Sun, 24 Apr 2022 14:54:50 +0200
#171 const qualifier and nonnull attributes
Also removes cxBufferExtract temporarily.
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 */
29 #include "cx/buffer.h"
30 #include "cx/utils.h"
32 #include <stdlib.h>
33 #include <string.h>
35 int cxBufferInit(
36 CxBuffer *buffer,
37 void *space,
38 size_t capacity,
39 CxAllocator const *allocator,
40 int flags
41 ) {
42 buffer->allocator = allocator;
43 buffer->flags = flags;
44 if (!space) {
45 buffer->bytes = cxMalloc(allocator, capacity);
46 if (buffer->bytes == NULL) {
47 return 1;
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;
57 buffer->pos = 0;
59 return 0;
60 }
62 void cxBufferDestroy(CxBuffer *buffer) {
63 if ((buffer->flags & CX_BUFFER_FREE_CONTENTS) == CX_BUFFER_FREE_CONTENTS) {
64 cxFree(buffer->allocator, buffer->bytes);
65 }
66 }
68 int cxBufferSeek(
69 CxBuffer *buffer,
70 off_t offset,
71 int whence
72 ) {
73 size_t npos;
74 switch (whence) {
75 case SEEK_CUR:
76 npos = buffer->pos;
77 break;
78 case SEEK_END:
79 npos = buffer->size;
80 break;
81 case SEEK_SET:
82 npos = 0;
83 break;
84 default:
85 return -1;
86 }
88 size_t opos = npos;
89 npos += offset;
91 if ((offset > 0 && npos < opos) || (offset < 0 && npos > opos)) {
92 return -1;
93 }
95 if (npos >= buffer->size) {
96 return -1;
97 } else {
98 buffer->pos = npos;
99 return 0;
100 }
102 }
104 void cxBufferClear(CxBuffer *buffer) {
105 memset(buffer->bytes, 0, buffer->size);
106 buffer->size = 0;
107 buffer->pos = 0;
108 }
110 int cxBufferEof(CxBuffer const *buffer) {
111 return buffer->pos >= buffer->size;
112 }
114 int cxBufferMinimumCapacity(
115 CxBuffer *buffer,
116 size_t additional_bytes
117 ) {
118 size_t newcap = buffer->capacity + additional_bytes;
120 // overflow protection
121 if (newcap < buffer->capacity) {
122 return -1;
123 }
125 unsigned char *newspace = realloc(buffer->bytes, newcap);
126 if (newspace) {
127 memset(newspace + buffer->size, 0, newcap - buffer->size);
128 buffer->bytes = newspace;
129 buffer->capacity = newcap;
130 } else {
131 return -1;
132 }
134 return 0;
135 }
137 size_t cxBufferWrite(
138 void const *ptr,
139 size_t size,
140 size_t nitems,
141 CxBuffer *buffer
142 ) {
143 size_t len;
144 if (cx_szmul(size, nitems, &len)) {
145 return 0;
146 }
147 size_t required = buffer->pos + len;
148 if (buffer->pos > required) {
149 return 0;
150 }
152 if (required > buffer->capacity) {
153 if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
154 if (cxBufferMinimumCapacity(buffer, required)) {
155 return 0;
156 }
157 } else {
158 len = buffer->capacity - buffer->pos;
159 if (size > 1) {
160 len -= len % size;
161 }
162 }
163 }
165 if (len == 0) {
166 return len;
167 }
169 memcpy(buffer->bytes + buffer->pos, ptr, len);
170 buffer->pos += len;
171 if (buffer->pos > buffer->size) {
172 buffer->size = buffer->pos;
173 }
175 return len / size;
176 }
178 size_t cxBufferRead(
179 void *ptr,
180 size_t size,
181 size_t nitems,
182 CxBuffer *buffer
183 ) {
184 size_t len;
185 if (cx_szmul(size, nitems, &len)) {
186 return 0;
187 }
188 if (buffer->pos + len > buffer->size) {
189 len = buffer->size - buffer->pos;
190 if (size > 1) len -= len % size;
191 }
193 if (len <= 0) {
194 return len;
195 }
197 memcpy(ptr, buffer->bytes + buffer->pos, len);
198 buffer->pos += len;
200 return len / size;
201 }
203 int cxBufferPut(
204 CxBuffer *buffer,
205 int c
206 ) {
207 if (buffer->pos >= buffer->capacity) {
208 if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
209 if (cxBufferMinimumCapacity(buffer, buffer->capacity + 1)) {
210 return EOF;
211 }
212 } else {
213 return EOF;
214 }
215 }
217 c &= 0xFF;
218 buffer->bytes[buffer->pos] = (unsigned char) c;
219 buffer->pos++;
220 if (buffer->pos > buffer->size) {
221 buffer->size = buffer->pos;
222 }
223 return c;
224 }
226 int cxBufferGet(CxBuffer *buffer) {
227 if (cxBufferEof(buffer)) {
228 return EOF;
229 } else {
230 int c = buffer->bytes[buffer->pos];
231 buffer->pos++;
232 return c;
233 }
234 }
236 size_t cxBufferPutString(
237 CxBuffer *buffer,
238 const char *str
239 ) {
240 return cxBufferWrite(str, 1, strlen(str), buffer);
241 }
243 int cxBufferShiftLeft(
244 CxBuffer *buffer,
245 size_t shift
246 ) {
247 if (shift >= buffer->size) {
248 buffer->pos = buffer->size = 0;
249 } else {
250 memmove(buffer->bytes, buffer->bytes + shift, buffer->size - shift);
251 buffer->size -= shift;
253 if (buffer->pos >= shift) {
254 buffer->pos -= shift;
255 } else {
256 buffer->pos = 0;
257 }
258 }
259 return 0;
260 }
262 int cxBufferShiftRight(
263 CxBuffer *buffer,
264 size_t shift
265 ) {
266 size_t req_capacity = buffer->size + shift;
267 size_t movebytes;
269 // auto extend buffer, if required and enabled
270 if (buffer->capacity < req_capacity) {
271 if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
272 if (cxBufferMinimumCapacity(buffer, req_capacity)) {
273 return 1;
274 }
275 movebytes = buffer->size;
276 } else {
277 movebytes = buffer->capacity - shift;
278 }
279 } else {
280 movebytes = buffer->size;
281 }
283 memmove(buffer->bytes + shift, buffer->bytes, movebytes);
284 buffer->size = shift + movebytes;
286 buffer->pos += shift;
287 if (buffer->pos > buffer->size) {
288 buffer->pos = buffer->size;
289 }
291 return 0;
292 }
294 int cxBufferShift(
295 CxBuffer *buffer,
296 off_t shift
297 ) {
298 if (shift < 0) {
299 return cxBufferShiftLeft(buffer, (size_t) (-shift));
300 } else if (shift > 0) {
301 return cxBufferShiftRight(buffer, (size_t) shift);
302 } else {
303 return 0;
304 }
305 }