1 /* $OpenBSD: getc.c,v 1.10 2016/01/06 22:28:52 millert Exp $ */
2
3 /*-
4 * Copyright (c) 1992, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 * Copyright (c) 1992, 1993, 1994, 1995, 1996
7 * Keith Bostic. All rights reserved.
8 *
9 * See the LICENSE file for redistribution information.
10 */
11
12 #include "config.h"
13
14 #include <sys/types.h>
15 #include <sys/queue.h>
16 #include <sys/time.h>
17
18 #include <bitstring.h>
19 #include <ctype.h>
20 #include <limits.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23
24 #include "../common/common.h"
25 #include "vi.h"
26
27 /*
28 * Character stream routines --
29 * These routines return the file a character at a time. There are two
30 * special cases. First, the end of a line, end of a file, start of a
31 * file and empty lines are returned as special cases, and no character
32 * is returned. Second, empty lines include lines that have only white
33 * space in them, because the vi search functions don't care about white
34 * space, and this makes it easier for them to be consistent.
35 */
36
37 /*
38 * cs_init --
39 * Initialize character stream routines.
40 *
41 * PUBLIC: int cs_init(SCR *, VCS *);
42 */
43 int
cs_init(SCR * sp,VCS * csp)44 cs_init(SCR *sp, VCS *csp)
45 {
46 int isempty;
47
48 if (db_eget(sp, csp->cs_lno, (char **) &csp->cs_bp, &csp->cs_len,
49 &isempty)) {
50 if (isempty)
51 msgq(sp, M_BERR, "Empty file");
52 return (1);
53 }
54 if (csp->cs_len == 0 || v_isempty(csp->cs_bp, csp->cs_len)) {
55 csp->cs_cno = 0;
56 csp->cs_flags = CS_EMP;
57 } else {
58 csp->cs_flags = 0;
59 csp->cs_ch = csp->cs_bp[csp->cs_cno];
60 }
61 return (0);
62 }
63
64 /*
65 * cs_next --
66 * Retrieve the next character.
67 *
68 * PUBLIC: int cs_next(SCR *, VCS *);
69 */
70 int
cs_next(SCR * sp,VCS * csp)71 cs_next(SCR *sp, VCS *csp)
72 {
73 char *p;
74
75 switch (csp->cs_flags) {
76 case CS_EMP: /* EMP; get next line. */
77 case CS_EOL: /* EOL; get next line. */
78 if (db_get(sp, ++csp->cs_lno, 0, &p, &csp->cs_len)) {
79 --csp->cs_lno;
80 csp->cs_flags = CS_EOF;
81 } else {
82 csp->cs_bp = p;
83 if (csp->cs_len == 0 ||
84 v_isempty(csp->cs_bp, csp->cs_len)) {
85 csp->cs_cno = 0;
86 csp->cs_flags = CS_EMP;
87 } else {
88 csp->cs_flags = 0;
89 csp->cs_ch = csp->cs_bp[csp->cs_cno = 0];
90 }
91 }
92 break;
93 case 0:
94 if (csp->cs_cno == csp->cs_len - 1)
95 csp->cs_flags = CS_EOL;
96 else
97 csp->cs_ch = csp->cs_bp[++csp->cs_cno];
98 break;
99 case CS_EOF: /* EOF. */
100 break;
101 default:
102 abort();
103 /* NOTREACHED */
104 }
105 return (0);
106 }
107
108 /*
109 * cs_fspace --
110 * If on a space, eat forward until something other than a
111 * whitespace character.
112 *
113 * XXX
114 * Semantics of checking the current character were coded for the fword()
115 * function -- once the other word routines are converted, they may have
116 * to change.
117 *
118 * PUBLIC: int cs_fspace(SCR *, VCS *);
119 */
120 int
cs_fspace(SCR * sp,VCS * csp)121 cs_fspace(SCR *sp, VCS *csp)
122 {
123 if (csp->cs_flags != 0 || !isblank(csp->cs_ch))
124 return (0);
125 for (;;) {
126 if (cs_next(sp, csp))
127 return (1);
128 if (csp->cs_flags != 0 || !isblank(csp->cs_ch))
129 break;
130 }
131 return (0);
132 }
133
134 /*
135 * cs_fblank --
136 * Eat forward to the next non-whitespace character.
137 *
138 * PUBLIC: int cs_fblank(SCR *, VCS *);
139 */
140 int
cs_fblank(SCR * sp,VCS * csp)141 cs_fblank(SCR *sp, VCS *csp)
142 {
143 for (;;) {
144 if (cs_next(sp, csp))
145 return (1);
146 if (csp->cs_flags == CS_EOL || csp->cs_flags == CS_EMP ||
147 (csp->cs_flags == 0 && isblank(csp->cs_ch)))
148 continue;
149 break;
150 }
151 return (0);
152 }
153
154 /*
155 * cs_prev --
156 * Retrieve the previous character.
157 *
158 * PUBLIC: int cs_prev(SCR *, VCS *);
159 */
160 int
cs_prev(SCR * sp,VCS * csp)161 cs_prev(SCR *sp, VCS *csp)
162 {
163 switch (csp->cs_flags) {
164 case CS_EMP: /* EMP; get previous line. */
165 case CS_EOL: /* EOL; get previous line. */
166 if (csp->cs_lno == 1) { /* SOF. */
167 csp->cs_flags = CS_SOF;
168 break;
169 }
170 if (db_get(sp, /* The line should exist. */
171 --csp->cs_lno, DBG_FATAL, (char **) &csp->cs_bp,
172 &csp->cs_len)) {
173 ++csp->cs_lno;
174 return (1);
175 }
176 if (csp->cs_len == 0 || v_isempty(csp->cs_bp, csp->cs_len)) {
177 csp->cs_cno = 0;
178 csp->cs_flags = CS_EMP;
179 } else {
180 csp->cs_flags = 0;
181 csp->cs_cno = csp->cs_len - 1;
182 csp->cs_ch = csp->cs_bp[csp->cs_cno];
183 }
184 break;
185 case CS_EOF: /* EOF: get previous char. */
186 case 0:
187 if (csp->cs_cno == 0)
188 if (csp->cs_lno == 1)
189 csp->cs_flags = CS_SOF;
190 else
191 csp->cs_flags = CS_EOL;
192 else
193 csp->cs_ch = csp->cs_bp[--csp->cs_cno];
194 break;
195 case CS_SOF: /* SOF. */
196 break;
197 default:
198 abort();
199 /* NOTREACHED */
200 }
201 return (0);
202 }
203
204 /*
205 * cs_bblank --
206 * Eat backward to the next non-whitespace character.
207 *
208 * PUBLIC: int cs_bblank(SCR *, VCS *);
209 */
210 int
cs_bblank(SCR * sp,VCS * csp)211 cs_bblank(SCR *sp, VCS *csp)
212 {
213 for (;;) {
214 if (cs_prev(sp, csp))
215 return (1);
216 if (csp->cs_flags == CS_EOL || csp->cs_flags == CS_EMP ||
217 (csp->cs_flags == 0 && isblank(csp->cs_ch)))
218 continue;
219 break;
220 }
221 return (0);
222 }
223