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[tor-commits] [tor/master] Treat the identity transformation as another kind of compression.
commit 1bc21111d82579b6472357d43f07a85142b6614a
Author: Nick Mathewson <nickm@xxxxxxxxxxxxxx>
Date: Thu Apr 27 10:00:41 2017 -0400
Treat the identity transformation as another kind of compression.
This will allow us to treat NO_METHOD as a real compression method,
and to simplify code that currently does
if (compressing) {
compress
} else {
copy
}
---
src/common/compress.c | 15 +++++++++++--
src/common/compress_none.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++
src/common/compress_none.h | 20 +++++++++++++++++
src/common/include.am | 4 +++-
4 files changed, 89 insertions(+), 3 deletions(-)
diff --git a/src/common/compress.c b/src/common/compress.c
index 9a24025..e1571c7 100644
--- a/src/common/compress.c
+++ b/src/common/compress.c
@@ -24,6 +24,7 @@
#include "torlog.h"
#include "compress.h"
#include "compress_lzma.h"
+#include "compress_none.h"
#include "compress_zlib.h"
#include "compress_zstd.h"
@@ -67,8 +68,12 @@ guess_compress_size(int compress, compress_method_t method,
size_t in_len)
{
// ignore these for now.
- (void)method;
(void)compression_level;
+ if (method == NO_METHOD) {
+ /* Guess that we'll need an extra byte, to avoid a needless realloc
+ * for nul-termination */
+ return (in_len < SIZE_MAX) ? in_len + 1 : in_len;
+ }
/* Always guess a factor of 2. */
if (compress) {
@@ -279,6 +284,7 @@ tor_compress_supports_method(compress_method_t method)
case ZSTD_METHOD:
return tor_zstd_method_supported();
case NO_METHOD:
+ return 1;
case UNKNOWN_METHOD:
default:
return 0;
@@ -436,7 +442,9 @@ tor_compress_new(int compress, compress_method_t method,
state->u.zstd_state = zstd_state;
break;
}
- case NO_METHOD:
+ case NO_METHOD: {
+ break;
+ }
case UNKNOWN_METHOD:
goto err;
}
@@ -484,6 +492,8 @@ tor_compress_process(tor_compress_state_t *state,
out, out_len, in, in_len,
finish);
case NO_METHOD:
+ return tor_cnone_compress_process(out, out_len, in, in_len,
+ finish);
case UNKNOWN_METHOD:
goto err;
}
@@ -511,6 +521,7 @@ tor_compress_free(tor_compress_state_t *state)
tor_zstd_compress_free(state->u.zstd_state);
break;
case NO_METHOD:
+ break;
case UNKNOWN_METHOD:
break;
}
diff --git a/src/common/compress_none.c b/src/common/compress_none.c
new file mode 100644
index 0000000..b76e601
--- /dev/null
+++ b/src/common/compress_none.c
@@ -0,0 +1,53 @@
+/* Copyright (c) 2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2017, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file compress_lzma.c
+ * \brief Compression backend for identity compression.
+ *
+ * We actually define this backend so that we can treat the identity transform
+ * as another case of compression.
+ *
+ * This module should never be invoked directly. Use the compress module
+ * instead.
+ **/
+
+#include "orconfig.h"
+
+#include "util.h"
+#include "torlog.h"
+#include "compress.h"
+#include "compress_none.h"
+
+/** Transfer some bytes using the identity transformation. Read up to
+ * *<b>in_len</b> bytes from *<b>in</b>, and write up to *<b>out_len</b> bytes
+ * to *<b>out</b>, adjusting the values as we go. If <b>finish</b> is true,
+ * we've reached the end of the input.
+ *
+ * Return TOR_COMPRESS_DONE if we've finished the entire
+ * compression/decompression.
+ * Return TOR_COMPRESS_OK if we're processed everything from the input.
+ * Return TOR_COMPRESS_BUFFER_FULL if we're out of space on <b>out</b>.
+ * Return TOR_COMPRESS_ERROR if the stream is corrupt.
+ */
+tor_compress_output_t
+tor_cnone_compress_process(char **out, size_t *out_len,
+ const char **in, size_t *in_len,
+ int finish)
+{
+ size_t n_to_copy = MIN(*in_len, *out_len);
+
+ memcpy(*out, *in, n_to_copy);
+ *out += n_to_copy;
+ *in += n_to_copy;
+ *out_len -= n_to_copy;
+ *in_len -= n_to_copy;
+ if (*in_len == 0) {
+ return finish ? TOR_COMPRESS_DONE : TOR_COMPRESS_OK;
+ } else {
+ return TOR_COMPRESS_BUFFER_FULL;
+ }
+}
+
diff --git a/src/common/compress_none.h b/src/common/compress_none.h
new file mode 100644
index 0000000..d1ebb4b
--- /dev/null
+++ b/src/common/compress_none.h
@@ -0,0 +1,20 @@
+/* Copyright (c) 2003, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2017, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file compress_none.h
+ * \brief Header for compress_none.c
+ **/
+
+#ifndef TOR_COMPRESS_NONE_H
+#define TOR_COMPRESS_NONE_H
+
+tor_compress_output_t
+tor_cnone_compress_process(char **out, size_t *out_len,
+ const char **in, size_t *in_len,
+ int finish);
+
+#endif // TOR_COMPRESS_NONE_H.
+
diff --git a/src/common/include.am b/src/common/include.am
index e285ef5..51b7da6 100644
--- a/src/common/include.am
+++ b/src/common/include.am
@@ -107,6 +107,7 @@ LIBOR_CRYPTO_A_SRC = \
src/common/aes.c \
src/common/compress.c \
src/common/compress_lzma.c \
+ src/common/compress_none.c \
src/common/compress_zlib.c \
src/common/compress_zstd.c \
src/common/crypto.c \
@@ -148,8 +149,9 @@ COMMONHEADERS = \
src/common/compat_openssl.h \
src/common/compat_threads.h \
src/common/compat_time.h \
- src/common/compress.h \
+ src/common/compress.h \
src/common/compress_lzma.h \
+ src/common/compress_none.h \
src/common/compress_zlib.h \
src/common/compress_zstd.h \
src/common/confline.h \
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