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This commit is contained in:
Sara Golemon
249
src/comp.c
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249
src/comp.c
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/* Copyright (c) 2004, Sara Golemon <sarag@users.sourceforge.net>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms,
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* with or without modification, are permitted provided
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* that the following conditions are met:
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*
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* Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the
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* following disclaimer.
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*
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* Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* Neither the name of the copyright holder nor the names
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* of any other contributors may be used to endorse or
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* promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*/
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#include "libssh2_priv.h"
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#include <zlib.h>
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/* ********
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* none *
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******** */
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/* {{{ libssh2_comp_method_none_comp
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* Minimalist compression: Absolutely none
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*/
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static int libssh2_comp_method_none_comp(LIBSSH2_SESSION *session, int compress,
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unsigned char **dest, unsigned long *dest_len, unsigned long payload_limit, int *free_dest,
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const unsigned char *src, unsigned long src_len, void **abstract)
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{
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*dest = (unsigned char *)src;
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*dest_len = src_len;
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*free_dest = 0;
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return 0;
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}
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/* }}} */
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static LIBSSH2_COMP_METHOD libssh2_comp_method_none = {
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"none",
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NULL,
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libssh2_comp_method_none_comp,
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NULL
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};
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#ifdef LIBSSH2_HAVE_ZLIB
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/* ********
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* zlib *
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******** */
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/* {{{ Memory management wrappers
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* Yes, I realize we're doing a callback to a callback,
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* Deal...
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*/
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static voidpf libssh2_comp_method_zlib_alloc(voidpf opaque, uInt items, uInt size)
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{
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LIBSSH2_SESSION *session = (LIBSSH2_SESSION*)opaque;
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return (voidpf)LIBSSH2_ALLOC(session, items * size);
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}
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static void libssh2_comp_method_zlib_free(voidpf opaque, voidpf address)
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{
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LIBSSH2_SESSION *session = (LIBSSH2_SESSION*)opaque;
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LIBSSH2_FREE(session, address);
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}
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/* }}} */
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/* {{{ libssh2_comp_method_zlib_init
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* All your bandwidth are belong to us (so save some)
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*/
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static int libssh2_comp_method_zlib_init(LIBSSH2_SESSION *session, int compress, void **abstract)
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{
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z_stream *strm;
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int status;
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strm = LIBSSH2_ALLOC(session, sizeof(z_stream));
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if (!strm) {
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libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate memory for zlib compression/decompression", 0);
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return -1;
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}
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memset(strm, 0, sizeof(z_stream));
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strm->opaque = (voidpf)session;
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strm->zalloc = (alloc_func)libssh2_comp_method_zlib_alloc;
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strm->zfree = (free_func)libssh2_comp_method_zlib_free;
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if (compress) {
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/* deflate */
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status = deflateInit(strm, Z_DEFAULT_COMPRESSION);
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} else {
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/* inflate */
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status = inflateInit(strm);
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}
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if (status != Z_OK) {
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LIBSSH2_FREE(session, strm);
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return -1;
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}
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*abstract = strm;
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return 0;
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}
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/* }}} */
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/* {{{ libssh2_comp_method_zlib_comp
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* zlib, a compression standard for all occasions
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*/
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static int libssh2_comp_method_zlib_comp(LIBSSH2_SESSION *session, int compress,
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unsigned char **dest, unsigned long *dest_len, unsigned long payload_limit, int *free_dest,
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const unsigned char *src, unsigned long src_len, void **abstract)
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{
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z_stream *strm = *abstract;
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/* A short-term alloc of a full data chunk is better than a series of reallocs */
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char *out;
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int out_maxlen = compress ? src_len : (2 * src_len);
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int limiter = 0;
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/* In practice they never come smaller than this */
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if (out_maxlen < 21) {
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out_maxlen = 21;
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}
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if (out_maxlen > payload_limit) {
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out_maxlen = payload_limit;
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}
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strm->next_in = (char *)src;
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strm->avail_in = src_len;
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out = strm->next_out = LIBSSH2_ALLOC(session, out_maxlen);
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strm->avail_out = out_maxlen;
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if (!strm->next_out) {
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libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate compression/decompression buffer", 0);
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return -1;
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}
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while (strm->avail_in) {
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int status;
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if (compress) {
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status = deflate(strm, Z_PARTIAL_FLUSH);
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} else {
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status = inflate(strm, Z_PARTIAL_FLUSH);
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}
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if (status != Z_OK) {
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libssh2_error(session, LIBSSH2_ERROR_ZLIB, "compress/decompression failure", 0);
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LIBSSH2_FREE(session, strm->next_out);
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return -1;
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}
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if (strm->avail_in) {
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unsigned long out_ofs = out_maxlen - strm->avail_out;
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out_maxlen += compress ? strm->avail_in : (2 * strm->avail_in);
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if ((out_maxlen > payload_limit) && !compress && limiter++) {
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libssh2_error(session, LIBSSH2_ERROR_ZLIB, "Excessive growth in decompression phase", 0);
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LIBSSH2_FREE(session, strm->next_out);
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return -1;
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}
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out = LIBSSH2_REALLOC(session, out, out_maxlen);
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if (!out) {
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libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to expand compress/decompression buffer", 0);
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return -1;
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}
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strm->next_out = out + out_ofs;
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strm->avail_out += compress ? strm->avail_in : (2 * strm->avail_in);
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}
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}
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*dest = out;
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*dest_len = out_maxlen - strm->avail_out;
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*free_dest = 1;
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return 0;
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}
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/* }}} */
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/* {{{ libssh2_comp_method_zlib_dtor
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* All done, no more compression for you
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*/
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static int libssh2_comp_method_zlib_dtor(LIBSSH2_SESSION *session, int compress, void **abstract)
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{
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z_stream *strm = *abstract;
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if (strm) {
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if (compress) {
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/* deflate */
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deflateEnd(strm);
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} else {
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/* inflate */
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inflateEnd(strm);
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}
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LIBSSH2_FREE(session, strm);
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}
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*abstract = NULL;
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return 0;
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}
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/* }}} */
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static LIBSSH2_COMP_METHOD libssh2_comp_method_zlib = {
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"zlib",
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libssh2_comp_method_zlib_init,
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libssh2_comp_method_zlib_comp,
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libssh2_comp_method_zlib_dtor,
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};
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#endif /* LIBSSH2_HAVE_ZLIB */
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/* ***********************
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* Compression Methods *
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*********************** */
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static LIBSSH2_COMP_METHOD *_libssh2_comp_methods[] = {
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#ifdef LIBSSH2_HAVE_ZLIB
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&libssh2_comp_method_zlib,
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#endif /* LIBSSH2_HAVE_ZLIB */
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&libssh2_comp_method_none,
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NULL
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};
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LIBSSH2_COMP_METHOD **libssh2_comp_methods(void) {
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return _libssh2_comp_methods;
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}
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