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switch to xmalloc stuff, me and xsa@ agreed on this a long
time ago, but we were being held back by jfb. too bad for him.

next step is to use fatal() through out the code for unrecoverable
errors instead of trying to be all nice and fluffy and reach main() again.

ok niallo@ and xsa@

/*	$OpenBSD: zlib.c,v 1.4 2005/12/10 20:27:45 joris Exp $	*/
/*
 * 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 <sys/param.h>

#include <stdlib.h>
#include <string.h>

#include "log.h"
#include "cvs.h"
#include "zlib.h"

#define CVS_ZLIB_BUFSIZE	1024

struct cvs_zlib_ctx {
	int		z_level;
	z_stream	z_instrm;
	z_stream	z_destrm;
};


/*
 * 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)) {
		cvs_log(LP_ERR, "invalid compression level %d "
		    "(must be between 0 and 9)", level);
		return (NULL);
	}

	ctx = (CVSZCTX *)xmalloc(sizeof(*ctx));
	if (ctx == NULL) {
		cvs_log(LP_ERRNO, "failed to allocate zlib context");
		return (NULL);
	}
	memset(ctx, 0, 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)) {
		cvs_log(LP_ERR, "failed to initialize zlib streams");
		xfree(ctx);
		return (NULL);
	}

	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)
{
	int bytes, ret;
	u_char buf[CVS_ZLIB_BUFSIZE];

	bytes = 0;
	cvs_buf_empty(dst);
	inflateReset(&(ctx->z_instrm));

	ctx->z_instrm.next_in = src;
	ctx->z_instrm.avail_in = slen;

	do {
		ctx->z_instrm.next_out = buf;
		ctx->z_instrm.avail_out = sizeof(buf);

		ret = inflate(&(ctx->z_instrm), Z_FINISH);
		if ((ret == Z_MEM_ERROR) || (ret == Z_BUF_ERROR) ||
		    (ret == Z_STREAM_ERROR) || (ret == Z_DATA_ERROR)) {
			cvs_log(LP_ERR, "inflate error: %s", ctx->z_instrm.msg);
			return (-1);
		}

		cvs_buf_append(dst, buf, ctx->z_instrm.avail_out);
		bytes += sizeof(buf) - ctx->z_instrm.avail_out;

	} while (ret != Z_STREAM_END);

	return (bytes);
}

/*
 * 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)
{
	int bytes, ret;
	u_char buf[CVS_ZLIB_BUFSIZE];

	bytes = 0;
	cvs_buf_empty(dst);
	deflateReset(&(ctx->z_destrm));

	ctx->z_destrm.next_in = src;
	ctx->z_destrm.avail_in = slen;

	do {
		ctx->z_destrm.next_out = buf;
		ctx->z_destrm.avail_out = sizeof(buf);
		ret = deflate(&(ctx->z_destrm), Z_FINISH);
		if ((ret == Z_STREAM_ERROR) || (ret == Z_BUF_ERROR)) {
			cvs_log(LP_ERR, "deflate error: %s", ctx->z_destrm.msg);
			return (-1);
		}

		if (cvs_buf_append(dst, buf,
		    sizeof(buf) - ctx->z_destrm.avail_out) < 0)
			return (-1);
		bytes += sizeof(buf) - ctx->z_destrm.avail_out;
	} while (ret != Z_STREAM_END);

	return (bytes);
}