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- /* Copyright 2004 Roger Dingledine */
- /* Copyright 2004-2005 Roger Dingledine, Nick Mathewson */
- /* See LICENSE for licensing information */
- /* $Id$ */
- const char torgzip_c_id[] =
- "$Id$";
- /**
- * \file torgzip.c
- * \brief A 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 <string.h>
- #ifdef HAVE_NETINET_IN_H
- #include <netinet/in.h>
- #endif
- #include "util.h"
- #include "log.h"
- #include "torgzip.h"
- static int gzip_is_supported = -1;
- /** Return true iff we support gzip-based compression. Otherwise, we need to
- * use zlib. */
- 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;
- }
- /** Given <b>in_len</b> bytes at <b>in</b>, compress them into a newly
- * allocated buffer, using the method described in <b>method</b>. Store the
- * compressed string in *<b>out</b>, and its length in *<b>out_len</b>.
- * Return 0 on success, -1 on failure.
- */
- 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 */
- warn(LD_GENERAL, "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) {
- warn(LD_GENERAL, "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 = (unsigned char*)*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 = (unsigned char*)(*out + offset);
- stream->avail_out = out_size - offset;
- break;
- default:
- warn(LD_GENERAL, "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) {
- warn(LD_GENERAL, "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;
- }
- /** Given or more zlib-compressed or gzip-compressed strings of total length
- * <b>in_len</b> bytes at <b>in</b>, uncompress them into a newly allocated
- * buffer, using the method described in <b>method</b>. Store the uncompressed
- * string in *<b>out</b>, and its length in *<b>out_len</b>. Return 0 on
- * success, -1 on failure.
- */
- int
- tor_gzip_uncompress(char **out, size_t *out_len,
- const char *in, size_t in_len,
- compress_method_t method,
- int complete_only)
- {
- struct z_stream_s *stream = NULL;
- size_t out_size;
- off_t offset;
- int r;
- 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 */
- warn(LD_GENERAL, "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) {
- warn(LD_GENERAL, "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 = (unsigned char*)*out;
- stream->avail_out = out_size;
- while (1) {
- switch (inflate(stream, complete_only ? Z_FINISH : Z_SYNC_FLUSH))
- {
- case Z_STREAM_END:
- if (stream->avail_in == 0)
- goto done;
- /* There may be more compressed data here. */
- if (inflateInit2(stream, method_bits(method)) != Z_OK) {
- warn(LD_GENERAL, "Error from inflateInit2: %s",
- stream->msg?stream->msg:"<no message>");
- goto err;
- }
- break;
- case Z_OK:
- if (!complete_only && stream->avail_in == 0)
- goto done;
- /* In case zlib doesn't work as I think.... */
- if (stream->avail_out >= stream->avail_in+16)
- break;
- case Z_BUF_ERROR:
- if (stream->avail_out > 0) {
- warn(LD_PROTOCOL, "possible truncated or corrupt zlib data");
- goto err;
- }
- offset = stream->next_out - (unsigned char*)*out;
- out_size *= 2;
- *out = tor_realloc(*out, out_size);
- stream->next_out = (unsigned char*)(*out + offset);
- stream->avail_out = out_size - offset;
- break;
- default:
- warn(LD_GENERAL, "Gzip decompression returned an error: %s",
- stream->msg ? stream->msg : "<no message>");
- goto err;
- }
- }
- done:
- *out_len = stream->next_out - (unsigned char*)*out;
- r = inflateEnd(stream);
- tor_free(stream);
- if (r != Z_OK) {
- warn(LD_GENERAL, "Error freeing gzip structures");
- goto err;
- }
- /* 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;
- }
- /** Try to tell whether the <b>in_len</b>-byte string in <b>in</b> is likely
- * to be compressed or not. If it is, return the likeliest compression method.
- * Otherwise, return 0.
- */
- int
- detect_compression_method(const char *in, size_t in_len)
- {
- if (in_len > 2 && !memcmp(in, "\x1f\x8b", 2)) {
- return GZIP_METHOD;
- } else if (in_len > 2 && (in[0] & 0x0f) == 8 &&
- (ntohs(get_uint16(in)) % 31) == 0) {
- return ZLIB_METHOD;
- } else {
- return 0;
- }
- }
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