1/**
2 * \file format_utils.h
3 * A collection of format conversion utility functions.
4 */
5
6/*
7 * Mesa 3-D graphics library
8 *
9 * Copyright (C) 1999-2006  Brian Paul  All Rights Reserved.
10 * Copyright (C) 2014  Intel Corporation  All Rights Reserved.
11 *
12 * Permission is hereby granted, free of charge, to any person obtaining a
13 * copy of this software and associated documentation files (the "Software"),
14 * to deal in the Software without restriction, including without limitation
15 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
16 * and/or sell copies of the Software, and to permit persons to whom the
17 * Software is furnished to do so, subject to the following conditions:
18 *
19 * The above copyright notice and this permission notice shall be included
20 * in all copies or substantial portions of the Software.
21 *
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
23 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
25 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
26 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
27 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
28 * OTHER DEALINGS IN THE SOFTWARE.
29 */
30
31#ifndef UTIL_FORMAT_UTILS_H
32#define UTIL_FORMAT_UTILS_H
33
34#include "util/half_float.h"
35#include "util/rounding.h"
36
37/* Extends an integer of size SRC_BITS to one of size DST_BITS linearly */
38#define EXTEND_NORMALIZED_INT(X, SRC_BITS, DST_BITS) \
39      (((X) * (int)(u_uintN_max(DST_BITS) / u_uintN_max(SRC_BITS))) + \
40       (((DST_BITS) % (SRC_BITS)) ? ((X) >> ((SRC_BITS) - (DST_BITS) % (SRC_BITS))) : 0))
41
42static inline float
43_mesa_unorm_to_float(unsigned x, unsigned src_bits)
44{
45   return x * (1.0f / (float)u_uintN_max(src_bits));
46}
47
48static inline float
49_mesa_snorm_to_float(int x, unsigned src_bits)
50{
51   if (x <= -u_intN_max(src_bits))
52      return -1.0f;
53   else
54      return x * (1.0f / (float)u_intN_max(src_bits));
55}
56
57static inline uint16_t
58_mesa_unorm_to_half(unsigned x, unsigned src_bits)
59{
60   return _mesa_float_to_half(_mesa_unorm_to_float(x, src_bits));
61}
62
63static inline uint16_t
64_mesa_snorm_to_half(int x, unsigned src_bits)
65{
66   return _mesa_float_to_half(_mesa_snorm_to_float(x, src_bits));
67}
68
69static inline unsigned
70_mesa_float_to_unorm(float x, unsigned dst_bits)
71{
72   if (x < 0.0f)
73      return 0;
74   else if (x > 1.0f)
75      return u_uintN_max(dst_bits);
76   else
77      return _mesa_i64roundevenf(x * u_uintN_max(dst_bits));
78}
79
80static inline unsigned
81_mesa_half_to_unorm(uint16_t x, unsigned dst_bits)
82{
83   return _mesa_float_to_unorm(_mesa_half_to_float(x), dst_bits);
84}
85
86static inline unsigned
87_mesa_unorm_to_unorm(unsigned x, unsigned src_bits, unsigned dst_bits)
88{
89   if (src_bits < dst_bits) {
90      return EXTEND_NORMALIZED_INT(x, src_bits, dst_bits);
91   } else if (src_bits > dst_bits) {
92      unsigned src_half = (1u << (src_bits - 1)) - 1;
93
94      if (src_bits + dst_bits > sizeof(x) * 8) {
95         assert(src_bits + dst_bits <= sizeof(uint64_t) * 8);
96         return (((uint64_t) x * u_uintN_max(dst_bits) + src_half) /
97                 u_uintN_max(src_bits));
98      } else {
99         return (x * u_uintN_max(dst_bits) + src_half) / u_uintN_max(src_bits);
100      }
101   } else {
102      return x;
103   }
104}
105
106static inline unsigned
107_mesa_snorm_to_unorm(int x, unsigned src_bits, unsigned dst_bits)
108{
109   if (x < 0)
110      return 0;
111   else
112      return _mesa_unorm_to_unorm(x, src_bits - 1, dst_bits);
113}
114
115static inline int
116_mesa_float_to_snorm(float x, unsigned dst_bits)
117{
118   if (x < -1.0f)
119      return -u_intN_max(dst_bits);
120   else if (x > 1.0f)
121      return u_intN_max(dst_bits);
122   else
123      return _mesa_lroundevenf(x * u_intN_max(dst_bits));
124}
125
126static inline int
127_mesa_half_to_snorm(uint16_t x, unsigned dst_bits)
128{
129   return _mesa_float_to_snorm(_mesa_half_to_float(x), dst_bits);
130}
131
132static inline int
133_mesa_unorm_to_snorm(unsigned x, unsigned src_bits, unsigned dst_bits)
134{
135   return _mesa_unorm_to_unorm(x, src_bits, dst_bits - 1);
136}
137
138static inline int
139_mesa_snorm_to_snorm(int x, unsigned src_bits, unsigned dst_bits)
140{
141   if (x < -u_intN_max(src_bits))
142      return -u_intN_max(dst_bits);
143   else if (src_bits < dst_bits)
144      return EXTEND_NORMALIZED_INT(x, src_bits - 1, dst_bits - 1);
145   else
146      return x >> (src_bits - dst_bits);
147}
148
149static inline unsigned
150_mesa_unsigned_to_unsigned(unsigned src, unsigned dst_size)
151{
152   return MIN2(src, u_uintN_max(dst_size));
153}
154
155static inline int
156_mesa_unsigned_to_signed(unsigned src, unsigned dst_size)
157{
158   return MIN2(src, (unsigned)u_intN_max(dst_size));
159}
160
161static inline int
162_mesa_signed_to_signed(int src, unsigned dst_size)
163{
164   return CLAMP(src, u_intN_min(dst_size), u_intN_max(dst_size));
165}
166
167static inline unsigned
168_mesa_signed_to_unsigned(int src, unsigned dst_size)
169{
170   return CLAMP(src, 0, u_uintN_max(dst_size));
171}
172
173static inline unsigned
174_mesa_float_to_unsigned(float src, unsigned dst_bits)
175{
176   if (src < 0.0f)
177      return 0;
178   if (src > (float)u_uintN_max(dst_bits))
179       return u_uintN_max(dst_bits);
180   return _mesa_signed_to_unsigned(src, dst_bits);
181}
182
183static inline unsigned
184_mesa_float_to_signed(float src, unsigned dst_bits)
185{
186   if (src < (float)(-u_intN_max(dst_bits)))
187      return -u_intN_max(dst_bits);
188   if (src > (float)u_intN_max(dst_bits))
189       return u_intN_max(dst_bits);
190   return _mesa_signed_to_signed(src, dst_bits);
191}
192
193static inline unsigned
194_mesa_half_to_unsigned(uint16_t src, unsigned dst_bits)
195{
196   if (_mesa_half_is_negative(src))
197      return 0;
198   return _mesa_unsigned_to_unsigned(_mesa_float_to_half(src), dst_bits);
199}
200
201static inline unsigned
202_mesa_half_to_signed(uint16_t src, unsigned dst_bits)
203{
204   return _mesa_float_to_signed(_mesa_half_to_float(src), dst_bits);
205}
206
207#endif /* UTIL_FORMAT_UTILS_H */
208