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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.
*
*/
#include <stdlib.h>
#include <string.h>
#include <grpc/compression.h>
#include <grpc/support/useful.h>
#include "src/core/lib/compression/algorithm_metadata.h"
#include "src/core/lib/surface/api_trace.h"
#include "src/core/lib/transport/static_metadata.h"
int grpc_compression_algorithm_parse(grpc_slice name,
grpc_compression_algorithm *algorithm) {
/* we use strncmp not only because it's safer (even though in this case it
* doesn't matter, given that we are comparing against string literals, but
* because this way we needn't have "name" nil-terminated (useful for slice
* data, for example) */
if (grpc_slice_cmp(name, GRPC_MDSTR_IDENTITY) == 0) {
*algorithm = GRPC_COMPRESS_NONE;
return 1;
} else if (grpc_slice_cmp(name, GRPC_MDSTR_GZIP) == 0) {
*algorithm = GRPC_COMPRESS_GZIP;
return 1;
} else if (grpc_slice_cmp(name, GRPC_MDSTR_DEFLATE) == 0) {
*algorithm = GRPC_COMPRESS_DEFLATE;
return 1;
} else {
return 0;
}
}
int grpc_compression_algorithm_name(grpc_compression_algorithm algorithm,
char **name) {
GRPC_API_TRACE("grpc_compression_algorithm_parse(algorithm=%d, name=%p)", 2,
((int)algorithm, name));
switch (algorithm) {
case GRPC_COMPRESS_NONE:
*name = "identity";
return 1;
case GRPC_COMPRESS_DEFLATE:
*name = "deflate";
return 1;
case GRPC_COMPRESS_GZIP:
*name = "gzip";
return 1;
case GRPC_COMPRESS_ALGORITHMS_COUNT:
return 0;
}
return 0;
}
grpc_compression_algorithm grpc_compression_algorithm_from_slice(
grpc_slice str) {
if (grpc_slice_cmp(str, GRPC_MDSTR_IDENTITY) == 0) return GRPC_COMPRESS_NONE;
if (grpc_slice_cmp(str, GRPC_MDSTR_DEFLATE) == 0)
return GRPC_COMPRESS_DEFLATE;
if (grpc_slice_cmp(str, GRPC_MDSTR_GZIP) == 0) return GRPC_COMPRESS_GZIP;
return GRPC_COMPRESS_ALGORITHMS_COUNT;
}
grpc_slice grpc_compression_algorithm_slice(
grpc_compression_algorithm algorithm) {
switch (algorithm) {
case GRPC_COMPRESS_NONE:
return GRPC_MDSTR_IDENTITY;
case GRPC_COMPRESS_DEFLATE:
return GRPC_MDSTR_DEFLATE;
case GRPC_COMPRESS_GZIP:
return GRPC_MDSTR_GZIP;
case GRPC_COMPRESS_ALGORITHMS_COUNT:
return grpc_empty_slice();
}
return grpc_empty_slice();
}
grpc_mdelem *grpc_compression_encoding_mdelem(
grpc_compression_algorithm algorithm) {
switch (algorithm) {
case GRPC_COMPRESS_NONE:
return GRPC_MDELEM_GRPC_ENCODING_IDENTITY;
case GRPC_COMPRESS_DEFLATE:
return GRPC_MDELEM_GRPC_ENCODING_DEFLATE;
case GRPC_COMPRESS_GZIP:
return GRPC_MDELEM_GRPC_ENCODING_GZIP;
default:
break;
}
return NULL;
}
void grpc_compression_options_init(grpc_compression_options *opts) {
memset(opts, 0, sizeof(*opts));
/* all enabled by default */
opts->enabled_algorithms_bitset = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
}
void grpc_compression_options_enable_algorithm(
grpc_compression_options *opts, grpc_compression_algorithm algorithm) {
GPR_BITSET(&opts->enabled_algorithms_bitset, algorithm);
}
void grpc_compression_options_disable_algorithm(
grpc_compression_options *opts, grpc_compression_algorithm algorithm) {
GPR_BITCLEAR(&opts->enabled_algorithms_bitset, algorithm);
}
int grpc_compression_options_is_algorithm_enabled(
const grpc_compression_options *opts,
grpc_compression_algorithm algorithm) {
return GPR_BITGET(opts->enabled_algorithms_bitset, algorithm);
}
/* TODO(dgq): Add the ability to specify parameters to the individual
* compression algorithms */
grpc_compression_algorithm grpc_compression_algorithm_for_level(
grpc_compression_level level, uint32_t accepted_encodings) {
GRPC_API_TRACE("grpc_compression_algorithm_for_level(level=%d)", 1,
((int)level));
if (level > GRPC_COMPRESS_LEVEL_HIGH) {
gpr_log(GPR_ERROR, "Unknown compression level %d.", (int)level);
abort();
}
const size_t num_supported =
GPR_BITCOUNT(accepted_encodings) - 1; /* discard NONE */
if (level == GRPC_COMPRESS_LEVEL_NONE || num_supported == 0) {
return GRPC_COMPRESS_NONE;
}
GPR_ASSERT(level > 0);
/* Establish a "ranking" or compression algorithms in increasing order of
* compression.
* This is simplistic and we will probably want to introduce other dimensions
* in the future (cpu/memory cost, etc). */
const grpc_compression_algorithm algos_ranking[] = {GRPC_COMPRESS_GZIP,
GRPC_COMPRESS_DEFLATE};
/* intersect algos_ranking with the supported ones keeping the ranked order */
grpc_compression_algorithm
sorted_supported_algos[GRPC_COMPRESS_ALGORITHMS_COUNT];
size_t algos_supported_idx = 0;
for (size_t i = 0; i < GPR_ARRAY_SIZE(algos_ranking); i++) {
const grpc_compression_algorithm alg = algos_ranking[i];
for (size_t j = 0; j < num_supported; j++) {
if (GPR_BITGET(accepted_encodings, alg) == 1) {
/* if \a alg in supported */
sorted_supported_algos[algos_supported_idx++] = alg;
break;
}
}
if (algos_supported_idx == num_supported) break;
}
switch (level) {
case GRPC_COMPRESS_LEVEL_NONE:
abort(); /* should have been handled already */
case GRPC_COMPRESS_LEVEL_LOW:
return sorted_supported_algos[0];
case GRPC_COMPRESS_LEVEL_MED:
return sorted_supported_algos[num_supported / 2];
case GRPC_COMPRESS_LEVEL_HIGH:
return sorted_supported_algos[num_supported - 1];
default:
abort();
};
}
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