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/*
* Copyright (c) 2017 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file parc_FileInputStream.h
* @ingroup inputoutput
* @brief A FileInputStream obtains input bytes from a file in a file system.
*
* What files are available depends on the host environment.
* FileInputStream is meant for reading streams of raw bytes such as image data.
*
*/
#ifndef libparc_parc_FileInputStream_h
#define libparc_parc_FileInputStream_h
#include <parc/algol/parc_File.h>
#include <parc/algol/parc_Buffer.h>
#include <parc/algol/parc_InputStream.h>
struct parc_file_input_stream;
/**
* @typedef PARCFileInputStream
* @brief Read streams of input
*/
typedef struct parc_file_input_stream PARCFileInputStream;
/**
* The mapping of a `PARCFileInputStream` to the generic `PARCInputStream`.
*
* Example:
* @code
* <#example#>
* @endcode
*/
PARCInputStreamInterface *PARCFileInputStreamAsPARCInputStream;
/**
* Create a `PARCFileInputStream` instance.
*
* @param [in] fileDescriptor An abstract indicator for accessing a specific file
*
* @return non-NULL A pointer to an instance of `PARCFileInputStream`
*
* Example:
* @code
* {
* <#example#>
* }
* @endcode
*/
PARCFileInputStream *parcFileInputStream_Create(int fileDescriptor);
/**
* Create a `PARCFileInputStream` instance by opening an existing {@link PARCFile} instance.
*
* The file specified by `PARCFile` must exist and readable.
*
* @param [in] file A pointer to a `PARCFile` instance representing the existing file.
*
* @return non-NULL A pointer to a `PARCFileInputStream` instance.
* @return NULL Memory could not be allocated.
*
* Example:
* @code
* {
* <#example#>
* }
* @endcode
*/
PARCFileInputStream *parcFileInputStream_Open(const PARCFile *file);
/**
* Acquire a new reference to an instance of `PARCFileInputStream`.
*
* The reference count to the instance is incremented.
*
* @param [in] inputStream The instance of `PARCFileInputStream` to which to refer.
*
* @return The same value as the input parameter @p inputStream
*
* Example:
* @code
* {
* <#example#>
* }
* @endcode
*/
PARCFileInputStream *parcFileInputStream_Acquire(const PARCFileInputStream *inputStream);
/**
* Release a `PARCFileInputStream` reference.
*
* Only the last invocation where the reference count is decremented to zero,
* will actually destroy the `PARCFileInputStream`.
*
* @param [in,out] inputStreamPtr is a pointer to the `PARCFileInputStream` reference.
*
* Example:
* @code
* <#example#>
* @endcode
*/
void parcFileInputStream_Release(PARCFileInputStream **inputStreamPtr);
/**
* Read a `PARCFileInputStream` into a {@link PARCBuffer}.
*
* The contents of the `PARCBuffer` are filled from the current position to the limit.
* When this function returns, the position is set to the end of the last successfully read byte of data.
*
* @param [in] inputStream The `PARCInputStream` to read.
* @param [in] buffer The `PARCBuffer` to read, from the current position of the buffer to its limit.
*
* @return true The entire contents of the `PARCBuffer`, from the current position to the limit, were filled.
* @return false The entire contents of the `PARCBuffer` were not filled.
*
* Example:
* @code
* {
* PARCFileOutputStream *stream =
* parcFileOutputStream_Create(open("/tmp/test_parc_FileOutputStream", O_CREAT|O_WRONLY|O_TRUNC, 0600));
*
* PARCBuffer *buffer = parcBuffer_Allocate(16 * 1024*1024);
*
* parcFileOutputStream_Write(stream, buffer);
*
* assertFalse(parcBuffer_HasRemaining(buffer), "Expected the buffer to be emtpy");
*
* parcBuffer_Release(&buffer);
*
* parcFileOutputStream_Release(&stream);
* }
* @endcode
*
*/
bool parcFileInputStream_Read(PARCFileInputStream *inputStream, PARCBuffer *buffer);
/**
* Read the content of a `PARCFileInputStream` into a {@link PARCBuffer}.
*
* @param [in] inputStream The `PARCFileInputStream` to read.
*
* @return non-NULL A pointer to a `PARCBuffer` instance containing the content of the `PARCFileInputStream`.
* @return NULl Memory could not be allocated.
*
* Example:
* @code
* {
* <#example#>
* }
* @endcode
*/
PARCBuffer *parcFileInputStream_ReadFile(PARCFileInputStream *inputStream);
#endif // libparc_parc_FileInputStream_h
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