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/*
*
* Copyright 2014, 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 "src/core/compression/message_compress.h"
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <zlib.h>
#define OUTPUT_BLOCK_SIZE 1024
static int zlib_body(z_stream *zs, gpr_slice_buffer *input,
gpr_slice_buffer *output,
int (*flate)(z_stream *zs, int flush)) {
int r;
int flush;
size_t i;
size_t output_bytes = 0;
gpr_slice outbuf = gpr_slice_malloc(OUTPUT_BLOCK_SIZE);
zs->avail_out = GPR_SLICE_LENGTH(outbuf);
zs->next_out = GPR_SLICE_START_PTR(outbuf);
flush = Z_NO_FLUSH;
for (i = 0; i < input->count; i++) {
if (i == input->count - 1) flush = Z_FINISH;
zs->avail_in = GPR_SLICE_LENGTH(input->slices[i]);
zs->next_in = GPR_SLICE_START_PTR(input->slices[i]);
do {
if (zs->avail_out == 0) {
output_bytes += GPR_SLICE_LENGTH(outbuf);
gpr_slice_buffer_add_indexed(output, outbuf);
outbuf = gpr_slice_malloc(OUTPUT_BLOCK_SIZE);
zs->avail_out = GPR_SLICE_LENGTH(outbuf);
zs->next_out = GPR_SLICE_START_PTR(outbuf);
}
r = flate(zs, flush);
if (r == Z_STREAM_ERROR) {
gpr_log(GPR_INFO, "zlib: stream error");
goto error;
}
} while (zs->avail_out == 0);
if (zs->avail_in) {
gpr_log(GPR_INFO, "zlib: not all input consumed");
goto error;
}
}
GPR_ASSERT(outbuf.refcount);
outbuf.data.refcounted.length -= zs->avail_out;
output_bytes += GPR_SLICE_LENGTH(outbuf);
gpr_slice_buffer_add_indexed(output, outbuf);
return 1;
error:
gpr_slice_unref(outbuf);
return 0;
}
static int zlib_compress(gpr_slice_buffer *input, gpr_slice_buffer *output,
int gzip) {
z_stream zs;
int r;
size_t i;
size_t count_before = output->count;
size_t length_before = output->length;
memset(&zs, 0, sizeof(zs));
r = deflateInit2(&zs, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 15 | (gzip ? 16 : 0),
8, Z_DEFAULT_STRATEGY);
if (r != Z_OK) {
gpr_log(GPR_ERROR, "deflateInit2 returns %d", r);
return 0;
}
r = zlib_body(&zs, input, output, deflate) && output->length < input->length;
if (!r) {
for (i = count_before; i < output->count; i++) {
gpr_slice_unref(output->slices[i]);
}
output->count = count_before;
output->length = length_before;
}
deflateEnd(&zs);
return r;
}
static int zlib_decompress(gpr_slice_buffer *input, gpr_slice_buffer *output,
int gzip) {
z_stream zs;
int r;
size_t i;
size_t count_before = output->count;
size_t length_before = output->length;
memset(&zs, 0, sizeof(zs));
r = inflateInit2(&zs, 15 | (gzip ? 16 : 0));
if (r != Z_OK) {
gpr_log(GPR_ERROR, "inflateInit2 returns %d", r);
return 0;
}
r = zlib_body(&zs, input, output, inflate);
if (!r) {
for (i = count_before; i < output->count; i++) {
gpr_slice_unref(output->slices[i]);
}
output->count = count_before;
output->length = length_before;
}
inflateEnd(&zs);
return r;
}
static int copy(gpr_slice_buffer *input, gpr_slice_buffer *output) {
size_t i;
for (i = 0; i < input->count; i++) {
gpr_slice_buffer_add(output, gpr_slice_ref(input->slices[i]));
}
return 1;
}
int compress_inner(grpc_compression_algorithm algorithm,
gpr_slice_buffer *input, gpr_slice_buffer *output) {
switch (algorithm) {
case GRPC_COMPRESS_NONE:
/* the fallback path always needs to be send uncompressed: we simply
rely on that here */
return 0;
case GRPC_COMPRESS_DEFLATE:
return zlib_compress(input, output, 0);
case GRPC_COMPRESS_GZIP:
return zlib_compress(input, output, 1);
case GRPC_COMPRESS_ALGORITHMS_COUNT:
break;
}
gpr_log(GPR_ERROR, "invalid compression algorithm %d", algorithm);
return 0;
}
int grpc_msg_compress(grpc_compression_algorithm algorithm,
gpr_slice_buffer *input, gpr_slice_buffer *output) {
if (!compress_inner(algorithm, input, output)) {
copy(input, output);
return 0;
}
return 1;
}
int grpc_msg_decompress(grpc_compression_algorithm algorithm,
gpr_slice_buffer *input, gpr_slice_buffer *output) {
switch (algorithm) {
case GRPC_COMPRESS_NONE:
return copy(input, output);
case GRPC_COMPRESS_DEFLATE:
return zlib_decompress(input, output, 0);
case GRPC_COMPRESS_GZIP:
return zlib_decompress(input, output, 1);
case GRPC_COMPRESS_ALGORITHMS_COUNT:
break;
}
gpr_log(GPR_ERROR, "invalid compression algorithm %d", algorithm);
return 0;
}
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