From 1aaae51eab737f05768487253dfcc2ebb95de887 Mon Sep 17 00:00:00 2001
From: Tau <tau@nowhere>
Date: Tue, 28 May 2019 15:35:33 -0400
Subject: [PATCH] Add ID generation sprocs for manual db interventions

---
 schema/init/meta.sql                      |  2 +-
 schema/init/util.sql                      | 81 +++++++++++++++++++++++
 schema/migrate/M0001-add-helper-funcs.sql | 81 +++++++++++++++++++++++
 3 files changed, 163 insertions(+), 1 deletion(-)
 create mode 100644 schema/init/util.sql
 create mode 100644 schema/migrate/M0001-add-helper-funcs.sql

diff --git a/schema/init/meta.sql b/schema/init/meta.sql
index 141bfe2..1cb26df 100644
--- a/schema/init/meta.sql
+++ b/schema/init/meta.sql
@@ -1,2 +1,2 @@
 create table "meta" ("schemaver" integer not null);
-insert into "meta" values (0);
+insert into "meta" values (1);
diff --git a/schema/init/util.sql b/schema/init/util.sql
new file mode 100644
index 0000000..7302f4b
--- /dev/null
+++ b/schema/init/util.sql
@@ -0,0 +1,81 @@
+-- Helper functions which might be useful in one-off queries.
+-- These are not utilised by any services; those have their own ID generators.
+
+create or replace function idnum(
+    str         text)
+    returns     bigint as $$
+declare
+    num         bigint;
+    x           integer;
+begin
+    num := 0;
+
+    for i in 1..11 loop
+        x := ascii(substr(str, i, 1));
+        num := num << 6;
+
+        if x >= 65 and x <= 90 then
+            -- A to Z
+            num = num | (x - 65);
+        elsif x >= 97 and x <= 122 then
+            -- a to z
+            num = num | (x - 71);
+        elsif x >= 48 and x <= 58 then
+            -- 0 to 9
+            num = num | (x + 4);
+        elsif x = 45 then
+            -- Dash
+            num = num | 62;
+        elsif x = 95 then
+            -- Underscore
+            num = num | 63;
+        else
+            raise 'Bad input';
+        end if;
+    end loop;
+
+    return num;
+end;
+$$ language plpgsql;
+
+create or replace function idstr(
+    num         bigint)
+    returns     text as $$
+declare
+    a           text;
+    pos         integer;
+    str         text;
+begin
+    a := 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_';
+    str := '';
+
+    for i in 1..11 loop
+        pos := (num & 63);
+        str := substr(a, pos + 1, 1) || str;
+        num := num >> 6;
+    end loop;
+
+    return str;
+end;
+$$ language plpgsql;
+
+create or replace function newid()
+    returns     bigint as $$
+declare
+    bytes       bytea;
+    result      bigint;
+begin
+    bytes := gen_random_bytes(8);
+    result := 0;
+
+    for i in 0..7 loop
+        result := (result << 8) | get_byte(bytes, i);
+    end loop;
+
+    -- Truncate high bit to ensure result is positive
+    -- This value is just the decimal representation of 0x7FFFFFFF`FFFFFFFF.
+
+    return result & 9223372036854775807;
+end;
+$$ language plpgsql;
+
diff --git a/schema/migrate/M0001-add-helper-funcs.sql b/schema/migrate/M0001-add-helper-funcs.sql
new file mode 100644
index 0000000..7302f4b
--- /dev/null
+++ b/schema/migrate/M0001-add-helper-funcs.sql
@@ -0,0 +1,81 @@
+-- Helper functions which might be useful in one-off queries.
+-- These are not utilised by any services; those have their own ID generators.
+
+create or replace function idnum(
+    str         text)
+    returns     bigint as $$
+declare
+    num         bigint;
+    x           integer;
+begin
+    num := 0;
+
+    for i in 1..11 loop
+        x := ascii(substr(str, i, 1));
+        num := num << 6;
+
+        if x >= 65 and x <= 90 then
+            -- A to Z
+            num = num | (x - 65);
+        elsif x >= 97 and x <= 122 then
+            -- a to z
+            num = num | (x - 71);
+        elsif x >= 48 and x <= 58 then
+            -- 0 to 9
+            num = num | (x + 4);
+        elsif x = 45 then
+            -- Dash
+            num = num | 62;
+        elsif x = 95 then
+            -- Underscore
+            num = num | 63;
+        else
+            raise 'Bad input';
+        end if;
+    end loop;
+
+    return num;
+end;
+$$ language plpgsql;
+
+create or replace function idstr(
+    num         bigint)
+    returns     text as $$
+declare
+    a           text;
+    pos         integer;
+    str         text;
+begin
+    a := 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_';
+    str := '';
+
+    for i in 1..11 loop
+        pos := (num & 63);
+        str := substr(a, pos + 1, 1) || str;
+        num := num >> 6;
+    end loop;
+
+    return str;
+end;
+$$ language plpgsql;
+
+create or replace function newid()
+    returns     bigint as $$
+declare
+    bytes       bytea;
+    result      bigint;
+begin
+    bytes := gen_random_bytes(8);
+    result := 0;
+
+    for i in 0..7 loop
+        result := (result << 8) | get_byte(bytes, i);
+    end loop;
+
+    -- Truncate high bit to ensure result is positive
+    -- This value is just the decimal representation of 0x7FFFFFFF`FFFFFFFF.
+
+    return result & 9223372036854775807;
+end;
+$$ language plpgsql;
+