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Diffstat (limited to 'libparc/parc/algol/parc_FileChunker.h')
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diff --git a/libparc/parc/algol/parc_FileChunker.h b/libparc/parc/algol/parc_FileChunker.h new file mode 100755 index 00000000..6ab0d267 --- /dev/null +++ b/libparc/parc/algol/parc_FileChunker.h @@ -0,0 +1,219 @@ +/* + * 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_FileChunker.h + * @ingroup ContentObject + * @brief A FileChunker is a chunker that segments the content of a file. + * + */ + +#ifndef libparc_parc_FileChunker_h +#define libparc_parc_FileChunker_h + +#include <parc/algol/parc_Chunker.h> + +#include <parc/algol/parc_File.h> + +struct parc_buffer_chunker; +/** + * @typedef PARCFileChunker + * @brief The PARC Chunker + */ +typedef struct parc_buffer_chunker PARCFileChunker; + +/** + * The mapping of a `PARCFileChunker` to the generic `PARCChunker`. + */ +extern PARCChunkerInterface *PARCFileChunkerAsChunker; + +/** + * Create a new chunker to segment data contained in a `PARCBuffer.` + * + * @param [in] file A `PARCFile` from which the data will be read. + * @param [in] chunkSize The size per chunk. + * + * @retval PARCFileChunker A newly allocated `PARCFileChunker` + * @retval NULL An error occurred. + * + * Example + * @code + * { + * PARCBuffer *dataToChunk = ... + * PARCFileChunker *chunker = PARCFileChunker_CreateFromBuffer(dataToChunk, 32); + * } + */ +PARCFileChunker *parcFileChunker_Create(PARCFile *file, size_t chunkSize); + +/** + * Increase the number of references to a `PARCFileChunker` instance. + * + * Note that new `PARCFileChunker` is not created, + * only that the given `PARCFileChunker` reference count is incremented. + * Discard the reference by invoking {@link PARCFileChunker_Release}. + * + * @param [in] chunker A pointer to the original `PARCFileChunker`. + * @return The value of the input parameter @p chunker. + * + * Example: + * @code + * { + * PARCFileChunker *original = parcFileChunker_Create(...); + * + * PARCFileChunker *reference = parcFileChunker_Acquire(original); + * + * parcFileChunker_Release(&original); + * parcFileChunker_Release(&reference); + * } + * @endcode + * + * @see parcFileChunker_Release + */ +PARCFileChunker *parcFileChunker_Acquire(const PARCFileChunker *chunker); + +/** + * Release a previously acquired reference to the specified instance, + * decrementing the reference count for the instance. + * + * The pointer to the instance is set to NULL as a side-effect of this function. + * + * If the invocation causes the last reference to the instance to be released, + * the instance is deallocated and the instance's implementation will perform + * additional cleanup and release other privately held references. + * + * @param [in,out] chunkerP A pointer to a pointer to the instance to release. + * + * + * Example: + * @code + * { + * ... + * + * PARCFileChunker *chunker = parcFileChunker_Acquire(instance); + * + * parcFileChunker_Release(&chunker); + * } + * @endcode + */ +void parcFileChunker_Release(PARCFileChunker **chunkerP); + +/** + * Determine if two `PARCFileChunker` instances are equal. + * + * The following equivalence relations on non-null `PARCFileChunker` instances are maintained: + * + * * It is reflexive: for any non-null reference value x, `parcFileChunker_Equals(x, x)` + * must return true. + * + * * It is symmetric: for any non-null reference values x and y, + * `parcFileChunker_Equals(x, y)` must return true if and only if + * `parcFileChunker_Equals(y, x)` returns true. + * + * * It is transitive: for any non-null reference values x, y, and z, if + * `parcFileChunker_Equals(x, y)` returns true and + * `parcFileChunker_Equals(y, z)` returns true, + * then `parcFileChunker_Equals(x, z)` must return true. + * + * * It is consistent: for any non-null reference values x and y, multiple + * invocations of `parcFileChunker_Equals(x, y)` consistently return true or + * consistently return false. + * + * * For any non-null reference value x, `parcFileChunker_Equals(x, NULL)` must + * return false. + * + * @param chunkerA A pointer to a `PARCFileChunker` instance. + * @param chunkerB A pointer to a `PARCFileChunker` instance. + * @return true if the two `PARCFileChunker` instances are equal. + * + * Example: + * @code + * { + * char *fileToChunk = ... + * PARCFileChunker *chunkerA = parcFileChunker_Create(fileToChunk, 32); + * PARCFileChunker *chunkerB = parcFileChunker_Create(fileToChunk, 32); + * + * bool equals = parcFileChunker_Equals(chunkerA, chunkerB); + * } + * @endcode + */ +bool parcFileChunker_Equals(const PARCFileChunker *chunkerA, const PARCFileChunker *chunkerB); + +/** + * Return an iterator to traverse the chunks of the underlying data in sequential order. + * + * This function can only be called once per chunker instance since the iterator + * will mutate internal state of the chunker. + * + * @param [in] chunker A `PARCFileChunker` instance. + * + * @return a `PARCIterator` that traverses the chunks of the underlying data. + * + * Example + * @code + * { + * char *fileToChunk = ... + * PARCFileChunker *chunker = parcFileChunker_Create(fileToChunk, 32); + * + * PARCIterator *itr = parcFileChunker_ForwardIterator(chunker); + * + * // use the iterator to traverse the chunker + * } + * @endcode + */ +PARCIterator *parcFileChunker_ForwardIterator(const PARCFileChunker *chunker); + +/** + * Return an iterator to traverse the chunks of the underlying data in sequential order. + * + * This function can only be called once per chunker instance since the iterator + * will mutate internal state of the chunker. + * + * @param [in] chunker A `PARCFileChunker` instance. + * + * @return a `PARCIterator` that traverses the chunks of the underlying data. + * + * Example + * @code + * { + * char *fileToChunk = ... + * PARCFileChunker *chunker = parcFileChunker_Create(fileToChunk, 32); + * + * PARCIterator *itr = parcFileChunker_ReverseIterator(chunker); + * + * // use the iterator to traverse the chunker + * } + * @endcode + */ +PARCIterator *parcFileChunker_ReverseIterator(const PARCFileChunker *chunker); + +/** + * Get the chunk size of a `PARCFileChunker.` + * + * @param [in] chunker A `PARCFileChunker` instance. + * + * @return the chunk size + * + * Example + * @code + * { + * PARCBuffer *dataToChunk = ... + * PARCFileChunker *chunker = ... + * + * size_t chunkSize = parcFileChunker_GetChunkSize(chunker); + * } + * @endcode + */ +size_t parcFileChunker_GetChunkSize(const PARCFileChunker *chunker); +#endif // libparc_parc_FileChunker_h |