From 29a6c17d6796119f57cfaae32b887cbd253a4c9f Mon Sep 17 00:00:00 2001
From: Nick Mathewson <nickm@torproject.org>
Date: Mon, 29 Aug 2005 18:01:38 +0000
Subject: [PATCH] Allow tor_gzip_uncompress to handle multiple concatenated
 compressed strings.

svn:r4882
---
 src/common/torgzip.c | 27 +++++++++++++++++++++++----
 src/or/test.c        | 12 +++++++++++-
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/src/common/torgzip.c b/src/common/torgzip.c
index f502c828b8..65f13b357f 100644
--- a/src/common/torgzip.c
+++ b/src/common/torgzip.c
@@ -30,6 +30,8 @@ const char torgzip_c_id[] = "$Id$";
 
 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)
 {
@@ -53,6 +55,11 @@ method_bits(compress_method_t method)
   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,
@@ -138,7 +145,12 @@ tor_gzip_compress(char **out, size_t *out_len,
   return -1;
 }
 
-/* DOCDOC -- sets *out to NULL on failure. */
+/** 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,
@@ -186,13 +198,20 @@ tor_gzip_uncompress(char **out, size_t *out_len,
     switch (inflate(stream, Z_FINISH))
       {
       case Z_STREAM_END:
-        goto done;
+        if (stream->avail_in == 0)
+          goto done;
+        if (inflateInit2(stream, method_bits(method)) != Z_OK) {
+          log_fn(LOG_WARN, "Error from inflateInit2: %s",
+                 stream->msg?stream->msg:"<no message>");
+          goto err;
+        }
+        break;
       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);
+        offset = stream->next_out - (unsigned char*)*out;
         out_size *= 2;
         *out = tor_realloc(*out, out_size);
         stream->next_out = (unsigned char*)(*out + offset);
@@ -205,7 +224,7 @@ tor_gzip_uncompress(char **out, size_t *out_len,
       }
   }
  done:
-  *out_len = stream->total_out;
+  *out_len = stream->next_out - (unsigned char*)*out;
   r = inflateEnd(stream);
   tor_free(stream);
   if (r != Z_OK) {
diff --git a/src/or/test.c b/src/or/test.c
index 067cb9c6c1..3ba9a7fcfa 100644
--- a/src/or/test.c
+++ b/src/or/test.c
@@ -908,7 +908,7 @@ test_gzip(void)
   char *buf1, *buf2=NULL, *buf3=NULL;
   size_t len1, len2;
 
-  buf1 = tor_strdup("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA");
+  buf1 = tor_strdup("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAZAAAAAAAAAAAAAAAAAAAZ");
   test_eq(detect_compression_method(buf1, strlen(buf1)), 0);
   if (is_gzip_supported()) {
     test_assert(!tor_gzip_compress(&buf2, &len1, buf1, strlen(buf1)+1,
@@ -935,6 +935,16 @@ test_gzip(void)
   test_assert(buf3);
   test_streq(buf1,buf3);
 
+  tor_free(buf3);
+  buf2 = tor_realloc(buf2, len1*2);
+  memcpy(buf2+len1, buf2, len1);
+  test_assert(!tor_gzip_uncompress(&buf3, &len2, buf2, len1*2, ZLIB_METHOD));
+  test_eq(len2, (strlen(buf1)+1)*2);
+  test_memeq(buf3,
+             "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAZAAAAAAAAAAAAAAAAAAAZ\0"
+             "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAZAAAAAAAAAAAAAAAAAAAZ\0",
+             (strlen(buf1)+1)*2);
+
   tor_free(buf2);
   tor_free(buf3);
   tor_free(buf1);