// 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.

#include "lib/jxl/headers.h"

#include <cstdint>

#include <limits>

#include "lib/jxl/fields.h"

#include "lib/jxl/frame_dimensions.h"

namespace jxl {

namespace {

struct Rational {

  constexpr explicit Rational(uint32_t num, uint32_t den)

      : num(num), den(den) {}

  // Returns floor(multiplicand * rational).

  constexpr uint32_t MulTruncate(uint32_t multiplicand) const {

    return static_cast<uint64_t>(multiplicand) * num / den;

  }

  uint32_t num;

  uint32_t den;

};

Rational FixedAspectRatios(uint32_t ratio) {

  JXL_DASSERT(0 != ratio && ratio < 8);

  // Other candidates: 5/4, 7/5, 14/9, 16/10, 5/3, 21/9, 12/5

  constexpr Rational kRatios[7] = {Rational(1, 1),    // square

                                   Rational(12, 10),  //

                                   Rational(4, 3),    // camera

                                   Rational(3, 2),    // mobile camera

                                   Rational(16, 9),   // camera/display

                                   Rational(5, 4),    //

                                   Rational(2, 1)};   //

  return kRatios[ratio - 1];

}

uint32_t FindAspectRatio(uint32_t xsize, uint32_t ysize) {

  for (uint32_t r = 1; r < 8; ++r) {

    if (xsize == FixedAspectRatios(r).MulTruncate(ysize)) {

      return r;

    }

  }

  return 0;  // Must send xsize instead

}

}  // namespace

size_t SizeHeader::xsize() const {

  if (ratio_ != 0) {

    return FixedAspectRatios(ratio_).MulTruncate(

        static_cast<uint32_t>(ysize()));

  }

  return small_ ? ((xsize_div8_minus_1_ + 1) * 8) : xsize_;

}

Status SizeHeader::Set(size_t xsize64, size_t ysize64) {

  constexpr size_t kDimensionCap = std::numeric_limits<uint32_t>::max();

  if (xsize64 > kDimensionCap || ysize64 > kDimensionCap) {

    return JXL_FAILURE("Image too large");

  }

  const uint32_t xsize32 = static_cast<uint32_t>(xsize64);

  const uint32_t ysize32 = static_cast<uint32_t>(ysize64);

  if (xsize64 == 0 || ysize64 == 0) return JXL_FAILURE("Empty image");

  ratio_ = FindAspectRatio(xsize32, ysize32);

  small_ = ysize64 <= 256 && (ysize64 % kBlockDim) == 0 &&

           (ratio_ != 0 || (xsize64 <= 256 && (xsize64 % kBlockDim) == 0));

  if (small_) {

    ysize_div8_minus_1_ = ysize32 / 8 - 1;

  } else {

    ysize_ = ysize32;

  }

  if (ratio_ == 0) {

    if (small_) {

      xsize_div8_minus_1_ = xsize32 / 8 - 1;

    } else {

      xsize_ = xsize32;

    }

  }

  JXL_ENSURE(xsize() == xsize64);

  JXL_ENSURE(ysize() == ysize64);

  return true;

}

Status PreviewHeader::Set(size_t xsize64, size_t ysize64) {

  const uint32_t xsize32 = static_cast<uint32_t>(xsize64);

  const uint32_t ysize32 = static_cast<uint32_t>(ysize64);

  if (xsize64 == 0 || ysize64 == 0) return JXL_FAILURE("Empty preview");

  div8_ = (xsize64 % kBlockDim) == 0 && (ysize64 % kBlockDim) == 0;

  if (div8_) {

    ysize_div8_ = ysize32 / 8;

  } else {

    ysize_ = ysize32;

  }

  ratio_ = FindAspectRatio(xsize32, ysize32);

  if (ratio_ == 0) {

    if (div8_) {

      xsize_div8_ = xsize32 / 8;

    } else {

      xsize_ = xsize32;

    }

  }

  JXL_ENSURE(xsize() == xsize64);

  JXL_ENSURE(ysize() == ysize64);

  return true;

}

size_t PreviewHeader::xsize() const {

  if (ratio_ != 0) {

    return FixedAspectRatios(ratio_).MulTruncate(

        static_cast<uint32_t>(ysize()));

  }

  return div8_ ? (xsize_div8_ * 8) : xsize_;

}

SizeHeader::SizeHeader() { Bundle::Init(this); }

Status SizeHeader::VisitFields(Visitor* JXL_RESTRICT visitor) {

  JXL_QUIET_RETURN_IF_ERROR(visitor->Bool(false, &small_));

  if (visitor->Conditional(small_)) {

    JXL_QUIET_RETURN_IF_ERROR(visitor->Bits(5, 0, &ysize_div8_minus_1_));

  }

  if (visitor->Conditional(!small_)) {

    // (Could still be small, but non-multiple of 8.)

    JXL_QUIET_RETURN_IF_ERROR(visitor->U32(BitsOffset(9, 1), BitsOffset(13, 1),

                                           BitsOffset(18, 1), BitsOffset(30, 1),

                                           1, &ysize_));

  }

  JXL_QUIET_RETURN_IF_ERROR(visitor->Bits(3, 0, &ratio_));

  if (visitor->Conditional(ratio_ == 0 && small_)) {

    JXL_QUIET_RETURN_IF_ERROR(visitor->Bits(5, 0, &xsize_div8_minus_1_));

  }

  if (visitor->Conditional(ratio_ == 0 && !small_)) {

    JXL_QUIET_RETURN_IF_ERROR(visitor->U32(BitsOffset(9, 1), BitsOffset(13, 1),

                                           BitsOffset(18, 1), BitsOffset(30, 1),

                                           1, &xsize_));

  }

  return true;

}

PreviewHeader::PreviewHeader() { Bundle::Init(this); }

Status PreviewHeader::VisitFields(Visitor* JXL_RESTRICT visitor) {

  JXL_QUIET_RETURN_IF_ERROR(visitor->Bool(false, &div8_));

  if (visitor->Conditional(div8_)) {

    JXL_QUIET_RETURN_IF_ERROR(visitor->U32(Val(16), Val(32), BitsOffset(5, 1),

                                           BitsOffset(9, 33), 1, &ysize_div8_));

  }

  if (visitor->Conditional(!div8_)) {

    JXL_QUIET_RETURN_IF_ERROR(visitor->U32(BitsOffset(6, 1), BitsOffset(8, 65),

                                           BitsOffset(10, 321),

                                           BitsOffset(12, 1345), 1, &ysize_));

  }

  JXL_QUIET_RETURN_IF_ERROR(visitor->Bits(3, 0, &ratio_));

  if (visitor->Conditional(ratio_ == 0 && div8_)) {

    JXL_QUIET_RETURN_IF_ERROR(visitor->U32(Val(16), Val(32), BitsOffset(5, 1),

                                           BitsOffset(9, 33), 1, &xsize_div8_));

  }

  if (visitor->Conditional(ratio_ == 0 && !div8_)) {

    JXL_QUIET_RETURN_IF_ERROR(visitor->U32(BitsOffset(6, 1), BitsOffset(8, 65),

                                           BitsOffset(10, 321),

                                           BitsOffset(12, 1345), 1, &xsize_));

  }

  return true;

}

AnimationHeader::AnimationHeader() { Bundle::Init(this); }

Status AnimationHeader::VisitFields(Visitor* JXL_RESTRICT visitor) {

  JXL_QUIET_RETURN_IF_ERROR(visitor->U32(Val(100), Val(1000), BitsOffset(10, 1),

                                         BitsOffset(30, 1), 1, &tps_numerator));

  JXL_QUIET_RETURN_IF_ERROR(visitor->U32(Val(1), Val(1001), BitsOffset(8, 1),

                                         BitsOffset(10, 1), 1,

                                         &tps_denominator));

  JXL_QUIET_RETURN_IF_ERROR(

      visitor->U32(Val(0), Bits(3), Bits(16), Bits(32), 0, &num_loops));

  JXL_QUIET_RETURN_IF_ERROR(visitor->Bool(false, &have_timecodes));

  return true;

}

Status ReadSizeHeader(BitReader* JXL_RESTRICT reader,

                      SizeHeader* JXL_RESTRICT size) {

  return Bundle::Read(reader, size);

}

}  // namespace jxl