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getc.c
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C/C++ Source or Header
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1996-04-27
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5KB
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235 lines
/*-
* Copyright (c) 1992, 1993, 1994
* The Regents of the University of California. All rights reserved.
* Copyright (c) 1992, 1993, 1994, 1995, 1996
* Keith Bostic. All rights reserved.
*
* See the LICENSE file for redistribution information.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)getc.c 10.10 (Berkeley) 3/6/96";
#endif /* not lint */
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/time.h>
#include <bitstring.h>
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include "../common/common.h"
#include "vi.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.
*
* PUBLIC: int cs_init __P((SCR *, VCS *));
*/
int
cs_init(sp, csp)
SCR *sp;
VCS *csp;
{
int isempty;
if (db_eget(sp, csp->cs_lno, &csp->cs_bp, &csp->cs_len, &isempty)) {
if (isempty)
msgq(sp, M_BERR, "177|Empty file");
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.
*
* PUBLIC: int cs_next __P((SCR *, VCS *));
*/
int
cs_next(sp, csp)
SCR *sp;
VCS *csp;
{
char *p;
switch (csp->cs_flags) {
case CS_EMP: /* EMP; get next line. */
case CS_EOL: /* EOL; get next line. */
if (db_get(sp, ++csp->cs_lno, 0, &p, &csp->cs_len)) {
--csp->cs_lno;
csp->cs_flags = CS_EOF;
} else {
csp->cs_bp = p;
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. */
break;
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.
*
* PUBLIC: int cs_fspace __P((SCR *, VCS *));
*/
int
cs_fspace(sp, csp)
SCR *sp;
VCS *csp;
{
if (csp->cs_flags != 0 || !isblank(csp->cs_ch))
return (0);
for (;;) {
if (cs_next(sp, 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.
*
* PUBLIC: int cs_fblank __P((SCR *, VCS *));
*/
int
cs_fblank(sp, csp)
SCR *sp;
VCS *csp;
{
for (;;) {
if (cs_next(sp, 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.
*
* PUBLIC: int cs_prev __P((SCR *, VCS *));
*/
int
cs_prev(sp, csp)
SCR *sp;
VCS *csp;
{
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;
}
if (db_get(sp, /* The line should exist. */
--csp->cs_lno, DBG_FATAL, &csp->cs_bp, &csp->cs_len)) {
++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_cno = csp->cs_len - 1;
csp->cs_ch = csp->cs_bp[csp->cs_cno];
}
break;
case CS_EOF: /* EOF: get previous char. */
case 0:
if (csp->cs_cno == 0)
if (csp->cs_lno == 1)
csp->cs_flags = CS_SOF;
else
csp->cs_flags = CS_EOL;
else
csp->cs_ch = csp->cs_bp[--csp->cs_cno];
break;
case CS_SOF: /* SOF. */
break;
default:
abort();
/* NOTREACHED */
}
return (0);
}
/*
* cs_bblank --
* Eat backward to the next non-whitespace character.
*
* PUBLIC: int cs_bblank __P((SCR *, VCS *));
*/
int
cs_bblank(sp, csp)
SCR *sp;
VCS *csp;
{
for (;;) {
if (cs_prev(sp, 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);
}