mbtiles.h"
+	#include "projection.h"
 }
 
 #define CMD_BITS 3
diff --git a/tile.h b/tile.h
index c41c32d1..81903613 100644
--- a/tile.h
+++ b/tile.h
@@ -24,6 +24,4 @@ struct index {
         struct index *next;
 };
 
-unsigned long long encode(unsigned int wx, unsigned int wy);
-
 long long write_tile(struct index *start, struct index *end, char *metabase, unsigned *file_bbox, int z, unsigned x, unsigned y, int detail, int basezoom, struct pool *file_keys, char *layername, sqlite3 *outdb, double droprate);