Add more const

src/node.c

@@ -28,6 +28,7 @@ static int strndiff(char * d1, char * d2, unsigned int n) {
     return d1 - o;
 }
 
+/*
 static int strdiff(char * d1, char * d2) {
     char * o = d1;
     while( *d1 == *d2 ) {
@@ -36,6 +37,7 @@ static int strdiff(char * d1, char * d2) {
     }
     return d1 - o;
 }
+*/
 
 
 /**
@@ -530,7 +532,7 @@ edge * r3_node_find_common_prefix(node *n, const char *path, int path_len, int *
                 } else if ( p < slug->begin ) {
                     break;
                 } else if ( p >= slug->end && p < (path + path_len) ) {
-                    offset = slug->end + 1;
+                    offset = (char*) slug->end + 1;
                     prefix = p - path;
                     continue;
                 } else {

src/slug.c

@@ -91,7 +91,7 @@ int r3_slug_parse(r3_slug_t *s, const char *needle, int needle_len, char *offset
 
     int cnt = 0;
     int state = 0;
-    char * p = offset;
+    const char * p = offset;
 
     while( (p-needle) < needle_len) {
         // escape one character

src/slug.h

@@ -11,19 +11,19 @@ typedef struct {
     /**
      * source path
      */
-    char * path;
+    const char * path;
 
     int path_len;
 
     /**
      * slug start pointer
      */
-    char * begin;
+    const char * begin;
 
     /**
      * slug end pointer
      */
-    char * end;
+    const char * end;
 
     /**
      * slug length
@@ -31,7 +31,7 @@ typedef struct {
     int len;
 
     // slug pattern pointer if we have one
-    char * pattern;
+    const char * pattern;
 
     // the length of custom pattern, if the pattern is found.
     int    pattern_len;