[multiple] optimize primitives, buffer_extend()

optimize buffer_* primitives

Other than buffer_string_set_length(), reallocate with one power-2 step
in size (or use the requested size, if larger).  This replaces the fixed
BUFFER_PIECE_SIZE round-up of only 64 bytes extension each reallocation,
which could lead to excessive reallocations in some scenarios.

buffer_extend() convenience routine to prep for batch append
(combines buffer_string_prepare_append() and buffer_commit())

mod_fastcgi, mod_scgi, mod_proxy and others now leverage buffer_extend()

mod_scgi directly performs little-endian encoding of short ints

http_response_write_header() optimizes writing response header,
leveraging buffer_extend()

modify mod_proxy to append line ends
similar to how it is done in http_response_write_header()
(removes one call to buffer_append_string_len())

1 files changed, 1 insertions, 3 deletions

diff --git a/src/mod_vhostdb_ldap.c b/src/mod_vhostdb_ldap.c
index a8fd2299..e0b8737b 100644
--- a/src/mod_vhostdb_ldap.c
+++ b/src/mod_vhostdb_ldap.c
@@ -242,12 +242,10 @@ static void mod_authn_append_ldap_filter_escape(buffer * const filter, const buf
         }
 
         /* escape * ( ) \ NUL ('\0') (and all UTF-8 chars with high bit set) */
-        buffer_string_prepare_append(filter, 3);
-        f = filter->ptr + buffer_string_length(filter);
+        f = buffer_extend(filter, 3);
         f[0] = '\\';
         f[1] = "0123456789abcdef"[(((unsigned char *)b)[i] >> 4) & 0xf];
         f[2] = "0123456789abcdef"[(((unsigned char *)b)[i]     ) & 0xf];
-        buffer_commit(filter, 3);
     }
 }