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[mLib] / struct / buf.c
1 /* -*-c-*-
2 *
3 * Buffer handling
4 *
5 * (c) 2001 Straylight/Edgeware
6 */
7
8 /*----- Licensing notice --------------------------------------------------*
9 *
10 * This file is part of the mLib utilities library.
11 *
12 * mLib is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
16 *
17 * mLib is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
21 *
22 * You should have received a copy of the GNU Library General Public
23 * License along with mLib; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
25 * MA 02111-1307, USA.
26 */
27
28 /*----- Header files ------------------------------------------------------*/
29
30 #include <assert.h>
31 #include <string.h>
32
33 #include "buf.h"
34
35 /*----- Main code ---------------------------------------------------------*/
36
37 /* --- @buf_init@ --- *
38 *
39 * Arguments: @buf *b@ = pointer to a buffer block
40 * @void *p@ = pointer to a buffer
41 * @size_t sz@ = size of the buffer
42 *
43 * Returns: ---
44 *
45 * Use: Initializes the buffer block appropriately.
46 */
47
48 void buf_init(buf *b, void *p, size_t sz)
49 {
50 b->base = b->p = p;
51 b->limit = b->p + sz;
52 b->f = 0;
53 }
54
55 /* --- @buf_break@ --- *
56 *
57 * Arguments: @buf *b@ = pointer to a buffer block
58 *
59 * Returns: Some negative value.
60 *
61 * Use: Marks a buffer as broken.
62 */
63
64 int buf_break(buf *b) { b->f |= BF_BROKEN; return (-1); }
65
66 /* --- @buf_flip@ --- *
67 *
68 * Arguments: @buf *b@ = pointer to a buffer block
69 *
70 * Returns: ---
71 *
72 * Use: Flips a buffer so that if you've just been writing to it,
73 * you can now read from the bit you've written.
74 */
75
76 void buf_flip(buf *b)
77 {
78 b->limit = b->p;
79 b->p = b->base;
80 }
81
82 /* --- @buf_ensure@ --- *
83 *
84 * Arguments: @buf *b@ = pointer to a buffer block
85 * @size_t sz@ = size of data wanted
86 *
87 * Returns: Zero if it worked, nonzero if there wasn't enough space.
88 *
89 * Use: Ensures that there are @sz@ bytes still in the buffer.
90 */
91
92 int buf_ensure(buf *b, size_t sz) { return (BENSURE(b, sz)); }
93
94 /* --- @buf_get@ --- *
95 *
96 * Arguments: @buf *b@ = pointer to a buffer block
97 * @size_t sz@ = size of the buffer
98 *
99 * Returns: Pointer to the place in the buffer.
100 *
101 * Use: Reserves a space in the buffer of the requested size, and
102 * returns its start address.
103 */
104
105 void *buf_get(buf *b, size_t sz)
106 {
107 void *p;
108 if (BENSURE(b, sz))
109 return (0);
110 p = BCUR(b);
111 BSTEP(b, sz);
112 return (p);
113 }
114
115 /* --- @buf_put@ --- *
116 *
117 * Arguments: @buf *b@ = pointer to a buffer block
118 * @const void *p@ = pointer to a buffer
119 * @size_t sz@ = size of the buffer
120 *
121 * Returns: Zero if it worked, nonzero if there wasn't enough space.
122 *
123 * Use: Fetches data from some place and puts it in the buffer
124 */
125
126 int buf_put(buf *b, const void *p, size_t sz)
127 {
128 if (BENSURE(b, sz))
129 return (-1);
130 memcpy(BCUR(b), p, sz);
131 BSTEP(b, sz);
132 return (0);
133 }
134
135 /* --- @buf_getbyte@ --- *
136 *
137 * Arguments: @buf *b@ = pointer to a buffer block
138 *
139 * Returns: A byte, or less than zero if there wasn't a byte there.
140 *
141 * Use: Gets a single byte from a buffer.
142 */
143
144 int buf_getbyte(buf *b)
145 {
146 if (BENSURE(b, 1))
147 return (-1);
148 return (*b->p++);
149 }
150
151 /* --- @buf_putbyte@ --- *
152 *
153 * Arguments: @buf *b@ = pointer to a buffer block
154 * @int ch@ = byte to write
155 *
156 * Returns: Zero if OK, nonzero if there wasn't enough space.
157 *
158 * Use: Puts a single byte in a buffer.
159 */
160
161 int buf_putbyte(buf *b, int ch)
162 {
163 if (BENSURE(b, 1))
164 return (-1);
165 *b->p++ = ch;
166 return (0);
167 }
168
169 /* --- @buf_getu{8,{16,24,32,64}{,l,b}}@ --- *
170 *
171 * Arguments: @buf *b@ = pointer to a buffer block
172 * @uintSZ *w@ = where to put the word
173 *
174 * Returns: Zero if OK, or nonzero if there wasn't a word there.
175 *
176 * Use: Gets a word of appropriate size and order from a buffer.
177 */
178
179 #define BUF_GETU_(n, W, w) \
180 int buf_getu##w(buf *b, uint##n *ww) \
181 { \
182 if (BENSURE(b, SZ_##W)) return (-1); \
183 *ww = LOAD##W(b->p); \
184 BSTEP(b, SZ_##W); \
185 return (0); \
186 }
187 DOUINTCONV(BUF_GETU_)
188
189 /* --- @buf_putu{8,{16,24,32,64}{,l,b}}@ --- *
190 *
191 * Arguments: @buf *b@ = pointer to a buffer block
192 * @uintSZ w@ = word to write
193 *
194 * Returns: Zero if OK, or nonzero if there wasn't enough space
195 *
196 * Use: Puts a word into a buffer with appropriate size and order.
197 */
198
199 #define BUF_PUTU_(n, W, w) \
200 int buf_putu##w(buf *b, uint##n ww) \
201 { \
202 if (BENSURE(b, SZ_##W)) return (-1); \
203 STORE##W(b->p, ww); \
204 BSTEP(b, SZ_##W); \
205 return (0); \
206 }
207 DOUINTCONV(BUF_PUTU_)
208
209 /* --- @findz@ --- *
210 *
211 * Arguments: @buf *b@ = pointer to a buffer block
212 * @size_t *nn@ = where to put the length
213 *
214 * Returns: Zero if OK, nonzero if there wasn't a null byte to be found.
215 *
216 * Use: Finds a terminating null byte. The length includes this
217 * terminator.
218 */
219
220 static int findz(buf *b, size_t *nn)
221 {
222 octet *p;
223
224 if ((p = memchr(BCUR(b), 0, BLEFT(b))) == 0) {
225 buf_break(b);
226 return (-1);
227 }
228 *nn = p - BCUR(b) + 1;
229 return (0);
230 }
231
232 /* --- @buf_getmem{8,{16,24,32,64}{,l,b},z} --- *
233 *
234 * Arguments: @buf *b@ = pointer to a buffer block
235 * @size_t *nn@ = where to put the length
236 *
237 * Returns: Pointer to the buffer data, or null.
238 *
239 * Use: Gets a chunk of memory from a buffer. The suffix is the
240 * width and byte order of the length; @z@ means null-
241 * terminated.
242 */
243
244 #define BUF_GETMEM_(n, W, w) \
245 void *buf_getmem##w(buf *b, size_t *nn) \
246 { \
247 uint##n sz; \
248 if (buf_getu##w(b, &sz)) return (0); \
249 *nn = sz; \
250 return (buf_get(b, sz)); \
251 }
252 DOUINTCONV(BUF_GETMEM_)
253
254 void *buf_getmemz(buf *b, size_t *nn)
255 {
256 if (findz(b, nn)) return (0);
257 return (buf_get(b, *nn));
258 }
259
260 /* --- @buf_putmem{8,{16,24,32,64}{,l,b},z} --- *
261 *
262 * Arguments: @buf *b@ = pointer to a buffer block
263 * @const void *p@ = pointer to data to write
264 * @size_t n@ = length to write
265 *
266 * Returns: Zero if OK, nonzero if there wasn't enough space.
267 *
268 * Use: Writes a chunk of data to a buffer. The suffix is the
269 * width and byte order of the length; @z@ means null-
270 * terminated.
271 */
272
273 #define BUF_PUTMEM_(n, W, w) \
274 int buf_putmem##w(buf *b, const void *p, size_t sz) \
275 { \
276 assert(sz <= MASK##W); \
277 if (buf_putu##w(b, sz) || buf_put(b, p, sz)) \
278 return (-1); \
279 return (0); \
280 }
281 DOUINTCONV(BUF_PUTMEM_)
282
283 int buf_putmemz(buf *b, const void *p, size_t n)
284 {
285 octet *q;
286
287 assert(!memchr(p, 0, n));
288 if ((q = buf_get(b, n + 1)) == 0)
289 return (-1);
290 memcpy(q, p, n);
291 q[n] = 0;
292 return (0);
293 }
294
295 /* --- @buf_getbuf{8,{16,24,32,64}{,l,b},z} --- *
296 *
297 * Arguments: @buf *b@ = pointer to a buffer block
298 * @buf *bb@ = where to put the result
299 *
300 * Returns: Zero if it worked, nonzero if there wasn't enough space.
301 *
302 * Use: Gets a block of data from a buffer, and writes its bounds to
303 * another buffer.
304 */
305
306 #define BUF_GETBUF_(n, W, w) \
307 int buf_getbuf##w(buf *b, buf *bb) \
308 { \
309 void *p; \
310 size_t sz; \
311 \
312 if ((p = buf_getmem##w(b, &sz)) == 0) \
313 return (-1); \
314 buf_init(bb, p, sz); \
315 return (0); \
316 }
317 BUF_DOSUFFIXES(BUF_GETBUF_)
318
319 /* --- @buf_putbuf{8,{16,24,32,64}{,l,b},z} --- *
320 *
321 * Arguments: @buf *b@ = pointer to a buffer block
322 * @buf *bb@ = buffer to write
323 *
324 * Returns: Zero if it worked, nonzero if there wasn't enough space.
325 *
326 * Use: Puts the contents of a buffer to a buffer.
327 */
328
329 #define BUF_PUTBUF_(n, W, w) \
330 int buf_putbuf##w(buf *b, buf *bb) \
331 { return (buf_putmem##w(b, BBASE(bb), BLEN(bb))); }
332 BUF_DOSUFFIXES(BUF_PUTBUF_)
333
334 /* --- @buf_putstr{8,{16,24,32,64}{,l,b},z} --- *
335 *
336 * Arguments: @buf *b@ = pointer to a buffer block
337 * @const char *p@ = string to write
338 *
339 * Returns: Zero if it worked, nonzero if there wasn't enough space.
340 *
341 * Use: Puts a null-terminated string to a buffer.
342 */
343
344 #define BUF_PUTSTR_(n, W, w) \
345 int buf_putstr##w(buf *b, const char *p) \
346 { return (buf_putmem##w(b, p, strlen(p))); }
347 BUF_DOSUFFIXES(BUF_PUTSTR_)
348
349 /*----- That's all, folks -------------------------------------------------*/
mLib utilities library