universe@39: /*
universe@39:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
universe@39:  *
universe@39:  * Copyright 2015 Olaf Wintermann. All rights reserved.
universe@39:  *
universe@39:  * Redistribution and use in source and binary forms, with or without
universe@39:  * modification, are permitted provided that the following conditions are met:
universe@39:  *
universe@39:  *   1. Redistributions of source code must retain the above copyright
universe@39:  *      notice, this list of conditions and the following disclaimer.
universe@39:  *
universe@39:  *   2. Redistributions in binary form must reproduce the above copyright
universe@39:  *      notice, this list of conditions and the following disclaimer in the
universe@39:  *      documentation and/or other materials provided with the distribution.
universe@39:  *
universe@39:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@39:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@39:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
universe@39:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
universe@39:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
universe@39:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
universe@39:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
universe@39:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
universe@39:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
universe@39:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
universe@39:  * POSSIBILITY OF SUCH DAMAGE.
universe@39:  */
universe@39: 
universe@39: /**
universe@39:  * @file buffer.h
universe@39:  * 
universe@39:  * Advanced buffer implementation.
universe@39:  * 
universe@39:  * Instances of UcxBuffer can be used to read from or to write to like one
universe@39:  * would do with a stream. This allows the use of ucx_stream_copy() to copy
universe@39:  * contents from one buffer to another.
universe@39:  * 
universe@39:  * Some features for convenient use of the buffer
universe@39:  * can be enabled. See the documentation of the macro constants for more
universe@39:  * information.
universe@39:  * 
universe@39:  * @author Mike Becker
universe@39:  * @author Olaf Wintermann
universe@39:  */
universe@39: 
universe@39: #ifndef UCX_BUFFER_H
universe@39: #define	UCX_BUFFER_H
universe@39: 
universe@39: #include "ucx.h"
universe@39: #include <sys/types.h>
universe@39: #include <stdio.h>
universe@39: 
universe@39: #ifdef	__cplusplus
universe@39: extern "C" {
universe@39: #endif
universe@39: 
universe@39: /**
universe@39:  * No buffer features enabled (all flags cleared).
universe@39:  */
universe@39: #define UCX_BUFFER_DEFAULT      0x00
universe@39: 
universe@39: /**
universe@39:  * If this flag is enabled, the buffer will automatically free its contents.
universe@39:  */
universe@39: #define UCX_BUFFER_AUTOFREE     0x01
universe@39: 
universe@39: /**
universe@39:  * If this flag is enabled, the buffer will automatically extends its capacity.
universe@39:  */
universe@39: #define UCX_BUFFER_AUTOEXTEND   0x02
universe@39: 
universe@39: /** UCX Buffer. */
universe@39: typedef struct {
universe@39:     /** A pointer to the buffer contents. */
universe@39:     char *space;
universe@39:     /** Current position of the buffer. */
universe@39:     size_t pos;
universe@39:     /** Current capacity (i.e. maximum size) of the buffer. */
universe@39:     size_t capacity;
universe@39:     /** Current size of the buffer content. */
universe@39:     size_t size;
universe@39:     /**
universe@39:      * Flag register for buffer features.
universe@39:      * @see #UCX_BUFFER_DEFAULT
universe@39:      * @see #UCX_BUFFER_AUTOFREE
universe@39:      * @see #UCX_BUFFER_AUTOEXTEND
universe@39:      */
universe@39:     int flags;
universe@39: } UcxBuffer;
universe@39: 
universe@39: /**
universe@39:  * Creates a new buffer.
universe@39:  * 
universe@39:  * <b>Note:</b> you may provide <code>NULL</code> as argument for
universe@39:  * <code>space</code>. Then this function will allocate the space and enforce
universe@39:  * the #UCX_BUFFER_AUTOFREE flag.
universe@39:  * 
universe@39:  * @param space pointer to the memory area, or <code>NULL</code> to allocate
universe@39:  * new memory
universe@39:  * @param capacity the capacity of the buffer
universe@39:  * @param flags buffer features (see UcxBuffer.flags)
universe@39:  * @return the new buffer
universe@39:  */
universe@39: UcxBuffer *ucx_buffer_new(void *space, size_t capacity, int flags);
universe@39: 
universe@39: /**
universe@39:  * Destroys a buffer.
universe@39:  * 
universe@39:  * If the #UCX_BUFFER_AUTOFREE feature is enabled, the contents of the buffer
universe@39:  * are also freed.
universe@39:  * 
universe@39:  * @param buffer the buffer to destroy
universe@39:  */
universe@39: void ucx_buffer_free(UcxBuffer* buffer);
universe@39: 
universe@39: /**
universe@39:  * Creates a new buffer and fills it with extracted content from another buffer.
universe@39:  * 
universe@39:  * <b>Note:</b> the #UCX_BUFFER_AUTOFREE feature is enforced for the new buffer.
universe@39:  * 
universe@39:  * @param src the source buffer
universe@39:  * @param start the start position of extraction
universe@39:  * @param length the count of bytes to extract (must not be zero)
universe@39:  * @param flags feature mask for the new buffer
universe@39:  * @return a new buffer containing the extraction
universe@39:  */
universe@39: UcxBuffer* ucx_buffer_extract(UcxBuffer *src,
universe@39:         size_t start, size_t length, int flags);
universe@39: 
universe@39: /**
universe@39:  * A shorthand macro for the full extraction of the buffer.
universe@39:  * 
universe@39:  * @param src the source buffer
universe@39:  * @param flags feature mask for the new buffer
universe@39:  * @return a new buffer with the extracted content
universe@39:  */
universe@39: #define ucx_buffer_clone(src,flags) \
universe@39:     ucx_buffer_extract(src, 0, (src)->capacity, flags)
universe@39: 
universe@39: /**
universe@39:  * Moves the position of the buffer.
universe@39:  * 
universe@39:  * The new position is relative to the <code>whence</code> argument.
universe@39:  *
universe@39:  * SEEK_SET marks the start of the buffer.
universe@39:  * SEEK_CUR marks the current position.
universe@39:  * SEEK_END marks the end of the buffer.
universe@39:  * 
universe@39:  * With an offset of zero, this function sets the buffer position to zero
universe@39:  * (SEEK_SET), the buffer size (SEEK_END) or leaves the buffer position
universe@39:  * unchanged (SEEK_CUR).
universe@39:  * 
universe@39:  * @param buffer
universe@39:  * @param offset position offset relative to <code>whence</code>
universe@39:  * @param whence one of SEEK_SET, SEEK_CUR or SEEK_END
universe@39:  * @return 0 on success, non-zero if the position is invalid
universe@39:  *
universe@39:  */
universe@39: int ucx_buffer_seek(UcxBuffer *buffer, off_t offset, int whence);
universe@39: 
universe@39: /**
universe@39:  * Clears the buffer by resetting the position and deleting the data.
universe@39:  * 
universe@39:  * The data is deleted by a zeroing it with call to <code>memset()</code>.
universe@39:  * 
universe@39:  * @param buffer the buffer to be cleared
universe@39:  */
universe@39: #define ucx_buffer_clear(buffer) memset(buffer->space, 0, buffer->size); \
universe@39:         buffer->size = 0; buffer->pos = 0;
universe@39: 
universe@39: /**
universe@39:  * Tests, if the buffer position has exceeded the buffer capacity.
universe@39:  * 
universe@39:  * @param buffer the buffer to test
universe@39:  * @return non-zero, if the current buffer position has exceeded the last
universe@39:  * available byte of the buffer.
universe@39:  */
universe@39: int ucx_buffer_eof(UcxBuffer *buffer);
universe@39: 
universe@39: 
universe@39: /**
universe@39:  * Extends the capacity of the buffer.
universe@39:  * 
universe@39:  * <b>Note:</b> The buffer capacity increased by a power of two. I.e.
universe@39:  * the buffer capacity is doubled, as long as it would not hold the current
universe@39:  * content plus the additional required bytes.
universe@39:  * 
universe@39:  * <b>Attention:</b> the argument provided is the number of <i>additional</i>
universe@39:  * bytes the buffer shall hold. It is <b>NOT</b> the total number of bytes the
universe@39:  * buffer shall hold.
universe@39:  * 
universe@39:  * @param buffer the buffer to extend
universe@39:  * @param additional_bytes the number of additional bytes the buffer shall
universe@39:  * <i>at least</i> hold
universe@39:  * @return 0 on success or a non-zero value on failure
universe@39:  */
universe@39: int ucx_buffer_extend(UcxBuffer *buffer, size_t additional_bytes);
universe@39: 
universe@39: /**
universe@39:  * Writes data to an UcxBuffer.
universe@39:  * 
universe@39:  * The position of the buffer is increased by the number of bytes written.
universe@39:  * 
universe@39:  * @param ptr a pointer to the memory area containing the bytes to be written
universe@39:  * @param size the length of one element
universe@39:  * @param nitems the element count
universe@39:  * @param buffer the UcxBuffer to write to
universe@39:  * @return the total count of bytes written
universe@39:  */
universe@39: size_t ucx_buffer_write(const void *ptr, size_t size, size_t nitems,
universe@39:         UcxBuffer *buffer);
universe@39: 
universe@39: /**
universe@39:  * Reads data from an UcxBuffer.
universe@39:  * 
universe@39:  * The position of the buffer is increased by the number of bytes read.
universe@39:  * 
universe@39:  * @param ptr a pointer to the memory area where to store the read data
universe@39:  * @param size the length of one element
universe@39:  * @param nitems the element count
universe@39:  * @param buffer the UcxBuffer to read from
universe@39:  * @return the total number of elements read
universe@39:  */
universe@39: size_t ucx_buffer_read(void *ptr, size_t size, size_t nitems,
universe@39:         UcxBuffer *buffer);
universe@39: 
universe@39: /**
universe@39:  * Writes a character to a buffer.
universe@39:  * 
universe@39:  * The least significant byte of the argument is written to the buffer. If the
universe@39:  * end of the buffer is reached and #UCX_BUFFER_AUTOEXTEND feature is enabled,
universe@39:  * the buffer capacity is extended by ucx_buffer_extend(). If the feature is
universe@39:  * disabled or buffer extension fails, <code>EOF</code> is returned.
universe@39:  * 
universe@39:  * On successful write the position of the buffer is increased.
universe@39:  * 
universe@39:  * @param buffer the buffer to write to
universe@39:  * @param c the character to write as <code>int</code> value
universe@39:  * @return the byte that has bean written as <code>int</code> value or
universe@39:  * <code>EOF</code> when the end of the stream is reached and automatic
universe@39:  * extension is not enabled or not possible
universe@39:  */
universe@39: int ucx_buffer_putc(UcxBuffer *buffer, int c);
universe@39: 
universe@39: /**
universe@39:  * Gets a character from a buffer.
universe@39:  * 
universe@39:  * The current position of the buffer is increased after a successful read.
universe@39:  * 
universe@39:  * @param buffer the buffer to read from
universe@39:  * @return the character as <code>int</code> value or <code>EOF</code>, if the
universe@39:  * end of the buffer is reached
universe@39:  */
universe@39: int ucx_buffer_getc(UcxBuffer *buffer);
universe@39: 
universe@39: /**
universe@39:  * Writes a string to a buffer.
universe@39:  * 
universe@39:  * @param buffer the buffer
universe@39:  * @param str the string
universe@39:  * @return the number of bytes written
universe@39:  */
universe@39: size_t ucx_buffer_puts(UcxBuffer *buffer, char *str);
universe@39: 
universe@39: #ifdef	__cplusplus
universe@39: }
universe@39: #endif
universe@39: 
universe@39: #endif	/* UCX_BUFFER_H */
universe@39: