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add defensive parens
[perl5.git] / hv_macro.h
1 #ifndef PERL_SEEN_HV_MACRO_H /* compile once */
2 #define PERL_SEEN_HV_MACRO_H
3
4 #if IVSIZE == 8
5 #define CAN64BITHASH
6 #endif
7
8 #ifdef CAN64BITHASH
9   #ifndef U64TYPE
10   /* This probably isn't going to work, but failing with a compiler error due to
11    lack of uint64_t is no worse than failing right now with an #error.  */
12   #define U64 uint64_t
13   #endif
14 #endif
15
16
17 /*-----------------------------------------------------------------------------
18  * Endianess and util macros
19  *
20  * The following 3 macros are defined in this section. The other macros defined
21  * are only needed to help derive these 3.
22  *
23  * U8TO16_LE(x)   Read a little endian unsigned 32-bit int
24  * U8TO32_LE(x)   Read a little endian unsigned 32-bit int
25  * U8TO28_LE(x)   Read a little endian unsigned 32-bit int
26  * ROTL32(x,r)      Rotate x left by r bits
27  * ROTL64(x,r)      Rotate x left by r bits
28  * ROTR32(x,r)      Rotate x right by r bits
29  * ROTR64(x,r)      Rotate x right by r bits
30  */
31
32 #ifndef U8TO16_LE
33   #define _shifted_octet(type,ptr,idx,shift) (((type)(((U8*)(ptr))[(idx)]))<<(shift))
34   #if (BYTEORDER == 0x1234 || BYTEORDER == 0x12345678)
35     #ifdef USE_UNALIGNED_PTR_DEREF
36         #define U8TO16_LE(ptr)   (*((const U16*)(ptr)))
37         #define U8TO32_LE(ptr)   (*((const U32*)(ptr)))
38         #define U8TO64_LE(ptr)   (*((const U64*)(ptr)))
39     #else
40         #define U8TO16_LE(ptr)   (_shifted_octet(U16,(ptr),0, 0)|\
41                                   _shifted_octet(U16,(ptr),1, 8))
42
43         #define U8TO32_LE(ptr)   (_shifted_octet(U32,(ptr),0, 0)|\
44                                   _shifted_octet(U32,(ptr),1, 8)|\
45                                   _shifted_octet(U32,(ptr),2,16)|\
46                                   _shifted_octet(U32,(ptr),3,24))
47
48         #define U8TO64_LE(ptr)   (_shifted_octet(U64,(ptr),0, 0)|\
49                                   _shifted_octet(U64,(ptr),1, 8)|\
50                                   _shifted_octet(U64,(ptr),2,16)|\
51                                   _shifted_octet(U64,(ptr),3,24)|\
52                                   _shifted_octet(U64,(ptr),4,32)|\
53                                   _shifted_octet(U64,(ptr),5,40)|\
54                                   _shifted_octet(U64,(ptr),6,48)|\
55                                   _shifted_octet(U64,(ptr),7,56))
56     #endif
57   #elif (BYTEORDER == 0x4321 || BYTEORDER == 0x87654321)
58         #define U8TO16_LE(ptr)   (_shifted_octet(U16,(ptr),1, 0)|\
59                                   _shifted_octet(U16,(ptr),0, 8))
60
61         #define U8TO32_LE(ptr)   (_shifted_octet(U32,(ptr),3, 0)|\
62                                   _shifted_octet(U32,(ptr),2, 8)|\
63                                   _shifted_octet(U32,(ptr),1,16)|\
64                                   _shifted_octet(U32,(ptr),0,24))
65
66         #define U8TO64_LE(ptr)   (_shifted_octet(U64,(ptr),7, 0)|\
67                                   _shifted_octet(U64,(ptr),6, 8)|\
68                                   _shifted_octet(U64,(ptr),5,16)|\
69                                   _shifted_octet(U64,(ptr),4,24)|\
70                                   _shifted_octet(U64,(ptr),3,32)|\
71                                   _shifted_octet(U64,(ptr),2,40)|\
72                                   _shifted_octet(U64,(ptr),1,48)|\
73                                   _shifted_octet(U64,(ptr),0,56))
74   #endif
75 #endif
76
77 /* Find best way to ROTL32/ROTL64 */
78 #if defined(_MSC_VER)
79   #include <stdlib.h>  /* Microsoft put _rotl declaration in here */
80   #define ROTL32(x,r)  _rotl(x,r)
81   #define ROTR32(x,r)  _rotr(x,r)
82   #define ROTL64(x,r)  _rotl64(x,r)
83   #define ROTR64(x,r)  _rotr64(x,r)
84 #else
85   /* gcc recognises this code and generates a rotate instruction for CPUs with one */
86   #define ROTL32(x,r)  (((U32)(x) << (r)) | ((U32)(x) >> (32 - (r))))
87   #define ROTR32(x,r)  (((U32)(x) << (32 - (r))) | ((U32)(x) >> (r)))
88   #define ROTL64(x,r)  ( ( (U64)(x) << (r) ) | ( (U64)(x) >> ( 64 - (r) ) ) )
89   #define ROTR64(x,r)  ( ( (U64)(x) << ( 64 - (r) ) ) | ( (U64)(x) >> (r) ) )
90 #endif
91
92
93 #ifdef UV_IS_QUAD
94 #define ROTL_UV(x,r) ROTL64(x,r)
95 #define ROTR_UV(x,r) ROTL64(x,r)
96 #else
97 #define ROTL_UV(x,r) ROTL32(x,r)
98 #define ROTR_UV(x,r) ROTR32(x,r)
99 #endif
100 #if IVSIZE == 8
101 #define CAN64BITHASH
102 #endif
103
104 #endif