expand: fix incorrect expansion exactly on tab boundary; shrink the code

function                                             old     new   delta
expand_main                                          698     676     -22
xputchar                                              53       -     -53

diff --git a/coreutils/expand.c b/coreutils/expand.c
index ee51c032fa4c8c03031976637a1dcdb3f2bdd3b3..3ca7e5c29454470be070c405d650c7d3d4f6aa92 100644 (file)
--- a/coreutils/expand.c
+++ b/coreutils/expand.c
@@ -29,51 +29,43 @@ enum {
        OPT_ALL         = 1 << 2,
 };
 
-static void xputchar(char c)
-{
-       if (putchar(c) < 0)
-               bb_error_msg_and_die(bb_msg_write_error);
-}
-
 #if ENABLE_EXPAND
-static void expand(FILE *file, unsigned tab_size, unsigned opt)
+static void expand(FILE *file, int tab_size, unsigned opt)
 {
        char *line;
-       char *ptr;
-       int convert;
-       unsigned pos;
 
-       /* Increment tab_size by 1 locally.*/
-       tab_size++;
+       tab_size = -tab_size;
 
        while ((line = xmalloc_fgets(file)) != NULL) {
-               convert = 1;
-               pos = 0;
-               ptr = line;
-               while (*line) {
-                       pos++;
-                       if (*line == '\t' && convert) {
-                               for (; pos < tab_size; pos++) {
-                                       xputchar(' ');
-                               }
-                       } else {
-                               if ((opt & OPT_INITIAL) && !isblank(*line)) {
-                                       convert = 0;
-                               }
-                               xputchar(*line);
+               int pos;
+               unsigned char c;
+               char *ptr = line;
+
+               goto start;
+               while ((c = *ptr) != '\0') {
+                       if ((opt & OPT_INITIAL) && !isblank(c)) {
+                               fputs(ptr, stdout);
+                               break;
                        }
-                       if (pos == tab_size) {
-                               pos = 0;
+                       ptr++;
+                       if (c == '\t') {
+                               c = ' ';
+                               while (++pos < 0)
+                                       bb_putchar(c);
+                       }
+                       bb_putchar(c);
+                       if (++pos >= 0) {
+ start:
+                               pos = tab_size;
                        }
-                       line++;
                }
-               free(ptr);
+               free(line);
        }
 }
 #endif
 
 #if ENABLE_UNEXPAND
-static void unexpand(FILE *file, unsigned int tab_size, unsigned opt)
+static void unexpand(FILE *file, unsigned tab_size, unsigned opt)
 {
        char *line;
        char *ptr;
@@ -101,11 +93,11 @@ static void unexpand(FILE *file, unsigned int tab_size, unsigned opt)
                                if (i) {
                                        for (; i > 0; i--) {
  put_tab:
-                                               xputchar('\t');
+                                               bb_putchar('\t');
                                        }
                                } else {
                                        for (i = pos % tab_size; i > 0; i--) {
-                                               xputchar(' ');
+                                               bb_putchar(' ');
                                        }
                                }
                                pos = 0;
@@ -116,7 +108,7 @@ static void unexpand(FILE *file, unsigned int tab_size, unsigned opt)
                                if (opt & OPT_ALL) {
                                        column++;
                                }
-                               xputchar(*line);
+                               bb_putchar(*line);
                                line++;
                        }
                }

diff --git a/testsuite/expand.tests b/testsuite/expand.tests
new file mode 100755 (executable)
index 0000000..3f4cda3
--- /dev/null
+++ b/testsuite/expand.tests
@@ -0,0 +1,15 @@
+#!/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 "expand" \
+       "expand" \
+       "        12345678        12345678\n" \
+       "" \
+       "\t12345678\t12345678\n" \
+
+exit $FAILCOUNT