--- /dev/null
+/*
+ *
+ * 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/support/port_platform.h>
+
+#include <grpc/slice.h>
+#include "src/core/lib/gprpp/memory.h"
+#include "src/core/lib/iomgr/error.h"
+#include "src/core/lib/transport/metadata.h"
+#include "src/core/lib/transport/static_metadata.h"
+
+/* 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 */
+struct grpc_chttp2_hptbl {
+ static uint32_t entries_for_bytes(uint32_t bytes) {
+ return (bytes + GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD - 1) /
+ GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD;
+ }
+ static constexpr uint32_t kInitialCapacity =
+ (GRPC_CHTTP2_INITIAL_HPACK_TABLE_SIZE + GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD -
+ 1) /
+ GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD;
+
+ grpc_chttp2_hptbl() {
+ GPR_DEBUG_ASSERT(!ents);
+ constexpr uint32_t AllocSize = sizeof(*ents) * kInitialCapacity;
+ ents = static_cast<grpc_mdelem*>(gpr_malloc(AllocSize));
+ memset(ents, 0, AllocSize);
+ }
+
+ /* the first used entry in ents */
+ uint32_t first_ent = 0;
+ /* how many entries are in the table */
+ uint32_t num_ents = 0;
+ /* the amount of memory used by the table, according to the hpack algorithm */
+ uint32_t mem_used = 0;
+ /* the max memory allowed to be used by the table, according to the hpack
+ algorithm */
+ uint32_t max_bytes = GRPC_CHTTP2_INITIAL_HPACK_TABLE_SIZE;
+ /* the currently agreed size of the table, according to the hpack algorithm */
+ uint32_t current_table_bytes = GRPC_CHTTP2_INITIAL_HPACK_TABLE_SIZE;
+ /* Maximum number of entries we could possibly fit in the table, given defined
+ overheads */
+ uint32_t max_entries = kInitialCapacity;
+ /* Number of entries allocated in ents */
+ uint32_t cap_entries = kInitialCapacity;
+ /* 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 = nullptr;
+};
+
+void grpc_chttp2_hptbl_destroy(grpc_chttp2_hptbl* tbl);
+void grpc_chttp2_hptbl_set_max_bytes(grpc_chttp2_hptbl* tbl,
+ uint32_t max_bytes);
+grpc_error* grpc_chttp2_hptbl_set_current_table_size(grpc_chttp2_hptbl* tbl,
+ uint32_t bytes);
+
+/* lookup a table entry based on its hpack index */
+grpc_mdelem grpc_chttp2_hptbl_lookup_dynamic_index(const grpc_chttp2_hptbl* tbl,
+ uint32_t tbl_index);
+grpc_mdelem grpc_chttp2_hptbl_lookup_ref_dynamic_index(
+ const grpc_chttp2_hptbl* tbl, uint32_t tbl_index);
+template <bool take_ref = false>
+inline grpc_mdelem grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl* tbl,
+ uint32_t index) {
+ /* Static table comes first, just return an entry from it.
+ NB: This imposes the constraint that the first
+ GRPC_CHTTP2_LAST_STATIC_ENTRY entries in the core static metadata table
+ must follow the hpack standard. If that changes, we *must* not rely on
+ reading the core static metadata table here; at that point we'd need our
+ own singleton static metadata in the correct order. */
+ if (index <= GRPC_CHTTP2_LAST_STATIC_ENTRY) {
+ return grpc_static_mdelem_manifested()[index - 1];
+ } else {
+ if (take_ref) {
+ return grpc_chttp2_hptbl_lookup_ref_dynamic_index(tbl, index);
+ } else {
+ return grpc_chttp2_hptbl_lookup_dynamic_index(tbl, index);
+ }
+ }
+}
+/* add a table entry to the index */
+grpc_error* grpc_chttp2_hptbl_add(grpc_chttp2_hptbl* tbl,
+ grpc_mdelem md) GRPC_MUST_USE_RESULT;
+
+size_t grpc_chttp2_get_size_in_hpack_table(grpc_mdelem elem,
+ bool use_true_binary_metadata);
+
+/* Returns the static hpack table index that corresponds to /a elem. Returns 0
+ if /a elem is not statically stored or if it is not in the static hpack
+ table */
+inline uintptr_t grpc_chttp2_get_static_hpack_table_index(grpc_mdelem md) {
+ uintptr_t index =
+ reinterpret_cast<grpc_core::StaticMetadata*>(GRPC_MDELEM_DATA(md)) -
+ grpc_static_mdelem_table();
+ if (index < GRPC_CHTTP2_LAST_STATIC_ENTRY) {
+ return index + 1; // Hpack static metadata element indices start at 1
+ }
+ return 0;
+}
+
+/* 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);
+
+#endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_TABLE_H */
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