/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 2016 Olaf Wintermann. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @file buffer.h
*
* Advanced buffer implementation.
*
* Instances of UcxBuffer can be used to read from or to write to like one
* would do with a stream. This allows the use of ucx_stream_copy() to copy
* contents from one buffer to another.
*
* Some features for convenient use of the buffer
* can be enabled. See the documentation of the macro constants for more
* information.
*
* @author Mike Becker
* @author Olaf Wintermann
*/
#ifndef UCX_BUFFER_H
#define UCX_BUFFER_H
#include "ucx.h"
#include <sys/types.h>
#include <stdio.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* No buffer features enabled (all flags cleared).
*/
#define UCX_BUFFER_DEFAULT 0x00
/**
* If this flag is enabled, the buffer will automatically free its contents.
*/
#define UCX_BUFFER_AUTOFREE 0x01
/**
* If this flag is enabled, the buffer will automatically extends its capacity.
*/
#define UCX_BUFFER_AUTOEXTEND 0x02
/** UCX Buffer. */
typedef struct {
/** A pointer to the buffer contents. */
char *space;
/** Current position of the buffer. */
size_t pos;
/** Current capacity (i.e. maximum size) of the buffer. */
size_t capacity;
/** Current size of the buffer content. */
size_t size;
/**
* Flag register for buffer features.
* @see #UCX_BUFFER_DEFAULT
* @see #UCX_BUFFER_AUTOFREE
* @see #UCX_BUFFER_AUTOEXTEND
*/
int flags;
} UcxBuffer;
/**
* Creates a new buffer.
*
* <b>Note:</b> you may provide <code>NULL</code> as argument for
* <code>space</code>. Then this function will allocate the space and enforce
* the #UCX_BUFFER_AUTOFREE flag.
*
* @param space pointer to the memory area, or <code>NULL</code> to allocate
* new memory
* @param capacity the capacity of the buffer
* @param flags buffer features (see UcxBuffer.flags)
* @return the new buffer
*/
UcxBuffer *ucx_buffer_new(void *space, size_t capacity, int flags);
/**
* Destroys a buffer.
*
* If the #UCX_BUFFER_AUTOFREE feature is enabled, the contents of the buffer
* are also freed.
*
* @param buffer the buffer to destroy
*/
void ucx_buffer_free(UcxBuffer* buffer);
/**
* Creates a new buffer and fills it with extracted content from another buffer.
*
* <b>Note:</b> the #UCX_BUFFER_AUTOFREE feature is enforced for the new buffer.
*
* @param src the source buffer
* @param start the start position of extraction
* @param length the count of bytes to extract (must not be zero)
* @param flags feature mask for the new buffer
* @return a new buffer containing the extraction
*/
UcxBuffer* ucx_buffer_extract(UcxBuffer *src,
size_t start, size_t length, int flags);
/**
* A shorthand macro for the full extraction of the buffer.
*
* @param src the source buffer
* @param flags feature mask for the new buffer
* @return a new buffer with the extracted content
*/
#define ucx_buffer_clone(src,flags) \
ucx_buffer_extract(src, 0, (src)->capacity, flags)
/**
* Moves the position of the buffer.
*
* The new position is relative to the <code>whence</code> argument.
*
* SEEK_SET marks the start of the buffer.
* SEEK_CUR marks the current position.
* SEEK_END marks the end of the buffer.
*
* With an offset of zero, this function sets the buffer position to zero
* (SEEK_SET), the buffer size (SEEK_END) or leaves the buffer position
* unchanged (SEEK_CUR).
*
* @param buffer
* @param offset position offset relative to <code>whence</code>
* @param whence one of SEEK_SET, SEEK_CUR or SEEK_END
* @return 0 on success, non-zero if the position is invalid
*
*/
int ucx_buffer_seek(UcxBuffer *buffer, off_t offset, int whence);
/**
* Clears the buffer by resetting the position and deleting the data.
*
* The data is deleted by a zeroing it with call to <code>memset()</code>.
*
* @param buffer the buffer to be cleared
*/
#define ucx_buffer_clear(buffer) memset(buffer->space, 0, buffer->size); \
buffer->size = 0; buffer->pos = 0;
/**
* Tests, if the buffer position has exceeded the buffer capacity.
*
* @param buffer the buffer to test
* @return non-zero, if the current buffer position has exceeded the last
* available byte of the buffer.
*/
int ucx_buffer_eof(UcxBuffer *buffer);
/**
* Extends the capacity of the buffer.
*
* <b>Note:</b> The buffer capacity increased by a power of two. I.e.
* the buffer capacity is doubled, as long as it would not hold the current
* content plus the additional required bytes.
*
* <b>Attention:</b> the argument provided is the number of <i>additional</i>
* bytes the buffer shall hold. It is <b>NOT</b> the total number of bytes the
* buffer shall hold.
*
* @param buffer the buffer to extend
* @param additional_bytes the number of additional bytes the buffer shall
* <i>at least</i> hold
* @return 0 on success or a non-zero value on failure
*/
int ucx_buffer_extend(UcxBuffer *buffer, size_t additional_bytes);
/**
* Writes data to a UcxBuffer.
*
* The position of the buffer is increased by the number of bytes written.
*
* @param ptr a pointer to the memory area containing the bytes to be written
* @param size the length of one element
* @param nitems the element count
* @param buffer the UcxBuffer to write to
* @return the total count of bytes written
*/
size_t ucx_buffer_write(const void *ptr, size_t size, size_t nitems,
UcxBuffer *buffer);
/**
* Reads data from a UcxBuffer.
*
* The position of the buffer is increased by the number of bytes read.
*
* @param ptr a pointer to the memory area where to store the read data
* @param size the length of one element
* @param nitems the element count
* @param buffer the UcxBuffer to read from
* @return the total number of elements read
*/
size_t ucx_buffer_read(void *ptr, size_t size, size_t nitems,
UcxBuffer *buffer);
/**
* Writes a character to a buffer.
*
* The least significant byte of the argument is written to the buffer. If the
* end of the buffer is reached and #UCX_BUFFER_AUTOEXTEND feature is enabled,
* the buffer capacity is extended by ucx_buffer_extend(). If the feature is
* disabled or buffer extension fails, <code>EOF</code> is returned.
*
* On successful write the position of the buffer is increased.
*
* @param buffer the buffer to write to
* @param c the character to write as <code>int</code> value
* @return the byte that has bean written as <code>int</code> value or
* <code>EOF</code> when the end of the stream is reached and automatic
* extension is not enabled or not possible
*/
int ucx_buffer_putc(UcxBuffer *buffer, int c);
/**
* Gets a character from a buffer.
*
* The current position of the buffer is increased after a successful read.
*
* @param buffer the buffer to read from
* @return the character as <code>int</code> value or <code>EOF</code>, if the
* end of the buffer is reached
*/
int ucx_buffer_getc(UcxBuffer *buffer);
/**
* Writes a string to a buffer.
*
* @param buffer the buffer
* @param str the string
* @return the number of bytes written
*/
size_t ucx_buffer_puts(UcxBuffer *buffer, char *str);
#ifdef __cplusplus
}
#endif
#endif /* UCX_BUFFER_H */