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/*
*
* Copyright 2015 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_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_TABLE_H
#define GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_TABLE_H
#include <grpc/slice.h>
#include <grpc/support/port_platform.h>
#include "src/core/lib/iomgr/error.h"
#include "src/core/lib/transport/metadata.h"
#ifdef __cplusplus
extern "C" {
#endif
/* HPACK header table */
/* last index in the static table */
#define GRPC_CHTTP2_LAST_STATIC_ENTRY 61
/* Initial table size as per the spec */
#define GRPC_CHTTP2_INITIAL_HPACK_TABLE_SIZE 4096
/* Maximum table size that we'll use */
#define GRPC_CHTTP2_MAX_HPACK_TABLE_SIZE GRPC_CHTTP2_INITIAL_HPACK_TABLE_SIZE
/* Per entry overhead bytes as per the spec */
#define GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD 32
#if 0
/* Maximum number of entries we could possibly fit in the table, given defined
overheads */
#define GRPC_CHTTP2_MAX_TABLE_COUNT \
((GRPC_CHTTP2_MAX_HPACK_TABLE_SIZE + GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD - 1) / \
GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD)
#endif
/* hpack decoder table */
typedef struct {
/* the first used entry in ents */
uint32_t first_ent;
/* how many entries are in the table */
uint32_t num_ents;
/* the amount of memory used by the table, according to the hpack algorithm */
uint32_t mem_used;
/* the max memory allowed to be used by the table, according to the hpack
algorithm */
uint32_t max_bytes;
/* the currently agreed size of the table, according to the hpack algorithm */
uint32_t current_table_bytes;
/* Maximum number of entries we could possibly fit in the table, given defined
overheads */
uint32_t max_entries;
/* Number of entries allocated in ents */
uint32_t cap_entries;
/* a circular buffer of headers - this is stored in the opposite order to
what hpack specifies, in order to simplify table management a little...
meaning lookups need to SUBTRACT from the end position */
grpc_mdelem *ents;
grpc_mdelem static_ents[GRPC_CHTTP2_LAST_STATIC_ENTRY];
} grpc_chttp2_hptbl;
/* initialize a hpack table */
void grpc_chttp2_hptbl_init(grpc_exec_ctx *exec_ctx, grpc_chttp2_hptbl *tbl);
void grpc_chttp2_hptbl_destroy(grpc_exec_ctx *exec_ctx, grpc_chttp2_hptbl *tbl);
void grpc_chttp2_hptbl_set_max_bytes(grpc_exec_ctx *exec_ctx,
grpc_chttp2_hptbl *tbl,
uint32_t max_bytes);
grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_exec_ctx *exec_ctx,
grpc_chttp2_hptbl *tbl,
uint32_t bytes);
/* lookup a table entry based on its hpack index */
grpc_mdelem grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
uint32_t index);
/* add a table entry to the index */
grpc_error *grpc_chttp2_hptbl_add(grpc_exec_ctx *exec_ctx,
grpc_chttp2_hptbl *tbl,
grpc_mdelem md) GRPC_MUST_USE_RESULT;
/* Find a key/value pair in the table... returns the index in the table of the
most similar entry, or 0 if the value was not found */
typedef struct {
uint32_t index;
int has_value;
} grpc_chttp2_hptbl_find_result;
grpc_chttp2_hptbl_find_result grpc_chttp2_hptbl_find(
const grpc_chttp2_hptbl *tbl, grpc_mdelem md);
#ifdef __cplusplus
}
#endif
#endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_TABLE_H */
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