1.1 --- a/ucx/buffer.h Mon Aug 12 14:43:22 2013 +0200
1.2 +++ b/ucx/buffer.h Tue Aug 13 14:20:12 2013 +0200
1.3 @@ -26,6 +26,23 @@
1.4 * POSSIBILITY OF SUCH DAMAGE.
1.5 */
1.6
1.7 +/**
1.8 + * @file buffer.h
1.9 + *
1.10 + * Advanced buffer implementation.
1.11 + *
1.12 + * Instances of UcxBuffer can be used to read from or to write to like one
1.13 + * would do with a stream. This allows the use of ucx_stream_copy() to copy
1.14 + * contents from one buffer to another.
1.15 + *
1.16 + * Some features for convenient use of the buffer
1.17 + * can be enabled. See the documentation of the macro constants for more
1.18 + * information.
1.19 + *
1.20 + * @author Mike Becker
1.21 + * @author Olaf Wintermann
1.22 + */
1.23 +
1.24 #ifndef UCX_BUFFER_H
1.25 #define UCX_BUFFER_H
1.26
1.27 @@ -37,94 +54,208 @@
1.28 extern "C" {
1.29 #endif
1.30
1.31 -/* no autoextend or autofree behaviour */
1.32 +/**
1.33 + * No buffer features enabled (all flags cleared).
1.34 + */
1.35 #define UCX_BUFFER_DEFAULT 0x00
1.36 -/* the buffer shall free the occupied memory space */
1.37 +/**
1.38 + * If this flag is enabled, the buffer will automatically free its contents.
1.39 + */
1.40 #define UCX_BUFFER_AUTOFREE 0x01
1.41 -/* the buffer may automatically double its size on write operations */
1.42 +/**
1.43 + * If this flag is enabled, the buffer will automatically extends its capacity.
1.44 + */
1.45 #define UCX_BUFFER_AUTOEXTEND 0x02
1.46
1.47 -/* the user shall not modify values, but may get the latest pointer */
1.48 +/** UCX Buffer. */
1.49 typedef struct {
1.50 + /** A pointer to the buffer contents. */
1.51 char *space;
1.52 + /** Current position of the buffer. */
1.53 size_t pos;
1.54 + /** Current capacity (i.e. maximum size) of the buffer. */
1.55 size_t capacity;
1.56 + /** Current size of the buffer content. */
1.57 size_t size;
1.58 + /**
1.59 + * Flag register for buffer features.
1.60 + * @see #UCX_BUFFER_DEFAULT
1.61 + * @see #UCX_BUFFER_AUTOFREE
1.62 + * @see #UCX_BUFFER_AUTOEXTEND
1.63 + */
1.64 int flags;
1.65 } UcxBuffer;
1.66
1.67 -/* if space is NULL, new space is allocated and the autofree flag is enforced */
1.68 +/**
1.69 + * Creates a new buffer.
1.70 + *
1.71 + * <b>Note:</b> you may provide <code>NULL</code> as argument for
1.72 + * <code>space</code>. Then this function will allocate the space and enforce
1.73 + * the #UCX_BUFFER_AUTOFREE flag.
1.74 + *
1.75 + * @param space pointer to the memory area, or <code>NULL</code> to allocate
1.76 + * new memory
1.77 + * @param size the size of the buffer
1.78 + * @param flags buffer features (see UcxBuffer.flags)
1.79 + * @return the new buffer
1.80 + */
1.81 UcxBuffer *ucx_buffer_new(void *space, size_t size, int flags);
1.82 +
1.83 +/**
1.84 + * Destroys a buffer.
1.85 + *
1.86 + * If the #UCX_BUFFER_AUTOFREE feature is enabled, the contents of the buffer
1.87 + * are also freed.
1.88 + *
1.89 + * @param buffer the buffer to destroy
1.90 + */
1.91 void ucx_buffer_free(UcxBuffer* buffer);
1.92
1.93 -/*
1.94 - * the autofree flag is enforced for the new buffer
1.95 - * if length is zero, the whole remaining buffer shall be extracted
1.96 - * the position of the new buffer is set to zero
1.97 +/**
1.98 + * Creates a new buffer and fills it with extracted content from another buffer.
1.99 + *
1.100 + * <b>Note:</b> the #UCX_BUFFER_AUTOFREE feature is enforced for the new buffer.
1.101 + *
1.102 + * @param src the source buffer
1.103 + * @param start the start position of extraction
1.104 + * @param length the count of bytes to extract or 0 if all of the remaining
1.105 + * bytes shall be extracted
1.106 + * @param flags feature mask for the new buffer
1.107 + * @return
1.108 */
1.109 UcxBuffer* ucx_buffer_extract(UcxBuffer *src,
1.110 size_t start, size_t length, int flags);
1.111 +
1.112 +/**
1.113 + * A shorthand macro for the full extraction of the buffer.
1.114 + *
1.115 + * @param src the source buffer
1.116 + * @param flags feature mask for the new buffer
1.117 + * @return a new buffer with the extracted content
1.118 + */
1.119 #define ucx_buffer_clone(src,flags) \
1.120 ucx_buffer_extract(src, 0, 0, flags)
1.121
1.122 -/*
1.123 - * Moves the position of the buffer to a new position relative to whence.
1.124 +/**
1.125 + * Moves the position of the buffer.
1.126 + *
1.127 + * The new position is relative to the <code>whence</code> argument.
1.128 *
1.129 - * SEEK_SET marks the start of the buffer
1.130 - * SEEK_CUR marks the current position
1.131 - * SEEK_END marks the first 0-byte in the buffer
1.132 - *
1.133 - * ucx_buffer_seek returns 0 on success and -1 if the new position is beyond the
1.134 - * bounds of the allocated buffer. In that case the position of the buffer
1.135 - * remains unchanged.
1.136 + * SEEK_SET marks the start of the buffer.
1.137 + * SEEK_CUR marks the current position.
1.138 + * SEEK_END marks the first 0-byte in the buffer.
1.139 + *
1.140 + * @param buffer
1.141 + * @param offset position offset relative to <code>whence</code>
1.142 + * @param whence one of SEEK_SET, SEEK_CUR or SEEK_END
1.143 + * @return 0 on success, non-zero if the position is invalid
1.144 *
1.145 */
1.146 int ucx_buffer_seek(UcxBuffer *buffer, off_t offset, int whence);
1.147
1.148 -#define ucx_buffer_clear(buffer) memset(buffer->space, 0, buffer->size); \
1.149 - buffer->size = 0; buffer->pos = 0;
1.150 +/**
1.151 + * Clears the buffer by resetting the position and deleting the data.
1.152 + *
1.153 + * The data is deleted by a zeroing it with call to <code>memset()</code>.
1.154 + *
1.155 + * @param buffer the buffer to be cleared
1.156 + */
1.157 +#define ucx_buffer_clear(buffer) memset(buffer->space, 0, buffer->size); \
1.158 + buffer->size = 0; buffer->pos = 0;
1.159
1.160 -/*
1.161 - * returns non-zero, if the current buffer position has exceeded the last
1.162 - * available byte of the underlying buffer
1.163 - *
1.164 +/**
1.165 + * Tests, if the buffer position has exceeded the buffer capacity.
1.166 + *
1.167 + * @param buffer the buffer to test
1.168 + * @return non-zero, if the current buffer position has exceeded the last
1.169 + * available byte of the buffer.
1.170 */
1.171 int ucx_buffer_eof(UcxBuffer *buffer);
1.172
1.173
1.174 -int ucx_buffere_extend(UcxBuffer *buffer, size_t len);
1.175 +/**
1.176 + * Extends the capacity of the buffer.
1.177 + *
1.178 + * <b>Note:</b> The buffer capacity increased by a power of two. I.e.
1.179 + * the buffer capacity is doubled, as long as it would not hold the current
1.180 + * content plus the additional required bytes.
1.181 + *
1.182 + * <b>Attention:</b> the argument provided is the count of <i>additional</i>
1.183 + * bytes the buffer shall hold. It is <b>NOT</b> the total count of bytes the
1.184 + * buffer shall hold.
1.185 + *
1.186 + * @param buffer the buffer to extend
1.187 + * @param additional_bytes the count of additional bytes the buffer shall
1.188 + * <i>at least</i> hold
1.189 + * @return 0 on success or a non-zero value on failure
1.190 + */
1.191 +int ucx_buffer_extend(UcxBuffer *buffer, size_t additional_bytes);
1.192
1.193 +/**
1.194 + * Writes data to an UcxBuffer.
1.195 + *
1.196 + * The position of the buffer is increased by the number of bytes read.
1.197 + *
1.198 + * @param ptr a pointer to the memory area containing the bytes to be written
1.199 + * @param size the length of one element
1.200 + * @param nitems the element count
1.201 + * @param buffer the UcxBuffer to write to
1.202 + * @return the total count of bytes written
1.203 + */
1.204 size_t ucx_buffer_write(const void *ptr, size_t size, size_t nitems,
1.205 UcxBuffer *buffer);
1.206
1.207 +/**
1.208 + * Reads data from an UcxBuffer.
1.209 + *
1.210 + * The position of the buffer is increased by the number of bytes read.
1.211 + *
1.212 + * @param ptr a pointer to the memory area where to store the read data
1.213 + * @param size the length of one element
1.214 + * @param nitems the element count
1.215 + * @param buffer the UcxBuffer to read from
1.216 + * @return the total count of bytes read
1.217 + */
1.218 size_t ucx_buffer_read(void *ptr, size_t size, size_t nitems,
1.219 UcxBuffer *buffer);
1.220
1.221 -int ucx_buffer_putc(UcxBuffer *b, int c);
1.222 -int ucx_buffer_getc(UcxBuffer *b);
1.223 +/**
1.224 + * Writes a character to a buffer.
1.225 + *
1.226 + * The least significant byte of the argument is written to the buffer. If the
1.227 + * end of the buffer is reached and #UCX_BUFFER_AUTOEXTEND feature is enabled,
1.228 + * the buffer capacity is extended by ucx_buffer_extend(). If the feature is
1.229 + * disabled or buffer extension fails, <code>EOF</code> is returned.
1.230 + *
1.231 + * On successful write the position of the buffer is increased.
1.232 + *
1.233 + * @param buffer the buffer to write to
1.234 + * @param c the character to write as <code>int</code> value
1.235 + * @return the byte that has bean written as <code>int</code> value or
1.236 + * <code>EOF</code> when the end of the stream is reached and automatic
1.237 + * extension is not enabled or not possible
1.238 + */
1.239 +int ucx_buffer_putc(UcxBuffer *buffer, int c);
1.240
1.241 +/**
1.242 + * Gets a character from a buffer.
1.243 + *
1.244 + * The current position of the buffer is increased after a successful read.
1.245 + *
1.246 + * @param buffer the buffer to read from
1.247 + * @return the character as <code>int</code> value or <code>EOF</code>, if the
1.248 + * end of the buffer is reached
1.249 + */
1.250 +int ucx_buffer_getc(UcxBuffer *buffer);
1.251
1.252 -/*
1.253 - * copies all bytes from s1 to s2
1.254 - * uses the read function r to read from s1 und writes the data using the
1.255 - * write function w to s2
1.256 - * returns the number of bytes copied
1.257 +/**
1.258 + * Writes a string to a buffer.
1.259 + *
1.260 + * @param buffer the buffer
1.261 + * @param str the string
1.262 + * @return the number of bytes written
1.263 */
1.264 -size_t ucx_buffer_generic_copy(void *s1, void *s2, read_func r, write_func w,
1.265 - size_t bufsize);
1.266 -
1.267 -size_t ucx_buffer_generic_ncopy(void *s1, void *s2, read_func r, write_func w,
1.268 - size_t bufsize, size_t n);
1.269 -
1.270 -#define UCX_DEFAULT_BUFFER_SIZE 0x1000
1.271 -
1.272 -#define ucx_buffer_copy(s1,s2,r,w) \
1.273 - ucx_buffer_generic_copy(s1, s2, (read_func)r, (write_func)w, \
1.274 - UCX_DEFAULT_BUFFER_SIZE)
1.275 -
1.276 -#define ucx_buffer_ncopy(s1,s2,r,w, n) \
1.277 - ucx_buffer_generic_ncopy(s1, s2, (read_func)r, (write_func)w, \
1.278 - UCX_DEFAULT_BUFFER_SIZE, n)
1.279 +size_t ucx_buffer_puts(UcxBuffer *buffer, char *str);
1.280
1.281 #ifdef __cplusplus
1.282 }
