1 files changed, 642 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jxl/fields.cc b/third_party/jpeg-xl/lib/jxl/fields.cc
new file mode 100644
index 0000000000..cd1e72bd94
--- /dev/null
+++ b/third_party/jpeg-xl/lib/jxl/fields.cc
@@ -0,0 +1,642 @@
+// 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/fields.h"
+
+#include <stddef.h>
+
+#include <algorithm>
+#include <cmath>
+#include <hwy/base.h>
+
+#include "lib/jxl/base/bits.h"
+#include "lib/jxl/base/printf_macros.h"
+
+namespace jxl {
+
+namespace {
+
+using ::jxl::fields_internal::VisitorBase;
+
+struct InitVisitor : public VisitorBase {
+  Status Bits(const size_t /*unused*/, const uint32_t default_value,
+              uint32_t* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  Status U32(const U32Enc /*unused*/, const uint32_t default_value,
+             uint32_t* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  Status U64(const uint64_t default_value,
+             uint64_t* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  Status Bool(bool default_value, bool* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  Status F16(const float default_value, float* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  // Always visit conditional fields to ensure they are initialized.
+  Status Conditional(bool /*condition*/) override { return true; }
+
+  Status AllDefault(const Fields& /*fields*/,
+                    bool* JXL_RESTRICT all_default) override {
+    // Just initialize this field and don't skip initializing others.
+    JXL_RETURN_IF_ERROR(Bool(true, all_default));
+    return false;
+  }
+
+  Status VisitNested(Fields* /*fields*/) override {
+    // Avoid re-initializing nested bundles (their ctors already called
+    // Bundle::Init for their fields).
+    return true;
+  }
+};
+
+// Similar to InitVisitor, but also initializes nested fields.
+struct SetDefaultVisitor : public VisitorBase {
+  Status Bits(const size_t /*unused*/, const uint32_t default_value,
+              uint32_t* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  Status U32(const U32Enc /*unused*/, const uint32_t default_value,
+             uint32_t* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  Status U64(const uint64_t default_value,
+             uint64_t* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  Status Bool(bool default_value, bool* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  Status F16(const float default_value, float* JXL_RESTRICT value) override {
+    *value = default_value;
+    return true;
+  }
+
+  // Always visit conditional fields to ensure they are initialized.
+  Status Conditional(bool /*condition*/) override { return true; }
+
+  Status AllDefault(const Fields& /*fields*/,
+                    bool* JXL_RESTRICT all_default) override {
+    // Just initialize this field and don't skip initializing others.
+    JXL_RETURN_IF_ERROR(Bool(true, all_default));
+    return false;
+  }
+};
+
+class AllDefaultVisitor : public VisitorBase {
+ public:
+  explicit AllDefaultVisitor() : VisitorBase() {}
+
+  Status Bits(const size_t bits, const uint32_t default_value,
+              uint32_t* JXL_RESTRICT value) override {
+    all_default_ &= *value == default_value;
+    return true;
+  }
+
+  Status U32(const U32Enc /*unused*/, const uint32_t default_value,
+             uint32_t* JXL_RESTRICT value) override {
+    all_default_ &= *value == default_value;
+    return true;
+  }
+
+  Status U64(const uint64_t default_value,
+             uint64_t* JXL_RESTRICT value) override {
+    all_default_ &= *value == default_value;
+    return true;
+  }
+
+  Status F16(const float default_value, float* JXL_RESTRICT value) override {
+    all_default_ &= std::abs(*value - default_value) < 1E-6f;
+    return true;
+  }
+
+  Status AllDefault(const Fields& /*fields*/,
+                    bool* JXL_RESTRICT /*all_default*/) override {
+    // Visit all fields so we can compute the actual all_default_ value.
+    return false;
+  }
+
+  bool AllDefault() const { return all_default_; }
+
+ private:
+  bool all_default_ = true;
+};
+
+class ReadVisitor : public VisitorBase {
+ public:
+  explicit ReadVisitor(BitReader* reader) : VisitorBase(), reader_(reader) {}
+
+  Status Bits(const size_t bits, const uint32_t /*default_value*/,
+              uint32_t* JXL_RESTRICT value) override {
+    *value = BitsCoder::Read(bits, reader_);
+    if (!reader_->AllReadsWithinBounds()) {
+      return JXL_STATUS(StatusCode::kNotEnoughBytes,
+                        "Not enough bytes for header");
+    }
+    return true;
+  }
+
+  Status U32(const U32Enc dist, const uint32_t /*default_value*/,
+             uint32_t* JXL_RESTRICT value) override {
+    *value = U32Coder::Read(dist, reader_);
+    if (!reader_->AllReadsWithinBounds()) {
+      return JXL_STATUS(StatusCode::kNotEnoughBytes,
+                        "Not enough bytes for header");
+    }
+    return true;
+  }
+
+  Status U64(const uint64_t /*default_value*/,
+             uint64_t* JXL_RESTRICT value) override {
+    *value = U64Coder::Read(reader_);
+    if (!reader_->AllReadsWithinBounds()) {
+      return JXL_STATUS(StatusCode::kNotEnoughBytes,
+                        "Not enough bytes for header");
+    }
+    return true;
+  }
+
+  Status F16(const float /*default_value*/,
+             float* JXL_RESTRICT value) override {
+    ok_ &= F16Coder::Read(reader_, value);
+    if (!reader_->AllReadsWithinBounds()) {
+      return JXL_STATUS(StatusCode::kNotEnoughBytes,
+                        "Not enough bytes for header");
+    }
+    return true;
+  }
+
+  void SetDefault(Fields* fields) override { Bundle::SetDefault(fields); }
+
+  bool IsReading() const override { return true; }
+
+  // This never fails because visitors are expected to keep reading until
+  // EndExtensions, see comment there.
+  Status BeginExtensions(uint64_t* JXL_RESTRICT extensions) override {
+    JXL_QUIET_RETURN_IF_ERROR(VisitorBase::BeginExtensions(extensions));
+    if (*extensions == 0) return true;
+
+    // For each nonzero bit, i.e. extension that is present:
+    for (uint64_t remaining_extensions = *extensions; remaining_extensions != 0;
+         remaining_extensions &= remaining_extensions - 1) {
+      const size_t idx_extension =
+          Num0BitsBelowLS1Bit_Nonzero(remaining_extensions);
+      // Read additional U64 (one per extension) indicating the number of bits
+      // (allows skipping individual extensions).
+      JXL_RETURN_IF_ERROR(U64(0, &extension_bits_[idx_extension]));
+      if (!SafeAdd(total_extension_bits_, extension_bits_[idx_extension],
+                   total_extension_bits_)) {
+        return JXL_FAILURE("Extension bits overflowed, invalid codestream");
+      }
+    }
+    // Used by EndExtensions to skip past any _remaining_ extensions.
+    pos_after_ext_size_ = reader_->TotalBitsConsumed();
+    JXL_ASSERT(pos_after_ext_size_ != 0);
+    return true;
+  }
+
+  Status EndExtensions() override {
+    JXL_QUIET_RETURN_IF_ERROR(VisitorBase::EndExtensions());
+    // Happens if extensions == 0: don't read size, done.
+    if (pos_after_ext_size_ == 0) return true;
+
+    // Not enough bytes as set by BeginExtensions or earlier. Do not return
+    // this as a JXL_FAILURE or false (which can also propagate to error
+    // through e.g. JXL_RETURN_IF_ERROR), since this may be used while
+    // silently checking whether there are enough bytes. If this case must be
+    // treated as an error, reader_>Close() will do this, just like is already
+    // done for non-extension fields.
+    if (!enough_bytes_) return true;
+
+    // Skip new fields this (old?) decoder didn't know about, if any.
+    const size_t bits_read = reader_->TotalBitsConsumed();
+    uint64_t end;
+    if (!SafeAdd(pos_after_ext_size_, total_extension_bits_, end)) {
+      return JXL_FAILURE("Invalid extension size, caused overflow");
+    }
+    if (bits_read > end) {
+      return JXL_FAILURE("Read more extension bits than budgeted");
+    }
+    const size_t remaining_bits = end - bits_read;
+    if (remaining_bits != 0) {
+      JXL_WARNING("Skipping %" PRIuS "-bit extension(s)", remaining_bits);
+      reader_->SkipBits(remaining_bits);
+      if (!reader_->AllReadsWithinBounds()) {
+        return JXL_STATUS(StatusCode::kNotEnoughBytes,
+                          "Not enough bytes for header");
+      }
+    }
+    return true;
+  }
+
+  Status OK() const { return ok_; }
+
+ private:
+  // Whether any error other than not enough bytes occurred.
+  bool ok_ = true;
+
+  // Whether there are enough input bytes to read from.
+  bool enough_bytes_ = true;
+  BitReader* const reader_;
+  // May be 0 even if the corresponding extension is present.
+  uint64_t extension_bits_[Bundle::kMaxExtensions] = {0};
+  uint64_t total_extension_bits_ = 0;
+  size_t pos_after_ext_size_ = 0;  // 0 iff extensions == 0.
+};
+
+class MaxBitsVisitor : public VisitorBase {
+ public:
+  Status Bits(const size_t bits, const uint32_t /*default_value*/,
+              uint32_t* JXL_RESTRICT /*value*/) override {
+    max_bits_ += BitsCoder::MaxEncodedBits(bits);
+    return true;
+  }
+
+  Status U32(const U32Enc enc, const uint32_t /*default_value*/,
+             uint32_t* JXL_RESTRICT /*value*/) override {
+    max_bits_ += U32Coder::MaxEncodedBits(enc);
+    return true;
+  }
+
+  Status U64(const uint64_t /*default_value*/,
+             uint64_t* JXL_RESTRICT /*value*/) override {
+    max_bits_ += U64Coder::MaxEncodedBits();
+    return true;
+  }
+
+  Status F16(const float /*default_value*/,
+             float* JXL_RESTRICT /*value*/) override {
+    max_bits_ += F16Coder::MaxEncodedBits();
+    return true;
+  }
+
+  Status AllDefault(const Fields& /*fields*/,
+                    bool* JXL_RESTRICT all_default) override {
+    JXL_RETURN_IF_ERROR(Bool(true, all_default));
+    return false;  // For max bits, assume nothing is default
+  }
+
+  // Always visit conditional fields to get a (loose) upper bound.
+  Status Conditional(bool /*condition*/) override { return true; }
+
+  Status BeginExtensions(uint64_t* JXL_RESTRICT /*extensions*/) override {
+    // Skip - extensions are not included in "MaxBits" because their length
+    // is potentially unbounded.
+    return true;
+  }
+
+  Status EndExtensions() override { return true; }
+
+  size_t MaxBits() const { return max_bits_; }
+
+ private:
+  size_t max_bits_ = 0;
+};
+
+class CanEncodeVisitor : public VisitorBase {
+ public:
+  explicit CanEncodeVisitor() : VisitorBase() {}
+
+  Status Bits(const size_t bits, const uint32_t /*default_value*/,
+              uint32_t* JXL_RESTRICT value) override {
+    size_t encoded_bits = 0;
+    ok_ &= BitsCoder::CanEncode(bits, *value, &encoded_bits);
+    encoded_bits_ += encoded_bits;
+    return true;
+  }
+
+  Status U32(const U32Enc enc, const uint32_t /*default_value*/,
+             uint32_t* JXL_RESTRICT value) override {
+    size_t encoded_bits = 0;
+    ok_ &= U32Coder::CanEncode(enc, *value, &encoded_bits);
+    encoded_bits_ += encoded_bits;
+    return true;
+  }
+
+  Status U64(const uint64_t /*default_value*/,
+             uint64_t* JXL_RESTRICT value) override {
+    size_t encoded_bits = 0;
+    ok_ &= U64Coder::CanEncode(*value, &encoded_bits);
+    encoded_bits_ += encoded_bits;
+    return true;
+  }
+
+  Status F16(const float /*default_value*/,
+             float* JXL_RESTRICT value) override {
+    size_t encoded_bits = 0;
+    ok_ &= F16Coder::CanEncode(*value, &encoded_bits);
+    encoded_bits_ += encoded_bits;
+    return true;
+  }
+
+  Status AllDefault(const Fields& fields,
+                    bool* JXL_RESTRICT all_default) override {
+    *all_default = Bundle::AllDefault(fields);
+    JXL_RETURN_IF_ERROR(Bool(true, all_default));
+    return *all_default;
+  }
+
+  Status BeginExtensions(uint64_t* JXL_RESTRICT extensions) override {
+    JXL_QUIET_RETURN_IF_ERROR(VisitorBase::BeginExtensions(extensions));
+    extensions_ = *extensions;
+    if (*extensions != 0) {
+      JXL_ASSERT(pos_after_ext_ == 0);
+      pos_after_ext_ = encoded_bits_;
+      JXL_ASSERT(pos_after_ext_ != 0);  // visited "extensions"
+    }
+    return true;
+  }
+  // EndExtensions = default.
+
+  Status GetSizes(size_t* JXL_RESTRICT extension_bits,
+                  size_t* JXL_RESTRICT total_bits) {
+    JXL_RETURN_IF_ERROR(ok_);
+    *extension_bits = 0;
+    *total_bits = encoded_bits_;
+    // Only if extension field was nonzero will we encode their sizes.
+    if (pos_after_ext_ != 0) {
+      JXL_ASSERT(encoded_bits_ >= pos_after_ext_);
+      *extension_bits = encoded_bits_ - pos_after_ext_;
+      // Also need to encode *extension_bits and bill it to *total_bits.
+      size_t encoded_bits = 0;
+      ok_ &= U64Coder::CanEncode(*extension_bits, &encoded_bits);
+      *total_bits += encoded_bits;
+
+      // TODO(janwas): support encoding individual extension sizes. We
+      // currently ascribe all bits to the first and send zeros for the
+      // others.
+      for (size_t i = 1; i < hwy::PopCount(extensions_); ++i) {
+        encoded_bits = 0;
+        ok_ &= U64Coder::CanEncode(0, &encoded_bits);
+        *total_bits += encoded_bits;
+      }
+    }
+    return true;
+  }
+
+ private:
+  bool ok_ = true;
+  size_t encoded_bits_ = 0;
+  uint64_t extensions_ = 0;
+  // Snapshot of encoded_bits_ after visiting the extension field, but NOT
+  // including the hidden extension sizes.
+  uint64_t pos_after_ext_ = 0;
+};
+}  // namespace
+
+void Bundle::Init(Fields* fields) {
+  InitVisitor visitor;
+  if (!visitor.Visit(fields)) {
+    JXL_ABORT("Init should never fail");
+  }
+}
+void Bundle::SetDefault(Fields* fields) {
+  SetDefaultVisitor visitor;
+  if (!visitor.Visit(fields)) {
+    JXL_ABORT("SetDefault should never fail");
+  }
+}
+bool Bundle::AllDefault(const Fields& fields) {
+  AllDefaultVisitor visitor;
+  if (!visitor.VisitConst(fields)) {
+    JXL_ABORT("AllDefault should never fail");
+  }
+  return visitor.AllDefault();
+}
+size_t Bundle::MaxBits(const Fields& fields) {
+  MaxBitsVisitor visitor;
+#if JXL_ENABLE_ASSERT
+  Status ret =
+#else
+  (void)
+#endif  // JXL_ENABLE_ASSERT
+      visitor.VisitConst(fields);
+  JXL_ASSERT(ret);
+  return visitor.MaxBits();
+}
+Status Bundle::CanEncode(const Fields& fields, size_t* extension_bits,
+                         size_t* total_bits) {
+  CanEncodeVisitor visitor;
+  JXL_QUIET_RETURN_IF_ERROR(visitor.VisitConst(fields));
+  JXL_QUIET_RETURN_IF_ERROR(visitor.GetSizes(extension_bits, total_bits));
+  return true;
+}
+Status Bundle::Read(BitReader* reader, Fields* fields) {
+  ReadVisitor visitor(reader);
+  JXL_RETURN_IF_ERROR(visitor.Visit(fields));
+  return visitor.OK();
+}
+bool Bundle::CanRead(BitReader* reader, Fields* fields) {
+  ReadVisitor visitor(reader);
+  Status status = visitor.Visit(fields);
+  // We are only checking here whether there are enough bytes. We still return
+  // true for other errors because it means there are enough bytes to determine
+  // there's an error. Use Read() to determine which error it is.
+  return status.code() != StatusCode::kNotEnoughBytes;
+}
+
+size_t BitsCoder::MaxEncodedBits(const size_t bits) { return bits; }
+
+Status BitsCoder::CanEncode(const size_t bits, const uint32_t value,
+                            size_t* JXL_RESTRICT encoded_bits) {
+  *encoded_bits = bits;
+  if (value >= (1ULL << bits)) {
+    return JXL_FAILURE("Value %u too large for %" PRIu64 " bits", value,
+                       static_cast<uint64_t>(bits));
+  }
+  return true;
+}
+
+uint32_t BitsCoder::Read(const size_t bits, BitReader* JXL_RESTRICT reader) {
+  return reader->ReadBits(bits);
+}
+
+size_t U32Coder::MaxEncodedBits(const U32Enc enc) {
+  size_t extra_bits = 0;
+  for (uint32_t selector = 0; selector < 4; ++selector) {
+    const U32Distr d = enc.GetDistr(selector);
+    if (d.IsDirect()) {
+      continue;
+    } else {
+      extra_bits = std::max<size_t>(extra_bits, d.ExtraBits());
+    }
+  }
+  return 2 + extra_bits;
+}
+
+Status U32Coder::CanEncode(const U32Enc enc, const uint32_t value,
+                           size_t* JXL_RESTRICT encoded_bits) {
+  uint32_t selector;
+  size_t total_bits;
+  const Status ok = ChooseSelector(enc, value, &selector, &total_bits);
+  *encoded_bits = ok ? total_bits : 0;
+  return ok;
+}
+
+uint32_t U32Coder::Read(const U32Enc enc, BitReader* JXL_RESTRICT reader) {
+  const uint32_t selector = reader->ReadFixedBits<2>();
+  const U32Distr d = enc.GetDistr(selector);
+  if (d.IsDirect()) {
+    return d.Direct();
+  } else {
+    return reader->ReadBits(d.ExtraBits()) + d.Offset();
+  }
+}
+
+Status U32Coder::ChooseSelector(const U32Enc enc, const uint32_t value,
+                                uint32_t* JXL_RESTRICT selector,
+                                size_t* JXL_RESTRICT total_bits) {
+#if JXL_ENABLE_ASSERT
+  const size_t bits_required = 32 - Num0BitsAboveMS1Bit(value);
+#endif  // JXL_ENABLE_ASSERT
+  JXL_ASSERT(bits_required <= 32);
+
+  *selector = 0;
+  *total_bits = 0;
+
+  // It is difficult to verify whether Dist32Byte are sorted, so check all
+  // selectors and keep the one with the fewest total_bits.
+  *total_bits = 64;  // more than any valid encoding
+  for (uint32_t s = 0; s < 4; ++s) {
+    const U32Distr d = enc.GetDistr(s);
+    if (d.IsDirect()) {
+      if (d.Direct() == value) {
+        *selector = s;
+        *total_bits = 2;
+        return true;  // Done, direct is always the best possible.
+      }
+      continue;
+    }
+    const size_t extra_bits = d.ExtraBits();
+    const uint32_t offset = d.Offset();
+    if (value < offset || value >= offset + (1ULL << extra_bits)) continue;
+
+    // Better than prior encoding, remember it:
+    if (2 + extra_bits < *total_bits) {
+      *selector = s;
+      *total_bits = 2 + extra_bits;
+    }
+  }
+
+  if (*total_bits == 64) {
+    return JXL_FAILURE("No feasible selector for %u", value);
+  }
+
+  return true;
+}
+
+uint64_t U64Coder::Read(BitReader* JXL_RESTRICT reader) {
+  uint64_t selector = reader->ReadFixedBits<2>();
+  if (selector == 0) {
+    return 0;
+  }
+  if (selector == 1) {
+    return 1 + reader->ReadFixedBits<4>();
+  }
+  if (selector == 2) {
+    return 17 + reader->ReadFixedBits<8>();
+  }
+
+  // selector 3, varint, groups have first 12, then 8, and last 4 bits.
+  uint64_t result = reader->ReadFixedBits<12>();
+
+  uint64_t shift = 12;
+  while (reader->ReadFixedBits<1>()) {
+    if (shift == 60) {
+      result |= static_cast<uint64_t>(reader->ReadFixedBits<4>()) << shift;
+      break;
+    }
+    result |= static_cast<uint64_t>(reader->ReadFixedBits<8>()) << shift;
+    shift += 8;
+  }
+
+  return result;
+}
+
+// Can always encode, but useful because it also returns bit size.
+Status U64Coder::CanEncode(uint64_t value, size_t* JXL_RESTRICT encoded_bits) {
+  if (value == 0) {
+    *encoded_bits = 2;  // 2 selector bits
+  } else if (value <= 16) {
+    *encoded_bits = 2 + 4;  // 2 selector bits + 4 payload bits
+  } else if (value <= 272) {
+    *encoded_bits = 2 + 8;  // 2 selector bits + 8 payload bits
+  } else {
+    *encoded_bits = 2 + 12;  // 2 selector bits + 12 payload bits
+    value >>= 12;
+    int shift = 12;
+    while (value > 0 && shift < 60) {
+      *encoded_bits += 1 + 8;  // 1 continuation bit + 8 payload bits
+      value >>= 8;
+      shift += 8;
+    }
+    if (value > 0) {
+      // This only could happen if shift == N - 4.
+      *encoded_bits += 1 + 4;  // 1 continuation bit + 4 payload bits
+    } else {
+      *encoded_bits += 1;  // 1 stop bit
+    }
+  }
+
+  return true;
+}
+
+Status F16Coder::Read(BitReader* JXL_RESTRICT reader,
+                      float* JXL_RESTRICT value) {
+  const uint32_t bits16 = reader->ReadFixedBits<16>();
+  const uint32_t sign = bits16 >> 15;
+  const uint32_t biased_exp = (bits16 >> 10) & 0x1F;
+  const uint32_t mantissa = bits16 & 0x3FF;
+
+  if (JXL_UNLIKELY(biased_exp == 31)) {
+    return JXL_FAILURE("F16 infinity or NaN are not supported");
+  }
+
+  // Subnormal or zero
+  if (JXL_UNLIKELY(biased_exp == 0)) {
+    *value = (1.0f / 16384) * (mantissa * (1.0f / 1024));
+    if (sign) *value = -*value;
+    return true;
+  }
+
+  // Normalized: convert the representation directly (faster than ldexp/tables).
+  const uint32_t biased_exp32 = biased_exp + (127 - 15);
+  const uint32_t mantissa32 = mantissa << (23 - 10);
+  const uint32_t bits32 = (sign << 31) | (biased_exp32 << 23) | mantissa32;
+  memcpy(value, &bits32, sizeof(bits32));
+  return true;
+}
+
+Status F16Coder::CanEncode(float value, size_t* JXL_RESTRICT encoded_bits) {
+  *encoded_bits = MaxEncodedBits();
+  if (std::isnan(value) || std::isinf(value)) {
+    return JXL_FAILURE("Should not attempt to store NaN and infinity");
+  }
+  return std::abs(value) <= 65504.0f;
+}
+
+}  // namespace jxl