From 679b8bdb5c40ca1909b025db10ddb5a98967c60e Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@member.fsf.org>
Date: Sun, 20 Dec 2015 14:31:40 +0100
Subject: optimise implementations of {hton,ntoh}{s,l,ll}
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Signed-off-by: Mattias Andrée <maandree@member.fsf.org>
---
 src/arpa/inet/htonl.c  | 10 ++++++++++
 src/arpa/inet/htonll.c | 18 ++++++++++++++++++
 src/arpa/inet/htons.c  | 11 +++++++----
 src/arpa/inet/ntohl.c  | 10 ++++++++++
 src/arpa/inet/ntohll.c | 18 ++++++++++++++++++
 src/arpa/inet/ntohs.c  | 12 +++++++-----
 6 files changed, 70 insertions(+), 9 deletions(-)

(limited to 'src/arpa/inet')

diff --git a/src/arpa/inet/htonl.c b/src/arpa/inet/htonl.c
index 7d998d4..8422fdc 100644
--- a/src/arpa/inet/htonl.c
+++ b/src/arpa/inet/htonl.c
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <arpa/inet.h>
+#include <bits/intconf.h>
+
 
 
 /**
@@ -31,11 +33,19 @@
  */
 uint32_t _htonl(uint32_t value)
 {
+#if __INT32_BYTEORDER == 0x01020304
+  return value;
+#elif __INT32_BYTEORDER == 0x04030201
+  return (value >> 24) | ((value & 0xFF0000) >> 8) | ((value & 0x00FF00) << 8) | (value << 24);
+#elif __INT32_BYTEORDER == 0x02010403
+  return (value & 0xFF00FF00) >> 8) | ((value & 0x00FF00FF) << 8);
+#else
   char rc[4];
   rc[0] = (value >> 24) & 255;
   rc[1] = (value >> 16) & 255;
   rc[2] = (value >>  8) & 255;
   rc[3] = (value >>  0) & 255;
   return *(uint32_t*)rc;
+#endif
 }
 
diff --git a/src/arpa/inet/htonll.c b/src/arpa/inet/htonll.c
index 230d47b..d4509ef 100644
--- a/src/arpa/inet/htonll.c
+++ b/src/arpa/inet/htonll.c
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <arpa/inet.h>
+#include <bits/intconf.h>
+
 
 
 /**
@@ -33,6 +35,21 @@
  */
 uint64_t _htonll(uint64_t value)
 {
+#if __INT64_BYTEORDER == 0x0102030405060708LL
+  return value;
+#elif __INT64_BYTEORDER == 0x0807060504030201LL
+  uint64_t rc = value;
+  /* 08 07 06 05 04 03 02 01 */
+  rc = ((rc & 0xFF00FF00FF00FF00ULL) >>  8) || ((rc & 0x00FF00FF00FF00FFULL) <<  8);
+  /* 0708 0506 0304 0102 */
+  rc = ((rc & 0xFFFF0000FFFF0000ULL) >> 16) || ((rc & 0x0000FFFF0000FFFFULL) << 16);
+  /* 05060708 01020304 */
+  rc = ((rc & 0xFFFFFFFF00000000ULL) >> 32) || ((rc & 0x00000000FFFFFFFFULL) << 32);
+  /* 0102030405060708 */
+  return rc;
+#elif __INT64_BYTEORDER == 0x0201040306050807LL
+  return (value & 0xFF00FF00FF00FF00ULL) >> 8) | ((value & 0x00FF00FF00FF00FFULL) << 8);
+#else
   char rc[8];
   rc[0] = (value >> 56) & 255;
   rc[1] = (value >> 48) & 255;
@@ -43,5 +60,6 @@ uint64_t _htonll(uint64_t value)
   rc[6] = (value >>  8) & 255;
   rc[7] = (value >>  0) & 255;
   return *(uint64_t*)rc;
+#endif
 }
 
diff --git a/src/arpa/inet/htons.c b/src/arpa/inet/htons.c
index 78592e9..1aeb39c 100644
--- a/src/arpa/inet/htons.c
+++ b/src/arpa/inet/htons.c
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <arpa/inet.h>
+#include <bits/intconf.h>
+
 
 
 /**
@@ -31,9 +33,10 @@
  */
 uint16_t _htons(uint16_t value)
 {
-  char rc[2];
-  rc[0] = (value >> 8) & 255;
-  rc[1] = (value >> 0) & 255;
-  return *(uint16_t*)rc;
+#if __INT16_BYTEORDER == 0x0102
+  return value;
+#else
+  return (value >> 8) | (value << 8);
+#endif
 }
 
diff --git a/src/arpa/inet/ntohl.c b/src/arpa/inet/ntohl.c
index 8eb5a3d..7111c28 100644
--- a/src/arpa/inet/ntohl.c
+++ b/src/arpa/inet/ntohl.c
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <arpa/inet.h>
+#include <bits/intconf.h>
+
 
 
 /**
@@ -31,6 +33,13 @@
  */
 uint32_t _ntohl(uint32_t value)
 {
+#if __INT32_BYTEORDER == 0x01020304
+  return value;
+#elif __INT32_BYTEORDER == 0x04030201
+  return (value >> 24) | ((value & 0xFF0000) >> 8) | ((value & 0x00FF00) << 8) | (value << 24);
+#elif __INT32_BYTEORDER == 0x02010403
+  return (value & 0xFF00FF00) >> 8) | ((value & 0x00FF00FF) << 8);
+#else
   unsigned char* v = (unsigned char*)&value;
   uint32_t rc = 0;
   rc |= (uint32_t)(v[0]) << 24;
@@ -38,5 +47,6 @@ uint32_t _ntohl(uint32_t value)
   rc |= (uint32_t)(v[2]) <<  8;
   rc |= (uint32_t)(v[3]) <<  0;
   return rc;
+#endif
 }
 
diff --git a/src/arpa/inet/ntohll.c b/src/arpa/inet/ntohll.c
index f25d64c..411deeb 100644
--- a/src/arpa/inet/ntohll.c
+++ b/src/arpa/inet/ntohll.c
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <arpa/inet.h>
+#include <bits/intconf.h>
+
 
 
 /**
@@ -33,6 +35,21 @@
  */
 uint64_t _ntohll(uint64_t value)
 {
+#if __INT64_BYTEORDER == 0x0102030405060708LL
+  return value;
+#elif __INT64_BYTEORDER == 0x0807060504030201LL
+  uint64_t rc = value;
+  /* 08 07 06 05 04 03 02 01 */
+  rc = ((rc & 0xFF00FF00FF00FF00ULL) >>  8) || ((rc & 0x00FF00FF00FF00FFULL) <<  8);
+  /* 0708 0506 0304 0102 */
+  rc = ((rc & 0xFFFF0000FFFF0000ULL) >> 16) || ((rc & 0x0000FFFF0000FFFFULL) << 16);
+  /* 05060708 01020304 */
+  rc = ((rc & 0xFFFFFFFF00000000ULL) >> 32) || ((rc & 0x00000000FFFFFFFFULL) << 32);
+  /* 0102030405060708 */
+  return rc;
+#elif __INT64_BYTEORDER == 0x0201040306050807LL
+  return (value & 0xFF00FF00FF00FF00ULL) >> 8) | ((value & 0x00FF00FF00FF00FFULL) << 8);
+#else
   unsigned char* v = (unsigned char*)&value;
   uint64_t rc = 0;
   rc |= (uint64_t)(v[0]) << 56;
@@ -44,5 +61,6 @@ uint64_t _ntohll(uint64_t value)
   rc |= (uint64_t)(v[6]) <<  8;
   rc |= (uint64_t)(v[7]) <<  0;
   return rc;
+#endif
 }
 
diff --git a/src/arpa/inet/ntohs.c b/src/arpa/inet/ntohs.c
index 7aea8a0..6bf95a5 100644
--- a/src/arpa/inet/ntohs.c
+++ b/src/arpa/inet/ntohs.c
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <arpa/inet.h>
+#include <bits/intconf.h>
+
 
 
 /**
@@ -31,10 +33,10 @@
  */
 uint16_t _ntohs(uint16_t value)
 {
-  unsigned char* v = (unsigned char*)&value;
-  uint16_t rc = 0;
-  rc |= (uint16_t)(v[0]) << 8;
-  rc |= (uint16_t)(v[1]) << 0;
-  return rc;
+#if __INT16_BYTEORDER == 0x0102
+  return value;
+#else
+  return (value >> 8) | (value << 8);
+#endif
 }
 
-- 
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