From 94abf9d9357a8f2ba7af6777adcb9a7aec41af31 Mon Sep 17 00:00:00 2001
From: christiaans <christiaans>
Date: Wed, 29 Mar 2006 10:15:43 +0000
Subject: [PATCH] Added LWIP_PLATFORM_BYTESWAP optimalisation flag and macro
 glue.

---
 CHANGELOG                    |  5 ++++-
 src/core/inet.c              | 16 ++++++++++++++--
 src/include/ipv4/lwip/inet.h | 14 +++++++++++++-
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 0bf28ac5..005109fc 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -19,7 +19,10 @@ HISTORY
 
 (CVS HEAD)
 
-  * [New changes go here]
+  2006-03-29 Christiaan Simons
+  * inet.c, inet.h: Added platform byteswap support.
+    Added LWIP_PLATFORM_BYTESWAP define (defaults to 0) and
+    optional LWIP_PLATFORM_HTONS(), LWIP_PLATFORM_HTONL() macros.
 
 (STABLE-1_1_1)
 
diff --git a/src/core/inet.c b/src/core/inet.c
index 556cbeb5..24cdad39 100644
--- a/src/core/inet.c
+++ b/src/core/inet.c
@@ -489,11 +489,23 @@ char *inet_ntoa(struct in_addr addr)
   return str;
 }
 
+/*
+ * These are reference implementations of the byte swapping functions.
+ * Again with the aim of being simple, correct and fully portable.
+ * Byte swapping is the second thing you would want to optimize. You will
+ * need to port it to your architecture and in your cc.h:
+ * 
+ * #define LWIP_PLATFORM_BYTESWAP 1
+ * #define LWIP_PLATFORM_HTONS(x) <your_htons>
+ * #define LWIP_PLATFORM_HTONL(x) <your_htonl>
+ *
+ * Note ntohs() and ntohl() are merely references to the htonx counterparts.
+ */
 
 #ifndef BYTE_ORDER
 #error BYTE_ORDER is not defined
 #endif
-#if BYTE_ORDER == LITTLE_ENDIAN
+#if (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN)
 
 u16_t
 htons(u16_t n)
@@ -522,4 +534,4 @@ ntohl(u32_t n)
   return htonl(n);
 }
 
-#endif /* BYTE_ORDER == LITTLE_ENDIAN */
+#endif /* (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN) */
diff --git a/src/include/ipv4/lwip/inet.h b/src/include/ipv4/lwip/inet.h
index 6d79aab7..52c67dee 100644
--- a/src/include/ipv4/lwip/inet.h
+++ b/src/include/ipv4/lwip/inet.h
@@ -64,12 +64,16 @@ char *inet_ntoa(struct in_addr addr); /* returns ptr to static buffer; not reent
 #undef ntohl
 #endif /* ntohl */
 
+#ifndef LWIP_PLATFORM_BYTESWAP
+#define LWIP_PLATFORM_BYTESWAP 0
+#endif
+
 #if BYTE_ORDER == BIG_ENDIAN
 #define htons(x) (x)
 #define ntohs(x) (x)
 #define htonl(x) (x)
 #define ntohl(x) (x)
-#else
+#else /* BYTE_ORDER != BIG_ENDIAN */
 #ifdef LWIP_PREFIX_BYTEORDER_FUNCS
 /* workaround for naming collisions on some platforms */
 #define htons lwip_htons
@@ -77,11 +81,19 @@ char *inet_ntoa(struct in_addr addr); /* returns ptr to static buffer; not reent
 #define htonl lwip_htonl
 #define ntohl lwip_ntohl
 #endif
+#if LWIP_PLATFORM_BYTESWAP
+#define htons(x) LWIP_PLATFORM_HTONS(x)
+#define ntohs(x) LWIP_PLATFORM_HTONS(x)
+#define htonl(x) LWIP_PLATFORM_HTONL(x)
+#define ntohl(x) LWIP_PLATFORM_HTONL(x)
+#else
 u16_t htons(u16_t x);
 u16_t ntohs(u16_t x);
 u32_t htonl(u32_t x);
 u32_t ntohl(u32_t x);
 #endif
 
+#endif
+
 #endif /* __LWIP_INET_H__ */