core: add reverse of string in evaluation of expressions with "rev:" (closes #1200)

4 files changed, 75 insertions, 26 deletions

diff --git a/src/core/wee-command.c b/src/core/wee-command.c
index e02968bb2..ff7821ccc 100644
--- a/src/core/wee-command.c
+++ b/src/core/wee-command.c
@@ -7392,17 +7392,18 @@ command_init ()
            "     or max chars displayed on screen "
            "(format: \"cutscr:max,suffix,string\" or "
            "\"cutscr:+max,suffix,string\")\n"
-           "  5. a color (format: \"color:xxx\", see \"Plugin API "
+           "  5. a reversed string (format: \"rev:xxx\")\n"
+           "  6. a color (format: \"color:xxx\", see \"Plugin API "
            "reference\", function \"color\")\n"
-           "  6. an info (format: \"info:name,arguments\", arguments are "
+           "  7. an info (format: \"info:name,arguments\", arguments are "
            "optional)\n"
-           "  7. current date/time (format: \"date\" or \"date:format\")\n"
-           "  8. an environment variable (format: \"env:XXX\")\n"
-           "  9. a ternary operator (format: "
+           "  8. current date/time (format: \"date\" or \"date:format\")\n"
+           "  9. an environment variable (format: \"env:XXX\")\n"
+           "  10. a ternary operator (format: "
            "\"if:condition?value_if_true:value_if_false\")\n"
-           "  10. an option (format: \"file.section.option\")\n"
-           "  11. a local variable in buffer\n"
-           "  12. a hdata name/variable (the value is automatically converted "
+           "  11. an option (format: \"file.section.option\")\n"
+           "  12. a local variable in buffer\n"
+           "  13. a hdata name/variable (the value is automatically converted "
            "to string), by default \"window\" and \"buffer\" point to current "
            "window/buffer.\n"
            "Format for hdata can be one of following:\n"
diff --git a/src/core/wee-eval.c b/src/core/wee-eval.c
index 2cba33a22..149344975 100644
--- a/src/core/wee-eval.c
+++ b/src/core/wee-eval.c
@@ -293,15 +293,16 @@ end:
  *   5. a string with max chars (format: cut:max,suffix,string or
  *      cut:+max,suffix,string) or max chars on screen
  *      (format: cutscr:max,suffix,string or cutscr:+max,suffix,string)
- *   6. a regex group captured (format: re:N (0.99) or re:+)
- *   7. a color (format: color:xxx)
- *   8. an info (format: info:name,arguments)
- *   9. current date/time (format: date or date:xxx)
- *  10. an environment variable (format: env:XXX)
- *  11. a ternary operator (format: if:condition?value_if_true:value_if_false)
- *  12. an option (format: file.section.option)
- *  13. a buffer local variable
- *  14. a hdata variable (format: hdata.var1.var2 or hdata[list].var1.var2
+ *   6. a reversed string (format: rev:xxx)
+ *   7. a regex group captured (format: re:N (0.99) or re:+)
+ *   8. a color (format: color:xxx)
+ *   9. an info (format: info:name,arguments)
+ *  10. current date/time (format: date or date:xxx)
+ *  11. an environment variable (format: env:XXX)
+ *  12. a ternary operator (format: if:condition?value_if_true:value_if_false)
+ *  13. an option (format: file.section.option)
+ *  14. a buffer local variable
+ *  15. a hdata variable (format: hdata.var1.var2 or hdata[list].var1.var2
  *                        or hdata[ptr].var1.var2)
  *
  * See /help in WeeChat for examples.
@@ -448,7 +449,13 @@ eval_replace_vars_cb (void *data, const char *text)
         return value;
     }
 
-    /* 6. regex group captured */
+    /* 6. reverse string */
+    if (strncmp (text, "rev:", 4) == 0)
+    {
+        return string_reverse (text + 4);
+    }
+
+    /* 7. regex group captured */
     if (strncmp (text, "re:", 3) == 0)
     {
         if (eval_context->regex && eval_context->regex->result)
@@ -479,7 +486,7 @@ eval_replace_vars_cb (void *data, const char *text)
         return strdup ("");
     }
 
-    /* 7. color code */
+    /* 8. color code */
     if (strncmp (text, "color:", 6) == 0)
     {
         ptr_value = gui_color_search_config (text + 6);
@@ -489,7 +496,7 @@ eval_replace_vars_cb (void *data, const char *text)
         return strdup ((ptr_value) ? ptr_value : "");
     }
 
-    /* 8. info */
+    /* 9. info */
     if (strncmp (text, "info:", 5) == 0)
     {
         ptr_value = NULL;
@@ -509,7 +516,7 @@ eval_replace_vars_cb (void *data, const char *text)
         return strdup ((ptr_value) ? ptr_value : "");
     }
 
-    /* 9. current date/time */
+    /* 10. current date/time */
     if ((strncmp (text, "date", 4) == 0) && (!text[4] || (text[4] == ':')))
     {
         date = time (NULL);
@@ -522,7 +529,7 @@ eval_replace_vars_cb (void *data, const char *text)
         return strdup ((rc > 0) ? str_value : "");
     }
 
-    /* 10. environment variable */
+    /* 11. environment variable */
     if (strncmp (text, "env:", 4) == 0)
     {
         ptr_value = getenv (text + 4);
@@ -530,7 +537,7 @@ eval_replace_vars_cb (void *data, const char *text)
             return strdup (ptr_value);
     }
 
-    /* 11: ternary operator: if:condition?value_if_true:value_if_false */
+    /* 12: ternary operator: if:condition?value_if_true:value_if_false */
     if (strncmp (text, "if:", 3) == 0)
     {
         value = NULL;
@@ -594,7 +601,7 @@ eval_replace_vars_cb (void *data, const char *text)
         return (value) ? value : strdup ("");
     }
 
-    /* 12. option: if found, return this value */
+    /* 13. option: if found, return this value */
     if (strncmp (text, "sec.data.", 9) == 0)
     {
         ptr_value = hashtable_get (secure_hashtable_data, text + 9);
@@ -627,7 +634,7 @@ eval_replace_vars_cb (void *data, const char *text)
         }
     }
 
-    /* 13. local variable in buffer */
+    /* 14. local variable in buffer */
     ptr_buffer = hashtable_get (eval_context->pointers, "buffer");
     if (ptr_buffer)
     {
@@ -636,7 +643,7 @@ eval_replace_vars_cb (void *data, const char *text)
             return strdup (ptr_value);
     }
 
-    /* 14. hdata */
+    /* 15. hdata */
     value = NULL;
     hdata_name = NULL;
     list_name = NULL;
diff --git a/src/core/wee-string.c b/src/core/wee-string.c
index f1231bb6b..6a2939da9 100644
--- a/src/core/wee-string.c
+++ b/src/core/wee-string.c
@@ -163,6 +163,46 @@ string_cut (const char *string, int length, int count_suffix, int screen,
 }
 
 /*
+ * Reverses a string.
+ *
+ * Note: result must be freed after use.
+ */
+
+char *
+string_reverse (const char *string)
+{
+    int length, char_size;
+    const char *ptr_string;
+    char *result, *ptr_result;
+
+    if (!string)
+        return NULL;
+
+    if (!string[0])
+        return strdup (string);
+
+    length = strlen (string);
+    result = malloc (length + 1);
+    if (!result)
+        return NULL;
+
+    ptr_string = string;
+    ptr_result = result + length;
+    ptr_result[0] = '\0';
+
+    while (ptr_string && ptr_string[0])
+    {
+        char_size = utf8_char_size (ptr_string);
+
+        ptr_result -= char_size;
+        memcpy (ptr_result, ptr_string, char_size);
+        ptr_string += char_size;
+    }
+
+    return result;
+}
+
+/*
  * Converts string to lower case (locale independent).
  */
 
diff --git a/src/core/wee-string.h b/src/core/wee-string.h
index 9d7257e70..1679a33ad 100644
--- a/src/core/wee-string.h
+++ b/src/core/wee-string.h
@@ -39,6 +39,7 @@ struct t_hashtable;
 extern char *string_strndup (const char *string, int length);
 extern char *string_cut (const char *string, int length, int count_suffix,
                          int screen, const char *cut_suffix);
+extern char *string_reverse (const char *string);
 extern void string_tolower (char *string);
 extern void string_toupper (char *string);
 extern int string_strcasecmp (const char *string1, const char *string2);