Accept multiple paths and distinguish between inner paths and the outer path.

- cameo/path.h, cameo/path.c (path_replace): replace a path in a list of
  paths with a different path
- cameo/path.h, cameo/path.c (path_find_leftmost): find the leftmost path
  in a list of paths
- cameo/path.h, cameo/path.c (path_free): move freeing of points to separate
  function free_points, for sharing with path_replace
- cameo/cameo.c (main): move path processing to new function process_paths
- cameo/cameo.c (process_paths): treat the leftmost path a outside path and
  process it last. Treat all others as inside paths.

cameo/cameo.c

@@ -13,12 +13,38 @@
 
 #include <stdlib.h>
 #include <stdio.h>
-#include <assert.h>
 
 #include "path.h"
 #include "gnuplot.h"
 
 
+
+static void process_path(struct path *path, int inside)
+{
+	int left;
+	struct path *new;
+
+	left = path_tool_is_left(path);
+	if (inside)
+		new = path_offset(path, !left, 0);
+	else
+		new = path_offset(path, left, 1);
+	path_replace(path, new);
+}
+
+
+static void process_paths(struct path *paths)
+{
+	struct path *leftmost, *path;
+
+	leftmost = path_find_leftmost(paths);
+	for (path = paths; path; path = path->next)
+		if (path != leftmost)
+			process_path(path, 1);
+	process_path(leftmost, 0);
+}
+
+
 static void usage(const char *name)
 {
 	fprintf(stderr, "usage: %s r_mm [in.gnuplot [out.gnuplot]]\n",
@@ -32,7 +58,6 @@ int main(int argc, char **argv)
 	char *in = NULL, *out = NULL;
 	double r;
 	struct path *paths;
-	int left;
 
 	switch (argc) {
 	case 4:
@@ -48,16 +73,9 @@ int main(int argc, char **argv)
 		usage(*argv);
 	}
 
-
-/*
- * To do:
- * - handle multiple paths
- */
 	paths = gnuplot_read(in, r);
-	assert(!paths->next); /* we don't handle this yet */
-//	paths = path_reverse(paths);
-	left = path_tool_is_left(paths);
-	paths = path_offset(paths, left, 1);
+	process_paths(paths);
 	gnuplot_write(out, paths);
+
 	return 0;
 }

cameo/path.c

@@ -20,6 +20,25 @@
 #include "path.h"
 
 
+static void free_points(struct point *points)
+{
+	struct point *next;
+
+	while (points) {
+		next = points->next;
+		free(points);
+		points = next;
+	}
+}
+
+
+void path_free(struct path *path)
+{
+	free_points(path->first);
+	free(path);
+}
+
+
 struct path *path_new(double r_tool)
 {
 	struct path *path;
@@ -77,6 +96,17 @@ void path_add(struct path *path, double x, double y, double z)
 }
 
 
+void path_replace(struct path *old, struct path *new)
+{
+	struct path *next = old->next;
+
+	free_points(old->first);
+	*old = *new;
+	old->next = next;
+	free(new);
+}
+
+
 struct path *path_reverse(const struct path *path)
 {
 	struct path *new;
@@ -265,14 +295,20 @@ struct path *path_offset(const struct path *path, int left, int notch)
 }
 
 
-void path_free(struct path *path)
+struct path *path_find_leftmost(struct path *path)
 {
-	struct point *next;
+	const struct point *p;
+	struct path *best = NULL;
+	double best_x = HUGE_VAL;
 
-	while (path->first) {
-		next = path->first->next;
-		free(path->first);
-		path->first = next;
+	while (path) {
+		for (p = path->first; p; p = p->next)
+			if (p->x < best_x) {
+				best = path;
+				best_x = p->x;
+				break;
+			}
+		path = path->next;
 	}
-	free(path);
+	return best;
 }

cameo/path.h

@@ -29,9 +29,11 @@ struct path {
 
 struct path *path_new(double r_tool);
 void path_add(struct path *path, double x, double y, double z);
+void path_replace(struct path *old, struct path *new);
 struct path *path_reverse(const struct path *path);
 int path_tool_is_left(const struct path *path);
 struct path *path_offset(const struct path *path, int left, int notch);
+struct path *path_find_leftmost(struct path *path);
 void path_free(struct path *path);
 
 #endif /* !PATH_H */