xref: /isa-l/igzip/bitbuf2.h (revision 22ec5c7469da5a39d3178e79b20df5f3eb450d7c)
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3 
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29 #ifndef BITBUF2_H
30 #define BITBUF2_H
31 
32 #include "igzip_lib.h"
33 
34 #if defined (__unix__) || (__APPLE__) || (__MINGW32__)
35 #define _mm_stream_si64x(dst, src) *((uint64_t*)dst) = src
36 #else
37 #include <intrin.h>
38 #endif
39 
40 #ifdef _WIN64
41 #pragma warning(disable: 4996)
42 #endif
43 
44 #ifdef _MSC_VER
45 #define inline __inline
46 #endif
47 
48 
49 /* MAX_BITBUF_BIT WRITE is the maximum number of bits than can be safely written
50  * by consecutive calls of write_bits. Note this assumes the bitbuf is in a
51  * state that is possible at the exit of write_bits */
52 #define MAX_BITBUF_BIT_WRITE 56
53 
54 static inline void init(struct BitBuf2 *me)
55 {
56 	me->m_bits = 0;
57 	me->m_bit_count = 0;
58 }
59 
60 static inline void set_buf(struct BitBuf2 *me, unsigned char *buf, unsigned int len)
61 {
62 	unsigned int slop = 8;
63 	me->m_out_buf = me->m_out_start = buf;
64 	me->m_out_end = buf + len - slop;
65 }
66 
67 static inline int is_full(struct BitBuf2 *me)
68 {
69 	return (me->m_out_buf > me->m_out_end);
70 }
71 
72 static inline uint8_t * buffer_ptr(struct BitBuf2 *me)
73 {
74 	return me->m_out_buf;
75 }
76 
77 static inline uint32_t buffer_used(struct BitBuf2 *me)
78 {
79 	return (uint32_t)(me->m_out_buf - me->m_out_start);
80 }
81 
82 static inline uint32_t buffer_bits_used(struct BitBuf2 *me)
83 {
84 	return (8 * (uint32_t)(me->m_out_buf - me->m_out_start) + me->m_bit_count);
85 }
86 
87 static inline void flush_bits(struct BitBuf2 *me)
88 {
89 	uint32_t bits;
90 	_mm_stream_si64x((int64_t *) me->m_out_buf, me->m_bits);
91 	bits = me->m_bit_count & ~7;
92 	me->m_bit_count -= bits;
93 	me->m_out_buf += bits/8;
94 	me->m_bits >>= bits;
95 
96 }
97 
98 /* Can write up to 8 bytes to output buffer */
99 static inline void flush(struct BitBuf2 *me)
100 {
101 	uint32_t bytes;
102 	if (me->m_bit_count) {
103 		_mm_stream_si64x((int64_t *) me->m_out_buf, me->m_bits);
104 		bytes = (me->m_bit_count + 7) / 8;
105 		me->m_out_buf += bytes;
106 	}
107 	me->m_bits = 0;
108 	me->m_bit_count = 0;
109 }
110 
111 static inline void check_space(struct BitBuf2 *me, uint32_t num_bits)
112 {
113 	/* Checks if bitbuf has num_bits extra space and flushes the bytes in
114 	 * the bitbuf if it doesn't. */
115 	if (63 - me->m_bit_count < num_bits)
116 		flush_bits(me);
117 }
118 
119 static inline void write_bits_unsafe(struct BitBuf2 *me, uint64_t code, uint32_t count)
120 {
121 	me->m_bits |= code << me->m_bit_count;
122 	me->m_bit_count += count;
123 }
124 
125 static inline void write_bits(struct BitBuf2 *me, uint64_t code, uint32_t count)
126 {	/* Assumes there is space to fit code into m_bits. */
127 	me->m_bits |= code << me->m_bit_count;
128 	me->m_bit_count += count;
129 	flush_bits(me);
130 }
131 
132 static inline void write_bits_flush(struct BitBuf2 *me, uint64_t code, uint32_t count)
133 {	/* Assumes there is space to fit code into m_bits. */
134 	me->m_bits |= code << me->m_bit_count;
135 	me->m_bit_count += count;
136 	flush(me);
137 }
138 
139 #endif //BITBUF2_H
140