vi/getc.c

   1 /*-
   2  * Copyright (c) 1992, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 1992, 1993, 1994, 1995, 1996
   5  *      Keith Bostic.  All rights reserved.
   6  *
   7  * See the LICENSE file for redistribution information.
   8  */
   9
  10 #include "config.h"
  11
  12 #ifndef lint
  13 static const char sccsid[] = "$Id: getc.c,v 10.11 2000/06/27 17:19:07 skimo Exp $ (Berkeley) $Date: 2000/06/27 17:19:07 $";
  14 #endif /* not lint */
  15
  16 #include <sys/types.h>
  17 #include <sys/queue.h>
  18 #include <sys/time.h>
  19
  20 #include <bitstring.h>
  21 #include <ctype.h>
  22 #include <limits.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25
  26 #include "../common/common.h"
  27 #include "vi.h"
  28
  29 /*
  30  * Character stream routines --
  31  *      These routines return the file a character at a time.  There are two
  32  *      special cases.  First, the end of a line, end of a file, start of a
  33  *      file and empty lines are returned as special cases, and no character
  34  *      is returned.  Second, empty lines include lines that have only white
  35  *      space in them, because the vi search functions don't care about white
  36  *      space, and this makes it easier for them to be consistent.
  37  */
  38
  39 /*
  40  * cs_init --
  41  *      Initialize character stream routines.
  42  *
  43  * PUBLIC: int cs_init __P((SCR *, VCS *));
  44  */
  45 int
  46 cs_init(sp, csp)
  47         SCR *sp;
  48         VCS *csp;
  49 {
  50         int isempty;
  51
  52         if (db_eget(sp, csp->cs_lno, &csp->cs_bp, &csp->cs_len, &isempty)) {
  53                 if (isempty)
  54                         msgq(sp, M_BERR, "177|Empty file");
  55                 return (1);
  56         }
  57         if (csp->cs_len == 0 || v_isempty(csp->cs_bp, csp->cs_len)) {
  58                 csp->cs_cno = 0;
  59                 csp->cs_flags = CS_EMP;
  60         } else {
  61                 csp->cs_flags = 0;
  62                 csp->cs_ch = csp->cs_bp[csp->cs_cno];
  63         }
  64         return (0);
  65 }
  66
  67 /*
  68  * cs_next --
  69  *      Retrieve the next character.
  70  *
  71  * PUBLIC: int cs_next __P((SCR *, VCS *));
  72  */
  73 int
  74 cs_next(sp, csp)
  75         SCR *sp;
  76         VCS *csp;
  77 {
  78         CHAR_T *p;
  79
  80         switch (csp->cs_flags) {
  81         case CS_EMP:                            /* EMP; get next line. */
  82         case CS_EOL:                            /* EOL; get next line. */
  83                 if (db_get(sp, ++csp->cs_lno, 0, &p, &csp->cs_len)) {
  84                         --csp->cs_lno;
  85                         csp->cs_flags = CS_EOF;
  86                 } else {
  87                         csp->cs_bp = p;
  88                         if (csp->cs_len == 0 ||
  89                             v_isempty(csp->cs_bp, csp->cs_len)) {
  90                                 csp->cs_cno = 0;
  91                                 csp->cs_flags = CS_EMP;
  92                         } else {
  93                                 csp->cs_flags = 0;
  94                                 csp->cs_ch = csp->cs_bp[csp->cs_cno = 0];
  95                         }
  96                 }
  97                 break;
  98         case 0:
  99                 if (csp->cs_cno == csp->cs_len - 1)
 100                         csp->cs_flags = CS_EOL;
 101                 else
 102                         csp->cs_ch = csp->cs_bp[++csp->cs_cno];
 103                 break;
 104         case CS_EOF:                            /* EOF. */
 105                 break;
 106         default:
 107                 abort();
 108                 /* NOTREACHED */
 109         }
 110         return (0);
 111 }
 112
 113 /*
 114  * cs_fspace --
 115  *      If on a space, eat forward until something other than a
 116  *      whitespace character.
 117  *
 118  * XXX
 119  * Semantics of checking the current character were coded for the fword()
 120  * function -- once the other word routines are converted, they may have
 121  * to change.
 122  *
 123  * PUBLIC: int cs_fspace __P((SCR *, VCS *));
 124  */
 125 int
 126 cs_fspace(sp, csp)
 127         SCR *sp;
 128         VCS *csp;
 129 {
 130         if (csp->cs_flags != 0 || !isblank(csp->cs_ch))
 131                 return (0);
 132         for (;;) {
 133                 if (cs_next(sp, csp))
 134                         return (1);
 135                 if (csp->cs_flags != 0 || !isblank(csp->cs_ch))
 136                         break;
 137         }
 138         return (0);
 139 }
 140
 141 /*
 142  * cs_fblank --
 143  *      Eat forward to the next non-whitespace character.
 144  *
 145  * PUBLIC: int cs_fblank __P((SCR *, VCS *));
 146  */
 147 int
 148 cs_fblank(sp, csp)
 149         SCR *sp;
 150         VCS *csp;
 151 {
 152         for (;;) {
 153                 if (cs_next(sp, csp))
 154                         return (1);
 155                 if (csp->cs_flags == CS_EOL || csp->cs_flags == CS_EMP ||
 156                     csp->cs_flags == 0 && isblank(csp->cs_ch))
 157                         continue;
 158                 break;
 159         }
 160         return (0);
 161 }
 162
 163 /*
 164  * cs_prev --
 165  *      Retrieve the previous character.
 166  *
 167  * PUBLIC: int cs_prev __P((SCR *, VCS *));
 168  */
 169 int
 170 cs_prev(sp, csp)
 171         SCR *sp;
 172         VCS *csp;
 173 {
 174         switch (csp->cs_flags) {
 175         case CS_EMP:                            /* EMP; get previous line. */
 176         case CS_EOL:                            /* EOL; get previous line. */
 177                 if (csp->cs_lno == 1) {         /* SOF. */
 178                         csp->cs_flags = CS_SOF;
 179                         break;
 180                 }
 181                 if (db_get(sp,                  /* The line should exist. */
 182                     --csp->cs_lno, DBG_FATAL, &csp->cs_bp, &csp->cs_len)) {
 183                         ++csp->cs_lno;
 184                         return (1);
 185                 }
 186                 if (csp->cs_len == 0 || v_isempty(csp->cs_bp, csp->cs_len)) {
 187                         csp->cs_cno = 0;
 188                         csp->cs_flags = CS_EMP;
 189                 } else {
 190                         csp->cs_flags = 0;
 191                         csp->cs_cno = csp->cs_len - 1;
 192                         csp->cs_ch = csp->cs_bp[csp->cs_cno];
 193                 }
 194                 break;
 195         case CS_EOF:                            /* EOF: get previous char. */
 196         case 0:
 197                 if (csp->cs_cno == 0)
 198                         if (csp->cs_lno == 1)
 199                                 csp->cs_flags = CS_SOF;
 200                         else
 201                                 csp->cs_flags = CS_EOL;
 202                 else
 203                         csp->cs_ch = csp->cs_bp[--csp->cs_cno];
 204                 break;
 205         case CS_SOF:                            /* SOF. */
 206                 break;
 207         default:
 208                 abort();
 209                 /* NOTREACHED */
 210         }
 211         return (0);
 212 }
 213
 214 /*
 215  * cs_bblank --
 216  *      Eat backward to the next non-whitespace character.
 217  *
 218  * PUBLIC: int cs_bblank __P((SCR *, VCS *));
 219  */
 220 int
 221 cs_bblank(sp, csp)
 222         SCR *sp;
 223         VCS *csp;
 224 {
 225         for (;;) {
 226                 if (cs_prev(sp, csp))
 227                         return (1);
 228                 if (csp->cs_flags == CS_EOL || csp->cs_flags == CS_EMP ||
 229                     csp->cs_flags == 0 && isblank(csp->cs_ch))
 230                         continue;
 231                 break;
 232         }
 233         return (0);
 234 }