Sun, 24 Apr 2022 17:29:34 +0200
do not implicitly zero freshly allocated memory
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 <stdio.h>
34 #include <string.h>
36 int cxBufferInit(
37 CxBuffer *buffer,
38 void *space,
39 size_t capacity,
40 CxAllocator const *allocator,
41 int flags
42 ) {
43 buffer->allocator = allocator;
44 buffer->flags = flags;
45 if (!space) {
46 buffer->bytes = cxMalloc(allocator, capacity);
47 if (buffer->bytes == NULL) {
48 return 1;
49 }
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 newcap
117 ) {
118 if (newcap <= buffer->capacity) {
119 return 0;
120 }
122 unsigned char *newspace = realloc(buffer->bytes, newcap);
123 if (newspace) {
124 buffer->bytes = newspace;
125 buffer->capacity = newcap;
126 return 0;
127 } else {
128 return -1;
129 }
130 }
132 size_t cxBufferWrite(
133 void const *ptr,
134 size_t size,
135 size_t nitems,
136 CxBuffer *buffer
137 ) {
138 size_t len;
139 if (cx_szmul(size, nitems, &len)) {
140 return 0;
141 }
142 size_t required = buffer->pos + len;
143 if (buffer->pos > required) {
144 return 0;
145 }
147 if (required > buffer->capacity) {
148 if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
149 if (cxBufferMinimumCapacity(buffer, required)) {
150 return 0;
151 }
152 } else {
153 len = buffer->capacity - buffer->pos;
154 if (size > 1) {
155 len -= len % size;
156 }
157 }
158 }
160 if (len == 0) {
161 return len;
162 }
164 memcpy(buffer->bytes + buffer->pos, ptr, len);
165 buffer->pos += len;
166 if (buffer->pos > buffer->size) {
167 buffer->size = buffer->pos;
168 }
170 return len / size;
171 }
173 size_t cxBufferRead(
174 void *ptr,
175 size_t size,
176 size_t nitems,
177 CxBuffer *buffer
178 ) {
179 size_t len;
180 if (cx_szmul(size, nitems, &len)) {
181 return 0;
182 }
183 if (buffer->pos + len > buffer->size) {
184 len = buffer->size - buffer->pos;
185 if (size > 1) len -= len % size;
186 }
188 if (len <= 0) {
189 return len;
190 }
192 memcpy(ptr, buffer->bytes + buffer->pos, len);
193 buffer->pos += len;
195 return len / size;
196 }
198 int cxBufferPut(
199 CxBuffer *buffer,
200 int c
201 ) {
202 if (buffer->pos >= buffer->capacity) {
203 if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
204 if (cxBufferMinimumCapacity(buffer, buffer->capacity + 1)) {
205 return EOF;
206 }
207 } else {
208 return EOF;
209 }
210 }
212 c &= 0xFF;
213 buffer->bytes[buffer->pos] = (unsigned char) c;
214 buffer->pos++;
215 if (buffer->pos > buffer->size) {
216 buffer->size = buffer->pos;
217 }
218 return c;
219 }
221 int cxBufferGet(CxBuffer *buffer) {
222 if (cxBufferEof(buffer)) {
223 return EOF;
224 } else {
225 int c = buffer->bytes[buffer->pos];
226 buffer->pos++;
227 return c;
228 }
229 }
231 size_t cxBufferPutString(
232 CxBuffer *buffer,
233 const char *str
234 ) {
235 return cxBufferWrite(str, 1, strlen(str), buffer);
236 }
238 int cxBufferShiftLeft(
239 CxBuffer *buffer,
240 size_t shift
241 ) {
242 if (shift >= buffer->size) {
243 buffer->pos = buffer->size = 0;
244 } else {
245 memmove(buffer->bytes, buffer->bytes + shift, buffer->size - shift);
246 buffer->size -= shift;
248 if (buffer->pos >= shift) {
249 buffer->pos -= shift;
250 } else {
251 buffer->pos = 0;
252 }
253 }
254 return 0;
255 }
257 int cxBufferShiftRight(
258 CxBuffer *buffer,
259 size_t shift
260 ) {
261 size_t req_capacity = buffer->size + shift;
262 size_t movebytes;
264 // auto extend buffer, if required and enabled
265 if (buffer->capacity < req_capacity) {
266 if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
267 if (cxBufferMinimumCapacity(buffer, req_capacity)) {
268 return 1;
269 }
270 movebytes = buffer->size;
271 } else {
272 movebytes = buffer->capacity - shift;
273 }
274 } else {
275 movebytes = buffer->size;
276 }
278 memmove(buffer->bytes + shift, buffer->bytes, movebytes);
279 buffer->size = shift + movebytes;
281 buffer->pos += shift;
282 if (buffer->pos > buffer->size) {
283 buffer->pos = buffer->size;
284 }
286 return 0;
287 }
289 int cxBufferShift(
290 CxBuffer *buffer,
291 off_t shift
292 ) {
293 if (shift < 0) {
294 return cxBufferShiftLeft(buffer, (size_t) (-shift));
295 } else if (shift > 0) {
296 return cxBufferShiftRight(buffer, (size_t) shift);
297 } else {
298 return 0;
299 }
300 }