tools/zep_dispatch: topogen: allow to pass worldfile

A world file might look like

```
A	5	3	10
B	10
C	20	20
```

Author: benpicco

dist/tools/zep_dispatch/topogen.c

@@ -5,10 +5,12 @@
  * License v2. See the file LICENSE for more details.
  */
 
+#include <ctype.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <string.h>
 #include <time.h>
 #include <math.h>
 #include <unistd.h>
@@ -17,6 +19,9 @@
 #define CONFIG_USE_NUMERIC_NAMES 1
 #endif
 
+#define DEFAULT_RANGE 25
+#define DELIM "\t ;,"
+
 struct node {
     char name[8];
     int x;
@@ -230,6 +235,7 @@ static void _print_help(const char *name)
                     " [-r <range>]"
                     " [-v <variance of range>]"
                     " [-n <nodes>]"
+                    " [-f <file>]"
                     " [-b][-g]"
                     "\n", name);
 
@@ -240,25 +246,101 @@ static void _print_help(const char *name)
     puts("\t-r <range>\tRadio range of the nodes");
     puts("\t-v <variance>\tmaximal random variance of radio range");
     puts("\t-n <nodes>\tnumber of nodes in the topology");
+    puts("\t-f <file>\tread world from file instead of generating it randomly\n");
     puts("\t-b\t\tbinary links: link quality is rounded to 100% or 0%");
     puts("\t-g\t\tnodes are organized as a grid");
 }
 
+static bool _is_empty(const char *line)
+{
+    while (*line) {
+        if (!isspace(*line++)) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+static int _from_file(struct world *w, FILE *file)
+{
+    char *line = NULL;
+    size_t len = 0;
+
+    /* count number of nodes */
+    while (getline(&line, &len, file) >= 0) {
+        /* skip comments & empty lines */
+        if (*line == '#' || _is_empty(line)) {
+            continue;
+        }
+
+        w->num_nodes++;
+    }
+    fseek(file, 0, SEEK_SET);
+
+    w->nodes = calloc(w->num_nodes, sizeof(*w->nodes));
+    struct node *n = w->nodes;
+
+    unsigned linenum = 0;
+    while (getline(&line, &len, file) >= 0) {
+        ++linenum;
+
+        /* skip comments & empty lines */
+        if (*line == '#' || _is_empty(line)) {
+            continue;
+        }
+        char *name = strtok(line, DELIM);
+        char *xpos = strtok(NULL, DELIM);
+        char *ypos = strtok(NULL, DELIM);
+        char *range = strtok(NULL, DELIM);
+
+        strncpy(n->name, name, sizeof(n->name) - 1);
+        if (xpos) {
+            n->x = atoi(xpos);
+        } else {
+            fprintf(stderr, "error on line %d: '%s' has no position\n", linenum, name);
+            return -1;
+        }
+        if (ypos) {
+            n->y = atoi(ypos);
+        }
+        if (range) {
+            n->r = atoi(range);
+        } else {
+            n->r = DEFAULT_RANGE;
+        }
+
+        if (n->x + n->r > w->w) {
+            w->w = n->x + n->r;
+        }
+        if (n->y + n->r > w->h) {
+            w->h = n->y + n->r;
+        }
+
+        ++n;
+    }
+
+    free(line);
+
+    return 0;
+}
+
 int main(int argc, char** argv)
 {
     const char *progname = argv[0];
+    char *worldmap = NULL;
 
     unsigned width  = 100;
     unsigned height = 100;
     unsigned seed   = time(NULL);
-    unsigned range  = 25;
+    unsigned range  = DEFAULT_RANGE;
     unsigned var    = 0;
     unsigned num    = 10;
     bool binary     = false;
     bool grid       = false;
     char c;
 
-    while ((c = getopt(argc, argv, "s:w:h:r:v:n:bg")) != -1) {
+    while ((c = getopt(argc, argv, "s:w:h:r:v:n:f:bg")) != -1) {
         switch (c) {
         case 'b':
             binary = true;
@@ -284,6 +366,9 @@ int main(int argc, char** argv)
         case 'n':
             num = atoi(optarg);
             break;
+        case 'f':
+            worldmap = optarg;
+            break;
         default:
             _print_help(progname);
             exit(1);
@@ -295,7 +380,21 @@ int main(int argc, char** argv)
     struct world w = {
         .grid = grid,
     };
-    world_gen(&w, num, width, height, range, var);
+
+    if (worldmap) {
+        FILE *file = fopen(worldmap, "r");
+        if (!file) {
+            fprintf(stderr, "can't open %s\n", worldmap);
+            return -1;
+        }
+        int res = _from_file(&w, file);
+        fclose(file);
+        if (res) {
+            return res;
+        }
+    } else {
+        world_gen(&w, num, width, height, range, var);
+    }
 
     printf("# seed = %u\n", seed);
     puts("# Connections");