buf.c revision 81220 
1/* buf.c: This file contains the scratch-file buffer routines for the
2   ed line editor. */
3/*-
4 * Copyright (c) 1993 Andrew Moore, Talke Studio.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#ifndef lint
30static const char rcsid[] =
31  "$FreeBSD: head/bin/ed/buf.c 81220 2001-08-06 22:01:31Z mike $";
32#endif /* not lint */
33
34#include <sys/file.h>
35#include <sys/stat.h>
36
37#include "ed.h"
38
39
40FILE *sfp;				/* scratch file pointer */
41off_t sfseek;				/* scratch file position */
42int seek_write;				/* seek before writing */
43line_t buffer_head;			/* incore buffer */
44
45/* get_sbuf_line: get a line of text from the scratch file; return pointer
46   to the text */
47char *
48get_sbuf_line(lp)
49	line_t *lp;
50{
51	static char *sfbuf = NULL;	/* buffer */
52	static int sfbufsz = 0;		/* buffer size */
53
54	int len, ct;
55
56	if (lp == &buffer_head)
57		return NULL;
58	seek_write = 1;				/* force seek on write */
59	/* out of position */
60	if (sfseek != lp->seek) {
61		sfseek = lp->seek;
62		if (fseek(sfp, sfseek, SEEK_SET) < 0) {
63			fprintf(stderr, "%s\n", strerror(errno));
64			errmsg = "cannot seek temp file";
65			return NULL;
66		}
67	}
68	len = lp->len;
69	REALLOC(sfbuf, sfbufsz, len + 1, NULL);
70	if ((ct = fread(sfbuf, sizeof(char), len, sfp)) <  0 || ct != len) {
71		fprintf(stderr, "%s\n", strerror(errno));
72		errmsg = "cannot read temp file";
73		return NULL;
74	}
75	sfseek += len;				/* update file position */
76	sfbuf[len] = '\0';
77	return sfbuf;
78}
79
80
81/* put_sbuf_line: write a line of text to the scratch file and add a line node
82   to the editor buffer;  return a pointer to the end of the text */
83const char *
84put_sbuf_line(cs)
85	const char *cs;
86{
87	line_t *lp;
88	int len, ct;
89	const char *s;
90
91	if ((lp = (line_t *) malloc(sizeof(line_t))) == NULL) {
92		fprintf(stderr, "%s\n", strerror(errno));
93		errmsg = "out of memory";
94		return NULL;
95	}
96	/* assert: cs is '\n' terminated */
97	for (s = cs; *s != '\n'; s++)
98		;
99	if (s - cs >= LINECHARS) {
100		errmsg = "line too long";
101		return NULL;
102	}
103	len = s - cs;
104	/* out of position */
105	if (seek_write) {
106		if (fseek(sfp, 0L, SEEK_END) < 0) {
107			fprintf(stderr, "%s\n", strerror(errno));
108			errmsg = "cannot seek temp file";
109			return NULL;
110		}
111		sfseek = ftell(sfp);
112		seek_write = 0;
113	}
114	/* assert: SPL1() */
115	if ((ct = fwrite(cs, sizeof(char), len, sfp)) < 0 || ct != len) {
116		sfseek = -1;
117		fprintf(stderr, "%s\n", strerror(errno));
118		errmsg = "cannot write temp file";
119		return NULL;
120	}
121	lp->len = len;
122	lp->seek  = sfseek;
123	add_line_node(lp);
124	sfseek += len;			/* update file position */
125	return ++s;
126}
127
128
129/* add_line_node: add a line node in the editor buffer after the current line */
130void
131add_line_node(lp)
132	line_t *lp;
133{
134	line_t *cp;
135
136	cp = get_addressed_line_node(current_addr);				/* this get_addressed_line_node last! */
137	INSQUE(lp, cp);
138	addr_last++;
139	current_addr++;
140}
141
142
143/* get_line_node_addr: return line number of pointer */
144long
145get_line_node_addr(lp)
146	line_t *lp;
147{
148	line_t *cp = &buffer_head;
149	long n = 0;
150
151	while (cp != lp && (cp = cp->q_forw) != &buffer_head)
152		n++;
153	if (n && cp == &buffer_head) {
154		errmsg = "invalid address";
155		return ERR;
156	 }
157	 return n;
158}
159
160
161/* get_addressed_line_node: return pointer to a line node in the editor buffer */
162line_t *
163get_addressed_line_node(n)
164	long n;
165{
166	static line_t *lp = &buffer_head;
167	static long on = 0;
168
169	SPL1();
170	if (n > on)
171		if (n <= (on + addr_last) >> 1)
172			for (; on < n; on++)
173				lp = lp->q_forw;
174		else {
175			lp = buffer_head.q_back;
176			for (on = addr_last; on > n; on--)
177				lp = lp->q_back;
178		}
179	else
180		if (n >= on >> 1)
181			for (; on > n; on--)
182				lp = lp->q_back;
183		else {
184			lp = &buffer_head;
185			for (on = 0; on < n; on++)
186				lp = lp->q_forw;
187		}
188	SPL0();
189	return lp;
190}
191
192
193extern int newline_added;
194
195char sfn[15] = "";				/* scratch file name */
196
197/* open_sbuf: open scratch file */
198int
199open_sbuf()
200{
201	int fd = -1;
202	int u;
203
204	isbinary = newline_added = 0;
205	u = umask(077);
206	strcpy(sfn, "/tmp/ed.XXXXXX");
207	if ((fd = mkstemp(sfn)) == -1 ||
208	    (sfp = fdopen(fd, "w+")) == NULL) {
209		if (fd != -1)
210			close(fd);
211		perror(sfn);
212		errmsg = "cannot open temp file";
213		umask(u);
214		return ERR;
215	}
216	umask(u);
217	return 0;
218}
219
220
221/* close_sbuf: close scratch file */
222int
223close_sbuf()
224{
225	if (sfp) {
226		if (fclose(sfp) < 0) {
227			fprintf(stderr, "%s: %s\n", sfn, strerror(errno));
228			errmsg = "cannot close temp file";
229			return ERR;
230		}
231		sfp = NULL;
232		unlink(sfn);
233	}
234	sfseek = seek_write = 0;
235	return 0;
236}
237
238
239/* quit: remove_lines scratch file and exit */
240void
241quit(n)
242	int n;
243{
244	if (sfp) {
245		fclose(sfp);
246		unlink(sfn);
247	}
248	exit(n);
249}
250
251
252unsigned char ctab[256];		/* character translation table */
253
254/* init_buffers: open scratch buffer; initialize line queue */
255void
256init_buffers()
257{
258	int i = 0;
259
260	/* Read stdin one character at a time to avoid i/o contention
261	   with shell escapes invoked by nonterminal input, e.g.,
262	   ed - <<EOF
263	   !cat
264	   hello, world
265	   EOF */
266	setbuffer(stdin, stdinbuf, 1);
267
268	/* Ensure stdout is line buffered. This avoids bogus delays
269	   of output if stdout is piped through utilities to a terminal. */
270	setvbuf(stdout, NULL, _IOLBF, 0);
271	if (open_sbuf() < 0)
272		quit(2);
273	REQUE(&buffer_head, &buffer_head);
274	for (i = 0; i < 256; i++)
275		ctab[i] = i;
276}
277
278
279/* translit_text: translate characters in a string */
280char *
281translit_text(s, len, from, to)
282	char *s;
283	int len;
284	int from;
285	int to;
286{
287	static int i = 0;
288
289	unsigned char *us;
290
291	ctab[i] = i;			/* restore table to initial state */
292	ctab[i = from] = to;
293	for (us = (unsigned char *) s; len-- > 0; us++)
294		*us = ctab[*us];
295	return s;
296}
297