Mercurial > hg > ucx / file comparison

comparison: src/buffer.c

src/buffer.c

changeset 483
929016224c3c
child 489
af6be1e123aa
equal deleted inserted replaced
482:0d998f19d130 483:929016224c3c
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
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 COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND 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 COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "cx/buffer.h"
30 #include "cx/utils.h"
31
32 #include <stdlib.h>
33 #include <string.h>
34
35 CxBuffer cxBufferCreate(
36 void *space,
37 size_t capacity,
38 int flags
39 ) {
40 CxBuffer buffer = (CxBuffer) malloc(sizeof(cx_buffer_s));
41 if (buffer) {
42 buffer->flags = flags;
43 if (!space) {
44 buffer->bytes = malloc(capacity);
45 if (!buffer->bytes) {
46 free(buffer);
47 return NULL;
48 }
49 memset(buffer->bytes, 0, capacity);
50 buffer->flags |= CX_BUFFER_FREE_CONTENTS;
51 } else {
52 buffer->bytes = space;
53 }
54 buffer->capacity = capacity;
55 buffer->size = 0;
56
57 buffer->pos = 0;
58 }
59
60 return buffer;
61 }
62
63 void cxBufferDestroy(CxBuffer buffer) {
64 if ((buffer->flags & CX_BUFFER_FREE_CONTENTS) == CX_BUFFER_FREE_CONTENTS) {
65 free(buffer->bytes);
66 }
67 free(buffer);
68 }
69
70 CxBuffer cxBufferExtract(
71 CxBuffer src,
72 size_t start,
73 size_t length,
74 int flags
75 ) {
76 if (src->size == 0 || length == 0 ||
77 ((size_t) -1) - start < length || start + length > src->capacity) {
78 return NULL;
79 }
80
81 CxBuffer dst = (CxBuffer) malloc(sizeof(cx_buffer_s));
82 if (dst) {
83 dst->bytes = malloc(length);
84 if (!dst->bytes) {
85 free(dst);
86 return NULL;
87 }
88 dst->capacity = length;
89 dst->size = length;
90 dst->flags = flags | CX_BUFFER_FREE_CONTENTS;
91 dst->pos = 0;
92 memcpy(dst->bytes, src->bytes + start, length);
93 }
94 return dst;
95 }
96
97 int cxBufferSeek(
98 CxBuffer buffer,
99 off_t offset,
100 int whence
101 ) {
102 size_t npos;
103 switch (whence) {
104 case SEEK_CUR:
105 npos = buffer->pos;
106 break;
107 case SEEK_END:
108 npos = buffer->size;
109 break;
110 case SEEK_SET:
111 npos = 0;
112 break;
113 default:
114 return -1;
115 }
116
117 size_t opos = npos;
118 npos += offset;
119
120 if ((offset > 0 && npos < opos) || (offset < 0 && npos > opos)) {
121 return -1;
122 }
123
124 if (npos >= buffer->size) {
125 return -1;
126 } else {
127 buffer->pos = npos;
128 return 0;
129 }
130
131 }
132
133 int cxBufferEof(CxBuffer buffer) {
134 return buffer->pos >= buffer->size;
135 }
136
137 int cxBufferMinimumCapacity(
138 CxBuffer buffer,
139 size_t additional_bytes
140 ) {
141 size_t newcap = buffer->capacity + additional_bytes;
142
143 // overflow protection
144 if (newcap < buffer->capacity) {
145 return -1;
146 }
147
148 unsigned char *newspace = realloc(buffer->bytes, newcap);
149 if (newspace) {
150 memset(newspace + buffer->size, 0, newcap - buffer->size);
151 buffer->bytes = newspace;
152 buffer->capacity = newcap;
153 } else {
154 return -1;
155 }
156
157 return 0;
158 }
159
160 size_t cxBufferWrite(
161 const void *ptr,
162 size_t size,
163 size_t nitems,
164 CxBuffer buffer
165 ) {
166 size_t len;
167 if (cx_szmul(size, nitems, &len)) {
168 return 0;
169 }
170 size_t required = buffer->pos + len;
171 if (buffer->pos > required) {
172 return 0;
173 }
174
175 if (required > buffer->capacity) {
176 if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
177 if (cxBufferMinimumCapacity(buffer, required)) {
178 return 0;
179 }
180 } else {
181 len = buffer->capacity - buffer->pos;
182 if (size > 1) {
183 len -= len % size;
184 }
185 }
186 }
187
188 if (len == 0) {
189 return len;
190 }
191
192 memcpy(buffer->bytes + buffer->pos, ptr, len);
193 buffer->pos += len;
194 if (buffer->pos > buffer->size) {
195 buffer->size = buffer->pos;
196 }
197
198 return len / size;
199 }
200
201 size_t cxBufferRead(
202 void *ptr,
203 size_t size,
204 size_t nitems,
205 CxBuffer buffer
206 ) {
207 size_t len;
208 if (cx_szmul(size, nitems, &len)) {
209 return 0;
210 }
211 if (buffer->pos + len > buffer->size) {
212 len = buffer->size - buffer->pos;
213 if (size > 1) len -= len % size;
214 }
215
216 if (len <= 0) {
217 return len;
218 }
219
220 memcpy(ptr, buffer->bytes + buffer->pos, len);
221 buffer->pos += len;
222
223 return len / size;
224 }
225
226 int cxBufferPut(
227 CxBuffer buffer,
228 int c
229 ) {
230 if (buffer->pos >= buffer->capacity) {
231 if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
232 if (cxBufferMinimumCapacity(buffer, buffer->capacity + 1)) {
233 return EOF;
234 }
235 } else {
236 return EOF;
237 }
238 }
239
240 c &= 0xFF;
241 buffer->bytes[buffer->pos] = (unsigned char) c;
242 buffer->pos++;
243 if (buffer->pos > buffer->size) {
244 buffer->size = buffer->pos;
245 }
246 return c;
247 }
248
249 int cxBufferGet(CxBuffer buffer) {
250 if (cxBufferEof(buffer)) {
251 return EOF;
252 } else {
253 int c = buffer->bytes[buffer->pos];
254 buffer->pos++;
255 return c;
256 }
257 }
258
259 size_t cxBufferPutString(
260 CxBuffer buffer,
261 const char *str
262 ) {
263 return cxBufferWrite(str, 1, strlen(str), buffer);
264 }
265
266 int cxBufferShiftLeft(
267 CxBuffer buffer,
268 size_t shift
269 ) {
270 if (shift >= buffer->size) {
271 buffer->pos = buffer->size = 0;
272 } else {
273 memmove(buffer->bytes, buffer->bytes + shift, buffer->size - shift);
274 buffer->size -= shift;
275
276 if (buffer->pos >= shift) {
277 buffer->pos -= shift;
278 } else {
279 buffer->pos = 0;
280 }
281 }
282 return 0;
283 }
284
285 int cxBufferShiftRight(
286 CxBuffer buffer,
287 size_t shift
288 ) {
289 size_t req_capacity = buffer->size + shift;
290 size_t movebytes;
291
292 // auto extend buffer, if required and enabled
293 if (buffer->capacity < req_capacity) {
294 if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
295 if (cxBufferMinimumCapacity(buffer, req_capacity)) {
296 return 1;
297 }
298 movebytes = buffer->size;
299 } else {
300 movebytes = buffer->capacity - shift;
301 }
302 } else {
303 movebytes = buffer->size;
304 }
305
306 memmove(buffer->bytes + shift, buffer->bytes, movebytes);
307 buffer->size = shift + movebytes;
308
309 buffer->pos += shift;
310 if (buffer->pos > buffer->size) {
311 buffer->pos = buffer->size;
312 }
313
314 return 0;
315 }
316
317 int cxBufferShift(
318 CxBuffer buffer,
319 off_t shift
320 ) {
321 if (shift < 0) {
322 return cxBufferShiftLeft(buffer, (size_t) (-shift));
323 } else if (shift > 0) {
324 return cxBufferShiftRight(buffer, (size_t) shift);
325 } else {
326 return 0;
327 }
328 }

Mercurial Repository: ucx

mercurial