Allow "/h <category> <length>" for histograms of words of a particular length

diff --git a/mnemon.c b/mnemon.c
index 446d449b736d1bb2a1743688aa7bc6d86d19a4dc..71234649e54c6048b39cb1c89554941f3e3cfeff 100644 (file)
--- a/mnemon.c
+++ b/mnemon.c
@@ -115,7 +115,21 @@ xstrdup (const char *s)
     char *ret;
 
     ret = strdup (s);
-    if (s == NULL) {
+    if (ret == NULL) {
+       fprintf (stderr, "Error: out of memory\n");
+       exit (1);
+    }
+
+    return ret;
+}
+
+static char *
+xstrndup (const char *s, size_t n)
+{
+    char *ret;
+
+    ret = strndup (s, n);
+    if (ret == NULL) {
        fprintf (stderr, "Error: out of memory\n");
        exit (1);
     }
@@ -797,6 +811,27 @@ mnemon_item_in_category (void *closure, item_t *item)
     return (mnemon_item_category (mnemon, item) == category);
 }
 
+typedef struct _item_in_category_of_length_closure
+{
+    mnemon_t *mnemon;
+    category_t *category;
+    int length;
+} item_in_category_of_length_closure_t;
+
+static int
+mnemon_item_in_category_of_length (void *closure, item_t *item)
+{
+    item_in_category_of_length_closure_t *iicolc = closure;
+    mnemon_t *mnemon = iicolc->mnemon;
+    category_t *category = iicolc->category;
+    int length = iicolc->length;
+
+    if (mnemon_item_category (mnemon, item) != category)
+       return 0;
+
+    return strlen (item->challenge) == length;
+}
+
 static void
 mnemon_select_item (mnemon_t    *mnemon,
                    bin_t       **bin_ret,
@@ -873,7 +908,8 @@ print_histogram_bar (double size,
 
 static void
 mnemon_print_histogram (mnemon_t    *mnemon,
-                       const char  *category_name)
+                       const char  *category_name,
+                       int          length)
 {
     int i, last_score, max;
     category_t *category = NULL;
@@ -882,6 +918,7 @@ mnemon_print_histogram (mnemon_t    *mnemon,
     item_match_predicate_t *predicate = NULL;
     void *closure = NULL;
     item_in_category_closure_t item_in_category;
+    item_in_category_of_length_closure_t item_in_category_of_length;
 
     if (mnemon->num_bins == 0)
        return;
@@ -889,10 +926,18 @@ mnemon_print_histogram (mnemon_t    *mnemon,
     if (category_name) {
        category = mnemon_get_category_if_exists (mnemon, category_name);
        if (category) {
-           predicate = mnemon_item_in_category;
-           item_in_category.mnemon = mnemon;
-           item_in_category.category = category;
-           closure = &item_in_category;
+           if (length) {
+               predicate = mnemon_item_in_category_of_length;
+               item_in_category_of_length.mnemon = mnemon;
+               item_in_category_of_length.category = category;
+               item_in_category_of_length.length = length;
+               closure = &item_in_category_of_length;
+           } else {
+               predicate = mnemon_item_in_category;
+               item_in_category.mnemon = mnemon;
+               item_in_category.category = category;
+               closure = &item_in_category;
+           }
        }
     }
 
@@ -921,15 +966,26 @@ mnemon_handle_command (mnemon_t           *mnemon,
                       const char       *command)
 {
     const char *arg;
+    int len;
     switch (command[0]) {
        case 'h':
+       {
+           char *category = NULL;
+           int length = 0;
+
            arg = command + 1;
-           while (*arg && isspace (*arg))
-               arg++;
-           if (*arg == '\0')
-               arg = NULL;
-           mnemon_print_histogram (mnemon, arg);
-           break;
+           arg += strspn (arg, " \t");
+           len = strcspn (arg, " \t");
+           if (len) {
+               category = xstrndup (arg, len);
+               arg += len;
+               arg += strspn (arg, " \t");
+               if (*arg)
+                   length = atoi (arg);
+           }
+           mnemon_print_histogram (mnemon, category, length);
+       }
+       break;
         default:
            printf ("Unknown command: %s\n", command);
            break;