third_party/s2cellid/README.chromium

Name: S2 CellId Library
Short Name: s2cellid
URL: 0
Version: 0
License: License: Apache Version 2.0
License File: NOT_SHIPPED
Security Critical: no
License Android Compatible: yes

Description:
This library extracted the core S2CellId functions from the S2 geometry
library.

Local Modifications:
- Extract subset of the whole s2 library, including only:
 - util/bits/bits.h
 - math/
   - mathutil.h mathutil.cc
   - vector.h
 - _fpcontractoff.h
 - r1interval.h
 - r2.h
 - r2rect.h r2rect.cc
 - s1angle.h s1angle.cc
 - s2cellid.h s2cellid.cc
 - s2coords.h s2coords.cc s2coords-internal.cc
 - s2latlng.h s2latlng.cc
 - s2point.h
- Extract functions under util/bits/bits.h:
 - Log2Floor*
 - FindLSBSetNonZero*
 - FindMSBSetNonZero*
 - Remove all uint128 declaration and implementation.
 - Remove corresponding comments.
 - Remove unnecessary dependencies.
 - Add Log2Floor_Portable impl.
 - Add FindLSBSetNonZero_Portable impl.
- Remove absl dependency:
  - Change uint8 -> uint8_t
  - Change uint16 -> uint16_t
  - Change uint32 -> uint32_t
  - Change uint64 -> uint64_t
  - Change int32 -> int32_t
  - Change int64 -> int64
  - Change GG_ULONGLONG -> static_cast<uint64_t>
  - Remove absl/base/macros.h and use chromium base/macros.h
- Change glog to use chromium base/logging.h
- Remove s2/base/strings/stringprintf.h to use chromium base/strings/stringprintf.h
- Remove base/casts.h and change implicit_cast to static_cast.
- Append std:: to string type.
- Under s2cellid:
  - Remove Encode declaration and implementation.
  - Remove Decode declaration and implementation.
  - Remove util/coding/coder.h dependency.
  - Change StringPrintf format from "Invalid: %016llx" to "Invalid: %016" PRIu64.
  - Disable 4146 warning on Windows (unary minus operator applied to unsigned type).
  - Disable 4018 warning on Windows ('<' : signed/unsigned mismatch).
- Under s2point.h
  - Remove s2/util/math/vector3_hash.h
  - Remove S2PointHash and comments.
- Under s1angle.h
  - Add _USE_MATH_DEFINES macro for _WIN32
- Add BUILD.gn file.
- Add DEPS file.
- Remove CMakeList.txt file.
- Remove CONTRIBUTING.md.
- Remove README.md.
- Remove docs.
- Remove ATTRIBUTE_PACKED.