Revamp to resemble the new unexpand.c better.

(usage): -i does not convert tabs after non-tabs.
(add_tab_stop): Renamed from add_tabstop.  All uses changed.
(parse_tab_stop): Renamed from parse_tabstop.  All uses changed.
(validate_tab_stop): Renamed from validate_tabstop.  All uses changed.
(next_file, main): Check fclose against 0, not EOF.
(expand): Remove unnecessary casts.
Add another loop nesting level, for lines, so that per-line variables
are initialized cleanly.
Revamp tab checking.  Check for write error immediately, rather
than just once at the end of the program.

diff --git a/src/expand.c b/src/expand.c
index 29e333e..7b4db1a 100644 (file)
--- a/src/expand.c
+++ b/src/expand.c
@@ -24,9 +24,9 @@
    --tabs=tab1[,tab2[,...]]
    -t tab1[,tab2[,...]]
    -tab1[,tab2[,...]]  If only one tab stop is given, set the tabs tab1
-                       spaces apart instead of the default 8.  Otherwise,
+                       columns apart instead of the default 8.  Otherwise,
                        set the tabs at columns tab1, tab2, etc. (numbered from
-                       0); replace any tabs beyond the tabstops given with
+                       0); replace any tabs beyond the tab stops given with
                        single spaces.
    --initial
    -i                  Only convert initial tabs on each line to spaces.
@@ -120,7 +120,7 @@ With no FILE, or when FILE is -, read standard input.\n\
 Mandatory arguments to long options are mandatory for short options too.\n\
 "), stdout);
       fputs (_("\
-  -i, --initial       do not convert TABs after non whitespace\n\
+  -i, --initial       do not convert tabs after non blanks\n\
   -t, --tabs=NUMBER   have tabs NUMBER characters apart, not 8\n\
 "), stdout);
       fputs (_("\
@@ -136,18 +136,18 @@ Mandatory arguments to long options are mandatory for short options too.\n\
 /* Add tab stop TABVAL to the end of `tab_list'.  */
 
 static void
-add_tabstop (uintmax_t tabval)
+add_tab_stop (uintmax_t tabval)
 {
   if (first_free_tab == n_tabs_allocated)
     tab_list = x2nrealloc (tab_list, &n_tabs_allocated, sizeof *tab_list);
   tab_list[first_free_tab++] = tabval;
 }
 
-/* Add the comma or blank separated list of tabstops STOPS
-   to the list of tabstops.  */
+/* Add the comma or blank separated list of tab stops STOPS
+   to the list of tab stops.  */
 
 static void
-parse_tabstops (char const *stops)
+parse_tab_stops (char const *stops)
 {
   bool have_tabval = false;
   uintmax_t tabval IF_LINT (= 0);
@@ -159,7 +159,7 @@ parse_tabstops (char const *stops)
       if (*stops == ',' || ISBLANK (to_uchar (*stops)))
        {
          if (have_tabval)
-           add_tabstop (tabval);
+           add_tab_stop (tabval);
          have_tabval = false;
        }
       else if (ISDIGIT (*stops))
@@ -198,14 +198,14 @@ parse_tabstops (char const *stops)
     exit (EXIT_FAILURE);
 
   if (have_tabval)
-    add_tabstop (tabval);
+    add_tab_stop (tabval);
 }
 
-/* Check that the list of tabstops TABS, with ENTRIES entries,
+/* Check that the list of tab stops TABS, with ENTRIES entries,
    contains only nonzero, ascending values.  */
 
 static void
-validate_tabstops (uintmax_t const *tabs, size_t entries)
+validate_tab_stops (uintmax_t const *tabs, size_t entries)
 {
   uintmax_t prev_tab = 0;
   size_t i;
@@ -240,7 +240,7 @@ next_file (FILE *fp)
        }
       if (fp == stdin)
        clearerr (fp);          /* Also clear EOF.  */
-      else if (fclose (fp) == EOF)
+      else if (fclose (fp) != 0)
        {
          error (0, errno, "%s", prev_file);
          exit_status = EXIT_FAILURE;
@@ -273,14 +273,10 @@ next_file (FILE *fp)
 static void
 expand (void)
 {
-  FILE *fp;                    /* Input stream.  */
-  size_t tab_index = 0;                /* Index in `tab_list' of next tabstop.  */
-  uintmax_t column = 0;                /* Column of next char.  */
-  uintmax_t next_tab_column;   /* Column the next tab stop is on.  */
-  bool convert = true;         /* If true, perform translations.  */
-
-  fp = next_file ((FILE *) NULL);
-  if (fp == NULL)
+  /* Input stream.  */
+  FILE *fp = next_file (NULL);
+
+  if (!fp)
     return;
 
   /* Binary I/O will preserve the original EOL style (DOS/Unix) of files.  */
@@ -288,74 +284,89 @@ expand (void)
 
   for (;;)
     {
-      int c = getc (fp);
-      if (c == EOF)
-       {
-         fp = next_file (fp);
-         if (fp)
-           {
-             SET_BINARY2 (fileno (fp), STDOUT_FILENO);
-             continue;
-           }
-         break;
-       }
+      /* Input character, or EOF.  */
+      int c;
 
-      if (c == '\n')
-       {
-         putchar (c);
-         tab_index = 0;
-         column = 0;
-         convert = true;
-       }
-      else if (c == '\t' && convert)
-       {
-         if (tab_size == 0)
-           {
-             /* Do not let tab_index == first_free_tab;
-                stop when it is 1 less.  */
-             while (tab_index < first_free_tab - 1
-                    && column >= tab_list[tab_index])
-               tab_index++;
-             next_tab_column = tab_list[tab_index];
-             if (tab_index < first_free_tab - 1)
-               tab_index++;
-             if (column >= next_tab_column)
-               next_tab_column = column + 1; /* Ran out of tab stops.  */
-           }
-         else
-           {
-             next_tab_column = column + tab_size - column % tab_size;
-           }
-         if (next_tab_column < column)
-           error (EXIT_FAILURE, 0, _("input line is too long"));
-         while (column < next_tab_column)
-           {
-             putchar (' ');
-             ++column;
-           }
-       }
-      else
+      /* If true, perform translations.  */
+      bool convert = true;
+
+
+      /* The following variables have valid values only when CONVERT
+        is true:  */
+
+      /* Column of next input character.  */
+      uintmax_t column = 0;
+
+      /* Index in TAB_LIST of next tab stop to examine.  */
+      size_t tab_index = 0;
+
+
+      /* Convert a line of text.  */
+
+      do
        {
+         while ((c = getc (fp)) < 0 && (fp = next_file (fp)))
+           SET_BINARY2 (fileno (fp), STDOUT_FILENO);
+
          if (convert)
            {
-             if (c == '\b')
+             if (c == '\t')
+               {
+                 /* Column the next input tab stop is on.  */
+                 uintmax_t next_tab_column;
+
+                 if (tab_size)
+                   next_tab_column = column + (tab_size - column % tab_size);
+                 else
+                   for (;;)
+                     if (tab_index == first_free_tab)
+                       {
+                         next_tab_column = column + 1;
+                         break;
+                       }
+                     else
+                       {
+                         uintmax_t tab = tab_list[tab_index++];
+                         if (column < tab)
+                           {
+                             next_tab_column = tab;
+                             break;
+                           }
+                       }
+
+                 if (next_tab_column < column)
+                   error (EXIT_FAILURE, 0, _("input line is too long"));
+
+                 while (++column < next_tab_column)
+                   if (putchar (' ') < 0)
+                     error (EXIT_FAILURE, errno, _("write error"));
+                     
+                 c = ' ';
+               }
+             else if (c == '\b')
                {
-                 if (column > 0)
-                   {
-                     column--;
-                     tab_index -= (tab_index != 0);
-                   }
+                 /* Go back one column, and force recalculation of the
+                    next tab stop.  */
+                 column -= !!column;
+                 tab_index -= !!tab_index;
                }
              else
                {
-                 ++column;
-                 if (column == 0)
+                 column++;
+                 if (!column)
                    error (EXIT_FAILURE, 0, _("input line is too long"));
-                 convert &= convert_entire_line;
                }
+
+             convert &= convert_entire_line | ISBLANK (c);
            }
-         putchar (c);
+
+         if (c < 0)
+           return;
+
+         if (putchar (c) < 0)
+           error (EXIT_FAILURE, errno, _("write error"));
        }
+      while (c != '\n');
     }
 }
 
@@ -396,11 +407,11 @@ main (int argc, char **argv)
          convert_entire_line = false;
          break;
        case 't':
-         parse_tabstops (optarg);
+         parse_tab_stops (optarg);
          break;
        case ',':
          if (have_tabval)
-           add_tabstop (tabval);
+           add_tab_stop (tabval);
          have_tabval = false;
          obsolete_tablist = true;
          break;
@@ -425,9 +436,9 @@ main (int argc, char **argv)
     }
 
   if (have_tabval)
-    add_tabstop (tabval);
+    add_tab_stop (tabval);
 
-  validate_tabstops (tab_list, first_free_tab);
+  validate_tab_stops (tab_list, first_free_tab);
 
   if (first_free_tab == 0)
     tab_size = 8;
@@ -440,7 +451,7 @@ main (int argc, char **argv)
 
   expand ();
 
-  if (have_read_stdin && fclose (stdin) == EOF)
+  if (have_read_stdin && fclose (stdin) != 0)
     error (EXIT_FAILURE, errno, "-");
 
   exit (exit_status);