shithub: openh264

Download patch

ref: 21687726d05641bd8d627128e6ce564df3a56aa2
parent: 1e744b1933ffe37c15d1ce426f923083124cdd5b
author: Martin Storsjö <martin@martin.st>
date: Wed Jan 29 09:30:04 EST 2014 

Avoid requiring byteswapping functions

Instead of byteswapping a 32 bit word and writing it out as a
whole (which could even possibly lead to crashes due to
incorrect alignment on some platforms), write it out explicitly
in the intended byte order.

This avoids having to set a define indicating the endianness.


--- a/codec/common/macros.h
+++ b/codec/common/macros.h
@@ -234,34 +234,6 @@
 #define   CALC_BI_STRIDE(width,bitcount)  ((((width * bitcount) + 31) & ~31) >> 3)
 
 
-#ifdef    WORDS_BIGENDIAN
-static inline uint32_t ENDIAN_FIX (uint32_t x) {
-return x;
-}
-#else //!WORDS_BIGENDIAN
-
-#if defined(_MSC_VER) && defined(_M_IX86)
-static inline uint32_t ENDIAN_FIX (uint32_t x) {
-__asm {
-  mov   eax,  x
-  bswap   eax
-  mov   x,    eax
-}
-return x;
-}
-#else  // GCC
-static inline uint32_t ENDIAN_FIX (uint32_t x) {
-#ifdef X86_ARCH
-__asm__ __volatile__ ("bswap %0":"+r" (x));
-#else
-x = ((x & 0xff000000) >> 24) | ((x & 0xff0000) >> 8) |
-    ((x & 0xff00) << 8) | ((x & 0xff) << 24);
-#endif
-return x;
-}
-#endif//GCC
-
-#endif//!WORDS_BIGENDIAN
 
 
 #ifndef BUTTERFLY1x2
--- a/codec/encoder/core/inc/svc_enc_golomb.h
+++ b/codec/encoder/core/inc/svc_enc_golomb.h
@@ -46,6 +46,12 @@
 
 namespace WelsSVCEnc {
 
+#define WRITE_BE_32(ptr, val) do { \
+        (ptr)[0] = (val) >> 24; \
+        (ptr)[1] = (val) >> 16; \
+        (ptr)[2] = (val) >>  8; \
+        (ptr)[3] = (val) >>  0; \
+    } while (0)
 /************************************************************************/
 /* GOLOMB CODIMG FOR WELS ENCODER                                       */
 /************************************************************************/
@@ -73,7 +79,7 @@
 	else {\
 	    (n) -= iLeftBits;\
 		uiCurBits = (uiCurBits<<iLeftBits) | ((v)>>(n));\
-		*((uint32_t*)pBufPtr) = ENDIAN_FIX(uiCurBits);\
+		WRITE_BE_32(pBufPtr, uiCurBits);\
 		pBufPtr += 4;\
 		uiCurBits = (v) & ((1<<(n))-1);\
 		iLeftBits = 32 - (n);\
@@ -141,7 +147,7 @@
 } else {
   n -= pBs->iLeftBits;
   pBs->uiCurBits = (pBs->uiCurBits << pBs->iLeftBits) | (kuiValue >> n);
-  * ((uint32_t*)pBs->pBufPtr) = ENDIAN_FIX (pBs->uiCurBits);
+  WRITE_BE_32(pBs->pBufPtr, pBs->uiCurBits);
   pBs->pBufPtr += 4;
   pBs->uiCurBits = kuiValue & ((1 << n) - 1);
   pBs->iLeftBits = 32 - n;
@@ -160,7 +166,7 @@
 
 
 static inline void BsFlush (SBitStringAux* pBs) {
-* (uint32_t*)pBs->pBufPtr = ENDIAN_FIX (pBs->uiCurBits << pBs->iLeftBits);
+WRITE_BE_32(pBs->pBufPtr, pBs->uiCurBits << pBs->iLeftBits);
 pBs->pBufPtr += 4 - pBs->iLeftBits / 8;
 pBs->iLeftBits = 32;
 pBs->uiCurBits = 0;	//  for future writing safe, 5/19/2010