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/* $OpenBSD: compress.c,v 1.5 2006/05/29 17:10:57 pat Exp $ */
/*
* Copyright (c) 2006 Patrick Latifi <pat@openbsd.org>
* Copyright (c) 2005 Jean-Francois Brousseau <jfb@openbsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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 "includes.h"
#include "log.h"
#include "cvs.h"
#include "compress.h"
#define CVS_ZLIB_BUFSIZE 1024
struct cvs_zlib_ctx {
int z_level;
z_stream z_instrm;
z_stream z_destrm;
};
struct zlib_ioctx {
z_stream *stream;
int (*reset)(z_stream *);
int (*io)(z_stream *, int);
int ioflags;
};
static int cvs_zlib_io(struct zlib_ioctx *, BUF *, u_char *, size_t);
/*
* cvs_zlib_newctx()
*
* Allocate a new ZLIB context structure used for both inflation and deflation
* of data with compression level <level>, which must be between 0 and 9. A
* value of 0 means no compression, and 9 is the highest level of compression.
*/
CVSZCTX *
cvs_zlib_newctx(int level)
{
CVSZCTX *ctx;
if (level < 0 || level > 9)
fatal("invalid compression level %d (must be between 0 and 9)",
level);
ctx = xcalloc(1, sizeof(*ctx));
ctx->z_level = level;
ctx->z_instrm.zalloc = Z_NULL;
ctx->z_instrm.zfree = Z_NULL;
ctx->z_instrm.opaque = Z_NULL;
ctx->z_destrm.zalloc = Z_NULL;
ctx->z_destrm.zfree = Z_NULL;
ctx->z_destrm.opaque = Z_NULL;
if (inflateInit(&(ctx->z_instrm)) != Z_OK ||
deflateInit(&(ctx->z_destrm), level) != Z_OK)
fatal("failed to initialize zlib streams");
return (ctx);
}
/*
* cvs_zlib_free()
*
* Free a ZLIB context previously allocated with cvs_zlib_newctx().
*/
void
cvs_zlib_free(CVSZCTX *ctx)
{
if (ctx != NULL) {
(void)inflateEnd(&(ctx->z_instrm));
(void)deflateEnd(&(ctx->z_destrm));
xfree(ctx);
}
}
/*
* cvs_zlib_inflate()
*
* Decompress the first <slen> bytes of <src> using the zlib context <ctx> and
* store the resulting data in <dst>.
* Returns the number of bytes inflated on success, or -1 on failure.
*/
int
cvs_zlib_inflate(CVSZCTX *ctx, BUF *dst, u_char *src, size_t slen)
{
struct zlib_ioctx zio;
zio.stream = &ctx->z_instrm;
zio.reset = inflateReset;
zio.io = inflate;
zio.ioflags = Z_FINISH;
return cvs_zlib_io(&zio, dst, src, slen);
}
/*
* cvs_zlib_deflate()
*
* Compress the first <slen> bytes of <src> using the zlib context <ctx> and
* store the resulting data in <dst>.
* Returns the number of bytes deflated on success, or -1 on failure.
*/
int
cvs_zlib_deflate(CVSZCTX *ctx, BUF *dst, u_char *src, size_t slen)
{
struct zlib_ioctx zio;
zio.stream = &ctx->z_destrm;
zio.reset = deflateReset;
zio.io = deflate;
zio.ioflags = Z_FINISH;
return cvs_zlib_io(&zio, dst, src, slen);
}
static int
cvs_zlib_io(struct zlib_ioctx *zio, BUF *dst, u_char *src, size_t slen)
{
int bytes, ret;
u_char buf[CVS_ZLIB_BUFSIZE];
z_stream *zstream = zio->stream;
bytes = 0;
cvs_buf_empty(dst);
if ((*zio->reset)(zstream) == Z_STREAM_ERROR)
fatal("%s error: %s", (zio->reset == inflateReset) ?
"inflate" : "deflate", zstream->msg);
zstream->next_in = src;
zstream->avail_in = slen;
do {
zstream->next_out = buf;
zstream->avail_out = sizeof(buf);
ret = (*zio->io)(zstream, zio->ioflags);
if (ret == Z_MEM_ERROR || ret == Z_STREAM_ERROR ||
ret == Z_BUF_ERROR || ret == Z_DATA_ERROR)
fatal("%s error: %s", (zio->reset == inflateReset) ?
"inflate" : "deflate", zstream->msg);
if (cvs_buf_append(dst, buf,
sizeof(buf) - zstream->avail_out) < 0)
return (-1);
bytes += sizeof(buf) - zstream->avail_out;
} while (ret != Z_STREAM_END);
return (bytes);
}
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