2 files changed, 34 insertions, 0 deletions
diff --git a/src/ckutil.c b/src/ckutil.c
index 79d7fd3..5f8da98 100644
--- a/src/ckutil.c
+++ b/src/ckutil.c
@@ -143,6 +143,38 @@ int str_is_empty(const char *s) {
   return 1;
 }
 
+int swap_tilde_and_home(char *ret, const char *s) {
+  if (!ret || !s) {
+    return -1;
+  }
+  char *home = getenv("HOME");
+  if (!home) {
+    return -1;
+  }
+  ulong i;
+  ulong homelen = strlen(home);
+
+  if (s[0] == '~') {
+    strcpy(ret, home);
+    for (i = 1; i < strlen(s); i++) {
+      ret[homelen - 1 + i] = s[i];
+    }
+    return 0;
+  }
+
+  for (i = 0; i < strlen(home); i++) {
+    if (s[i] != home[i]) {
+      return -1;
+    }
+  }
+  /* s starts with $HOME */
+  strcpy(ret, "~");
+  for (i = homelen; i < strlen(s); i++) {
+    ret[i + 1 - homelen] = s[i];
+  }
+  return 0;
+}
+
 int util_own_grp_copy(const char *dest, const char *original) {
   if (!dest || !original) {
     return -1;
diff --git a/src/ckutil.h b/src/ckutil.h
index 8ca9ca1..72216ef 100644
--- a/src/ckutil.h
+++ b/src/ckutil.h
@@ -59,6 +59,8 @@ extern void str_join_dirname_with_basename(char *ret, const char *path,
  * else returns 0. */
 extern int str_is_empty(const char *s);
 
+extern int swap_tilde_and_home(char *ret, const char *s);
+
 /*********************/
 /* utility functions */
 /*********************/