initial import of aequitas code

.clang-format

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+---
+Cpp11BracedListStyle: 'false'
+SpaceBeforeParens: ControlStatements
+SpaceInEmptyParentheses: 'true'
+SpacesInSquareBrackets: 'true'
+UseTab: Never
+AlignConsecutiveAssignments: 'true'
+
+
+...

.github/workflows/build_and_test.yml

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+name: Aequitas Build and Test
+on:
+  push:
+  pull_request:
+jobs:
+  build-and-test:
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+        version: [REL_14_STABLE, REL_15_STABLE, REL_16_STABLE]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Test details
+        run: echo Build and test Aequitas on ${{ matrix.os }} with PostgreSQL ${{ matrix.version }} branch
+
+      - name: Checkout and build PostgreSQL code
+        run: |
+          sudo apt-get update -qq
+          sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9
+          sudo apt-get install -y build-essential libreadline-dev zlib1g-dev flex bison libxml2-dev libxslt-dev libssl-dev libxml2-utils xsltproc ccache pkg-config libc++-dev libc++abi-dev libglib2.0-dev libtinfo5 cmake libstdc++-12-dev
+          rm -rf postgres
+          git clone --branch ${{ matrix.version }} --single-branch --depth 1 https://github.com/postgres/postgres.git
+          pushd postgres
+          git branch
+          ./configure --prefix=$PWD/inst/  --enable-cassert --enable-debug --with-openssl
+          make -j4 install
+
+      - name: Start Postgres
+        run: |
+          pushd postgres
+          cd inst/bin
+          ./initdb -D data
+          ./pg_ctl -D data -l logfile start
+          popd
+
+      - name: Checkout aequitas extension code
+        uses: actions/checkout@v2
+        with:
+          path: aequitas
+
+      - name: Build and test aequitas extension
+        id: regression-tests
+        run: |
+          export PATH="${PWD}/postgres/inst/bin:$PATH"
+          pushd aequitas
+          make install
+          make installcheck
+          popd
+
+      - name: Print regression.diffs if regression tests failed
+        if: failure() && steps.regression-tests.outcome != 'success'
+        run: |
+          cat aequitas/regression.diffs

.gitignore

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+*.so
+*.o
+.clangd
+
+results
+

LICENSE

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+Copyright (c) 2024, Hydra Inc
+
+Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and this paragraph and the following two paragraphs appear in all copies.
+
+IN NO EVENT SHALL Hydra Inc BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF Hydra Inc HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+Hydra Inc SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN “AS IS” BASIS, AND Hydra Inc HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+
+Some parts of this code is Copyright (c) 2008-2016, Wojciech Muła.

Makefile

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+.PHONY: lintcheck
+
+SRCS = src/text.cpp
+OBJS = $(subst .cpp,.o, $(SRCS))
+
+MODULE_big = aequitas
+
+PG_CPPFLAGS = -O3 -std=c++17 -I src/sse -g
+
+UNAME_S := $(shell uname -m)
+ifeq ($(UNAME_S),arm64)
+	PG_CPPFLAGS += -stdlib=libc++ -DHAVE_NEON_INSTRUCTIONS=1
+endif
+ifeq ($(UNAME_S),arm64)
+	PG_CPPFLAGS += -stdlib=libc++ -DHAVE_NEON_INSTRUCTIONS=1
+endif
+ifeq ($(UNAME_S),x86_64)
+	SHLIB_LINK += -lrt -std=c++17 -msse4.2
+	PG_CPPFLAGS += -msse4.2
+endif
+
+EXTENSION = aequitas
+DATA = aequitas--1.0.0.sql
+PGFILEDESC = "Aequitas - tools for testing equality"
+
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+
+REGRESS = equality strstr
+
+include $(PGXS)
+
+lintcheck:
+	clang-tidy $(SRCS) -- -I$(INCLUDEDIR) -I$(INCLUDEDIR_SERVER) -I$(PWD)/include -std=c++17

README.md

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+# Aequitas - Text Comparison for PostgreSQL
+
+Aequitas is an extension for PostgreSQL that provides string comparisons using SSE4.2 on x86_64 platforms, and SWAR64 on aarch64 and arm64 platforms.
+
+## Usage
+
+After installation:
+
+```sql
+CREATE EXTENSION aequitas;
+```
+
+This will create a `schema` called aequitas that contains the comparison functions:
+
+`aequitas.equals(a TEXT, b TEXT)` - returns `BOOLEAN`, `true` if there is an exact match, and `false` if there is not.
+
+`aequitas.strstr(haystack TEXT, needle TEXT)` - returns `INTEGER`, the position of where the needle is found in the haystack, or `-1` if it is not found.

aequitas--1.0.0.sql

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+CREATE SCHEMA IF NOT EXISTS aequitas;
+
+CREATE OR REPLACE FUNCTION aequitas.strstr(left TEXT, right TEXT)
+  RETURNS INTEGER
+  AS 'MODULE_PATHNAME', 'pg_strstr'
+  LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;
+
+CREATE OR REPLACE FUNCTION aequitas.equals(left TEXT, right TEXT)
+  RETURNS BOOLEAN
+  AS 'MODULE_PATHNAME', 'pg_equals'
+  LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;

aequitas.control

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+# compare extension
+comment = 'tools for comparing strings'
+default_version = '1.0.0'
+module_pathname = '$libdir/aequitas'
+relocatable = true

expected/equality.out

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+CREATE EXTENSION aequitas;
+-- no match
+SELECT aequitas.equals('hello', 'world');
+ equals 
+--------
+ f
+(1 row)
+
+-- match
+SELECT aequitas.equals('hello', 'hello');
+ equals 
+--------
+ t
+(1 row)
+
+-- match on a 16 byte boundary
+SELECT aequitas.equals('1234567890123456', '1234567890123456');
+ equals 
+--------
+ t
+(1 row)
+
+-- no match when partial
+SELECT aequitas.equals('123456', '12345');
+ equals 
+--------
+ f
+(1 row)
+

expected/strstr.out

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+CREATE EXTENSION aequitas;
+ERROR:  extension "aequitas" already exists
+-- no match
+SELECT aequitas.strstr('hello', 'world');
+ strstr 
+--------
+     -1
+(1 row)
+
+-- match with 0
+SELECT aequitas.strstr('hello', 'hello');
+ strstr 
+--------
+      0
+(1 row)
+
+-- match on a 16 byte boundary
+SELECT aequitas.strstr('1234567890123456', '1234567890123456');
+ strstr 
+--------
+      0
+(1 row)
+
+-- match when partial
+SELECT aequitas.strstr('123456', '12345');
+ strstr 
+--------
+      0
+(1 row)
+
+-- needle found in haystack
+SELECT aequitas.strstr('hello world', 'ello');
+ strstr 
+--------
+      1
+(1 row)
+
+-- haystack in needle not found
+SELECT aequitas.strstr('ello', 'hello world');
+ strstr 
+--------
+     -1
+(1 row)
+

sql/equality.sql

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+CREATE EXTENSION aequitas;
+
+-- no match
+SELECT aequitas.equals('hello', 'world');
+
+-- match
+SELECT aequitas.equals('hello', 'hello');
+
+-- match on a 16 byte boundary
+SELECT aequitas.equals('1234567890123456', '1234567890123456');
+
+-- no match when partial
+SELECT aequitas.equals('123456', '12345');

sql/strstr.sql

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+CREATE EXTENSION aequitas;
+
+-- no match
+SELECT aequitas.strstr('hello', 'world');
+
+-- match with 0
+SELECT aequitas.strstr('hello', 'hello');
+
+-- match on a 16 byte boundary
+SELECT aequitas.strstr('1234567890123456', '1234567890123456');
+
+-- match when partial
+SELECT aequitas.strstr('123456', '12345');
+
+-- needle found in haystack
+SELECT aequitas.strstr('hello world', 'ello');
+
+-- haystack in needle not found
+SELECT aequitas.strstr('ello', 'hello world');

src/sse/LICENSE

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+Copyright (c) 2008-2016, Wojciech Muła
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

src/sse/common.h

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+#pragma once
+
+#define FORCE_INLINE inline __attribute__((always_inline))
+#define MAYBE_UNUSED inline __attribute__((unused))
+
+#if defined(HAVE_NEON_INSTRUCTIONS)
+#   include <arm_neon.h>
+#   define USE_SIMPLE_MEMCMP // for fixed-memcmp.cpp
+#else
+#   include <immintrin.h>
+#endif