1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/ucx/buffer.h Tue Aug 23 13:49:38 2016 +0200
1.3 @@ -0,0 +1,270 @@
1.4 +/*
1.5 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
1.6 + *
1.7 + * Copyright 2015 Olaf Wintermann. All rights reserved.
1.8 + *
1.9 + * Redistribution and use in source and binary forms, with or without
1.10 + * modification, are permitted provided that the following conditions are met:
1.11 + *
1.12 + * 1. Redistributions of source code must retain the above copyright
1.13 + * notice, this list of conditions and the following disclaimer.
1.14 + *
1.15 + * 2. Redistributions in binary form must reproduce the above copyright
1.16 + * notice, this list of conditions and the following disclaimer in the
1.17 + * documentation and/or other materials provided with the distribution.
1.18 + *
1.19 + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.20 + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.21 + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.22 + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
1.23 + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.24 + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.25 + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.26 + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.27 + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.28 + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.29 + * POSSIBILITY OF SUCH DAMAGE.
1.30 + */
1.31 +
1.32 +/**
1.33 + * @file buffer.h
1.34 + *
1.35 + * Advanced buffer implementation.
1.36 + *
1.37 + * Instances of UcxBuffer can be used to read from or to write to like one
1.38 + * would do with a stream. This allows the use of ucx_stream_copy() to copy
1.39 + * contents from one buffer to another.
1.40 + *
1.41 + * Some features for convenient use of the buffer
1.42 + * can be enabled. See the documentation of the macro constants for more
1.43 + * information.
1.44 + *
1.45 + * @author Mike Becker
1.46 + * @author Olaf Wintermann
1.47 + */
1.48 +
1.49 +#ifndef UCX_BUFFER_H
1.50 +#define UCX_BUFFER_H
1.51 +
1.52 +#include "ucx.h"
1.53 +#include <sys/types.h>
1.54 +#include <stdio.h>
1.55 +
1.56 +#ifdef __cplusplus
1.57 +extern "C" {
1.58 +#endif
1.59 +
1.60 +/**
1.61 + * No buffer features enabled (all flags cleared).
1.62 + */
1.63 +#define UCX_BUFFER_DEFAULT 0x00
1.64 +
1.65 +/**
1.66 + * If this flag is enabled, the buffer will automatically free its contents.
1.67 + */
1.68 +#define UCX_BUFFER_AUTOFREE 0x01
1.69 +
1.70 +/**
1.71 + * If this flag is enabled, the buffer will automatically extends its capacity.
1.72 + */
1.73 +#define UCX_BUFFER_AUTOEXTEND 0x02
1.74 +
1.75 +/** UCX Buffer. */
1.76 +typedef struct {
1.77 + /** A pointer to the buffer contents. */
1.78 + char *space;
1.79 + /** Current position of the buffer. */
1.80 + size_t pos;
1.81 + /** Current capacity (i.e. maximum size) of the buffer. */
1.82 + size_t capacity;
1.83 + /** Current size of the buffer content. */
1.84 + size_t size;
1.85 + /**
1.86 + * Flag register for buffer features.
1.87 + * @see #UCX_BUFFER_DEFAULT
1.88 + * @see #UCX_BUFFER_AUTOFREE
1.89 + * @see #UCX_BUFFER_AUTOEXTEND
1.90 + */
1.91 + int flags;
1.92 +} UcxBuffer;
1.93 +
1.94 +/**
1.95 + * Creates a new buffer.
1.96 + *
1.97 + * <b>Note:</b> you may provide <code>NULL</code> as argument for
1.98 + * <code>space</code>. Then this function will allocate the space and enforce
1.99 + * the #UCX_BUFFER_AUTOFREE flag.
1.100 + *
1.101 + * @param space pointer to the memory area, or <code>NULL</code> to allocate
1.102 + * new memory
1.103 + * @param capacity the capacity of the buffer
1.104 + * @param flags buffer features (see UcxBuffer.flags)
1.105 + * @return the new buffer
1.106 + */
1.107 +UcxBuffer *ucx_buffer_new(void *space, size_t capacity, int flags);
1.108 +
1.109 +/**
1.110 + * Destroys a buffer.
1.111 + *
1.112 + * If the #UCX_BUFFER_AUTOFREE feature is enabled, the contents of the buffer
1.113 + * are also freed.
1.114 + *
1.115 + * @param buffer the buffer to destroy
1.116 + */
1.117 +void ucx_buffer_free(UcxBuffer* buffer);
1.118 +
1.119 +/**
1.120 + * Creates a new buffer and fills it with extracted content from another buffer.
1.121 + *
1.122 + * <b>Note:</b> the #UCX_BUFFER_AUTOFREE feature is enforced for the new buffer.
1.123 + *
1.124 + * @param src the source buffer
1.125 + * @param start the start position of extraction
1.126 + * @param length the count of bytes to extract (must not be zero)
1.127 + * @param flags feature mask for the new buffer
1.128 + * @return a new buffer containing the extraction
1.129 + */
1.130 +UcxBuffer* ucx_buffer_extract(UcxBuffer *src,
1.131 + size_t start, size_t length, int flags);
1.132 +
1.133 +/**
1.134 + * A shorthand macro for the full extraction of the buffer.
1.135 + *
1.136 + * @param src the source buffer
1.137 + * @param flags feature mask for the new buffer
1.138 + * @return a new buffer with the extracted content
1.139 + */
1.140 +#define ucx_buffer_clone(src,flags) \
1.141 + ucx_buffer_extract(src, 0, (src)->capacity, flags)
1.142 +
1.143 +/**
1.144 + * Moves the position of the buffer.
1.145 + *
1.146 + * The new position is relative to the <code>whence</code> argument.
1.147 + *
1.148 + * SEEK_SET marks the start of the buffer.
1.149 + * SEEK_CUR marks the current position.
1.150 + * SEEK_END marks the end of the buffer.
1.151 + *
1.152 + * With an offset of zero, this function sets the buffer position to zero
1.153 + * (SEEK_SET), the buffer size (SEEK_END) or leaves the buffer position
1.154 + * unchanged (SEEK_CUR).
1.155 + *
1.156 + * @param buffer
1.157 + * @param offset position offset relative to <code>whence</code>
1.158 + * @param whence one of SEEK_SET, SEEK_CUR or SEEK_END
1.159 + * @return 0 on success, non-zero if the position is invalid
1.160 + *
1.161 + */
1.162 +int ucx_buffer_seek(UcxBuffer *buffer, off_t offset, int whence);
1.163 +
1.164 +/**
1.165 + * Clears the buffer by resetting the position and deleting the data.
1.166 + *
1.167 + * The data is deleted by a zeroing it with call to <code>memset()</code>.
1.168 + *
1.169 + * @param buffer the buffer to be cleared
1.170 + */
1.171 +#define ucx_buffer_clear(buffer) memset(buffer->space, 0, buffer->size); \
1.172 + buffer->size = 0; buffer->pos = 0;
1.173 +
1.174 +/**
1.175 + * Tests, if the buffer position has exceeded the buffer capacity.
1.176 + *
1.177 + * @param buffer the buffer to test
1.178 + * @return non-zero, if the current buffer position has exceeded the last
1.179 + * available byte of the buffer.
1.180 + */
1.181 +int ucx_buffer_eof(UcxBuffer *buffer);
1.182 +
1.183 +
1.184 +/**
1.185 + * Extends the capacity of the buffer.
1.186 + *
1.187 + * <b>Note:</b> The buffer capacity increased by a power of two. I.e.
1.188 + * the buffer capacity is doubled, as long as it would not hold the current
1.189 + * content plus the additional required bytes.
1.190 + *
1.191 + * <b>Attention:</b> the argument provided is the number of <i>additional</i>
1.192 + * bytes the buffer shall hold. It is <b>NOT</b> the total number of bytes the
1.193 + * buffer shall hold.
1.194 + *
1.195 + * @param buffer the buffer to extend
1.196 + * @param additional_bytes the number of additional bytes the buffer shall
1.197 + * <i>at least</i> hold
1.198 + * @return 0 on success or a non-zero value on failure
1.199 + */
1.200 +int ucx_buffer_extend(UcxBuffer *buffer, size_t additional_bytes);
1.201 +
1.202 +/**
1.203 + * Writes data to an UcxBuffer.
1.204 + *
1.205 + * The position of the buffer is increased by the number of bytes written.
1.206 + *
1.207 + * @param ptr a pointer to the memory area containing the bytes to be written
1.208 + * @param size the length of one element
1.209 + * @param nitems the element count
1.210 + * @param buffer the UcxBuffer to write to
1.211 + * @return the total count of bytes written
1.212 + */
1.213 +size_t ucx_buffer_write(const void *ptr, size_t size, size_t nitems,
1.214 + UcxBuffer *buffer);
1.215 +
1.216 +/**
1.217 + * Reads data from an UcxBuffer.
1.218 + *
1.219 + * The position of the buffer is increased by the number of bytes read.
1.220 + *
1.221 + * @param ptr a pointer to the memory area where to store the read data
1.222 + * @param size the length of one element
1.223 + * @param nitems the element count
1.224 + * @param buffer the UcxBuffer to read from
1.225 + * @return the total number of elements read
1.226 + */
1.227 +size_t ucx_buffer_read(void *ptr, size_t size, size_t nitems,
1.228 + UcxBuffer *buffer);
1.229 +
1.230 +/**
1.231 + * Writes a character to a buffer.
1.232 + *
1.233 + * The least significant byte of the argument is written to the buffer. If the
1.234 + * end of the buffer is reached and #UCX_BUFFER_AUTOEXTEND feature is enabled,
1.235 + * the buffer capacity is extended by ucx_buffer_extend(). If the feature is
1.236 + * disabled or buffer extension fails, <code>EOF</code> is returned.
1.237 + *
1.238 + * On successful write the position of the buffer is increased.
1.239 + *
1.240 + * @param buffer the buffer to write to
1.241 + * @param c the character to write as <code>int</code> value
1.242 + * @return the byte that has bean written as <code>int</code> value or
1.243 + * <code>EOF</code> when the end of the stream is reached and automatic
1.244 + * extension is not enabled or not possible
1.245 + */
1.246 +int ucx_buffer_putc(UcxBuffer *buffer, int c);
1.247 +
1.248 +/**
1.249 + * Gets a character from a buffer.
1.250 + *
1.251 + * The current position of the buffer is increased after a successful read.
1.252 + *
1.253 + * @param buffer the buffer to read from
1.254 + * @return the character as <code>int</code> value or <code>EOF</code>, if the
1.255 + * end of the buffer is reached
1.256 + */
1.257 +int ucx_buffer_getc(UcxBuffer *buffer);
1.258 +
1.259 +/**
1.260 + * Writes a string to a buffer.
1.261 + *
1.262 + * @param buffer the buffer
1.263 + * @param str the string
1.264 + * @return the number of bytes written
1.265 + */
1.266 +size_t ucx_buffer_puts(UcxBuffer *buffer, char *str);
1.267 +
1.268 +#ifdef __cplusplus
1.269 +}
1.270 +#endif
1.271 +
1.272 +#endif /* UCX_BUFFER_H */
1.273 +
