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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.
*
*/
#include "src/core/ext/transport/chttp2/transport/stream_map.h"
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/useful.h>
void grpc_chttp2_stream_map_init(grpc_chttp2_stream_map* map,
size_t initial_capacity) {
GPR_ASSERT(initial_capacity > 1);
map->keys = (uint32_t*)gpr_malloc(sizeof(uint32_t) * initial_capacity);
map->values = (void**)gpr_malloc(sizeof(void*) * initial_capacity);
map->count = 0;
map->free = 0;
map->capacity = initial_capacity;
}
void grpc_chttp2_stream_map_destroy(grpc_chttp2_stream_map* map) {
gpr_free(map->keys);
gpr_free(map->values);
}
static size_t compact(uint32_t* keys, void** values, size_t count) {
size_t i, out;
for (i = 0, out = 0; i < count; i++) {
if (values[i]) {
keys[out] = keys[i];
values[out] = values[i];
out++;
}
}
return out;
}
void grpc_chttp2_stream_map_add(grpc_chttp2_stream_map* map, uint32_t key,
void* value) {
size_t count = map->count;
size_t capacity = map->capacity;
uint32_t* keys = map->keys;
void** values = map->values;
GPR_ASSERT(count == 0 || keys[count - 1] < key);
GPR_ASSERT(value);
GPR_ASSERT(grpc_chttp2_stream_map_find(map, key) == nullptr);
if (count == capacity) {
if (map->free > capacity / 4) {
count = compact(keys, values, count);
map->free = 0;
} else {
/* resize when less than 25% of the table is free, because compaction
won't help much */
map->capacity = capacity = 3 * capacity / 2;
map->keys = keys =
(uint32_t*)gpr_realloc(keys, capacity * sizeof(uint32_t));
map->values = values =
(void**)gpr_realloc(values, capacity * sizeof(void*));
}
}
keys[count] = key;
values[count] = value;
map->count = count + 1;
}
static void** find(grpc_chttp2_stream_map* map, uint32_t key) {
size_t min_idx = 0;
size_t max_idx = map->count;
size_t mid_idx;
uint32_t* keys = map->keys;
void** values = map->values;
uint32_t mid_key;
if (max_idx == 0) return nullptr;
while (min_idx < max_idx) {
/* find the midpoint, avoiding overflow */
mid_idx = min_idx + ((max_idx - min_idx) / 2);
mid_key = keys[mid_idx];
if (mid_key < key) {
min_idx = mid_idx + 1;
} else if (mid_key > key) {
max_idx = mid_idx;
} else /* mid_key == key */
{
return &values[mid_idx];
}
}
return nullptr;
}
void* grpc_chttp2_stream_map_delete(grpc_chttp2_stream_map* map, uint32_t key) {
void** pvalue = find(map, key);
void* out = nullptr;
if (pvalue != nullptr) {
out = *pvalue;
*pvalue = nullptr;
map->free += (out != nullptr);
/* recognize complete emptyness and ensure we can skip
* defragmentation later */
if (map->free == map->count) {
map->free = map->count = 0;
}
GPR_ASSERT(grpc_chttp2_stream_map_find(map, key) == nullptr);
}
return out;
}
void* grpc_chttp2_stream_map_find(grpc_chttp2_stream_map* map, uint32_t key) {
void** pvalue = find(map, key);
return pvalue != nullptr ? *pvalue : nullptr;
}
size_t grpc_chttp2_stream_map_size(grpc_chttp2_stream_map* map) {
return map->count - map->free;
}
void* grpc_chttp2_stream_map_rand(grpc_chttp2_stream_map* map) {
if (map->count == map->free) {
return nullptr;
}
if (map->free != 0) {
map->count = compact(map->keys, map->values, map->count);
map->free = 0;
GPR_ASSERT(map->count > 0);
}
return map->values[((size_t)rand()) % map->count];
}
void grpc_chttp2_stream_map_for_each(grpc_chttp2_stream_map* map,
void (*f)(void* user_data, uint32_t key,
void* value),
void* user_data) {
size_t i;
for (i = 0; i < map->count; i++) {
if (map->values[i]) {
f(user_data, map->keys[i], map->values[i]);
}
}
}
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