--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/ucx/buffer.h Mon Feb 04 17:49:50 2019 +0100
@@ -0,0 +1,339 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2017 Mike Becker, 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)
+
+
+/**
+ * Shifts the contents of the buffer by the given offset.
+ *
+ * If the offset is positive, the contents are shifted to the right.
+ * If auto extension is enabled, the buffer grows, if necessary.
+ * In case the auto extension fails, this function returns a non-zero value and
+ * no contents are changed.
+ * If auto extension is disabled, the contents that do not fit into the buffer
+ * are discarded.
+ *
+ * If the offset is negative, the contents are shifted to the left where the
+ * first <code>shift</code> bytes are discarded.
+ * The new size of the buffer is the old size minus
+ * the absolute shift value.
+ * If this value is larger than the buffer size, the buffer is emptied (but
+ * not cleared, see the security note below).
+ *
+ * The buffer position gets shifted alongside with the content but is kept
+ * within the boundaries of the buffer.
+ *
+ * <b>Security note:</b> the shifting operation does <em>not</em> erase the
+ * previously occupied memory cells. You can easily do that manually, e.g. by
+ * calling <code>memset(buffer->space, 0, shift)</code> for a right shift or
+ * <code>memset(buffer->size, 0, buffer->capacity-buffer->size)</code>
+ * for a left shift.
+ *
+ * @param buffer the buffer
+ * @param shift the shift offset (negative means left shift)
+ * @return 0 on success, non-zero if a required auto-extension fails
+ */
+int ucx_buffer_shift(UcxBuffer* buffer, off_t shift);
+
+/**
+ * Shifts the buffer to the right.
+ * See ucx_buffer_shift() for details.
+ *
+ * @param buffer the buffer
+ * @param shift the shift offset
+ * @return 0 on success, non-zero if a required auto-extension fails
+ * @see ucx_buffer_shift()
+ */
+int ucx_buffer_shift_right(UcxBuffer* buffer, size_t shift);
+
+/**
+ * Shifts the buffer to the left.
+ *
+ * See ucx_buffer_shift() for details. Note, however, that this method expects
+ * a positive shift offset.
+ *
+ * Since a left shift cannot fail due to memory allocation problems, this
+ * function always returns zero.
+ *
+ * @param buffer the buffer
+ * @param shift the shift offset
+ * @return always zero
+ * @see ucx_buffer_shift()
+ */
+int ucx_buffer_shift_left(UcxBuffer* buffer, size_t shift);
+
+
+/**
+ * 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, const char *str);
+
+/**
+ * Returns the complete buffer content as sstr_t.
+ * @param buffer the buffer
+ * @return the result of <code>sstrn()</code> with the buffer space and size
+ * as arguments
+ */
+#define ucx_buffer_to_sstr(buffer) sstrn((buffer)->space, (buffer)->size)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* UCX_BUFFER_H */
+