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1 | /* -*-c-*- |
2 | * |
3 | * $Id: dstr.c,v 1.1 1998/06/17 23:44:42 mdw Exp $ |
4 | * |
5 | * Handle dynamically growing strings |
6 | * |
7 | * (c) 1998 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
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 General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with mLib; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: dstr.c,v $ |
32 | * Revision 1.1 1998/06/17 23:44:42 mdw |
33 | * Initial revision |
34 | * |
35 | */ |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #include <stdio.h> |
40 | #include <stdlib.h> |
41 | #include <string.h> |
42 | |
43 | #include "alloc.h" |
44 | #include "dstr.h" |
45 | |
46 | /*----- Tunable constants -------------------------------------------------*/ |
47 | |
48 | #define DSTR_INITSZ 256 /* Initial buffer size */ |
49 | |
50 | /*----- Main code ---------------------------------------------------------*/ |
51 | |
52 | /* --- @dstr_create@ --- * |
53 | * |
54 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
55 | * |
56 | * Returns: --- |
57 | * |
58 | * Use: Initialises a dynamic string. |
59 | */ |
60 | |
61 | void dstr_create(dstr *d) |
62 | { |
63 | d->sz = 0; |
64 | d->len = 0; |
65 | d->buf = 0; |
66 | } |
67 | |
68 | /* --- @dstr_destroy@ --- * |
69 | * |
70 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
71 | * |
72 | * Returns: --- |
73 | * |
74 | * Use: Reclaims the space used by a dynamic string. |
75 | */ |
76 | |
77 | void dstr_destroy(dstr *d) |
78 | { |
79 | if (d->buf) |
80 | free(d->buf); |
81 | d->buf = 0; |
82 | d->len = 0; |
83 | d->sz = 0; |
84 | } |
85 | |
86 | /* --- @dstr_reset@ --- * |
87 | * |
88 | * Arguments: @dstr *d@ = pointer to a dynaimc string block |
89 | * |
90 | * Returns: --- |
91 | * |
92 | * Use: Resets a string so that new data gets put at the beginning. |
93 | */ |
94 | |
95 | void dstr_reset(dstr *d) |
96 | { |
97 | d->len = 0; |
98 | } |
99 | |
100 | /* --- @dstr_ensure@ --- * |
101 | * |
102 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
103 | * @size_t sz@ = amount of free space to ensure |
104 | * |
105 | * Returns: --- |
106 | * |
107 | * Use: Ensures that at least @sz@ bytes are available in the |
108 | * given string. |
109 | */ |
110 | |
111 | void dstr_ensure(dstr *d, size_t sz) |
112 | { |
113 | size_t rq = d->len + sz; |
114 | size_t nsz; |
115 | |
116 | /* --- If we have enough space, just leave it --- */ |
117 | |
118 | if (rq <= d->sz) |
119 | return; |
120 | |
121 | /* --- Grow the buffer --- * |
122 | * |
123 | * For small buffers, just double the size. For big buffers, make them |
124 | * a multiple of some suitably large chunk size. |
125 | */ |
126 | |
127 | nsz = d->sz; |
128 | |
129 | do { |
130 | if (nsz == 0) |
131 | nsz = DSTR_INITSZ; |
132 | else if (d->sz < 0x1000) |
133 | nsz <<= 1; |
134 | else |
135 | nsz = (rq + 0x0fff) & ~0x0fff; |
136 | } while (rq > nsz); |
137 | |
138 | if (d->buf) |
139 | d->buf = xrealloc(d->buf, nsz); |
140 | else |
141 | d->buf = xmalloc(nsz); |
142 | d->sz = nsz; |
143 | } |
144 | |
145 | /* --- @dstr_putc@ --- * |
146 | * |
147 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
148 | * @char ch@ = character to append |
149 | * |
150 | * Returns: --- |
151 | * |
152 | * Use: Appends a character to a string. |
153 | */ |
154 | |
155 | void dstr_putc(dstr *d, char ch) |
156 | { |
157 | DPUTC(d, ch); |
158 | } |
159 | |
160 | /* --- @dstr_putz@ --- * |
161 | * |
162 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
163 | * |
164 | * Returns: --- |
165 | * |
166 | * Use: Appends a null byte to a string. The null byte does not |
167 | * contribute to the string's length, and will be overwritten |
168 | * by subsequent `put' operations. |
169 | */ |
170 | |
171 | void dstr_putz(dstr *d) |
172 | { |
173 | DPUTZ(d); |
174 | } |
175 | |
176 | /* --- @dstr_puts@ --- * |
177 | * |
178 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
179 | * @const char *s@ = pointer to string to append |
180 | * |
181 | * Returns: --- |
182 | * |
183 | * Use: Appends a character string to a string. A trailing null |
184 | * byte is added, as for @dstr_putz@. |
185 | */ |
186 | |
187 | void dstr_puts(dstr *d, const char *s) |
188 | { |
189 | DPUTS(d, s); |
190 | } |
191 | |
192 | /* --- @dstr_putd@ --- * |
193 | * |
194 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
195 | * @const dstr *s@ = pointer to a dynamic string to append |
196 | * |
197 | * Returns: --- |
198 | * |
199 | * Use: Appends a dynamic string to a string. A trailing null |
200 | * byte is added, as for @dstr_putz@. |
201 | */ |
202 | |
203 | void dstr_putd(dstr *d, const dstr *s) |
204 | { |
205 | DPUTD(d, s); |
206 | } |
207 | |
208 | /* --- @dstr_putm@ --- * |
209 | * |
210 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
211 | * @const void *p@ = pointer to a block to append |
212 | * @size_t sz@ = size of the block |
213 | * |
214 | * Returns: Appends an arbitrary data block to a string. No trailing |
215 | * null is appended. |
216 | */ |
217 | |
218 | void dstr_putm(dstr *d, const void *p, size_t sz) |
219 | { |
220 | DPUTM(d, p, sz); |
221 | } |
222 | |
223 | /* --- @dstr_tidy@ --- * |
224 | * |
225 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
226 | * |
227 | * Returns: --- |
228 | * |
229 | * Use: Reduces the amount of memory used by a string. A trailing |
230 | * null byte is added, as for @dstr_putz@. |
231 | */ |
232 | |
233 | void dstr_tidy(dstr *d) |
234 | { |
235 | dstr_putz(d); |
236 | d->buf = xrealloc(d->buf, d->len + 1); |
237 | d->sz = d->len + 1; |
238 | } |
239 | |
240 | /* --- @dstr_putline@ --- * |
241 | * |
242 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
243 | * @FILE *fp@ = a stream to read from |
244 | * |
245 | * Returns: The number of characters read into the buffer, or @EOF@ if |
246 | * end-of-file was reached before any characters were read. |
247 | * |
248 | * Use: Appends the next line from the given input stream to the |
249 | * string. A trailing newline is not added; a trailing null |
250 | * byte is appended, as for @dstr_putz@. |
251 | */ |
252 | |
253 | int dstr_putline(dstr *d, FILE *fp) |
254 | { |
255 | size_t left = d->sz - d->len; |
256 | size_t off = d->len; |
257 | int rd = 0; |
258 | int ch; |
259 | |
260 | for (;;) { |
261 | |
262 | /* --- Make sure there's some buffer space --- */ |
263 | |
264 | if (!left) { |
265 | dstr_ensure(d, 1); |
266 | left = d->sz - off; |
267 | } |
268 | |
269 | /* --- Read the next byte --- */ |
270 | |
271 | ch = getc(fp); |
272 | |
273 | /* --- End-of-file when no characters read is special --- */ |
274 | |
275 | if (ch == EOF && !rd) |
276 | return (EOF); |
277 | |
278 | /* --- End-of-file or newline ends the loop --- */ |
279 | |
280 | if (ch == EOF || ch == '\n') { |
281 | d->buf[off] = 0; |
282 | d->len = off; |
283 | return rd; |
284 | } |
285 | |
286 | /* --- Append the character and continue --- */ |
287 | |
288 | d->buf[off++] = ch; |
289 | left--; rd++; |
290 | } |
291 | } |
292 | |
293 | /* --- @dstr_write@ --- * |
294 | * |
295 | * Arguments: @dstr *d@ = pointer to a dynamic string block |
296 | * @FILE *fp@ = a stream to write on |
297 | * |
298 | * Returns: The number of bytes written (as for @fwrite@). |
299 | * |
300 | * Use: Writes a dynamic string to a file. |
301 | */ |
302 | |
303 | size_t dstr_write(dstr *d, FILE *fp) |
304 | { |
305 | return (fwrite(d->buf, 1, d->len, fp)); |
306 | } |
307 | |
308 | /*----- That's all, folks -------------------------------------------------*/ |