[Feature] Use in-place deflation for strings

diff --git a/src/libutil/util.c b/src/libutil/util.c
index 915d77222c808e4a1de02f5a55795cc6bb07c8de..539c5070da924c44be101f53ce132cb727bc0d69 100644 (file)
--- a/src/libutil/util.c
+++ b/src/libutil/util.c
@@ -2241,61 +2241,63 @@ gboolean
 rspamd_fstring_gzip (rspamd_fstring_t **in)
 {
        z_stream strm;
-       gint rc;
-       rspamd_fstring_t *comp, *buf = *in;
-       gchar *p;
-       gsize remain;
+       rspamd_fstring_t *buf = *in;
+       int ret;
+       unsigned tmp_remain;
+       unsigned char temp[BUFSIZ];
 
        memset (&strm, 0, sizeof (strm));
-       rc = deflateInit2 (&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
+       ret = deflateInit2 (&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
                        MAX_WBITS + 16, MAX_MEM_LEVEL - 1, Z_DEFAULT_STRATEGY);
 
-       if (rc != Z_OK) {
+       if (ret != Z_OK) {
                return FALSE;
        }
 
-       comp = rspamd_fstring_sized_new (deflateBound (&strm, buf->len));
-
+       strm.next_in = buf->str;
        strm.avail_in = buf->len;
-       strm.next_in = (guchar *)buf->str;
-       p = comp->str;
-       remain = comp->allocated;
-
-       while (strm.avail_in != 0) {
-               strm.avail_out = remain;
-               strm.next_out = p;
-
-               rc = deflate (&strm, Z_FINISH);
 
-               if (rc != Z_OK && rc != Z_BUF_ERROR) {
-                       if (rc == Z_STREAM_END) {
-                               break;
-                       }
-                       else {
-                               rspamd_fstring_free (comp);
-                               deflateEnd (&strm);
+       strm.next_out = temp;
+       strm.avail_out = sizeof(temp) > buf->allocated ? buf->allocated : sizeof(temp);
+       ret = deflate(&strm, Z_FINISH);
+       if (ret == Z_STREAM_ERROR) {
+               return FALSE;
+       }
 
-                               return FALSE;
-                       }
+       /* Try to compress in-place */
+       tmp_remain = strm.next_out - temp;
+       if (tmp_remain <= (strm.avail_in ? buf->len - strm.avail_in : buf->allocated)) {
+               memcpy(buf, temp, tmp_remain);
+               strm.next_out = (unsigned char *)buf->str + tmp_remain;
+               tmp_remain = 0;
+               while (ret == Z_OK) {
+                       strm.avail_out = strm.avail_in ? strm.next_in - strm.next_out :
+                                                         ((unsigned char *)buf->str + buf->allocated) - strm.next_out;
+                       ret = deflate(&strm, Z_FINISH);
                }
-
-               comp->len = strm.total_out;
-
-               if (strm.avail_out == 0 && strm.avail_in != 0) {
-                       /* Need to allocate more */
-                       remain = comp->len;
-                       comp = rspamd_fstring_grow (comp, strm.avail_in);
-                       p = comp->str + remain;
-                       remain = comp->allocated - remain;
+               if (ret != Z_BUF_ERROR || strm.avail_in == 0) {
+                       buf->len = strm.next_out - (unsigned char *)buf->str;
+                       return ret == Z_STREAM_END;
                }
        }
 
-       deflateEnd (&strm);
-       comp->len = strm.total_out;
-       rspamd_fstring_free (buf); /* We replace buf with its compressed version */
-       *in = comp;
-
-       return TRUE;
+       /*
+        * The case when input and output has caught each other, hold the remaining
+        * in a temporary buffer and compress it separately
+        */
+       unsigned char *hold = g_malloc (strm.avail_in);
+       memcpy(hold, strm.next_in, strm.avail_in);
+       strm.next_in = hold;
+       if (tmp_remain) {
+               memcpy(buf, temp, tmp_remain);
+               strm.next_out = (unsigned char *)buf->str + tmp_remain;
+       }
+       strm.avail_out = ((unsigned char *)buf->str + buf->allocated) - strm.next_out;
+       ret = deflate(&strm, Z_FINISH);
+       g_free (hold);
+       buf->len = strm.next_out - (unsigned char *)buf->str;
+
+       return ret == Z_STREAM_END;
 }
 
 static gboolean