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/* Copyright 2004 Roger Dingledine */
/* See LICENSE for licensing information */
/* $Id$ */
const char torgzip_c_id[] = "$Id$";
/**
* \file torgzip.c
*
* \brief Simple in-memory gzip implementation.
**/
#include "orconfig.h"
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#ifdef MS_WINDOWS
#include "..\..\contrib\zlib\zlib.h"
#else
#include <zlib.h>
#endif
#include "util.h"
#include "log.h"
#include "torgzip.h"
static int gzip_is_supported = -1;
int
is_gzip_supported(void)
{
if (gzip_is_supported >= 0)
return gzip_is_supported;
if (!strcmpstart(ZLIB_VERSION, "0.") ||
!strcmpstart(ZLIB_VERSION, "1.0") ||
!strcmpstart(ZLIB_VERSION, "1.1"))
gzip_is_supported = 0;
else
gzip_is_supported = 1;
return gzip_is_supported;
}
static INLINE int
method_bits(compress_method_t method)
{
/* Bits+16 means "use gzip" in zlib >= 1.2 */
return method == GZIP_METHOD ? 15+16 : 15;
}
int
tor_gzip_compress(char **out, size_t *out_len,
const char *in, size_t in_len,
compress_method_t method)
{
struct z_stream_s *stream = NULL;
size_t out_size;
off_t offset;
tor_assert(out);
tor_assert(out_len);
tor_assert(in);
if (method == GZIP_METHOD && !is_gzip_supported()) {
/* Old zlib version don't support gzip in deflateInit2 */
log_fn(LOG_WARN, "Gzip not supported with zlib %s", ZLIB_VERSION);
return -1;
}
*out = NULL;
stream = tor_malloc_zero(sizeof(struct z_stream_s));
stream->zalloc = Z_NULL;
stream->zfree = Z_NULL;
stream->opaque = NULL;
stream->next_in = (unsigned char*) in;
stream->avail_in = in_len;
if (deflateInit2(stream, Z_BEST_COMPRESSION, Z_DEFLATED,
method_bits(method),
8, Z_DEFAULT_STRATEGY) != Z_OK) {
log_fn(LOG_WARN, "Error from deflateInit2: %s",
stream->msg?stream->msg:"<no message>");
goto err;
}
/* Guess 50% compression. */
out_size = in_len / 2;
if (out_size < 1024) out_size = 1024;
*out = tor_malloc(out_size);
stream->next_out = *out;
stream->avail_out = out_size;
while (1) {
switch (deflate(stream, Z_FINISH))
{
case Z_STREAM_END:
goto done;
case Z_OK:
/* In case zlib doesn't work as I think .... */
if (stream->avail_out >= stream->avail_in+16)
break;
case Z_BUF_ERROR:
offset = stream->next_out - ((unsigned char*)*out);
out_size *= 2;
*out = tor_realloc(*out, out_size);
stream->next_out = *out + offset;
stream->avail_out = out_size - offset;
break;
default:
log_fn(LOG_WARN, "Gzip compression didn't finish: %s",
stream->msg ? stream->msg : "<no message>");
goto err;
}
}
done:
*out_len = stream->total_out;
if (deflateEnd(stream)!=Z_OK) {
log_fn(LOG_WARN, "Error freeing gzip structures");
goto err;
}
tor_free(stream);
return 0;
err:
if (stream) {
deflateEnd(stream);
tor_free(stream);
}
if (*out) {
tor_free(*out);
}
return -1;
}
int
tor_gzip_uncompress(char **out, size_t *out_len,
const char *in, size_t in_len,
compress_method_t method)
{
struct z_stream_s *stream = NULL;
size_t out_size;
off_t offset;
tor_assert(out);
tor_assert(out_len);
tor_assert(in);
if (method == GZIP_METHOD && !is_gzip_supported()) {
/* Old zlib version don't support gzip in inflateInit2 */
log_fn(LOG_WARN, "Gzip not supported with zlib %s", ZLIB_VERSION);
return -1;
}
*out = NULL;
stream = tor_malloc_zero(sizeof(struct z_stream_s));
stream->zalloc = Z_NULL;
stream->zfree = Z_NULL;
stream->opaque = NULL;
stream->next_in = (unsigned char*) in;
stream->avail_in = in_len;
if (inflateInit2(stream,
method_bits(method)) != Z_OK) {
log_fn(LOG_WARN, "Error from inflateInit2: %s",
stream->msg?stream->msg:"<no message>");
goto err;
}
out_size = in_len * 2; /* guess 50% compression. */
if (out_size < 1024) out_size = 1024;
*out = tor_malloc(out_size);
stream->next_out = *out;
stream->avail_out = out_size;
while (1) {
switch (inflate(stream, Z_FINISH))
{
case Z_STREAM_END:
goto done;
case Z_OK:
/* In case zlib doesn't work as I think.... */
if (stream->avail_out >= stream->avail_in+16)
break;
case Z_BUF_ERROR:
offset = stream->next_out - ((unsigned char*)*out);
out_size *= 2;
*out = tor_realloc(*out, out_size);
stream->next_out = *out + offset;
stream->avail_out = out_size - offset;
break;
default:
log_fn(LOG_WARN, "Gzip decompression returned an error: %s",
stream->msg ? stream->msg : "<no message>");
goto err;
}
}
done:
*out_len = stream->total_out;
if (inflateEnd(stream)!=Z_OK) {
log_fn(LOG_WARN, "Error freeing gzip structures");
goto err;
}
tor_free(stream);
/* NUL-terminate output. */
if (out_size == *out_len)
*out = tor_realloc(*out, out_size + 1);
(*out)[*out_len] = '\0';
return 0;
err:
if (stream) {
inflateEnd(stream);
tor_free(stream);
}
if (*out) {
tor_free(*out);
}
return -1;
}
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