table-select: Only cut headers into two if needed in table_select_slice().

Until now, when including headers in the table it returns,
table_select_slice() has always either returned the entire original table
or a set of chunks: left header, selected body, right header.  However, it
is possible to do better when the selected body includes all the cells
up to, say, the right header: then you only need a single chunk to include
the body and the right header.  Besides saving memory, this also has the
advantage that, if a joined cell crosses between the body and the header,
it is not cut into two pieces by chunking.  It doesn't make too much sense
to join a cell across body and header, but this still makes it easier to
render better if someone does that.

The testsuite includes a few tables that do join a cell across body and
header.  This commit improves the output for one and changes some ugly
output to different ugly output for another.  Additional changes in an
upcoming commit fix the latter and some other tables too.

diff --git a/src/output/table-select.c b/src/output/table-select.c
index 00d0ee99318434ff1d357577105e0199541fadc9..5bbc8caa1eb948bec775c2d27ff652696356487f 100644 (file)
--- a/src/output/table-select.c
+++ b/src/output/table-select.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc.
+   Copyright (C) 2009, 2010, 2011, 2014 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -94,24 +94,30 @@ table_select_slice (struct table *subtable, enum table_axis axis,
 {
   struct table *table;
   int rect[TABLE_N_AXES][2];
+  bool h0, h1;
 
-  if (add_headers)
+  h0 = add_headers && subtable->h[axis][0] > 0;
+  if (h0 && z0 == subtable->h[axis][0])
     {
-      if (z0 == subtable->h[axis][0]
-          && z1 == subtable->n[axis] - subtable->h[axis][1])
-        return subtable;
-
-      if (subtable->h[axis][0])
-        table_ref (subtable);
-      if (subtable->h[axis][1])
-        table_ref (subtable);
+      z0 = 0;
+      h0 = false;
     }
-  else
+
+  h1 = add_headers && subtable->h[axis][1] > 0;
+  if (h1 && z1 == subtable->n[axis] - subtable->h[axis][1])
     {
-      if (z0 == 0 && z1 == subtable->n[axis])
-        return subtable;
+      z1 = subtable->n[axis];
+      h1 = false;
     }
 
+  if (z0 == 0 && z1 == subtable->n[axis])
+    return subtable;
+
+  if (h0)
+    table_ref (subtable);
+  if (h1)
+    table_ref (subtable);
+
   rect[TABLE_HORZ][0] = 0;
   rect[TABLE_VERT][0] = 0;
   rect[TABLE_HORZ][1] = subtable->n[TABLE_HORZ];
@@ -120,22 +126,18 @@ table_select_slice (struct table *subtable, enum table_axis axis,
   rect[axis][1] = z1;
   table = table_select (subtable, rect);
 
-  if (add_headers)
-    {
-      if (subtable->h[axis][0])
-        table = table_paste (
-          table_select_slice (subtable, axis, 0, subtable->h[axis][0],
-                              false),
-          table, axis);
-
-      if (subtable->h[axis][1])
-        table = table_paste (
-          table,
-          table_select_slice (subtable, axis,
-                              subtable->n[axis] - subtable->h[axis][1],
-                              subtable->n[axis], false),
-          axis);
-    }
+  if (h0)
+    table = table_paste (
+      table_select_slice (subtable, axis, 0, subtable->h[axis][0], false),
+      table, axis);
+
+  if (h1)
+    table = table_paste (
+      table,
+      table_select_slice (subtable, axis,
+                          subtable->n[axis] - subtable->h[axis][1],
+                          subtable->n[axis], false),
+      axis);
 
   return table;
 }

diff --git a/tests/output/render.at b/tests/output/render.at
index 721c2cd481da2699d0160e74528c243c7d65753a..4bc14d809bb4c3bd86e40b6d9199633b31039fe9 100644 (file)
--- a/tests/output/render.at
+++ b/tests/output/render.at
@@ -743,7 +743,7 @@ AT_CHECK([render-test --width=10 input], [0], [dnl
 +-+u+-+-+
 |A|v|B|E|
 +-+-+C+-+
-|K K|D|L|
+|IJK|D|L|
 +-+-+-+M|
 |Q|RST|N|
 +-+---+-+
@@ -789,7 +789,7 @@ op|h|q|
 +-+-+r|
 |xyz|s|
 +-+-+-+
-|E|F H|
+|E|  F|
 +-+-+-+
 |L|O|P|
 |M+-+-+