// 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/icc_codec.h"

#include <jxl/memory_manager.h>

#include <cstdint>

#include "lib/jxl/base/status.h"

#include "lib/jxl/dec_ans.h"

#include "lib/jxl/fields.h"

#include "lib/jxl/icc_codec_common.h"

#include "lib/jxl/padded_bytes.h"

namespace jxl {

namespace {

// Shuffles or interleaves bytes, for example with width 2, turns "ABCDabcd"

// into "AaBbCcDd". Transposes a matrix of ceil(size / width) columns and

// width rows. There are size elements, size may be < width * height, if so the

// last elements of the rightmost column are missing, the missing spots are

// transposed along with the filled spots, and the result has the missing

// elements at the end of the bottom row. The input is the input matrix in

// scanline order but with missing elements skipped (which may occur in multiple

// locations), the output is the result matrix in scanline order (with

// no need to skip missing elements as they are past the end of the data).

Status Shuffle(JxlMemoryManager* memory_manager, uint8_t* data, size_t size,

               size_t width) {

  size_t height = (size + width - 1) / width;  // amount of rows of output

  PaddedBytes result(memory_manager);

  JXL_ASSIGN_OR_RETURN(result,

                       PaddedBytes::WithInitialSpace(memory_manager, size));

  // i = output index, j input index

  size_t s = 0;

  size_t j = 0;

  for (size_t i = 0; i < size; i++) {

    result[i] = data[j];

    j += height;

    if (j >= size) j = ++s;

  }

  for (size_t i = 0; i < size; i++) {

    data[i] = result[i];

  }

  return true;

}

// TODO(eustas): should be 20, or even 18, once DecodeVarInt is improved;

//               currently DecodeVarInt does not signal the errors, and marks

//               11 bytes as used even if only 10 are used (and 9 is enough for

//               63-bit values).

constexpr const size_t kPreambleSize = 22;  // enough for reading 2 VarInts

uint64_t DecodeVarInt(const uint8_t* input, size_t inputSize, size_t* pos) {

  size_t i;

  uint64_t ret = 0;

  for (i = 0; *pos + i < inputSize && i < 10; ++i) {

    ret |= static_cast<uint64_t>(input[*pos + i] & 127)

           << static_cast<uint64_t>(7 * i);

    // If the next-byte flag is not set, stop

    if ((input[*pos + i] & 128) == 0) break;

  }

  // TODO(user): Return a decoding error if i == 10.

  *pos += i + 1;

  return ret;

}

}  // namespace

// Mimics the beginning of UnpredictICC for quick validity check.

// At least kPreambleSize bytes of data should be valid at invocation time.

Status CheckPreamble(const PaddedBytes& data, size_t enc_size) {

  const uint8_t* enc = data.data();

  size_t size = data.size();

  size_t pos = 0;

  uint64_t osize = DecodeVarInt(enc, size, &pos);

  JXL_RETURN_IF_ERROR(CheckIs32Bit(osize));

  if (pos >= size) return JXL_FAILURE("Out of bounds");

  uint64_t csize = DecodeVarInt(enc, size, &pos);

  JXL_RETURN_IF_ERROR(CheckIs32Bit(csize));

  JXL_RETURN_IF_ERROR(CheckOutOfBounds(pos, csize, size));

  // We expect that UnpredictICC inflates input, not the other way round.

  if (osize + 65536 < enc_size) return JXL_FAILURE("Malformed ICC");

  // NB(eustas): 64 MiB ICC should be enough for everything!?

  const size_t output_limit = 1 << 28;

  if (output_limit && osize > output_limit) {

    return JXL_FAILURE("Decoded ICC is too large");

  }

  return true;

}

// Decodes the result of PredictICC back to a valid ICC profile.

Status UnpredictICC(const uint8_t* enc, size_t size, PaddedBytes* result) {

  if (!result->empty()) return JXL_FAILURE("result must be empty initially");

  JxlMemoryManager* memory_manager = result->memory_manager();

  size_t pos = 0;

  // TODO(lode): technically speaking we need to check that the entire varint

  // decoding never goes out of bounds, not just the first byte. This requires

  // a DecodeVarInt function that returns an error code. It is safe to use

  // DecodeVarInt with out of bounds values, it silently returns, but the

  // specification requires an error. Idem for all DecodeVarInt below.

  if (pos >= size) return JXL_FAILURE("Out of bounds");

  uint64_t osize = DecodeVarInt(enc, size, &pos);  // Output size

  JXL_RETURN_IF_ERROR(CheckIs32Bit(osize));

  if (pos >= size) return JXL_FAILURE("Out of bounds");

  uint64_t csize = DecodeVarInt(enc, size, &pos);  // Commands size

  // Every command is translated to at least on byte.

  JXL_RETURN_IF_ERROR(CheckIs32Bit(csize));

  size_t cpos = pos;  // pos in commands stream

  JXL_RETURN_IF_ERROR(CheckOutOfBounds(pos, csize, size));

  size_t commands_end = cpos + csize;

  pos = commands_end;  // pos in data stream

  // Header

  PaddedBytes header{memory_manager};

  JXL_RETURN_IF_ERROR(header.append(ICCInitialHeaderPrediction(osize)));

  for (size_t i = 0; i <= kICCHeaderSize; i++) {

    if (result->size() == osize) {

      if (cpos != commands_end) return JXL_FAILURE("Not all commands used");

      if (pos != size) return JXL_FAILURE("Not all data used");

      return true;  // Valid end

    }

    if (i == kICCHeaderSize) break;  // Done

    ICCPredictHeader(result->data(), result->size(), header.data(), i);

    if (pos >= size) return JXL_FAILURE("Out of bounds");

    JXL_RETURN_IF_ERROR(result->push_back(enc[pos++] + header[i]));

  }

  if (cpos >= commands_end) return JXL_FAILURE("Out of bounds");

  // Tag list

  uint64_t numtags = DecodeVarInt(enc, size, &cpos);

  if (numtags != 0) {

    numtags--;

    JXL_RETURN_IF_ERROR(CheckIs32Bit(numtags));

    JXL_RETURN_IF_ERROR(AppendUint32(numtags, result));

    uint64_t prevtagstart = kICCHeaderSize + numtags * 12;

    uint64_t prevtagsize = 0;

    for (;;) {

      if (result->size() > osize) return JXL_FAILURE("Invalid result size");

      if (cpos > commands_end) return JXL_FAILURE("Out of bounds");

      if (cpos == commands_end) break;  // Valid end

      uint8_t command = enc[cpos++];

      uint8_t tagcode = command & 63;

      Tag tag;

      if (tagcode == 0) {

        break;

      } else if (tagcode == kCommandTagUnknown) {

        JXL_RETURN_IF_ERROR(CheckOutOfBounds(pos, 4, size));

        tag = DecodeKeyword(enc, size, pos);

        pos += 4;

      } else if (tagcode == kCommandTagTRC) {

        tag = kRtrcTag;

      } else if (tagcode == kCommandTagXYZ) {

        tag = kRxyzTag;

      } else {

        if (tagcode - kCommandTagStringFirst >= kNumTagStrings) {

          return JXL_FAILURE("Unknown tagcode");

        }

        tag = *kTagStrings[tagcode - kCommandTagStringFirst];

      }

      JXL_RETURN_IF_ERROR(AppendKeyword(tag, result));

      uint64_t tagstart;

      uint64_t tagsize = prevtagsize;

      if (tag == kRxyzTag || tag == kGxyzTag || tag == kBxyzTag ||

          tag == kKxyzTag || tag == kWtptTag || tag == kBkptTag ||

          tag == kLumiTag) {

        tagsize = 20;

      }

      if (command & kFlagBitOffset) {

        if (cpos >= commands_end) return JXL_FAILURE("Out of bounds");

        tagstart = DecodeVarInt(enc, size, &cpos);

      } else {

        JXL_RETURN_IF_ERROR(CheckIs32Bit(prevtagstart));

        tagstart = prevtagstart + prevtagsize;

      }

      JXL_RETURN_IF_ERROR(CheckIs32Bit(tagstart));

      JXL_RETURN_IF_ERROR(AppendUint32(tagstart, result));

      if (command & kFlagBitSize) {

        if (cpos >= commands_end) return JXL_FAILURE("Out of bounds");

        tagsize = DecodeVarInt(enc, size, &cpos);

      }

      JXL_RETURN_IF_ERROR(CheckIs32Bit(tagsize));

      JXL_RETURN_IF_ERROR(AppendUint32(tagsize, result));

      prevtagstart = tagstart;

      prevtagsize = tagsize;

      if (tagcode == kCommandTagTRC) {

        JXL_RETURN_IF_ERROR(AppendKeyword(kGtrcTag, result));

        JXL_RETURN_IF_ERROR(AppendUint32(tagstart, result));

        JXL_RETURN_IF_ERROR(AppendUint32(tagsize, result));

        JXL_RETURN_IF_ERROR(AppendKeyword(kBtrcTag, result));

        JXL_RETURN_IF_ERROR(AppendUint32(tagstart, result));

        JXL_RETURN_IF_ERROR(AppendUint32(tagsize, result));

      }

      if (tagcode == kCommandTagXYZ) {

        JXL_RETURN_IF_ERROR(CheckIs32Bit(tagstart + tagsize * 2));

        JXL_RETURN_IF_ERROR(AppendKeyword(kGxyzTag, result));

        JXL_RETURN_IF_ERROR(AppendUint32(tagstart + tagsize, result));

        JXL_RETURN_IF_ERROR(AppendUint32(tagsize, result));

        JXL_RETURN_IF_ERROR(AppendKeyword(kBxyzTag, result));

        JXL_RETURN_IF_ERROR(AppendUint32(tagstart + tagsize * 2, result));

        JXL_RETURN_IF_ERROR(AppendUint32(tagsize, result));

      }

    }

  }

  // Main Content

  for (;;) {

    if (result->size() > osize) return JXL_FAILURE("Invalid result size");

    if (cpos > commands_end) return JXL_FAILURE("Out of bounds");

    if (cpos == commands_end) break;  // Valid end

    uint8_t command = enc[cpos++];

    if (command == kCommandInsert) {

      if (cpos >= commands_end) return JXL_FAILURE("Out of bounds");

      uint64_t num = DecodeVarInt(enc, size, &cpos);

      JXL_RETURN_IF_ERROR(CheckOutOfBounds(pos, num, size));

      for (size_t i = 0; i < num; i++) {

        JXL_RETURN_IF_ERROR(result->push_back(enc[pos++]));

      }

    } else if (command == kCommandShuffle2 || command == kCommandShuffle4) {

      if (cpos >= commands_end) return JXL_FAILURE("Out of bounds");

      uint64_t num = DecodeVarInt(enc, size, &cpos);

      JXL_RETURN_IF_ERROR(CheckOutOfBounds(pos, num, size));

      PaddedBytes shuffled(memory_manager);

      JXL_ASSIGN_OR_RETURN(shuffled,

                           PaddedBytes::WithInitialSpace(memory_manager, num));

      for (size_t i = 0; i < num; i++) {

        shuffled[i] = enc[pos + i];

      }

      if (command == kCommandShuffle2) {

        JXL_RETURN_IF_ERROR(Shuffle(memory_manager, shuffled.data(), num, 2));

      } else if (command == kCommandShuffle4) {

        JXL_RETURN_IF_ERROR(Shuffle(memory_manager, shuffled.data(), num, 4));

      }

      for (size_t i = 0; i < num; i++) {

        JXL_RETURN_IF_ERROR(result->push_back(shuffled[i]));

        pos++;

      }

    } else if (command == kCommandPredict) {

      JXL_RETURN_IF_ERROR(CheckOutOfBounds(cpos, 2, commands_end));

      uint8_t flags = enc[cpos++];

      size_t width = (flags & 3) + 1;

      if (width == 3) return JXL_FAILURE("Invalid width");

      int order = (flags & 12) >> 2;

      if (order == 3) return JXL_FAILURE("Invalid order");

      uint64_t stride = width;

      if (flags & 16) {

        if (cpos >= commands_end) return JXL_FAILURE("Out of bounds");

        stride = DecodeVarInt(enc, size, &cpos);

        if (stride < width) {

          return JXL_FAILURE("Invalid stride");

        }

      }

      // If stride * 4 >= result->size(), return failure. The check

      // "size == 0 || ((size - 1) >> 2) < stride" corresponds to

      // "stride * 4 >= size", but does not suffer from integer overflow.

      // This check is more strict than necessary but follows the specification

      // and the encoder should ensure this is followed.

      if (result->empty() || ((result->size() - 1u) >> 2u) < stride) {

        return JXL_FAILURE("Invalid stride");

      }

      if (cpos >= commands_end) return JXL_FAILURE("Out of bounds");

      uint64_t num = DecodeVarInt(enc, size, &cpos);  // in bytes

      JXL_RETURN_IF_ERROR(CheckOutOfBounds(pos, num, size));

      PaddedBytes shuffled(memory_manager);

      JXL_ASSIGN_OR_RETURN(shuffled,

                           PaddedBytes::WithInitialSpace(memory_manager, num));

      for (size_t i = 0; i < num; i++) {

        shuffled[i] = enc[pos + i];

      }

      if (width > 1) {

        JXL_RETURN_IF_ERROR(

            Shuffle(memory_manager, shuffled.data(), num, width));

      }

      size_t start = result->size();

      for (size_t i = 0; i < num; i++) {

        uint8_t predicted = LinearPredictICCValue(result->data(), start, i,

                                                  stride, width, order);

        JXL_RETURN_IF_ERROR(result->push_back(predicted + shuffled[i]));

      }

      pos += num;

    } else if (command == kCommandXYZ) {

      JXL_RETURN_IF_ERROR(AppendKeyword(kXyz_Tag, result));

      for (int i = 0; i < 4; i++) {

        JXL_RETURN_IF_ERROR(result->push_back(0));

      }

      JXL_RETURN_IF_ERROR(CheckOutOfBounds(pos, 12, size));

      for (size_t i = 0; i < 12; i++) {

        JXL_RETURN_IF_ERROR(result->push_back(enc[pos++]));

      }

    } else if (command >= kCommandTypeStartFirst &&

               command < kCommandTypeStartFirst + kNumTypeStrings) {

      JXL_RETURN_IF_ERROR(AppendKeyword(

          *kTypeStrings[command - kCommandTypeStartFirst], result));

      for (size_t i = 0; i < 4; i++) {

        JXL_RETURN_IF_ERROR(result->push_back(0));

      }

    } else {

      return JXL_FAILURE("Unknown command");

    }

  }

  if (pos != size) return JXL_FAILURE("Not all data used");

  if (result->size() != osize) return JXL_FAILURE("Invalid result size");

  return true;

}

Status ICCReader::Init(BitReader* reader) {

  JXL_RETURN_IF_ERROR(CheckEOI(reader));

  JxlMemoryManager* memory_manager = decompressed_.memory_manager();

  used_bits_base_ = reader->TotalBitsConsumed();

  if (bits_to_skip_ == 0) {

    enc_size_ = U64Coder::Read(reader);

    if (enc_size_ > 268435456) {

      // Avoid too large memory allocation for invalid file.

      return JXL_FAILURE("Too large encoded profile");

    }

    JXL_RETURN_IF_ERROR(DecodeHistograms(

        memory_manager, reader, kNumICCContexts, &code_, &context_map_));

    JXL_ASSIGN_OR_RETURN(ans_reader_, ANSSymbolReader::Create(&code_, reader));

    i_ = 0;

    JXL_RETURN_IF_ERROR(

        decompressed_.resize(std::min<size_t>(i_ + 0x400, enc_size_)));

    for (; i_ < std::min<size_t>(2, enc_size_); i_++) {

      decompressed_[i_] = ans_reader_.ReadHybridUint(

          ICCANSContext(i_, i_ > 0 ? decompressed_[i_ - 1] : 0,

                        i_ > 1 ? decompressed_[i_ - 2] : 0),

          reader, context_map_);

    }

    if (enc_size_ > kPreambleSize) {

      for (; i_ < kPreambleSize; i_++) {

        decompressed_[i_] = ans_reader_.ReadHybridUint(

            ICCANSContext(i_, decompressed_[i_ - 1], decompressed_[i_ - 2]),

            reader, context_map_);

      }

      JXL_RETURN_IF_ERROR(CheckEOI(reader));

      JXL_RETURN_IF_ERROR(CheckPreamble(decompressed_, enc_size_));

    }

    bits_to_skip_ = reader->TotalBitsConsumed() - used_bits_base_;

  } else {

    reader->SkipBits(bits_to_skip_);

  }

  return true;

}

Status ICCReader::Process(BitReader* reader, PaddedBytes* icc) {

  ANSSymbolReader::Checkpoint checkpoint;

  size_t saved_i = 0;

  auto save = [&]() {

    ans_reader_.Save(&checkpoint);

    bits_to_skip_ = reader->TotalBitsConsumed() - used_bits_base_;

    saved_i = i_;

  };

  save();

  auto check_and_restore = [&]() {

    Status status = CheckEOI(reader);

    if (!status) {

      // not enough bytes.

      ans_reader_.Restore(checkpoint);

      i_ = saved_i;

      return status;

    }

    return Status(true);

  };

  for (; i_ < enc_size_; i_++) {

    if (i_ % ANSSymbolReader::kMaxCheckpointInterval == 0 && i_ > 0) {

      JXL_RETURN_IF_ERROR(check_and_restore());

      save();

      if ((i_ > 0) && (((i_ & 0xFFFF) == 0))) {

        float used_bytes =

            (reader->TotalBitsConsumed() - used_bits_base_) / 8.0f;

        if (i_ > used_bytes * 256) return JXL_FAILURE("Corrupted stream");

      }

      JXL_RETURN_IF_ERROR(

          decompressed_.resize(std::min<size_t>(i_ + 0x400, enc_size_)));

    }

    JXL_ENSURE(i_ >= 2);

    decompressed_[i_] = ans_reader_.ReadHybridUint(

        ICCANSContext(i_, decompressed_[i_ - 1], decompressed_[i_ - 2]), reader,

        context_map_);

  }

  JXL_RETURN_IF_ERROR(check_and_restore());

  bits_to_skip_ = reader->TotalBitsConsumed() - used_bits_base_;

  if (!ans_reader_.CheckANSFinalState()) {

    return JXL_FAILURE("Corrupted ICC profile");

  }

  icc->clear();

  return UnpredictICC(decompressed_.data(), decompressed_.size(), icc);

}

Status ICCReader::CheckEOI(BitReader* reader) {

  if (reader->AllReadsWithinBounds()) return true;

  return JXL_STATUS(StatusCode::kNotEnoughBytes,

                    "Not enough bytes for reading ICC profile");

}

}  // namespace jxl