88c5f205fa
The Buffer code in the VNC server is useful for the IO channel code, so pull it out into a shared module, QIOBuffer. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
119 lines
3.0 KiB
C
119 lines
3.0 KiB
C
/*
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* QEMU generic buffers
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*
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* Copyright (c) 2015 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef QEMU_BUFFER_H__
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#define QEMU_BUFFER_H__
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#include "qemu-common.h"
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typedef struct Buffer Buffer;
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/**
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* Buffer:
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*
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* The Buffer object provides a simple dynamically resizing
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* array, with separate tracking of capacity and usage. This
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* is typically useful when buffering I/O or processing data.
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*/
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struct Buffer {
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size_t capacity;
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size_t offset;
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uint8_t *buffer;
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};
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/**
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* buffer_reserve:
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* @buffer: the buffer object
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* @len: the minimum required free space
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*
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* Ensure that the buffer has space allocated for at least
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* @len bytes. If the current buffer is too small, it will
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* be reallocated, possibly to a larger size than requested.
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*/
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void buffer_reserve(Buffer *buffer, size_t len);
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/**
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* buffer_reset:
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* @buffer: the buffer object
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*
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* Reset the length of the stored data to zero, but do
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* not free / reallocate the memory buffer
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*/
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void buffer_reset(Buffer *buffer);
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/**
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* buffer_free:
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* @buffer: the buffer object
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*
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* Reset the length of the stored data to zero and also
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* free the internal memory buffer
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*/
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void buffer_free(Buffer *buffer);
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/**
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* buffer_append:
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* @buffer: the buffer object
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* @data: the data block to append
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* @len: the length of @data in bytes
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*
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* Append the contents of @data to the end of the buffer.
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* The caller must ensure that the buffer has sufficient
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* free space for @len bytes, typically by calling the
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* buffer_reserve() method prior to appending.
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*/
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void buffer_append(Buffer *buffer, const void *data, size_t len);
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/**
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* buffer_advance:
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* @buffer: the buffer object
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* @len: the number of bytes to skip
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*
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* Remove @len bytes of data from the head of the buffer.
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* The internal buffer will not be reallocated, so will
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* have at least @len bytes of free space after this
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* call completes
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*/
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void buffer_advance(Buffer *buffer, size_t len);
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/**
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* buffer_end:
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* @buffer: the buffer object
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*
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* Get a pointer to the tail end of the internal buffer
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* The returned pointer is only valid until the next
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* call to buffer_reserve().
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*
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* Returns: the tail of the buffer
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*/
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uint8_t *buffer_end(Buffer *buffer);
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/**
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* buffer_empty:
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* @buffer: the buffer object
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*
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* Determine if the buffer contains any current data
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*
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* Returns: true if the buffer holds data, false otherwise
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*/
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gboolean buffer_empty(Buffer *buffer);
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#endif /* QEMU_BUFFER_H__ */
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