1 // Copyright (c) the JPEG XL Project Authors. All rights reserved.
2 //
3 // Use of this source code is governed by a BSD-style
4 // license that can be found in the LICENSE file.
5
6 #ifndef LIB_JXL_COEFF_ORDER_H_
7 #define LIB_JXL_COEFF_ORDER_H_
8
9 #include <stddef.h>
10 #include <stdint.h>
11
12 #include "lib/jxl/ac_strategy.h"
13 #include "lib/jxl/aux_out_fwd.h"
14 #include "lib/jxl/base/compiler_specific.h"
15 #include "lib/jxl/base/status.h"
16 #include "lib/jxl/coeff_order_fwd.h"
17 #include "lib/jxl/common.h"
18 #include "lib/jxl/dct_util.h"
19 #include "lib/jxl/dec_bit_reader.h"
20
21 namespace jxl {
22
23 // Those offsets get multiplied by kDCTBlockSize.
24 static constexpr size_t kCoeffOrderOffset[] = {
25 0, 1, 2, 3, 4, 5, 6, 10, 14, 18,
26 34, 50, 66, 68, 70, 72, 76, 80, 84, 92,
27 100, 108, 172, 236, 300, 332, 364, 396, 652, 908,
28 1164, 1292, 1420, 1548, 2572, 3596, 4620, 5132, 5644, 6156,
29 };
30 static_assert(3 * kNumOrders + 1 ==
31 sizeof(kCoeffOrderOffset) / sizeof(*kCoeffOrderOffset),
32 "Update this array when adding or removing order types.");
33
CoeffOrderOffset(size_t order,size_t c)34 static constexpr size_t CoeffOrderOffset(size_t order, size_t c) {
35 return kCoeffOrderOffset[3 * order + c] * kDCTBlockSize;
36 }
37
38 static constexpr size_t kCoeffOrderMaxSize =
39 kCoeffOrderOffset[3 * kNumOrders] * kDCTBlockSize;
40
41 // Mapping from AC strategy to order bucket. Strategies with different natural
42 // orders must have different buckets.
43 constexpr uint8_t kStrategyOrder[] = {
44 0, 1, 1, 1, 2, 3, 4, 4, 5, 5, 6, 6, 1, 1,
45 1, 1, 1, 1, 7, 8, 8, 9, 10, 10, 11, 12, 12,
46 };
47
48 static_assert(AcStrategy::kNumValidStrategies ==
49 sizeof(kStrategyOrder) / sizeof(*kStrategyOrder),
50 "Update this array when adding or removing AC strategies.");
51
52 constexpr uint32_t kPermutationContexts = 8;
53
54 uint32_t CoeffOrderContext(uint32_t val);
55
56 Status DecodeCoeffOrders(uint16_t used_orders, uint32_t used_acs,
57 coeff_order_t* order, BitReader* br);
58
59 Status DecodePermutation(size_t skip, size_t size, coeff_order_t* order,
60 BitReader* br);
61
62 } // namespace jxl
63
64 #endif // LIB_JXL_COEFF_ORDER_H_
65