From 4ec4c36e111254ebdfa8001f845003a99e81193e Mon Sep 17 00:00:00 2001
From: Peter Wu <lekensteyn@gmail.com>
Date: Sat, 7 Dec 2013 17:44:12 +0100
Subject: common-bytes: fix color termination

Previously, the colors were not cleared as an attempt to optimize
printing. New approach (requiring less LOC as well): print color if
it does not equal the current state (previous color).
---
 common-bytes.py | 39 +++++++++++++++++----------------------
 1 file changed, 17 insertions(+), 22 deletions(-)

diff --git a/common-bytes.py b/common-bytes.py
index 1210ec0..2376fb6 100755
--- a/common-bytes.py
+++ b/common-bytes.py
@@ -129,12 +129,19 @@ def mark_skippable(colormap, line_width):
 
     return skip_mask
 
+colors = {
+CELL_ALLSAME:       CLEAR_COLOR,
+CELL_COMMON:        "\033[0;32m", # green,
+CELL_COMMON_SHARED: "\033[0;33m", # yellow
+CELL_OUTLIER:       "\033[1;31m", # red
+}
+
 # Display input, coloring changes
 def display_changes(lines, line_width, colormap, skip_mask, enable_skip):
     skipping = False
     for lineno, line in enumerate(lines):
         line_out = ""
-        is_colored = False
+        prev_color = CLEAR_COLOR
         line_color = colormap[lineno]
         for col in range(0, line_width):
             # skip common cells?
@@ -144,37 +151,25 @@ def display_changes(lines, line_width, colormap, skip_mask, enable_skip):
                     continue
                 elif skip_mask[col] > 0:
                     # N columns can be skipped (N = skip_mask[col])
-                    line_out += "\033[1;30m..{}..".format(skip_mask[col])
-                    is_colored = True
+                    prev_color = "\033[1;30m"
+                    line_out += prev_color + "..{}..".format(skip_mask[col])
                     skipping = True
                     continue
                 else:
                     # end of skippable columns
                     skipping = False
 
-            # only change colors if not skipping
-            if skip_mask[col] != -1:
-                coloring = line_color[col]
-                if coloring == CELL_ALLSAME:
-                    if is_colored:
-                        line_out += CLEAR_COLOR
-                        is_colored = False
-                elif coloring == CELL_COMMON:
-                    line_out += "\033[0;32m" # green
-                    is_colored = True
-                elif coloring == CELL_COMMON_SHARED:
-                    line_out += "\033[0;33m" # yellow
-                    is_colored = True
-                elif coloring == CELL_OUTLIER:
-                    line_out += "\033[1;31m" # red
-                    is_colored = True
-                else:
-                    raise AssertionError("Invalid coloring state")
+            # apply coloring
+            coloring = line_color[col]
+            new_color = colors[coloring]
+            if prev_color != new_color:
+                line_out += new_color
+                prev_color = new_color
 
             line_out += line[col]
 
         # Any colors must be cleared at the end of the line
-        if is_colored:
+        if prev_color != CLEAR_COLOR:
             line_out += CLEAR_COLOR
 
         print(line_out)
-- 
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