120 lines
3.8 KiB
C
120 lines
3.8 KiB
C
/*
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* FreeRDP: A Remote Desktop Protocol Implementation
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* Stream Utils
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*
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* Copyright 2011 Vic Lee
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <winpr/crt.h>
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#include <freerdp/utils/stream.h>
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/**
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* Allocates and initializes a STREAM structure.
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* STREAM are used to ease data access in read and write operations.
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* They consist of a buffer containing the data we want to access, and an offset associated to it, and keeping
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* track of the 'current' position in the stream. A list of functions can then be used to read/write different
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* type of data to/from it.
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* @see stream.h for the list of data access functions.
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*
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* @param size [in] - size of the buffer that will ba allocated to the stream.
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* If 0, there will be no buffer attached to the stream. The caller
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* then needs to call stream_attach() to link an existing buffer to this stream.
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* Caution: calling stream_attach() on a stream with an existing buffer will result
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* in this buffer being lost, and possible memory leak.
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*
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* @return A pointer to an allocated and initialized STREAM structure.
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* This pointer need to be deallocated using the stream_free() function.
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*/
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STREAM* stream_new(int size)
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{
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STREAM* stream;
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stream = malloc(sizeof(STREAM));
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ZeroMemory(stream, sizeof(STREAM));
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if (stream != NULL)
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{
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if (size != 0)
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{
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size = size > 0 ? size : 0x400;
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stream->data = (BYTE*) malloc(size);
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ZeroMemory(stream->data, size);
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stream->p = stream->data;
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stream->size = size;
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}
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}
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return stream;
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}
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/**
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* This function is used to deallocate a stream that was allocated using stream_new().
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* Caution: the buffer linked to the stream will be deallocated in the process. If this buffer was attached
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* using the stream_attach() function, the stream_detach() function needs to be called before calling stream_free()
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* otherwise it will be freed in the process.
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*
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* @param stream [in] - Pointer to the STREAM structure that needs to be deallocated.
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* This pointer is invalid on return.
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*/
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void stream_free(STREAM* stream)
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{
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if (stream != NULL)
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{
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if (stream->data != NULL)
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free(stream->data);
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free(stream);
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}
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}
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/**
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* This function is used to extend the size of an existing stream.
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* It will infact extend the attached buffer, fill the newly allocated region with 0, and reset the current
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* stream position.
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* If the stream did not have a buffer attached, a new one will be allocated and attached.
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*
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* @param stream [in/out] pointer to the STREAM structure that needs to be extended.
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* @param request_size [in] Number of bytes to add to the existing stream.
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* If the value is < the existing size, then the existing size is doubled.
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*/
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void stream_extend(STREAM* stream, int request_size)
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{
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int pos;
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int original_size;
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int increased_size;
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pos = stream_get_pos(stream);
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original_size = stream->size;
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increased_size = (request_size > original_size ? request_size : original_size);
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stream->size += increased_size;
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if (original_size == 0)
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stream->data = (BYTE*) malloc(stream->size);
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else
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stream->data = (BYTE*) realloc(stream->data, stream->size);
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memset(stream->data + original_size, 0, increased_size);
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stream_set_pos(stream, pos);
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}
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