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[elpa] master 87c8aaa 1/2: Improve performance of poker-hand-value by a

From: Mario Lang
Subject: [elpa] master 87c8aaa 1/2: Improve performance of poker-hand-value by a factor of 4
Date: Fri, 5 Aug 2016 00:05:26 +0000 (UTC)

branch: master
commit 87c8aaaf72326f0fd3c9fbb1a9dd6a050890ce3a
Author: Mario Lang <address@hidden>
Commit: Mario Lang <address@hidden>

    Improve performance of poker-hand-value by a factor of 4
    `cl-count' is unnecessarily expensive, as it at least uses `length' and 
    which we really don't need in this performance cricital code path.
    Rewriting it without `cl-count' turns up another opportunity to speed up,
    as we actually don't need to check the whole list to count occurances of
    unique elements.  For one, we can start counting from 1 (not 0) if
    we encounter the first element, and we only need to check the rest of the
    list of cards.  Also, stop using `mapcar' with `poker-card-rank'
    to allow it to actually be inlined.  This turns out to make poker-hand-value
    *a lot* faster. Mission accomplished.
 packages/poker/poker.el |   22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/packages/poker/poker.el b/packages/poker/poker.el
index 61888ae..d2896e7 100644
--- a/packages/poker/poker.el
+++ b/packages/poker/poker.el
@@ -93,15 +93,25 @@ RANK is one of `poker-ranks' and SUIT is one of 
 The result is a 24 bit integer where the leftmost 4 bits (0-8) indicate the 
 of hand, and the remaining nibbles are rank values of decisive cards.
 The highest possible value is therefore #x8CBA98 and the lowest is #x053210."
-  (let* ((ranks (mapcar #'poker-card-rank hand))
-        (rank-counts (sort (mapcar (lambda (rank) (cons (cl-count rank ranks) 
-                                   (cl-remove-duplicates ranks))
+  (let* ((rank-counts (sort (let ((cards hand) result)
+                             (while cards
+                               (let ((rank (poker-card-rank (car cards))))
+                                 (unless (rassq rank result)
+                                   (push (cons (let ((count 1))
+                                                 (dolist (card (cdr cards) 
+                                                   (when (eq (poker-card-rank 
+                                                             rank)
+                                                     (setq count (1+ count)))))
+                                               rank)
+                                         result)))
+                               (setq cards (cdr cards)))
+                             result)
                            (lambda (lhs rhs) (or (> (car lhs) (car rhs))
                                                  (and (= (car lhs) (car rhs))
                                                       (> (cdr lhs) (cdr 
-        (ranks-length (length rank-counts)))
-    (setq ranks (mapcar #'cdr rank-counts)
-         rank-counts (mapcar #'car rank-counts))
+        (ranks-length (length rank-counts))
+        (ranks (mapcar #'cdr rank-counts)))
+    (setq rank-counts (mapcar #'car rank-counts))
     (logior (cond
             ((eq ranks-length 4) #x100000)
             ((eq ranks-length 5)

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