2.11BSD#431 - /usr/src/local/mp/io.c

   1: 
   2: /*  @(#)io.c 1.4 92/02/17
   3:  *
   4:  *  Copyright (c) Steve Holden and Rich Burridge.
   5:  *                All rights reserved.
   6:  *
   7:  *  Permission is given to distribute these sources, as long as the
   8:  *  copyright messages are not removed, and no monies are exchanged.
   9:  *
  10:  *  No responsibility is taken for any errors inherent either
  11:  *  to the comments or the code of this program, but if reported
  12:  *  to me then an attempt will be made to fix them.
  13:  */
  14: 
  15: #include "mp.h"
  16: #include "extern.h"
  17: 
  18: 
  19: /* Emptyline returns true if its argument is empty or whitespace only */
  20: 
  21: bool
  22: emptyline(str)
  23: char *str ;
  24: {
  25:   while (*str)
  26:     {
  27:       if (!isspace(*str)) return(FALSE) ;
  28:       str++ ;
  29:     }
  30:   return(TRUE) ;
  31: }
  32: 
  33: 
  34: /*  Read an input line into nextline, setting end_of_file, end_of_page
  35:  *  and end_of_line appropriately.
  36:  */
  37: 
  38: void
  39: readline()
  40: {
  41:   int c ;
  42:   int i = 0 ;      /* Index into current line being read. */
  43:   int len = 0 ;    /* Length of the current line. */
  44: 
  45:   if (end_of_file) return ;
  46:   end_of_page = end_of_line = FALSE ;
  47: 
  48:   while (len < llen && (c = getc(fp)) != EOF && c != '\n' && c != '\f')
  49:     {
  50:       if (c == '\t')
  51:         {
  52:           do
  53:             {
  54:               nextline[i++] = ' ' ;
  55:               len++ ;
  56:             }
  57:           while (len % 8 != 0 && len <= llen) ;
  58:         }
  59:       else
  60:         {
  61:           nextline[i++] = c ;
  62:           len++ ;
  63:         }
  64:       if (c == '\b')
  65:         {
  66:           len -= 2 ;
  67:           i -= 2 ;
  68:         }
  69:     }
  70:   nextline[i] = '\0' ;
  71: 
  72:   if (len == llen && c != EOF && c != '\n' && c != '\f')
  73:     {
  74:       c = getc(fp) ;
  75:       if (c != EOF && c != '\n' && c != '\f') UNGETC(c, fp) ;
  76:     }
  77: 
  78:   if (elm_if && c == '\f')
  79:     {
  80:       len-- ;
  81:       i-- ;
  82:     }
  83: 
  84:   switch (c)
  85:     {
  86:       case EOF  : if (i == 0) end_of_file = TRUE ;
  87:                   else
  88:                     {
  89:                       UNGETC(c, fp) ;
  90:                       end_of_line = TRUE ;
  91:                     }
  92:                   break ;
  93:       case '\n' : end_of_line = TRUE ;
  94:                   break ;
  95: 
  96: /*  /usr/ucb/mail for some unknown reason, appends a bogus formfeed at
  97:  *  the end of piped output. The next character is checked; if it's an
  98:  *  EOF, then end_of_file is set, else the character is put back.
  99:  */
 100: 
 101:       case '\f' : if ((c = getc(fp)) == EOF) end_of_file = TRUE ;
 102:                   else UNGETC(c, fp) ;
 103: 
 104:                   end_of_line = TRUE ;
 105:                   end_of_page = TRUE ;
 106:                   break ;
 107:     }
 108:   clen = len + 1 ;          /* Current line length (includes newline). */
 109: }

Defined functions