pg_tre third-party components
=============================

This extension statically links and ships components with their own
licenses. Their terms apply to the corresponding parts of the binary
distribution.

1. TRE (approximate regex library)
   ---------------------------------
   Vendored at vendor/tre as a git submodule.
   Upstream: https://github.com/laurikari/tre (pinned to tag v0.9.0).
   License: BSD 2-clause (see vendor/tre/LICENSE).
   Role: used as the approximate-match recheck engine. Statically linked
   into pg_tre.so.

2. Lime (parser generator)
   -------------------------
   Vendored at vendor/lime as a git submodule.
   Upstream: https://codeberg.org/gregburd/lime.
   License: Public Domain (Lemon lineage; see vendor/lime/README.md).
   Role: build-time code generator only. Lime itself is NOT linked into
   pg_tre.so; only the C code it emits from src/query/tre_grammar.y is
   compiled in, and that code is under the pg_tre MIT license.

3. sparsemap (compressed bitmap)
   -----------------------------
   Upstream: https://codeberg.org/gregburd/sparsemap
   Source files src/util/sparsemap.c / include/pg_tre/sparsemap.h
   are vendored into the pg_tre tree (with adjusted include paths).
   License: MIT (see the header of sparsemap.h).
   Role: in-tree bitmap primitive used by posting trees, pending lists,
   and range summaries. Statically linked into pg_tre.so.

Summary for redistributors:
  The combined binary pg_tre.so contains code under MIT (pg_tre core and
  sparsemap), BSD 2-clause (TRE), and PostgreSQL license (PG headers).
  All terms are redistribution-friendly; see each component's LICENSE
  file for exact wording.