Add first evr extension files (#1)

Makefile

@@ -0,0 +1,6 @@
+EXTENSION = evr
+DATA = evr--0.0.1.sql
+
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)

evr--0.0.1.sql

@@ -0,0 +1,125 @@
+\echo Use "CREATE EXTENSION evr" to load this file. \quit
+
+create type evr_array_item as (
+  n       NUMERIC,
+  s       TEXT
+);
+
+create type evr_t as (
+  epoch INT,
+  version evr_array_item[],
+  release evr_array_item[]
+);
+
+CREATE FUNCTION evr_trigger() RETURNS trigger AS $$
+  BEGIN
+    NEW.evr = (select ROW(coalesce(NEW.epoch::numeric,0),
+                          rpmver_array(coalesce(NEW.version,'empty'))::evr_array_item[],
+                          rpmver_array(coalesce(NEW.release,'empty'))::evr_array_item[])::evr_t);
+    RETURN NEW;
+  END;
+$$ language 'plpgsql';
+
+create or replace FUNCTION empty(t TEXT)
+	RETURNS BOOLEAN as $$
+	BEGIN
+		return t ~ '^[[:space:]]*$';
+	END;
+$$ language 'plpgsql';
+
+create or replace FUNCTION isalpha(ch CHAR)
+  RETURNS BOOLEAN as $$
+  BEGIN
+    if ascii(ch) between ascii('a') and ascii('z') or
+        ascii(ch) between ascii('A') and ascii('Z')
+    then
+      return TRUE;
+    end if;
+    return FALSE;
+  END;
+$$ language 'plpgsql';
+
+create or replace FUNCTION isalphanum(ch CHAR)
+	RETURNS BOOLEAN as $$
+	BEGIN
+		if ascii(ch) between ascii('a') and ascii('z') or
+			ascii(ch) between ascii('A') and ascii('Z') or
+			ascii(ch) between ascii('0') and ascii('9')
+		then
+			return TRUE;
+		end if;
+		return FALSE;
+	END;
+$$ language 'plpgsql';
+
+create or replace function isdigit(ch CHAR)
+	RETURNS BOOLEAN as $$
+	BEGIN
+	  if ascii(ch) between ascii('0') and ascii('9')
+	  then
+		return TRUE;
+	  end if;
+	  return FALSE;
+	END ;
+$$ language 'plpgsql';
+
+create or replace FUNCTION rpmver_array (string1 IN VARCHAR)
+	RETURNS evr_array_item[] as $$
+	declare
+		str1 VARCHAR := string1;
+		digits VARCHAR(10) := '0123456789';
+		lc_alpha VARCHAR(27) := 'abcdefghijklmnopqrstuvwxyz';
+		uc_alpha VARCHAR(27) := 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
+		alpha VARCHAR(54) := lc_alpha || uc_alpha;
+		one VARCHAR;
+		isnum BOOLEAN;
+		ver_array evr_array_item[] := ARRAY[]::evr_array_item[];
+	BEGIN
+		if str1 is NULL
+		then
+			RAISE EXCEPTION 'VALUE_ERROR.';
+		end if;
+
+		one := str1;
+		<<segment_loop>>
+		while one <> ''
+		loop
+			declare
+				segm1 VARCHAR;
+				segm1_n NUMERIC := 0;
+			begin
+				-- Throw out all non-alphanum characters
+				while one <> '' and not isalphanum(one)
+				loop
+					one := substr(one, 2);
+				end loop;
+				str1 := one;
+				if str1 <> '' and isdigit(str1)
+				then
+					str1 := ltrim(str1, digits);
+					isnum := true;
+				else
+					str1 := ltrim(str1, alpha);
+					isnum := false;
+				end if;
+				if str1 <> ''
+				then segm1 := substr(one, 1, length(one) - length(str1));
+				else segm1 := one;
+				end if;
+
+				if segm1 = '' then return ver_array; end if; /* arbitrary */
+				if isnum
+				then
+					segm1 := ltrim(segm1, '0');
+					if segm1 <> '' then segm1_n := segm1::numeric; end if;
+					segm1 := NULL;
+				else
+				end if;
+				ver_array := array_append(ver_array, (segm1_n, segm1)::evr_array_item);
+				one := str1;
+			end;
+		end loop segment_loop;
+
+		return ver_array;
+	END ;
+$$ language 'plpgsql';

evr.control

@@ -0,0 +1,4 @@
+# evr extension
+comment = 'evr datatype'
+default_version = '0.0.1'
+relocatable=true