api: add random integer number in evaluation of expressions with "random:min,max"

3 files changed, 82 insertions, 12 deletions

diff --git a/src/core/wee-command.c b/src/core/wee-command.c
index 80a1bb444..beacd126f 100644
--- a/src/core/wee-command.c
+++ b/src/core/wee-command.c
@@ -7586,10 +7586,11 @@ command_init ()
            "\"if:condition?value_if_true:value_if_false\")\n"
            "  17. result of an expression with parentheses and operators "
            "+ - * / // % ** (format: \"calc:xxx\")\n"
-           "  18. a translated string (format: \"translate:xxx\")\n"
-           "  19. an option (format: \"file.section.option\")\n"
-           "  20. a local variable in buffer\n"
-           "  21. a hdata name/variable (the value is automatically converted "
+           "  18. a random integer number (format: \"random:min,max\")\n"
+           "  19. a translated string (format: \"translate:xxx\")\n"
+           "  20. an option (format: \"file.section.option\")\n"
+           "  21. a local variable in buffer\n"
+           "  22. 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"
@@ -7631,6 +7632,7 @@ command_init ()
            "  /eval -n ${repeat:5,-}                         ==> -----\n"
            "  /eval -n ${length:test}                        ==> 4\n"
            "  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
+           "  /eval -n ${random:0,10}                        ==> 3\n"
            "  /eval -n ${base_encode:64,test}                ==> dGVzdA==\n"
            "  /eval -n ${base_decode:64,dGVzdA==}            ==> test\n"
            "  /eval -n ${translate:Plugin}                   ==> Extension\n"
diff --git a/src/core/wee-eval.c b/src/core/wee-eval.c
index a1020ce9e..397b951ce 100644
--- a/src/core/wee-eval.c
+++ b/src/core/wee-eval.c
@@ -726,13 +726,64 @@ eval_string_if (const char *text, struct t_eval_context *eval_context)
 }
 
 /*
+ * Returns a random integer number.
+ *
+ * Note: result must be freed after use.
+ */
+
+char *
+eval_string_random (const char *text)
+{
+    char *pos, *error, *tmp, result[128];
+    long min_number, max_number;
+
+    if (!text || !text[0])
+        goto error;
+
+    pos = strchr (text, ',');
+    if (!pos)
+        goto error;
+
+    tmp = strndup (text, pos - text);
+    if (!tmp)
+        goto error;
+    min_number = strtol (tmp, &error, 10);
+    if (!error || error[0])
+    {
+        free (tmp);
+        goto error;
+    }
+    free (tmp);
+
+    max_number = strtol (pos + 1, &error, 10);
+    if (!error || error[0])
+        goto error;
+
+    if (min_number > max_number)
+        goto error;
+    if (max_number - min_number > RAND_MAX)
+        goto error;
+
+    /*
+     * using modulo division on the random() value produces a biased result,
+     * but this is enough for our usage here
+     */
+    snprintf (result, sizeof (result),
+              "%ld", min_number + (random () % (max_number - min_number + 1)));
+    return strdup (result);
+
+error:
+    return strdup ("0");
+}
+
+/*
  * Translates text.
  *
  * Note: result must be freed after use.
  */
 
 char *
-eval_translate (const char *text)
+eval_string_translate (const char *text)
 {
     const char *ptr_string;
 
@@ -1053,11 +1104,13 @@ end:
  *  18. an environment variable (format: env:XXX)
  *  19. a ternary operator (format: if:condition?value_if_true:value_if_false)
  *  20. calculate result of an expression (format: calc:xxx)
- *  21. a translated string (format: translate:xxx)
- *  22. an option (format: file.section.option)
- *  23. a buffer local variable
- *  24. a pointer name from hashtable "pointers"
- *  25. a hdata variable (format: hdata.var1.var2 or hdata[list].var1.var2
+ *  21. a random integer number in the range from "min" to "max"
+ *      (format: random:min,max)
+ *  22. a translated string (format: translate:xxx)
+ *  23. an option (format: file.section.option)
+ *  24. a buffer local variable
+ *  25. a pointer name from hashtable "pointers"
+ *  26. a hdata variable (format: hdata.var1.var2 or hdata[list].var1.var2
  *                        or hdata[ptr].var1.var2 or hdata[ptr_name].var1.var2)
  *
  * See /help in WeeChat for examples.
@@ -1306,11 +1359,20 @@ eval_replace_vars_cb (void *data, const char *text)
     }
 
     /*
-     * 21. translated text
+     * 21. random number
+     */
+    if (strncmp (text, "random:", 7) == 0)
+    {
+        value = eval_string_random (text + 7);
+        goto end;
+    }
+
+    /*
+     * 22. translated text
      */
     if (strncmp (text, "translate:", 10) == 0)
     {
-        value = eval_translate (text + 10);
+        value = eval_string_translate (text + 10);
         goto end;
     }
 
diff --git a/src/core/weechat.c b/src/core/weechat.c
index cd83add1f..1900ca6e1 100644
--- a/src/core/weechat.c
+++ b/src/core/weechat.c
@@ -47,6 +47,7 @@
 #include <getopt.h>
 #include <sys/stat.h>
 #include <sys/time.h>
+#include <sys/types.h>
 #include <time.h>
 #include <signal.h>
 
@@ -610,6 +611,11 @@ weechat_init (int argc, char *argv[], void (*gui_init_cb)())
     weechat_first_start_time = time (NULL); /* initialize start time        */
     gettimeofday (&weechat_current_start_timeval, NULL);
 
+    /* set the seed for the pseudo-random integer generator */
+    srand ((weechat_current_start_timeval.tv_sec
+            * weechat_current_start_timeval.tv_usec)
+           ^ getpid ());
+
     signal_init ();                     /* initialize signals               */
     hdata_init ();                      /* initialize hdata                 */
     hook_init ();                       /* initialize hooks                 */