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