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Issue 1953443002: Update to libjpeg_turbo 1.4.90 (Closed) Base URL: https://chromium.googlesource.com/chromium/deps/libjpeg_turbo.git@master
Patch Set: Created 4 years, 7 months ago
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1 /* 1 /*
2 * jfdctflt.c 2 * jfdctflt.c
3 * 3 *
4 * Copyright (C) 1994-1996, Thomas G. Lane. 4 * Copyright (C) 1994-1996, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software. 5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file. 6 * For conditions of distribution and use, see the accompanying README.ijg
7 * file.
7 * 8 *
8 * This file contains a floating-point implementation of the 9 * This file contains a floating-point implementation of the
9 * forward DCT (Discrete Cosine Transform). 10 * forward DCT (Discrete Cosine Transform).
10 * 11 *
11 * This implementation should be more accurate than either of the integer 12 * This implementation should be more accurate than either of the integer
12 * DCT implementations. However, it may not give the same results on all 13 * DCT implementations. However, it may not give the same results on all
13 * machines because of differences in roundoff behavior. Speed will depend 14 * machines because of differences in roundoff behavior. Speed will depend
14 * on the hardware's floating point capacity. 15 * on the hardware's floating point capacity.
15 * 16 *
16 * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT 17 * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
17 * on each column. Direct algorithms are also available, but they are 18 * on each column. Direct algorithms are also available, but they are
18 * much more complex and seem not to be any faster when reduced to code. 19 * much more complex and seem not to be any faster when reduced to code.
19 * 20 *
20 * This implementation is based on Arai, Agui, and Nakajima's algorithm for 21 * This implementation is based on Arai, Agui, and Nakajima's algorithm for
21 * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in 22 * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
22 * Japanese, but the algorithm is described in the Pennebaker & Mitchell 23 * Japanese, but the algorithm is described in the Pennebaker & Mitchell
23 * JPEG textbook (see REFERENCES section in file README). The following code 24 * JPEG textbook (see REFERENCES section in file README.ijg). The following
24 * is based directly on figure 4-8 in P&M. 25 * code is based directly on figure 4-8 in P&M.
25 * While an 8-point DCT cannot be done in less than 11 multiplies, it is 26 * While an 8-point DCT cannot be done in less than 11 multiplies, it is
26 * possible to arrange the computation so that many of the multiplies are 27 * possible to arrange the computation so that many of the multiplies are
27 * simple scalings of the final outputs. These multiplies can then be 28 * simple scalings of the final outputs. These multiplies can then be
28 * folded into the multiplications or divisions by the JPEG quantization 29 * folded into the multiplications or divisions by the JPEG quantization
29 * table entries. The AA&N method leaves only 5 multiplies and 29 adds 30 * table entries. The AA&N method leaves only 5 multiplies and 29 adds
30 * to be done in the DCT itself. 31 * to be done in the DCT itself.
31 * The primary disadvantage of this method is that with a fixed-point 32 * The primary disadvantage of this method is that with a fixed-point
32 * implementation, accuracy is lost due to imprecise representation of the 33 * implementation, accuracy is lost due to imprecise representation of the
33 * scaled quantization values. However, that problem does not arise if 34 * scaled quantization values. However, that problem does not arise if
34 * we use floating point arithmetic. 35 * we use floating point arithmetic.
35 */ 36 */
36 37
37 #define JPEG_INTERNALS 38 #define JPEG_INTERNALS
38 #include "jinclude.h" 39 #include "jinclude.h"
39 #include "jpeglib.h" 40 #include "jpeglib.h"
40 #include "jdct.h"» » /* Private declarations for DCT subsystem */ 41 #include "jdct.h" /* Private declarations for DCT subsystem */
41 42
42 #ifdef DCT_FLOAT_SUPPORTED 43 #ifdef DCT_FLOAT_SUPPORTED
43 44
44 45
45 /* 46 /*
46 * This module is specialized to the case DCTSIZE = 8. 47 * This module is specialized to the case DCTSIZE = 8.
47 */ 48 */
48 49
49 #if DCTSIZE != 8 50 #if DCTSIZE != 8
50 Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ 51 Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
51 #endif 52 #endif
52 53
53 54
54 /* 55 /*
55 * Perform the forward DCT on one block of samples. 56 * Perform the forward DCT on one block of samples.
56 */ 57 */
57 58
58 GLOBAL(void) 59 GLOBAL(void)
59 jpeg_fdct_float (FAST_FLOAT * data) 60 jpeg_fdct_float (FAST_FLOAT *data)
60 { 61 {
61 FAST_FLOAT tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; 62 FAST_FLOAT tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
62 FAST_FLOAT tmp10, tmp11, tmp12, tmp13; 63 FAST_FLOAT tmp10, tmp11, tmp12, tmp13;
63 FAST_FLOAT z1, z2, z3, z4, z5, z11, z13; 64 FAST_FLOAT z1, z2, z3, z4, z5, z11, z13;
64 FAST_FLOAT *dataptr; 65 FAST_FLOAT *dataptr;
65 int ctr; 66 int ctr;
66 67
67 /* Pass 1: process rows. */ 68 /* Pass 1: process rows. */
68 69
69 dataptr = data; 70 dataptr = data;
70 for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { 71 for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
71 tmp0 = dataptr[0] + dataptr[7]; 72 tmp0 = dataptr[0] + dataptr[7];
72 tmp7 = dataptr[0] - dataptr[7]; 73 tmp7 = dataptr[0] - dataptr[7];
73 tmp1 = dataptr[1] + dataptr[6]; 74 tmp1 = dataptr[1] + dataptr[6];
74 tmp6 = dataptr[1] - dataptr[6]; 75 tmp6 = dataptr[1] - dataptr[6];
75 tmp2 = dataptr[2] + dataptr[5]; 76 tmp2 = dataptr[2] + dataptr[5];
76 tmp5 = dataptr[2] - dataptr[5]; 77 tmp5 = dataptr[2] - dataptr[5];
77 tmp3 = dataptr[3] + dataptr[4]; 78 tmp3 = dataptr[3] + dataptr[4];
78 tmp4 = dataptr[3] - dataptr[4]; 79 tmp4 = dataptr[3] - dataptr[4];
79 80
80 /* Even part */ 81 /* Even part */
81 82
82 tmp10 = tmp0 + tmp3;» /* phase 2 */ 83 tmp10 = tmp0 + tmp3; /* phase 2 */
83 tmp13 = tmp0 - tmp3; 84 tmp13 = tmp0 - tmp3;
84 tmp11 = tmp1 + tmp2; 85 tmp11 = tmp1 + tmp2;
85 tmp12 = tmp1 - tmp2; 86 tmp12 = tmp1 - tmp2;
86 87
87 dataptr[0] = tmp10 + tmp11; /* phase 3 */ 88 dataptr[0] = tmp10 + tmp11; /* phase 3 */
88 dataptr[4] = tmp10 - tmp11; 89 dataptr[4] = tmp10 - tmp11;
89 90
90 z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */ 91 z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */
91 dataptr[2] = tmp13 + z1;» /* phase 5 */ 92 dataptr[2] = tmp13 + z1; /* phase 5 */
92 dataptr[6] = tmp13 - z1; 93 dataptr[6] = tmp13 - z1;
93 94
94 /* Odd part */ 95 /* Odd part */
95 96
96 tmp10 = tmp4 + tmp5;» /* phase 2 */ 97 tmp10 = tmp4 + tmp5; /* phase 2 */
97 tmp11 = tmp5 + tmp6; 98 tmp11 = tmp5 + tmp6;
98 tmp12 = tmp6 + tmp7; 99 tmp12 = tmp6 + tmp7;
99 100
100 /* The rotator is modified from fig 4-8 to avoid extra negations. */ 101 /* The rotator is modified from fig 4-8 to avoid extra negations. */
101 z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */ 102 z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */
102 z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */ 103 z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */
103 z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */ 104 z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */
104 z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */ 105 z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */
105 106
106 z11 = tmp7 + z3;» » /* phase 5 */ 107 z11 = tmp7 + z3; /* phase 5 */
107 z13 = tmp7 - z3; 108 z13 = tmp7 - z3;
108 109
109 dataptr[5] = z13 + z2;» /* phase 6 */ 110 dataptr[5] = z13 + z2; /* phase 6 */
110 dataptr[3] = z13 - z2; 111 dataptr[3] = z13 - z2;
111 dataptr[1] = z11 + z4; 112 dataptr[1] = z11 + z4;
112 dataptr[7] = z11 - z4; 113 dataptr[7] = z11 - z4;
113 114
114 dataptr += DCTSIZE;»» /* advance pointer to next row */ 115 dataptr += DCTSIZE; /* advance pointer to next row */
115 } 116 }
116 117
117 /* Pass 2: process columns. */ 118 /* Pass 2: process columns. */
118 119
119 dataptr = data; 120 dataptr = data;
120 for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { 121 for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
121 tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7]; 122 tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
122 tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7]; 123 tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
123 tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6]; 124 tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
124 tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6]; 125 tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
125 tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5]; 126 tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
126 tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5]; 127 tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
127 tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4]; 128 tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
128 tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4]; 129 tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];
129 130
130 /* Even part */ 131 /* Even part */
131 132
132 tmp10 = tmp0 + tmp3;» /* phase 2 */ 133 tmp10 = tmp0 + tmp3; /* phase 2 */
133 tmp13 = tmp0 - tmp3; 134 tmp13 = tmp0 - tmp3;
134 tmp11 = tmp1 + tmp2; 135 tmp11 = tmp1 + tmp2;
135 tmp12 = tmp1 - tmp2; 136 tmp12 = tmp1 - tmp2;
136 137
137 dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */ 138 dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */
138 dataptr[DCTSIZE*4] = tmp10 - tmp11; 139 dataptr[DCTSIZE*4] = tmp10 - tmp11;
139 140
140 z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */ 141 z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */
141 dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */ 142 dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */
142 dataptr[DCTSIZE*6] = tmp13 - z1; 143 dataptr[DCTSIZE*6] = tmp13 - z1;
143 144
144 /* Odd part */ 145 /* Odd part */
145 146
146 tmp10 = tmp4 + tmp5;» /* phase 2 */ 147 tmp10 = tmp4 + tmp5; /* phase 2 */
147 tmp11 = tmp5 + tmp6; 148 tmp11 = tmp5 + tmp6;
148 tmp12 = tmp6 + tmp7; 149 tmp12 = tmp6 + tmp7;
149 150
150 /* The rotator is modified from fig 4-8 to avoid extra negations. */ 151 /* The rotator is modified from fig 4-8 to avoid extra negations. */
151 z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */ 152 z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */
152 z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */ 153 z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */
153 z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */ 154 z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */
154 z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */ 155 z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */
155 156
156 z11 = tmp7 + z3;» » /* phase 5 */ 157 z11 = tmp7 + z3; /* phase 5 */
157 z13 = tmp7 - z3; 158 z13 = tmp7 - z3;
158 159
159 dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */ 160 dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */
160 dataptr[DCTSIZE*3] = z13 - z2; 161 dataptr[DCTSIZE*3] = z13 - z2;
161 dataptr[DCTSIZE*1] = z11 + z4; 162 dataptr[DCTSIZE*1] = z11 + z4;
162 dataptr[DCTSIZE*7] = z11 - z4; 163 dataptr[DCTSIZE*7] = z11 - z4;
163 164
164 dataptr++;» » » /* advance pointer to next column */ 165 dataptr++; /* advance pointer to next column */
165 } 166 }
166 } 167 }
167 168
168 #endif /* DCT_FLOAT_SUPPORTED */ 169 #endif /* DCT_FLOAT_SUPPORTED */
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