usr.bin/vi/nvi/getc.c

/*-
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)getc.c      8.6 (Berkeley) 10/26/93";
#endif /* not lint */

#include <sys/types.h>

#include <ctype.h>

#include "vi.h"
#include "vcmd.h"

/*
 * Character stream routines --
 *      These routines return the file a character at a time.  There are two
 *      special cases.  First, the end of a line, end of a file, start of a
 *      file and empty lines are returned as special cases, and no character
 *      is returned.  Second, empty lines include lines that have only white
 *      space in them, because the vi search functions don't care about white
 *      space, and this makes it easier for them to be consistent.
 */

/*
 * cs_init --
 *      Initialize character stream routines.
 */
int
cs_init(sp, ep, csp)
        SCR *sp;
        EXF *ep;
        VCS *csp;
{
        recno_t lno;

        if ((csp->cs_bp =
            file_gline(sp, ep, csp->cs_lno, &csp->cs_len)) == NULL) {
                if (file_lline(sp, ep, &lno))
                        return (1);
                if (lno == 0)
                        msgq(sp, M_BERR, "Empty file.");
                else
                        GETLINE_ERR(sp, csp->cs_lno);
                return (1);
        }
        if (csp->cs_len == 0 || v_isempty(csp->cs_bp, csp->cs_len)) {
                csp->cs_cno = 0;
                csp->cs_flags = CS_EMP;
        } else {
                csp->cs_flags = 0;
                csp->cs_ch = csp->cs_bp[csp->cs_cno];
        }
        return (0);
}

/*
 * cs_next --
 *      Retrieve the next character.
 */
int
cs_next(sp, ep, csp)
        SCR *sp;
        EXF *ep;
        VCS *csp;
{
        recno_t slno;

        switch (csp->cs_flags) {
        case CS_EMP:                            /* EMP; get next line. */
        case CS_EOL:                            /* EOL; get next line. */
                slno = csp->cs_lno;             /* Save current line. */
                if ((csp->cs_bp =
                    file_gline(sp, ep, ++csp->cs_lno, &csp->cs_len)) == NULL) {
                        csp->cs_lno = slno;
                        if (file_lline(sp, ep, &slno))
                                return (1);
                        if (slno > csp->cs_lno) {
                                GETLINE_ERR(sp, csp->cs_lno);
                                return (1);
                        }
                        csp->cs_flags = CS_EOF;
                } else if (csp->cs_len == 0 ||
                    v_isempty(csp->cs_bp, csp->cs_len)) {
                        csp->cs_cno = 0;
                        csp->cs_flags = CS_EMP;
                } else {
                        csp->cs_flags = 0;
                        csp->cs_ch = csp->cs_bp[csp->cs_cno = 0];
                }
                break;
        case 0:
                if (csp->cs_cno == csp->cs_len - 1)
                        csp->cs_flags = CS_EOL;
                else
                        csp->cs_ch = csp->cs_bp[++csp->cs_cno];
                break;
        case CS_EOF:                            /* EOF; only returned once. */
        default:
                abort();
                /* NOTREACHED */
        }
        return (0);
}

/*
 * cs_fspace --
 *      If on a space, eat forward until something other than a
 *      whitespace character.
 *
 * XXX
 * Semantics of checking the current character were coded for the fword()
 * function -- once the other word routines are converted, they may have
 * to change.
 */
int
cs_fspace(sp, ep, csp)
        SCR *sp;
        EXF *ep;
        VCS *csp;
{
        if (csp->cs_flags != 0 || !isblank(csp->cs_ch))
                return (0);
        for (;;) {
                if (cs_next(sp, ep, csp))
                        return (1);
                if (csp->cs_flags != 0 || !isblank(csp->cs_ch))
                        break;
        }
        return (0);
}

/*
 * cs_fblank --
 *      Eat forward to the next non-whitespace character.
 */
int
cs_fblank(sp, ep, csp)
        SCR *sp;
        EXF *ep;
        VCS *csp;
{
        for (;;) {
                if (cs_next(sp, ep, csp))
                        return (1);
                if (csp->cs_flags == CS_EOL || csp->cs_flags == CS_EMP ||
                    csp->cs_flags == 0 && isblank(csp->cs_ch))
                        continue;
                break;
        }
        return (0);
}

/*
 * cs_prev --
 *      Retrieve the previous character.
 */
int
cs_prev(sp, ep, csp)
        SCR *sp;
        EXF *ep;
        VCS *csp;
{
        recno_t slno;

        switch (csp->cs_flags) {
        case CS_EMP:                            /* EMP; get previous line. */
        case CS_EOL:                            /* EOL; get previous line. */
                if (csp->cs_lno == 1) {         /* SOF. */
                        csp->cs_flags = CS_SOF;
                        break;
                }
                slno = csp->cs_lno;             /* Save current line. */
                if ((csp->cs_bp =               /* Line should exist. */
                    file_gline(sp, ep, --csp->cs_lno, &csp->cs_len)) == NULL) {
                        GETLINE_ERR(sp, csp->cs_lno);
                        csp->cs_lno = slno;
                        return (1);
                }
                if (csp->cs_len == 0 || v_isempty(csp->cs_bp, csp->cs_len)) {
                        csp->cs_cno = 0;
                        csp->cs_flags = CS_EMP;
                } else {
                        csp->cs_flags = 0;
                        csp->cs_cno = csp->cs_len - 1;
                        csp->cs_ch = csp->cs_bp[csp->cs_cno];
                }
                break;
        case 0:
                if (csp->cs_cno == 0)
                        csp->cs_flags = CS_EOL;
                else
                        csp->cs_ch = csp->cs_bp[--csp->cs_cno];
                break;
        case CS_SOF:                            /* SOF; only returned once. */
        default:
                abort();
                /* NOTREACHED */
        }
        return (0);
}

/*
 * cs_bblank --
 *      Eat backward to the next non-whitespace character.
 */
int
cs_bblank(sp, ep, csp)
        SCR *sp;
        EXF *ep;
        VCS *csp;
{
        for (;;) {
                if (cs_prev(sp, ep, csp))
                        return (1);
                if (csp->cs_flags == CS_EOL || csp->cs_flags == CS_EMP ||
                    csp->cs_flags == 0 && isblank(csp->cs_ch))
                        continue;
                break;
        }
        return (0);
}