mirror of https://code.videolan.org/videolan/vlc
Improve byte order inline functions
* Use GCC built-ins for 32-bits and 64-bits byte swap where available. * Load/store with single memcpy() instead of many byte operations. * Do not use bits operations for the local byte order. * Do not use reserved C keywords with leading underscores.
This commit is contained in:
Rémi Denis-Courmont
parent
f7db1e80a3
commit
9ff7bdc468
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@ -630,6 +630,46 @@ static inline unsigned popcount (unsigned x)
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#endif
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}
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/** Byte swap (16 bits) */
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VLC_USED
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static inline uint16_t bswap16 (uint16_t x)
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{
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return (x << 8) | (x >> 8);
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}
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/** Byte swap (32 bits) */
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VLC_USED
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static inline uint32_t bswap32 (uint32_t x)
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{
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#if VLC_GCC_VERSION(4,3)
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return __builtin_bswap32 (x);
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#else
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return ((x & 0x000000FF) << 24)
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| ((x & 0x0000FF00) << 8)
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| ((x & 0x00FF0000) >> 8)
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| ((x & 0xFF000000) >> 24);
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#endif
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}
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/** Byte swap (64 bits) */
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VLC_USED
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static inline uint64_t bswap64 (uint64_t x)
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{
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#if VLC_GCC_VERSION(4,3)
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return __builtin_bswap64 (x);
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#else
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return ((x & 0x00000000000000FF) << 56)
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| ((x & 0x000000000000FF00) << 40)
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| ((x & 0x0000000000FF0000) << 24)
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| ((x & 0x00000000FF000000) << 8)
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| ((x & 0x000000FF00000000) >> 8)
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| ((x & 0x0000FF0000000000) >> 24)
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| ((x & 0x00FF000000000000) >> 40)
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| ((x & 0xFF00000000000000) >> 56);
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#endif
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}
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/* Free and set set the variable to NULL */
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#define FREENULL(a) do { free( a ); a = NULL; } while(0)
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@ -641,123 +681,140 @@ VLC_API char const * vlc_error( int ) VLC_USED;
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/* MSB (big endian)/LSB (little endian) conversions - network order is always
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* MSB, and should be used for both network communications and files. */
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#ifdef WORDS_BIGENDIAN
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# define hton16(i) ((uint16_t)(i))
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# define hton32(i) ((uint32_t)(i))
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# define hton64(i) ((uint32_t)(i))
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#else
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# define hton16(i) bswap16(i)
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# define hton32(i) bswap32(i)
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# define hton64(i) bswap64(i)
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#endif
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#define ntoh16(i) hton16(i)
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#define ntoh32(i) hton32(i)
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#define ntoh64(i) hton64(i)
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/** Reads 16 bits in network byte order */
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VLC_USED
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static inline uint16_t U16_AT( const void * _p )
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static inline uint16_t U16_AT (const void *p)
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{
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const uint8_t * p = (const uint8_t *)_p;
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return ( ((uint16_t)p[0] << 8) | p[1] );
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uint16_t x;
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memcpy (&x, p, sizeof (x));
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return ntoh16 (x);
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}
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/** Reads 32 bits in network byte order */
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VLC_USED
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static inline uint32_t U32_AT( const void * _p )
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static inline uint32_t U32_AT (const void *p)
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{
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const uint8_t * p = (const uint8_t *)_p;
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return ( ((uint32_t)p[0] << 24) | ((uint32_t)p[1] << 16)
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| ((uint32_t)p[2] << 8) | p[3] );
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uint32_t x;
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memcpy (&x, p, sizeof (x));
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return ntoh32 (x);
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}
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/** Reads 64 bits in network byte order */
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VLC_USED
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static inline uint64_t U64_AT( const void * _p )
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static inline uint64_t U64_AT (const void *p)
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{
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const uint8_t * p = (const uint8_t *)_p;
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return ( ((uint64_t)p[0] << 56) | ((uint64_t)p[1] << 48)
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| ((uint64_t)p[2] << 40) | ((uint64_t)p[3] << 32)
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| ((uint64_t)p[4] << 24) | ((uint64_t)p[5] << 16)
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| ((uint64_t)p[6] << 8) | p[7] );
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uint64_t x;
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memcpy (&x, p, sizeof (x));
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return ntoh64 (x);
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}
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#define GetWBE(p) U16_AT(p)
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#define GetDWBE(p) U32_AT(p)
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#define GetQWBE(p) U64_AT(p)
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/** Reads 16 bits in little-endian order */
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VLC_USED
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static inline uint16_t GetWLE( const void * _p )
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static inline uint16_t GetWLE (const void *p)
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{
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const uint8_t * p = (const uint8_t *)_p;
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return ( ((uint16_t)p[1] << 8) | p[0] );
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uint16_t x;
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memcpy (&x, p, sizeof (x));
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#ifdef WORDS_BIGENDIAN
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x = bswap16 (x);
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#endif
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return x;
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}
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/** Reads 32 bits in little-endian order */
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VLC_USED
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static inline uint32_t GetDWLE( const void * _p )
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static inline uint32_t GetDWLE (const void *p)
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{
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const uint8_t * p = (const uint8_t *)_p;
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return ( ((uint32_t)p[3] << 24) | ((uint32_t)p[2] << 16)
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| ((uint32_t)p[1] << 8) | p[0] );
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uint32_t x;
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memcpy (&x, p, sizeof (x));
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#ifdef WORDS_BIGENDIAN
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x = bswap32 (x);
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#endif
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return x;
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}
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/** Reads 64 bits in little-endian order */
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VLC_USED
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static inline uint64_t GetQWLE( const void * _p )
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static inline uint64_t GetQWLE (const void *p)
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{
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const uint8_t * p = (const uint8_t *)_p;
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return ( ((uint64_t)p[7] << 56) | ((uint64_t)p[6] << 48)
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| ((uint64_t)p[5] << 40) | ((uint64_t)p[4] << 32)
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| ((uint64_t)p[3] << 24) | ((uint64_t)p[2] << 16)
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| ((uint64_t)p[1] << 8) | p[0] );
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uint64_t x;
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memcpy (&x, p, sizeof (x));
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#ifdef WORDS_BIGENDIAN
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x = bswap64 (x);
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#endif
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return x;
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}
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#define GetWBE( p ) U16_AT( p )
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#define GetDWBE( p ) U32_AT( p )
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#define GetQWBE( p ) U64_AT( p )
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/* Helper writer functions */
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#define SetWLE( p, v ) _SetWLE( (uint8_t*)(p), v)
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static inline void _SetWLE( uint8_t *p, uint16_t i_dw )
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/** Writes 16 bits in network byte order */
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static inline void SetWLE (void *p, uint16_t w)
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{
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p[1] = ( i_dw >> 8 )&0xff;
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p[0] = ( i_dw )&0xff;
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w = hton16 (w);
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memcpy (p, &w, sizeof (w));
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}
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#define SetDWLE( p, v ) _SetDWLE( (uint8_t*)(p), v)
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static inline void _SetDWLE( uint8_t *p, uint32_t i_dw )
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/** Writes 32 bits in network byte order */
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static inline void SetDWLE (void *p, uint32_t dw)
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{
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p[3] = ( i_dw >> 24 )&0xff;
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p[2] = ( i_dw >> 16 )&0xff;
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p[1] = ( i_dw >> 8 )&0xff;
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p[0] = ( i_dw )&0xff;
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}
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#define SetQWLE( p, v ) _SetQWLE( (uint8_t*)(p), v)
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static inline void _SetQWLE( uint8_t *p, uint64_t i_qw )
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{
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SetDWLE( p, i_qw&0xffffffff );
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SetDWLE( p+4, ( i_qw >> 32)&0xffffffff );
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}
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#define SetWBE( p, v ) _SetWBE( (uint8_t*)(p), v)
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static inline void _SetWBE( uint8_t *p, uint16_t i_dw )
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{
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p[0] = ( i_dw >> 8 )&0xff;
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p[1] = ( i_dw )&0xff;
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dw = hton32 (dw);
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memcpy (p, &dw, sizeof (dw));
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}
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#define SetDWBE( p, v ) _SetDWBE( (uint8_t*)(p), v)
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static inline void _SetDWBE( uint8_t *p, uint32_t i_dw )
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/** Writes 64 bits in network byte order */
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static inline void SetQWLE (void *p, uint64_t qw)
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{
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p[0] = ( i_dw >> 24 )&0xff;
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p[1] = ( i_dw >> 16 )&0xff;
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p[2] = ( i_dw >> 8 )&0xff;
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p[3] = ( i_dw )&0xff;
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}
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#define SetQWBE( p, v ) _SetQWBE( (uint8_t*)(p), v)
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static inline void _SetQWBE( uint8_t *p, uint64_t i_qw )
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{
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SetDWBE( p+4, i_qw&0xffffffff );
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SetDWBE( p, ( i_qw >> 32)&0xffffffff );
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qw = hton64 (qw);
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memcpy (p, &qw, sizeof (qw));
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}
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#define hton16(i) htons(i)
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#define hton32(i) htonl(i)
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#define ntoh16(i) ntohs(i)
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#define ntoh32(i) ntohl(i)
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VLC_USED
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static inline uint64_t ntoh64 (uint64_t ll)
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/** Writes 16 bits in little endian order */
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static inline void SetWBE (void *p, uint16_t w)
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{
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union { uint64_t qw; uint8_t b[16]; } v = { ll };
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return ((uint64_t)v.b[0] << 56)
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| ((uint64_t)v.b[1] << 48)
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| ((uint64_t)v.b[2] << 40)
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| ((uint64_t)v.b[3] << 32)
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| ((uint64_t)v.b[4] << 24)
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| ((uint64_t)v.b[5] << 16)
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| ((uint64_t)v.b[6] << 8)
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| ((uint64_t)v.b[7] << 0);
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#ifdef WORDS_BIGENDIAN
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w = bswap16 (w);
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#endif
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memcpy (p, &w, sizeof (w));
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}
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/** Writes 32 bits in little endian order */
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static inline void SetDWBE (void *p, uint32_t dw)
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{
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#ifdef WORDS_BIGENDIAN
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dw = bswap32 (dw);
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#endif
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memcpy (p, &dw, sizeof (dw));
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}
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/** Writes 64 bits in little endian order */
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static inline void SetQWBE (void *p, uint64_t qw)
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{
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#ifdef WORDS_BIGENDIAN
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qw = bswap32 (qw);
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#endif
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memcpy (p, &qw, sizeof (qw));
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}
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#define hton64(i) ntoh64(i)
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/* */
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#define VLC_UNUSED(x) (void)(x)
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