3 * $Id: lbuf.c,v 1.2 1999/05/17 20:36:08 mdw Exp $
5 * Block-to-line buffering
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
14 * mLib is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
19 * mLib is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
24 * You should have received a copy of the GNU Library General Public
25 * License along with mLib; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.2 1999/05/17 20:36:08 mdw
34 * Make the magical constants for the buffer flags uppercase.
36 * Revision 1.1 1999/05/14 21:01:14 mdw
37 * Integrated `select' handling bits from the background resolver project.
41 /*----- Header files ------------------------------------------------------*/
49 /*----- Main code ---------------------------------------------------------*/
51 /* --- @lbuf_flush@ --- *
53 * Arguments: @lbuf *b@ = pointer to buffer block
54 * @char *p@ = pointer to where to start searching
55 * @size_t len@ = length of new material added
59 * Use: Flushes any complete lines in a line buffer. New material
60 * is assumed to have been added starting at @p@. If @p@ is
61 * null, then the scan starts at the beginning of the buffer,
62 * and the size of data already in the buffer is used in place
65 * It is assumed that the buffer is initially enabled. You
66 * shouldn't be contributing data to a disabled buffer anyway.
67 * However, the buffer handler may at some point disable itself,
68 * and @lbuf_flush@ can cope with this eventuality. Any pending
69 * data is left at the start of the buffer and can be flushed
70 * out by calling @lbuf_flush(b, 0, 0)@ if the buffer is ever
74 void lbuf_flush(lbuf *b, char *p, size_t len)
76 char *l; /* Limit of data in buffer */
77 char *q; /* Roving pointer through string */
78 char *base; /* Base address of current line */
79 int cr; /* Carriage return state */
81 /* --- Initialize variables as necessary --- */
92 /* --- Clear @base@ if I'm discarding an overlong line --- */
94 if (b->len == sizeof(b->buf))
99 /* --- Now I march through the string --- */
101 for (q = p; q < l; q++) {
103 /* --- Quickly discard uninteresting characters --- */
105 if (*q != '\r' && *q != '\n') {
114 /* --- Two choices here --- *
116 * I can either be strict about CRLF line ends, or I can be shoddy
117 * and allow bare LFs. I'll do the latter, although I oughtn't,
118 * because it makes testing interactively and with Unix text files
127 /* --- I have a positive ID on a linefeed --- *
129 * If I'm interested in this string, report it to my owner.
134 q[-1] = 0; /* Exercise: why is this safe? */
138 if (!(b->f & LBUF_ENABLE)) {
147 /* --- Sift through the aftermath --- */
150 size_t len = l - base;
151 if (len == sizeof(b->buf)) {
154 } else if (base != b->buf)
155 memmove(b->buf, base, len);
164 /* --- @lbuf_close@ --- *
166 * Arguments: @lbuf *b@ = pointer to buffer block
170 * Use: Empties the buffer of any data currently lurking in it, and
171 * informs the client that this has happened. It's assumed that
172 * the buffer is enabled: you shouldn't be reading close events
173 * on disabled buffers.
176 void lbuf_close(lbuf *b)
178 if (b->len && b->len != sizeof(b->buf)) {
180 b->func(b->buf, b->p);
182 if (b->f & LBUF_ENABLE)
186 /* --- @lbuf_free@ --- *
188 * Arguments: @lbuf *b@ = pointer to buffer block
189 * @char **p@ = output pointer to free space
191 * Returns: Free buffer size.
193 * Use: Returns the free portion of a line buffer. Data can then be
194 * written to this portion, and split out into lines by calling
198 size_t lbuf_free(lbuf *b, char **p)
200 /* --- There's a special case to consider --- *
202 * If a line from the file wouldn't fit in the buffer, I truncate it and
203 * return what would fit. The rest of the line ought to be discarded.
204 * This condition is signalled by @len = sizeof(buf)@, and means that the
205 * entire buffer is OK to be trashed. In other cases, @len@ is the amount
206 * of space currently occupied in the buffer. This special case is the
207 * reason this routine exists.
210 if (b->len == 0 || b->len == sizeof(b->buf)) {
211 *p = b->buf + b->len;
212 return (sizeof(b->buf) - b->len);
215 return (sizeof(b->buf));
219 /* --- @lbuf_snarf@ --- *
221 * Arguments: @lbuf *b@ = pointer to buffer block
222 * @const void *p@ = pointer to input data buffer
223 * @size_t sz@ = size of data in input buffer
227 * Use: Snarfs the data from the input buffer and spits it out as
228 * lines. This interface ignores the complexities of dealing
229 * with disablement: you should be using @lbuf_free@ to
230 * contribute data if you want to cope with that.
233 void lbuf_snarf(lbuf *b, const void *p, size_t sz)
240 bsz = lbuf_free(b, &bp);
244 lbuf_flush(b, bp, bsz);
250 /* --- @lbuf_init@ --- *
252 * Arguments: @lbuf *b@ = pointer to buffer block
253 * @void (*func)(char *s, void *p)@ = handler function
254 * @void *p@ = argument pointer for @func@
258 * Use: Initializes a line buffer block. Any recognized lines are
259 * passed to @func@ for processing.
262 void lbuf_init(lbuf *b,
263 void (*func)(char */*s*/, void */*p*/),
272 /*----- That's all, folks -------------------------------------------------*/