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/*
*
* Copyright 2015, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HPACK_ENCODER_H
#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HPACK_ENCODER_H
#include "src/core/transport/chttp2/frame.h"
#include "src/core/transport/metadata.h"
#include "src/core/transport/metadata_batch.h"
#include <grpc/support/port_platform.h>
#include <grpc/support/slice.h>
#include <grpc/support/slice_buffer.h>
#define GRPC_CHTTP2_HPACKC_NUM_FILTERS 256
#define GRPC_CHTTP2_HPACKC_NUM_VALUES 256
/* initial table size, per spec */
#define GRPC_CHTTP2_HPACKC_INITIAL_TABLE_SIZE 4096
/* maximum table size we'll actually use */
#define GRPC_CHTTP2_HPACKC_MAX_TABLE_SIZE (1024 * 1024)
typedef struct {
gpr_uint32 filter_elems_sum;
gpr_uint32 max_table_size;
gpr_uint32 max_table_elems;
gpr_uint32 cap_table_elems;
/** if non-zero, advertise to the decoder that we'll start using a table
of this size */
gpr_uint8 advertise_table_size_change;
/** maximum number of bytes we'll use for the decode table (to guard against
peers ooming us by setting decode table size high) */
gpr_uint32 max_usable_size;
/* one before the lowest usable table index */
gpr_uint32 tail_remote_index;
gpr_uint32 table_size;
gpr_uint32 table_elems;
/* filter tables for elems: this tables provides an approximate
popularity count for particular hashes, and are used to determine whether
a new literal should be added to the compression table or not.
They track a single integer that counts how often a particular value has
been seen. When that count reaches max (255), all values are halved. */
gpr_uint8 filter_elems[GRPC_CHTTP2_HPACKC_NUM_FILTERS];
/* entry tables for keys & elems: these tables track values that have been
seen and *may* be in the decompressor table */
grpc_mdstr *entries_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES];
grpc_mdelem *entries_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
gpr_uint32 indices_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES];
gpr_uint32 indices_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
gpr_uint16 *table_elem_size;
} grpc_chttp2_hpack_compressor;
void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor *c);
void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor *c);
void grpc_chttp2_hpack_compressor_set_max_table_size(
grpc_chttp2_hpack_compressor *c, gpr_uint32 max_table_size);
void grpc_chttp2_hpack_compressor_set_max_usable_size(
grpc_chttp2_hpack_compressor *c, gpr_uint32 max_table_size);
void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor *c, gpr_uint32 id,
grpc_metadata_batch *metadata, int is_eof,
gpr_slice_buffer *outbuf);
#endif /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_HPACK_ENCODER_H */
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