Source code
Revision control
Copy as Markdown
Other Tools
// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#ifndef LIB_JXL_COEFF_ORDER_FWD_H_
#define LIB_JXL_COEFF_ORDER_FWD_H_
// Breaks circular dependency between ac_strategy and coeff_order.
#include <cstddef>
#include <cstdint>
#include "lib/jxl/base/compiler_specific.h"
namespace jxl {
// Needs at least 16 bits. A 32-bit type speeds up DecodeAC by 2% at the cost of
// more memory.
using coeff_order_t = uint32_t;
// Maximum number of orders to be used. Note that this needs to be multiplied by
// the number of channels. One per "size class" (plus one extra for DCT8),
// shared between transforms of size XxY and of size YxX.
constexpr uint8_t kNumOrders = 13;
// DCT coefficients are laid out in such a way that the number of rows of
// coefficients is always the smaller coordinate.
JXL_INLINE constexpr size_t CoefficientRows(size_t rows, size_t columns) {
return rows < columns ? rows : columns;
}
JXL_INLINE constexpr size_t CoefficientColumns(size_t rows, size_t columns) {
return rows < columns ? columns : rows;
}
JXL_INLINE void CoefficientLayout(size_t* JXL_RESTRICT rows,
size_t* JXL_RESTRICT columns) {
size_t r = *rows;
size_t c = *columns;
*rows = CoefficientRows(r, c);
*columns = CoefficientColumns(r, c);
}
} // namespace jxl
#endif // LIB_JXL_COEFF_ORDER_FWD_H_