Switched to using temp buffer for processing string.

[sixel.git] / sixel.el

diff --git a/sixel.el b/sixel.el
index 6bcef4e..ae7a2aa 100644 (file)
--- a/sixel.el
+++ b/sixel.el
@@ -14,12 +14,6 @@
   "Retrieve data string."
   (substring string (1+ (string-match "q" string))))
 
-(defvar sixel-colour-map nil
-  "Map of two-character names to RGB colour triples.")
-
-(defvar sixel-current-colour nil
-  "Current colour.")
-
 (defun sixel-compute-row-length (string)
   (apply 'max
          (mapcar
@@ -30,63 +24,67 @@
                          (split-string substr "$"))))
           (split-string string -))))
 
-(defun sixel-tag-bits (n tag bit-count)
-  "Create a list of length BIT-COUNT with the elements corresponding to the
-true bits of N set to TAG."
-  (if (= bit-count 0)
-      nil
-    (cons (if (= (% n 2) 1)
-              tag
-            nil)
-          (sixel-tag-bits (/ n 2) tag (1- bit-count)))))
+(defun sixel-tag-bits (sixel n tag)
+  "Set bits of SIXEL corresponding to N with to the value TAG."
+  (dotimes (i 6)
+    (if (= (% n 2) 1)
+        (aset sixel i tag))
+    (setq n (/ n 2))))
 
-(defun sixel-make-sixel-from-char (char tag)
-  "Retrieve sequence of bits to be set."
-  (sixel-tag-bits (- char 63) tag 6))
+(defun sixel-tag-sixel-in-row (row-variable index char tag)
+  "Tag the bits of the sixel at INDEX in the list identified by
+the variable ROW-VARIABLE corresponding to input character CHAR
+with TAG."
+  (while (not (< index (length (symbol-value row-variable))))
+    (add-to-list row-variable (make-vector 6 nil)))
+  (let ((sixel (elt (symbol-value row-variable) index)))
+    (sixel-tag-bits sixel (- char 63) tag)))
 
-(defun sixel-union (sixel1 sixel2)
-  "Returns a union of the two sixels, SIXEL1 and SIXEL2.
-When both sixels specify a tag for the same pixel, the tag
-from SIXEL2 wins."
-  (seq-mapn (lambda (tag1 tag2)
-              (or tag2 tag1))
-            sixel1 sixel2))
-
-(defun sixel-process-row (string)
-  (let ((idx-in 0)
-        (idx-out 0)
-        result)
-    (while (< idx-in (length string))
-      (let (trunc-string (substring string index-in))
+(defun sixel-process-data (string)
+  "Convert sixel string into a list of lists representing individual sixels."
+  (with-temp-buffer
+    (insert string)
+    (goto-char (point-min))
+    (let ((idx-out 0)
+          this-row rows
+          current-colour colour-map
+          finished)
+      (while  (not finished)
         (cond
-         ((string-match "^#\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\)"
-                        trunc-string)
-          (let ((tag (intern (string-to (match-string 1 trunc-string))))
-                (mode (match-string 2 trunc-string))
-                (r (string-to-number (match-string 3 trunc-string)))
-                (g (string-to-number (match-string 4 trunc-string)))
-                (b (string-to-number (match-string 5 trunc-string))))
-            (add-to-list 'sixel-colour-map (list (tag r g b)))
-            (setq idx-in (match-end 0))))
-         ((string-match "^#\\([0-9]+\\)" trunc-string)
+         ((looking-at "#\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\)")
+          (let ((tag (intern (match-string 1)))
+                (mode (match-string 2))
+                (r (string-to-number (match-string 3)))
+                (g (string-to-number (match-string 4)))
+                (b (string-to-number (match-string 5))))
+            (push (list tag r g b) colour-map)))
+
+         ((looking-at "#\\([0-9]+\\)")
           (let ((tag (intern (match-string 1 trunc-string))))
-            (setq current-colour tag)
-            (setq idx-in (match-end 0))))
-         ((string-match "^!\\([0-9]+\\)\\([?-~]\\)" trunc-string)
-          (let ((repeat-count (string-to-number (match-string 1 trunc-string)))
+            (setq current-colour tag)))
+
+         ((looking-at "$")
+          (setq idx-out 0))
+
+         ((looking-at "^-")
+          (push this-row 'rows)
+          (setq this-row nil)
+          (setq idx-out 0))
+
+         ((looking-at "^!\\([0-9]+\\)\\([?-~]\\)")
+          (let ((repeat-count (string-to-number (match-string 1)))
                 (char (elt (match-string 2 trunc-string) 0)))
             (dotimes (i repeat-count)
-              (unless (< idx-out (length result))
-                (add-to-list result (make-vector 6 nil)))
-              (let ((sixel (elt result idx-out))))))))))))
-                
-              
+              (sixel-tag-sixel-in-row 'result idx-out char current-colour))))
+
+         ((looking-at "^\\([?-~]\\)")
+          (let ((char (elt (match-string 1 trunc-string) 0)))
+            (sixel-tag-sixel-in-row 'result idx-out char current-colour)))
 
-(sixel-get-rows test-string)
+         ((= (point) (point-max))
+          (setq finished t))
 
-(defun sixel-to-xpm (string)
-  "Converts the given sixel string into an XPM image."
+         (t (error "Invalid characters found in input string.")))
 
-  (let* ((sp (split-string string "q"))
-         (control-string (car sp))
-         ())))
+        (goto-char (match-end 0)))
+      (push this-row 'rows))))