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/*
*
* Copyright 2017 gRPC authors.
*
* 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.
*
*/
#ifndef GRPC_CORE_LIB_COMPRESSION_STREAM_COMPRESSION_H
#define GRPC_CORE_LIB_COMPRESSION_STREAM_COMPRESSION_H
#include <stdbool.h>
#include <grpc/slice_buffer.h>
#include <zlib.h>
/* Stream compression/decompression context */
typedef struct grpc_stream_compression_context {
z_stream zs;
int (*flate)(z_stream *zs, int flush);
} grpc_stream_compression_context;
typedef enum grpc_stream_compression_method {
GRPC_STREAM_COMPRESSION_COMPRESS = 0,
GRPC_STREAM_COMPRESSION_DECOMPRESS,
GRPC_STREAM_COMPRESSION_METHOD_COUNT
} grpc_stream_compression_method;
typedef enum grpc_stream_compression_flush {
GRPC_STREAM_COMPRESSION_FLUSH_NONE = 0,
GRPC_STREAM_COMPRESSION_FLUSH_SYNC,
GRPC_STREAM_COMPRESSION_FLUSH_FINISH,
GRPC_STREAM_COMPRESSION_FLUSH_COUNT
} grpc_stream_compression_flush;
/**
* Compress bytes provided in \a in with a given context, with an optional flush
* at the end of compression. Emits at most \a max_output_size compressed bytes
* into \a out. If all the bytes in input buffer \a in are depleted and \a flush
* is not GRPC_STREAM_COMPRESSION_FLUSH_NONE, the corresponding flush method is
* executed. The total number of bytes emitted is outputed in \a output_size.
*
* A SYNC flush indicates that the entire messages in \a in can be decompressed
* from \a out. A FINISH flush implies a SYNC flush, and that any further
* compression will not be dependent on the state of the current context and any
* previous compressed bytes. It allows corresponding decompression context to
* be dropped when reaching this boundary.
*/
bool grpc_stream_compress(grpc_stream_compression_context *ctx,
grpc_slice_buffer *in, grpc_slice_buffer *out,
size_t *output_size, size_t max_output_size,
grpc_stream_compression_flush flush);
/**
* Decompress bytes provided in \a in with a given context. Emits at most \a
* max_output_size decompressed bytes into \a out. If decompression process
* reached the end of a gzip stream, \a end_of_context is set to true; otherwise
* it is set to false. The total number of bytes emitted is outputed in \a
* output_size.
*/
bool grpc_stream_decompress(grpc_stream_compression_context *ctx,
grpc_slice_buffer *in, grpc_slice_buffer *out,
size_t *output_size, size_t max_output_size,
bool *end_of_context);
/**
* Creates a stream compression context. \a pending_bytes_buffer is the input
* buffer for compression/decompression operations. \a method specifies whether
* the context is for compression or decompression.
*/
grpc_stream_compression_context *grpc_stream_compression_context_create(
grpc_stream_compression_method method);
/**
* Destroys a stream compression context.
*/
void grpc_stream_compression_context_destroy(
grpc_stream_compression_context *ctx);
#endif /* GRPC_CORE_LIB_COMPRESSION_STREAM_COMPRESSION_H */
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