Mon, 05 May 2014 15:56:39 +0200
improved more buffer tests + some doc fixes
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2013 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 /**
30 * @file buffer.h
31 *
32 * Advanced buffer implementation.
33 *
34 * Instances of UcxBuffer can be used to read from or to write to like one
35 * would do with a stream. This allows the use of ucx_stream_copy() to copy
36 * contents from one buffer to another.
37 *
38 * Some features for convenient use of the buffer
39 * can be enabled. See the documentation of the macro constants for more
40 * information.
41 *
42 * @author Mike Becker
43 * @author Olaf Wintermann
44 */
46 #ifndef UCX_BUFFER_H
47 #define UCX_BUFFER_H
49 #include "ucx.h"
50 #include <sys/types.h>
51 #include <stdio.h>
53 #ifdef __cplusplus
54 extern "C" {
55 #endif
57 /**
58 * No buffer features enabled (all flags cleared).
59 */
60 #define UCX_BUFFER_DEFAULT 0x00
62 /**
63 * If this flag is enabled, the buffer will automatically free its contents.
64 */
65 #define UCX_BUFFER_AUTOFREE 0x01
67 /**
68 * If this flag is enabled, the buffer will automatically extends its capacity.
69 */
70 #define UCX_BUFFER_AUTOEXTEND 0x02
72 /** UCX Buffer. */
73 typedef struct {
74 /** A pointer to the buffer contents. */
75 char *space;
76 /** Current position of the buffer. */
77 size_t pos;
78 /** Current capacity (i.e. maximum size) of the buffer. */
79 size_t capacity;
80 /** Current size of the buffer content. */
81 size_t size;
82 /**
83 * Flag register for buffer features.
84 * @see #UCX_BUFFER_DEFAULT
85 * @see #UCX_BUFFER_AUTOFREE
86 * @see #UCX_BUFFER_AUTOEXTEND
87 */
88 int flags;
89 } UcxBuffer;
91 /**
92 * Creates a new buffer.
93 *
94 * <b>Note:</b> you may provide <code>NULL</code> as argument for
95 * <code>space</code>. Then this function will allocate the space and enforce
96 * the #UCX_BUFFER_AUTOFREE flag.
97 *
98 * @param space pointer to the memory area, or <code>NULL</code> to allocate
99 * new memory
100 * @param size the size of the buffer
101 * @param flags buffer features (see UcxBuffer.flags)
102 * @return the new buffer
103 */
104 UcxBuffer *ucx_buffer_new(void *space, size_t size, int flags);
106 /**
107 * Destroys a buffer.
108 *
109 * If the #UCX_BUFFER_AUTOFREE feature is enabled, the contents of the buffer
110 * are also freed.
111 *
112 * @param buffer the buffer to destroy
113 */
114 void ucx_buffer_free(UcxBuffer* buffer);
116 /**
117 * Creates a new buffer and fills it with extracted content from another buffer.
118 *
119 * <b>Note:</b> the #UCX_BUFFER_AUTOFREE feature is enforced for the new buffer.
120 *
121 * @param src the source buffer
122 * @param start the start position of extraction
123 * @param length the count of bytes to extract or 0 if all of the remaining
124 * bytes shall be extracted
125 * @param flags feature mask for the new buffer
126 * @return a new buffer containing the extraction
127 */
128 UcxBuffer* ucx_buffer_extract(UcxBuffer *src,
129 size_t start, size_t length, int flags);
131 /**
132 * A shorthand macro for the full extraction of the buffer.
133 *
134 * @param src the source buffer
135 * @param flags feature mask for the new buffer
136 * @return a new buffer with the extracted content
137 */
138 #define ucx_buffer_clone(src,flags) \
139 ucx_buffer_extract(src, 0, 0, flags)
141 /**
142 * Moves the position of the buffer.
143 *
144 * The new position is relative to the <code>whence</code> argument.
145 *
146 * SEEK_SET marks the start of the buffer.
147 * SEEK_CUR marks the current position.
148 * SEEK_END marks the end of the buffer.
149 *
150 * With an offset of zero, this function sets the buffer position to zero
151 * (SEEK_SET), the buffer size (SEEK_END) or leaves the buffer position
152 * unchanged (SEEK_CUR).
153 *
154 * @param buffer
155 * @param offset position offset relative to <code>whence</code>
156 * @param whence one of SEEK_SET, SEEK_CUR or SEEK_END
157 * @return 0 on success, non-zero if the position is invalid
158 *
159 */
160 int ucx_buffer_seek(UcxBuffer *buffer, off_t offset, int whence);
162 /**
163 * Clears the buffer by resetting the position and deleting the data.
164 *
165 * The data is deleted by a zeroing it with call to <code>memset()</code>.
166 *
167 * @param buffer the buffer to be cleared
168 */
169 #define ucx_buffer_clear(buffer) memset(buffer->space, 0, buffer->size); \
170 buffer->size = 0; buffer->pos = 0;
172 /**
173 * Tests, if the buffer position has exceeded the buffer capacity.
174 *
175 * @param buffer the buffer to test
176 * @return non-zero, if the current buffer position has exceeded the last
177 * available byte of the buffer.
178 */
179 int ucx_buffer_eof(UcxBuffer *buffer);
182 /**
183 * Extends the capacity of the buffer.
184 *
185 * <b>Note:</b> The buffer capacity increased by a power of two. I.e.
186 * the buffer capacity is doubled, as long as it would not hold the current
187 * content plus the additional required bytes.
188 *
189 * <b>Attention:</b> the argument provided is the count of <i>additional</i>
190 * bytes the buffer shall hold. It is <b>NOT</b> the total count of bytes the
191 * buffer shall hold.
192 *
193 * @param buffer the buffer to extend
194 * @param additional_bytes the count of additional bytes the buffer shall
195 * <i>at least</i> hold
196 * @return 0 on success or a non-zero value on failure
197 */
198 int ucx_buffer_extend(UcxBuffer *buffer, size_t additional_bytes);
200 /**
201 * Writes data to an UcxBuffer.
202 *
203 * The position of the buffer is increased by the number of bytes read.
204 *
205 * @param ptr a pointer to the memory area containing the bytes to be written
206 * @param size the length of one element
207 * @param nitems the element count
208 * @param buffer the UcxBuffer to write to
209 * @return the total count of bytes written
210 */
211 size_t ucx_buffer_write(const void *ptr, size_t size, size_t nitems,
212 UcxBuffer *buffer);
214 /**
215 * Reads data from an UcxBuffer.
216 *
217 * The position of the buffer is increased by the number of bytes read.
218 *
219 * @param ptr a pointer to the memory area where to store the read data
220 * @param size the length of one element
221 * @param nitems the element count
222 * @param buffer the UcxBuffer to read from
223 * @return the total number of elements read
224 */
225 size_t ucx_buffer_read(void *ptr, size_t size, size_t nitems,
226 UcxBuffer *buffer);
228 /**
229 * Writes a character to a buffer.
230 *
231 * The least significant byte of the argument is written to the buffer. If the
232 * end of the buffer is reached and #UCX_BUFFER_AUTOEXTEND feature is enabled,
233 * the buffer capacity is extended by ucx_buffer_extend(). If the feature is
234 * disabled or buffer extension fails, <code>EOF</code> is returned.
235 *
236 * On successful write the position of the buffer is increased.
237 *
238 * @param buffer the buffer to write to
239 * @param c the character to write as <code>int</code> value
240 * @return the byte that has bean written as <code>int</code> value or
241 * <code>EOF</code> when the end of the stream is reached and automatic
242 * extension is not enabled or not possible
243 */
244 int ucx_buffer_putc(UcxBuffer *buffer, int c);
246 /**
247 * Gets a character from a buffer.
248 *
249 * The current position of the buffer is increased after a successful read.
250 *
251 * @param buffer the buffer to read from
252 * @return the character as <code>int</code> value or <code>EOF</code>, if the
253 * end of the buffer is reached
254 */
255 int ucx_buffer_getc(UcxBuffer *buffer);
257 /**
258 * Writes a string to a buffer.
259 *
260 * @param buffer the buffer
261 * @param str the string
262 * @return the number of bytes written
263 */
264 size_t ucx_buffer_puts(UcxBuffer *buffer, char *str);
266 #ifdef __cplusplus
267 }
268 #endif
270 #endif /* UCX_BUFFER_H */