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.
7 * See the LICENSE file for redistribution information.
13 static const char sccsid[] = "$Id: getc.c,v 10.13 2011/12/27 00:49:31 zy Exp $";
16 #include <sys/types.h>
17 #include <sys/queue.h>
20 #include <bitstring.h>
26 #include "../common/common.h"
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.
41 * Initialize character stream routines.
43 * PUBLIC: int cs_init __P((SCR *, VCS *));
46 cs_init(SCR *sp, VCS *csp)
50 if (db_eget(sp, csp->cs_lno, &csp->cs_bp, &csp->cs_len, &isempty)) {
52 msgq(sp, M_BERR, "177|Empty file");
55 if (csp->cs_len == 0 || v_isempty(csp->cs_bp, csp->cs_len)) {
57 csp->cs_flags = CS_EMP;
60 csp->cs_ch = csp->cs_bp[csp->cs_cno];
67 * Retrieve the next character.
69 * PUBLIC: int cs_next __P((SCR *, VCS *));
72 cs_next(SCR *sp, VCS *csp)
76 switch (csp->cs_flags) {
77 case CS_EMP: /* EMP; get next line. */
78 case CS_EOL: /* EOL; get next line. */
79 if (db_get(sp, ++csp->cs_lno, 0, &p, &csp->cs_len)) {
81 csp->cs_flags = CS_EOF;
84 if (csp->cs_len == 0 ||
85 v_isempty(csp->cs_bp, csp->cs_len)) {
87 csp->cs_flags = CS_EMP;
90 csp->cs_ch = csp->cs_bp[csp->cs_cno = 0];
95 if (csp->cs_cno == csp->cs_len - 1)
96 csp->cs_flags = CS_EOL;
98 csp->cs_ch = csp->cs_bp[++csp->cs_cno];
100 case CS_EOF: /* EOF. */
111 * If on a space, eat forward until something other than a
112 * whitespace character.
115 * Semantics of checking the current character were coded for the fword()
116 * function -- once the other word routines are converted, they may have
119 * PUBLIC: int cs_fspace __P((SCR *, VCS *));
122 cs_fspace(SCR *sp, VCS *csp)
124 if (csp->cs_flags != 0 || !ISBLANK(csp->cs_ch))
127 if (cs_next(sp, csp))
129 if (csp->cs_flags != 0 || !ISBLANK(csp->cs_ch))
137 * Eat forward to the next non-whitespace character.
139 * PUBLIC: int cs_fblank __P((SCR *, VCS *));
142 cs_fblank(SCR *sp, VCS *csp)
145 if (cs_next(sp, csp))
147 if (csp->cs_flags == CS_EOL || csp->cs_flags == CS_EMP ||
148 (csp->cs_flags == 0 && ISBLANK(csp->cs_ch)))
157 * Retrieve the previous character.
159 * PUBLIC: int cs_prev __P((SCR *, VCS *));
162 cs_prev(SCR *sp, VCS *csp)
164 switch (csp->cs_flags) {
165 case CS_EMP: /* EMP; get previous line. */
166 case CS_EOL: /* EOL; get previous line. */
167 if (csp->cs_lno == 1) { /* SOF. */
168 csp->cs_flags = CS_SOF;
171 if (db_get(sp, /* The line should exist. */
172 --csp->cs_lno, DBG_FATAL, &csp->cs_bp, &csp->cs_len)) {
176 if (csp->cs_len == 0 || v_isempty(csp->cs_bp, csp->cs_len)) {
178 csp->cs_flags = CS_EMP;
181 csp->cs_cno = csp->cs_len - 1;
182 csp->cs_ch = csp->cs_bp[csp->cs_cno];
185 case CS_EOF: /* EOF: get previous char. */
187 if (csp->cs_cno == 0)
188 if (csp->cs_lno == 1)
189 csp->cs_flags = CS_SOF;
191 csp->cs_flags = CS_EOL;
193 csp->cs_ch = csp->cs_bp[--csp->cs_cno];
195 case CS_SOF: /* SOF. */
206 * Eat backward to the next non-whitespace character.
208 * PUBLIC: int cs_bblank __P((SCR *, VCS *));
211 cs_bblank(SCR *sp, VCS *csp)
214 if (cs_prev(sp, csp))
216 if (csp->cs_flags == CS_EOL || csp->cs_flags == CS_EMP ||
217 (csp->cs_flags == 0 && ISBLANK(csp->cs_ch)))