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universe@483 | 1 | /* |
universe@483 | 2 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. |
universe@483 | 3 | * |
universe@483 | 4 | * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved. |
universe@483 | 5 | * |
universe@483 | 6 | * Redistribution and use in source and binary forms, with or without |
universe@483 | 7 | * modification, are permitted provided that the following conditions are met: |
universe@483 | 8 | * |
universe@483 | 9 | * 1. Redistributions of source code must retain the above copyright |
universe@483 | 10 | * notice, this list of conditions and the following disclaimer. |
universe@483 | 11 | * |
universe@483 | 12 | * 2. Redistributions in binary form must reproduce the above copyright |
universe@483 | 13 | * notice, this list of conditions and the following disclaimer in the |
universe@483 | 14 | * documentation and/or other materials provided with the distribution. |
universe@483 | 15 | * |
universe@483 | 16 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
universe@483 | 17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
universe@483 | 18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
universe@483 | 19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
universe@483 | 20 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
universe@483 | 21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
universe@483 | 22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
universe@483 | 23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
universe@483 | 24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
universe@483 | 25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
universe@483 | 26 | * POSSIBILITY OF SUCH DAMAGE. |
universe@483 | 27 | */ |
universe@483 | 28 | |
universe@483 | 29 | /** |
universe@483 | 30 | * \file buffer.h |
universe@483 | 31 | * |
universe@483 | 32 | * \brief Advanced buffer implementation. |
universe@483 | 33 | * |
universe@483 | 34 | * Instances of CxBuffer can be used to read from or to write to like one |
universe@483 | 35 | * would do with a stream. |
universe@483 | 36 | * |
universe@483 | 37 | * Some features for convenient use of the buffer |
universe@483 | 38 | * can be enabled. See the documentation of the macro constants for more |
universe@483 | 39 | * information. |
universe@483 | 40 | * |
universe@483 | 41 | * \author Mike Becker |
universe@483 | 42 | * \author Olaf Wintermann |
universe@483 | 43 | * \version 3.0 |
universe@483 | 44 | * \copyright 2-Clause BSD License |
universe@483 | 45 | */ |
universe@483 | 46 | |
universe@483 | 47 | #ifndef UCX_BUFFER_H |
universe@484 | 48 | #define UCX_BUFFER_H |
universe@483 | 49 | |
universe@484 | 50 | #include "common.h" |
universe@483 | 51 | #include <stdio.h> |
universe@483 | 52 | |
universe@483 | 53 | #ifdef __cplusplus |
universe@483 | 54 | extern "C" { |
universe@483 | 55 | #endif |
universe@483 | 56 | |
universe@483 | 57 | /** |
universe@483 | 58 | * No buffer features enabled (all flags cleared). |
universe@483 | 59 | */ |
universe@483 | 60 | #define CX_BUFFER_DEFAULT 0x00 |
universe@483 | 61 | |
universe@483 | 62 | /** |
universe@483 | 63 | * If this flag is enabled, the buffer will automatically free its contents when destroyed. |
universe@483 | 64 | */ |
universe@483 | 65 | #define CX_BUFFER_FREE_CONTENTS 0x01 |
universe@483 | 66 | |
universe@483 | 67 | /** |
universe@483 | 68 | * If this flag is enabled, the buffer will automatically extends its capacity. |
universe@483 | 69 | */ |
universe@483 | 70 | #define CX_BUFFER_AUTO_EXTEND 0x02 |
universe@483 | 71 | |
universe@483 | 72 | /** Structure for the UCX buffer data. */ |
universe@483 | 73 | typedef struct { |
universe@483 | 74 | /** A pointer to the buffer contents. */ |
universe@483 | 75 | union { |
universe@483 | 76 | /** |
universe@483 | 77 | * Data is interpreted as text. |
universe@483 | 78 | */ |
universe@483 | 79 | char *space; |
universe@483 | 80 | /** |
universe@483 | 81 | * Data is interpreted as binary. |
universe@483 | 82 | */ |
universe@483 | 83 | unsigned char *bytes; |
universe@483 | 84 | }; |
universe@483 | 85 | /** Current position of the buffer. */ |
universe@483 | 86 | size_t pos; |
universe@483 | 87 | /** Current capacity (i.e. maximum size) of the buffer. */ |
universe@483 | 88 | size_t capacity; |
universe@483 | 89 | /** Current size of the buffer content. */ |
universe@483 | 90 | size_t size; |
universe@483 | 91 | /** |
universe@483 | 92 | * Flag register for buffer features. |
universe@485 | 93 | * @see #CX_BUFFER_DEFAULT |
universe@485 | 94 | * @see #CX_BUFFER_FREE_CONTENTS |
universe@485 | 95 | * @see #CX_BUFFER_AUTO_EXTEND |
universe@483 | 96 | */ |
universe@483 | 97 | int flags; |
universe@483 | 98 | } cx_buffer_s; |
universe@483 | 99 | |
universe@483 | 100 | /** |
universe@483 | 101 | * UCX buffer. |
universe@483 | 102 | */ |
universe@483 | 103 | typedef cx_buffer_s *CxBuffer; |
universe@483 | 104 | |
universe@483 | 105 | /** |
universe@483 | 106 | * Creates a new buffer. |
universe@483 | 107 | * |
universe@483 | 108 | * \note You may provide \c NULL as argument for \p space. |
universe@483 | 109 | * Then this function will allocate the space and enforce |
universe@483 | 110 | * the #CX_BUFFER_FREE_CONTENTS flag. |
universe@483 | 111 | * |
universe@485 | 112 | * @param space pointer to the memory area, or <code>NULL</code> to allocate |
universe@483 | 113 | * new memory |
universe@485 | 114 | * @param capacity the capacity of the buffer |
universe@485 | 115 | * @param flags buffer features (see cx_buffer_s.flags) |
universe@485 | 116 | * @return the new buffer |
universe@483 | 117 | */ |
universe@483 | 118 | CxBuffer cxBufferCreate( |
universe@483 | 119 | void *space, |
universe@483 | 120 | size_t capacity, |
universe@483 | 121 | int flags |
universe@483 | 122 | ); |
universe@483 | 123 | |
universe@483 | 124 | /** |
universe@483 | 125 | * Destroys a buffer. |
universe@483 | 126 | * |
universe@483 | 127 | * If the #CX_BUFFER_FREE_CONTENTS feature is enabled, the contents of the buffer |
universe@483 | 128 | * are also freed. |
universe@483 | 129 | * |
universe@485 | 130 | * @param buffer the buffer to destroy |
universe@483 | 131 | */ |
universe@483 | 132 | void cxBufferDestroy(CxBuffer buffer); |
universe@483 | 133 | |
universe@483 | 134 | /** |
universe@483 | 135 | * Creates a new buffer and fills it with content copied from another buffer. |
universe@483 | 136 | * |
universe@483 | 137 | * \note The #CX_BUFFER_FREE_CONTENTS feature is enforced for the new buffer. |
universe@483 | 138 | * |
universe@485 | 139 | * @param src the source buffer |
universe@485 | 140 | * @param start the start position of extraction |
universe@485 | 141 | * @param length the count of bytes to extract (must not be zero) |
universe@485 | 142 | * @param flags features for the new buffer (#CX_BUFFER_FREE_CONTENTS will always be enabled) |
universe@485 | 143 | * @return a new buffer containing the extraction |
universe@483 | 144 | */ |
universe@483 | 145 | CxBuffer cxBufferExtract( |
universe@483 | 146 | CxBuffer src, |
universe@483 | 147 | size_t start, |
universe@483 | 148 | size_t length, |
universe@483 | 149 | int flags |
universe@483 | 150 | ); |
universe@483 | 151 | |
universe@483 | 152 | /** |
universe@483 | 153 | * A shorthand macro for copying an entire buffer. |
universe@483 | 154 | * |
universe@485 | 155 | * @param src the source buffer |
universe@485 | 156 | * @param flags features for the new buffer (#CX_BUFFER_FREE_CONTENTS will always be enabled) |
universe@485 | 157 | * @return a new buffer with the copied content |
universe@483 | 158 | */ |
universe@483 | 159 | #define cxBufferClone(src, flags) cxBufferExtract(src, 0, (src)->capacity, flags) |
universe@483 | 160 | |
universe@483 | 161 | |
universe@483 | 162 | /** |
universe@483 | 163 | * Shifts the contents of the buffer by the given offset. |
universe@483 | 164 | * |
universe@483 | 165 | * If the offset is positive, the contents are shifted to the right. |
universe@483 | 166 | * If auto extension is enabled, the buffer grows, if necessary. |
universe@483 | 167 | * In case the auto extension fails, this function returns a non-zero value and |
universe@483 | 168 | * no contents are changed. |
universe@483 | 169 | * If auto extension is disabled, the contents that do not fit into the buffer |
universe@483 | 170 | * are discarded. |
universe@483 | 171 | * |
universe@483 | 172 | * If the offset is negative, the contents are shifted to the left where the |
universe@483 | 173 | * first \p shift bytes are discarded. |
universe@483 | 174 | * The new size of the buffer is the old size minus the absolute shift value. |
universe@483 | 175 | * If this value is larger than the buffer size, the buffer is emptied (but |
universe@483 | 176 | * not cleared, see the security note below). |
universe@483 | 177 | * |
universe@483 | 178 | * The buffer position gets shifted alongside with the content but is kept |
universe@483 | 179 | * within the boundaries of the buffer. |
universe@483 | 180 | * |
universe@483 | 181 | * \note For situations where \c off_t is not large enough, there are specialized cxBufferShiftLeft() and |
universe@483 | 182 | * cxBufferShiftRight() functions using a \c size_t as parameter type. |
universe@483 | 183 | * |
universe@485 | 184 | * \attention |
universe@485 | 185 | * Security Note: The shifting operation does \em not erase the previously occupied memory cells. |
universe@485 | 186 | * But you can easily do that manually, e.g. by calling |
universe@483 | 187 | * <code>memset(buffer->bytes, 0, shift)</code> for a right shift or |
universe@483 | 188 | * <code>memset(buffer->size, 0, buffer->capacity - buffer->size)</code> |
universe@483 | 189 | * for a left shift. |
universe@483 | 190 | * |
universe@485 | 191 | * @param buffer the buffer |
universe@485 | 192 | * @param shift the shift offset (negative means left shift) |
universe@485 | 193 | * @return 0 on success, non-zero if a required auto-extension fails |
universe@483 | 194 | */ |
universe@483 | 195 | int cxBufferShift( |
universe@483 | 196 | CxBuffer buffer, |
universe@483 | 197 | off_t shift |
universe@483 | 198 | ); |
universe@483 | 199 | |
universe@483 | 200 | /** |
universe@483 | 201 | * Shifts the buffer to the right. |
universe@483 | 202 | * See cxBufferShift() for details. |
universe@483 | 203 | * |
universe@485 | 204 | * @param buffer the buffer |
universe@485 | 205 | * @param shift the shift offset |
universe@485 | 206 | * @return 0 on success, non-zero if a required auto-extension fails |
universe@485 | 207 | * @see cxBufferShift() |
universe@483 | 208 | */ |
universe@483 | 209 | int cxBufferShiftRight( |
universe@483 | 210 | CxBuffer buffer, |
universe@483 | 211 | size_t shift |
universe@483 | 212 | ); |
universe@483 | 213 | |
universe@483 | 214 | /** |
universe@483 | 215 | * Shifts the buffer to the left. |
universe@483 | 216 | * See cxBufferShift() for details. |
universe@483 | 217 | * |
universe@483 | 218 | * \note Since a left shift cannot fail due to memory allocation problems, this |
universe@483 | 219 | * function always returns zero. |
universe@483 | 220 | * |
universe@485 | 221 | * @param buffer the buffer |
universe@485 | 222 | * @param shift the positive shift offset |
universe@485 | 223 | * @return always zero |
universe@485 | 224 | * @see cxBufferShift() |
universe@483 | 225 | */ |
universe@483 | 226 | int cxBufferShiftLeft( |
universe@483 | 227 | CxBuffer buffer, |
universe@483 | 228 | size_t shift |
universe@483 | 229 | ); |
universe@483 | 230 | |
universe@483 | 231 | |
universe@483 | 232 | /** |
universe@483 | 233 | * Moves the position of the buffer. |
universe@483 | 234 | * |
universe@483 | 235 | * The new position is relative to the \p whence argument. |
universe@483 | 236 | * |
universe@483 | 237 | * \li \c SEEK_SET marks the start of the buffer. |
universe@483 | 238 | * \li \c SEEK_CUR marks the current position. |
universe@483 | 239 | * \li \c SEEK_END marks the end of the buffer. |
universe@483 | 240 | * |
universe@483 | 241 | * With an offset of zero, this function sets the buffer position to zero |
universe@483 | 242 | * (\c SEEK_SET), the buffer size (\c SEEK_END) or leaves the buffer position |
universe@483 | 243 | * unchanged (\c SEEK_CUR). |
universe@483 | 244 | * |
universe@485 | 245 | * @param buffer the buffer |
universe@485 | 246 | * @param offset position offset relative to \p whence |
universe@485 | 247 | * @param whence one of \c SEEK_SET, \c SEEK_CUR or \c SEEK_END |
universe@485 | 248 | * @return 0 on success, non-zero if the position is invalid |
universe@483 | 249 | * |
universe@483 | 250 | */ |
universe@483 | 251 | int cxBufferSeek( |
universe@483 | 252 | CxBuffer buffer, |
universe@483 | 253 | off_t offset, |
universe@483 | 254 | int whence |
universe@483 | 255 | ); |
universe@483 | 256 | |
universe@483 | 257 | /** |
universe@483 | 258 | * Clears the buffer by resetting the position and deleting the data. |
universe@483 | 259 | * |
universe@483 | 260 | * The data is deleted by zeroing it with a call to memset(). |
universe@483 | 261 | * |
universe@485 | 262 | * @param buffer the buffer to be cleared |
universe@483 | 263 | */ |
universe@483 | 264 | #define cxBufferClear(buffer) memset((buffer)->bytes, 0, (buffer)->size); \ |
universe@483 | 265 | (buffer)->size = 0; (buffer)->pos = 0; |
universe@483 | 266 | |
universe@483 | 267 | /** |
universe@483 | 268 | * Tests, if the buffer position has exceeded the buffer capacity. |
universe@483 | 269 | * |
universe@485 | 270 | * @param buffer the buffer to test |
universe@485 | 271 | * @return non-zero, if the current buffer position has exceeded the last |
universe@483 | 272 | * available byte of the buffer. |
universe@483 | 273 | */ |
universe@483 | 274 | int cxBufferEof(CxBuffer buffer); |
universe@483 | 275 | |
universe@483 | 276 | |
universe@483 | 277 | /** |
universe@483 | 278 | * Ensures that the buffer has a minimum capacity. |
universe@483 | 279 | * |
universe@483 | 280 | * If the current capacity is not sufficient, the buffer will be extended. |
universe@483 | 281 | * |
universe@485 | 282 | * @param buffer the buffer |
universe@485 | 283 | * @param capacity the minimum required capacity for this buffer |
universe@485 | 284 | * @return 0 on success or a non-zero value on failure |
universe@483 | 285 | */ |
universe@483 | 286 | int cxBufferMinimumCapacity( |
universe@483 | 287 | CxBuffer buffer, |
universe@483 | 288 | size_t capacity |
universe@483 | 289 | ); |
universe@483 | 290 | |
universe@483 | 291 | /** |
universe@483 | 292 | * Writes data to a CxBuffer. |
universe@483 | 293 | * |
universe@483 | 294 | * The position of the buffer is increased by the number of bytes written. |
universe@483 | 295 | * |
universe@483 | 296 | * \note The signature is compatible with the fwrite() family of functions. |
universe@483 | 297 | * |
universe@485 | 298 | * @param ptr a pointer to the memory area containing the bytes to be written |
universe@485 | 299 | * @param size the length of one element |
universe@485 | 300 | * @param nitems the element count |
universe@485 | 301 | * @param buffer the CxBuffer to write to |
universe@485 | 302 | * @return the total count of bytes written |
universe@483 | 303 | */ |
universe@483 | 304 | size_t cxBufferWrite( |
universe@489 | 305 | void const *ptr, |
universe@483 | 306 | size_t size, |
universe@483 | 307 | size_t nitems, |
universe@483 | 308 | CxBuffer buffer |
universe@483 | 309 | ); |
universe@483 | 310 | |
universe@483 | 311 | /** |
universe@483 | 312 | * Reads data from a CxBuffer. |
universe@483 | 313 | * |
universe@483 | 314 | * The position of the buffer is increased by the number of bytes read. |
universe@483 | 315 | * |
universe@483 | 316 | * \note The signature is compatible with the fread() family of functions. |
universe@483 | 317 | * |
universe@485 | 318 | * @param ptr a pointer to the memory area where to store the read data |
universe@485 | 319 | * @param size the length of one element |
universe@485 | 320 | * @param nitems the element count |
universe@485 | 321 | * @param buffer the CxBuffer to read from |
universe@485 | 322 | * @return the total number of elements read |
universe@483 | 323 | */ |
universe@483 | 324 | size_t cxBufferRead( |
universe@483 | 325 | void *ptr, |
universe@483 | 326 | size_t size, |
universe@483 | 327 | size_t nitems, |
universe@483 | 328 | CxBuffer buffer |
universe@483 | 329 | ); |
universe@483 | 330 | |
universe@483 | 331 | /** |
universe@483 | 332 | * Writes a character to a buffer. |
universe@483 | 333 | * |
universe@483 | 334 | * The least significant byte of the argument is written to the buffer. If the |
universe@483 | 335 | * end of the buffer is reached and #CX_BUFFER_AUTO_EXTEND feature is enabled, |
universe@483 | 336 | * the buffer capacity is extended by cxBufferMinimumCapacity(). If the feature is |
universe@483 | 337 | * disabled or buffer extension fails, \c EOF is returned. |
universe@483 | 338 | * |
universe@483 | 339 | * On successful write, the position of the buffer is increased. |
universe@483 | 340 | * |
universe@485 | 341 | * @param buffer the buffer to write to |
universe@485 | 342 | * @param c the character to write |
universe@485 | 343 | * @return the byte that has bean written or \c EOF when the end of the stream is |
universe@483 | 344 | * reached and automatic extension is not enabled or not possible |
universe@483 | 345 | */ |
universe@483 | 346 | int cxBufferPut( |
universe@483 | 347 | CxBuffer buffer, |
universe@483 | 348 | int c |
universe@483 | 349 | ); |
universe@483 | 350 | |
universe@483 | 351 | /** |
universe@483 | 352 | * Gets a character from a buffer. |
universe@483 | 353 | * |
universe@483 | 354 | * The current position of the buffer is increased after a successful read. |
universe@483 | 355 | * |
universe@485 | 356 | * @param buffer the buffer to read from |
universe@485 | 357 | * @return the character or \c EOF, if the end of the buffer is reached |
universe@483 | 358 | */ |
universe@483 | 359 | int cxBufferGet(CxBuffer buffer); |
universe@483 | 360 | |
universe@483 | 361 | /** |
universe@483 | 362 | * Writes a string to a buffer. |
universe@483 | 363 | * |
universe@485 | 364 | * @param buffer the buffer |
universe@485 | 365 | * @param str the zero-terminated string |
universe@485 | 366 | * @return the number of bytes written |
universe@483 | 367 | */ |
universe@483 | 368 | size_t cxBufferPutString( |
universe@483 | 369 | CxBuffer buffer, |
universe@483 | 370 | const char *str |
universe@483 | 371 | ); |
universe@483 | 372 | |
universe@483 | 373 | #ifdef __cplusplus |
universe@483 | 374 | } |
universe@483 | 375 | #endif |
universe@483 | 376 | |
universe@483 | 377 | #endif /* UCX_BUFFER_H */ |