Factor RDP algorithm out into its own file(s)

Author: derickr

config.m4

@@ -5,5 +5,5 @@ PHP_ARG_ENABLE(geospatial, whether to enable geospatial support,
 [  --enable-geospatial           Enable geospatial support])
 
 if test "$PHP_GEOSPATIAL" != "no"; then
-  PHP_NEW_EXTENSION(geospatial, geospatial.c geo_array.c geohash.c, $ext_shared)
+  PHP_NEW_EXTENSION(geospatial, geospatial.c geo_array.c geohash.c rdp.c, $ext_shared)
 fi

geospatial.c

@@ -34,6 +34,7 @@
 #include "geo_array.h"
 #include "geo_lat_long.h"
 #include "geohash.h"
+#include "rdp.h"
 #include "Zend/zend_exceptions.h"
 #include "ext/spl/spl_exceptions.h"
 
@@ -804,60 +805,6 @@ int geojson_linestring_to_array(zval *line, geo_array **array)
 	return 0;
 }
 
-double rdp_find_perpendicular_distable(double pX, double pY, double p1X, double p1Y, double p2X, double p2Y)
-{
-	double slope, intercept, result;
-
-	if (p1X == p2X) {
-		return fabs(pX - p1X);
-	} else {
-		slope = (p2Y - p1Y) / (p2X - p1X);
-		intercept = p1Y - (slope * p1X);
-		result = fabs(slope * pX - pY + intercept) / sqrt(pow(slope, 2) + 1);
-		return result;
-	}
-}
-
-void rdp_simplify(geo_array *points, double epsilon, int start, int end)
-{
-	double firstX = points->x[start];
-	double firstY = points->y[start];
-	double lastX = points->x[end];
-	double lastY = points->y[end];
-	int    index = -1;
-	double dist  = 0.0, current_dist;
-	int    i;
-
-	if (end - start < 2) {
-		return;
-	}
-
-	for (i = start + 1; i < end; i++) {
-		if (!points->status[i]) {
-			continue;
-		}
-
-		current_dist = rdp_find_perpendicular_distable(points->x[i], points->y[i], firstX, firstY, lastX, lastY);
-
-		if (current_dist > dist) {
-			dist = current_dist;
-			index = i;
-		}
-	}
-
-	if (dist > epsilon) {
-		rdp_simplify(points, epsilon, start, index);
-		rdp_simplify(points, epsilon, index, end);
-
-		return;
-	} else {
-		for (i = start + 1; i < end; i++) {
-			points->status[i] = 0;
-		}
-		return;
-	}
-}
-
 /* {{{ proto array rdp_simplify(array points, float epsilon)
    Simplifies a 2D dimensional line according to the Ramer-Douglas-Peucker algorithm */
 PHP_FUNCTION(rdp_simplify)

package.xml

@@ -52,9 +52,11 @@
    <file name="geohash.h" role="src" />
    <file name="php_geospatial_arginfo.h" role="src" />
    <file name="php_geospatial.h" role="src" />
+   <file name="rdp.h" role="src" />
    <file name="geo_array.c" role="src" />
    <file name="geohash.c" role="src" />
    <file name="geospatial.c" role="src" />
+   <file name="rdp.c" role="src" />
   </dir> <!-- / -->
  </contents>
  <dependencies>

rdp.c

@@ -0,0 +1,75 @@
+/*
+  +----------------------------------------------------------------------+
+  | PHP                                                                  |
+  +----------------------------------------------------------------------+
+  | Copyright (c) 1997-2024 The PHP Group                                |
+  +----------------------------------------------------------------------+
+  | This source file is subject to version 3.01 of the PHP license,      |
+  | that is bundled with this package in the file LICENSE, and is        |
+  | available through the world-wide-web at the following url:           |
+  | http://www.php.net/license/3_01.txt                                  |
+  | If you did not receive a copy of the PHP license and are unable to   |
+  | obtain it through the world-wide-web, please send a note to          |
+  | license@php.net so we can mail you a copy immediately.               |
+  +----------------------------------------------------------------------+
+  | Authors: Derick Rethans <github@derickrethans.nl>                    |
+  +----------------------------------------------------------------------+
+*/
+#include <math.h>
+
+#include "geo_array.h"
+
+static double rdp_find_perpendicular_distable(double pX, double pY, double p1X, double p1Y, double p2X, double p2Y)
+{
+	double slope, intercept, result;
+
+	if (p1X == p2X) {
+		return fabs(pX - p1X);
+	} else {
+		slope = (p2Y - p1Y) / (p2X - p1X);
+		intercept = p1Y - (slope * p1X);
+		result = fabs(slope * pX - pY + intercept) / sqrt(pow(slope, 2) + 1);
+		return result;
+	}
+}
+
+void rdp_simplify(geo_array *points, double epsilon, int start, int end)
+{
+	double firstX = points->x[start];
+	double firstY = points->y[start];
+	double lastX = points->x[end];
+	double lastY = points->y[end];
+	int    index = -1;
+	double dist  = 0.0, current_dist;
+	int    i;
+
+	if (end - start < 2) {
+		return;
+	}
+
+	for (i = start + 1; i < end; i++) {
+		if (!points->status[i]) {
+			continue;
+		}
+
+		current_dist = rdp_find_perpendicular_distable(points->x[i], points->y[i], firstX, firstY, lastX, lastY);
+
+		if (current_dist > dist) {
+			dist = current_dist;
+			index = i;
+		}
+	}
+
+	if (dist > epsilon) {
+		rdp_simplify(points, epsilon, start, index);
+		rdp_simplify(points, epsilon, index, end);
+
+		return;
+	} else {
+		for (i = start + 1; i < end; i++) {
+			points->status[i] = 0;
+		}
+		return;
+	}
+}
+

rdp.h

@@ -0,0 +1,21 @@
+/*
+  +----------------------------------------------------------------------+
+  | PHP                                                                  |
+  +----------------------------------------------------------------------+
+  | Copyright (c) 1997-2024 The PHP Group                                |
+  +----------------------------------------------------------------------+
+  | This source file is subject to version 3.01 of the PHP license,      |
+  | that is bundled with this package in the file LICENSE, and is        |
+  | available through the world-wide-web at the following url:           |
+  | http://www.php.net/license/3_01.txt                                  |
+  | If you did not receive a copy of the PHP license and are unable to   |
+  | obtain it through the world-wide-web, please send a note to          |
+  | license@php.net so we can mail you a copy immediately.               |
+  +----------------------------------------------------------------------+
+  | Authors: Derick Rethans <github@derickrethans.nl>                    |
+  +----------------------------------------------------------------------+
+*/
+#include "geo_array.h"
+
+void rdp_simplify(geo_array *points, double epsilon, int start, int end);
+