unexpand: fix incorrect expansion, add test for it

function                                             old     new   delta
expand_main                                          676     656     -20

diff --git a/coreutils/expand.c b/coreutils/expand.c
index 3ca7e5c29454470be070c405d650c7d3d4f6aa92..0967e253462ff99427fca305eb34f94a38d774c7 100644 (file)
--- a/coreutils/expand.c
+++ b/coreutils/expand.c
@@ -68,51 +68,39 @@ static void expand(FILE *file, int tab_size, unsigned opt)
 static void unexpand(FILE *file, unsigned tab_size, unsigned opt)
 {
        char *line;
-       char *ptr;
-       int convert;
-       int pos;
-       int i = 0;
-       unsigned column = 0;
 
        while ((line = xmalloc_fgets(file)) != NULL) {
-               convert = 1;
-               pos = 0;
-               ptr = line;
-               while (*line) {
-                       while ((*line == ' ' || *line == '\t') && convert) {
-                               pos += (*line == ' ') ? 1 : tab_size;
-                               line++;
+               char *ptr = line;
+               unsigned column = 0;
+
+               while (*ptr) {
+                       unsigned n;
+
+                       while (*ptr == ' ') {
                                column++;
-                               if ((opt & OPT_ALL) && column == tab_size) {
-                                       column = 0;
-                                       goto put_tab;
-                               }
+                               ptr++;
+                       }
+                       if (*ptr == '\t') {
+                               column += tab_size - (column % tab_size);
+                               ptr++;
+                               continue;
                        }
-                       if (pos) {
-                               i = pos / tab_size;
-                               if (i) {
-                                       for (; i > 0; i--) {
- put_tab:
-                                               bb_putchar('\t');
-                                       }
-                               } else {
-                                       for (i = pos % tab_size; i > 0; i--) {
-                                               bb_putchar(' ');
-                                       }
-                               }
-                               pos = 0;
-                       } else {
-                               if (opt & OPT_INITIAL) {
-                                       convert = 0;
-                               }
-                               if (opt & OPT_ALL) {
-                                       column++;
-                               }
-                               bb_putchar(*line);
-                               line++;
+
+                       n = column / tab_size;
+                       column = column % tab_size;
+                       while (n--)
+                               putchar('\t');
+
+                       if ((opt & OPT_INITIAL) && ptr != line) {
+                               printf("%*s%s", column, "", ptr);
+                               break;
                        }
+                       n = strcspn(ptr, "\t ");
+                       printf("%*s%.*s", column, "", n, ptr);
+                       ptr += n;
+                       column = (column + n) % tab_size;
                }
-               free(ptr);
+               free(line);
        }
 }
 #endif

diff --git a/testsuite/unexpand.tests b/testsuite/unexpand.tests
new file mode 100755 (executable)
index 0000000..e7f42c5
--- /dev/null
+++ b/testsuite/unexpand.tests
@@ -0,0 +1,30 @@
+#!/bin/sh
+# Copyright 2008 by Denys Vlasenko
+# Licensed under GPL v2, see file LICENSE for details.
+
+. testing.sh
+
+# testing "test name" "options" "expected result" "file input" "stdin"
+
+testing "unexpand case 1" "unexpand" \
+       "\t12345678\n" "" "        12345678\n" \
+
+testing "unexpand case 2" "unexpand" \
+       "\t 12345678\n" "" "         12345678\n" \
+
+testing "unexpand case 3" "unexpand" \
+       "\t  12345678\n" "" "          12345678\n" \
+
+testing "unexpand case 4" "unexpand" \
+       "\t12345678\n" "" "       \t12345678\n" \
+
+testing "unexpand case 5" "unexpand" \
+       "\t12345678\n" "" "      \t12345678\n" \
+
+testing "unexpand case 6" "unexpand" \
+       "\t12345678\n" "" "     \t12345678\n" \
+
+testing "unexpand case 7" "unexpand" \
+       "123\t 45678\n" "" "123 \t 45678\n" \
+
+exit $FAILCOUNT