Index: .efiles
==================================================================
--- .efiles
+++ .efiles
@@ -3,5 +3,6 @@
 www/index.md
 www/changelog.md
 src/lib.rs
 src/hashing.rs
 src/text.rs
+src/transcode.rs

Index: Cargo.toml
==================================================================
--- Cargo.toml
+++ Cargo.toml
@@ -1,8 +1,8 @@
 [package]
 name = "sqlfuncs"
-version = "0.1.0"
+version = "0.1.1"
 edition = "2021"
 license = "0BSD"
 # https://crates.io/category_slugs
 categories = [ "database" ]
 keywords = [ "sqlite", "rusqlite", "functions" ]
@@ -22,10 +22,11 @@
 [badges]
 maintenance = { status = "actively-developed" }
 
 [dependencies]
 digest = { version = "0.10.7" }
+hex = { version = "0.4.3" }
 orphanage = { version = "0.1.4" }
 rusqlite = { version = "0.34.0", features = ["functions"] }
 sha2 = { version = "0.10.8" }
 sha3 = { version = "0.10.8" }
 

Index: src/hashing.rs
==================================================================
--- src/hashing.rs
+++ src/hashing.rs
@@ -4,11 +4,11 @@
 //! `sha2/224`, `sha2/256`, `sha2/384`, `sha2/512`, `sha3/224`, `sha3/256`,
 //! `sha3/384`, `sha3/512`
 
 use digest::Digest;
 
-use rusqlite::{functions::FunctionFlags, Connection, Error};
+use rusqlite::{Connection, Error, functions::FunctionFlags};
 
 
 fn mkhasher(algo: &str) -> Result<Box<dyn digest::DynDigest>, Error> {
   match algo {
     "sha2/224" => Ok(Box::new(sha2::Sha224::new())),
@@ -47,10 +47,15 @@
 ///     row.get(0)
 ///   }
 ///   ).unwrap();
 /// assert_eq!(&hstr[..8], "09ca7e4e");
 /// ```
+///
+/// ## SQLite function properties
+/// - Deterministic
+/// - Innocuous
+/// - UTF8
 #[allow(clippy::missing_errors_doc)]
 pub fn hashstr(conn: &Connection) -> Result<(), Error> {
   conn.create_scalar_function(
     "hashstr",
     2,
@@ -94,10 +99,15 @@
 ///     row.get(0)
 ///   }
 ///   ).unwrap();
 /// assert_eq!(&hstr[..8], "09ca7e4e");
 /// ```
+///
+/// ## SQLite function properties
+/// - Deterministic
+/// - Innocuous
+/// - UTF8
 #[allow(clippy::missing_errors_doc)]
 pub fn hashblob(conn: &Connection) -> Result<(), Error> {
   conn.create_scalar_function(
     "hashblob",
     2,

Index: src/lib.rs
==================================================================
--- src/lib.rs
+++ src/lib.rs
@@ -1,6 +1,7 @@
 //! Collection of scalar functions for use with SQLite through rusqlite.
 
 pub mod hashing;
 pub mod text;
+pub mod transcode;
 
 // vim: set ft=rust et sw=2 ts=2 sts=2 cinoptions=2 tw=79 :

Index: src/text.rs
==================================================================
--- src/text.rs
+++ src/text.rs
@@ -1,10 +1,10 @@
 //! A collection of functions intended to work with text strings.
 
-use rusqlite::{functions::FunctionFlags, Connection, Error};
+use rusqlite::{Connection, Error, functions::FunctionFlags};
 
-use orphanage::strx::{validate_objname, RndStr};
+use orphanage::strx::{RndStr, validate_objname};
 
 
 /// Add a `randomstr()` SQL function to the connection object.
 ///
 /// The SQL function `randomstr()` takes a single argument:
@@ -25,10 +25,14 @@
 ///   id   INTEGER PRIMARY KEY,
 ///   salt TEXT NOT NULL DEFAULT (randomstr(8))
 /// );
 /// "#, []);
 /// ```
+///
+/// ## SQLite function properties
+/// - Innocuous
+/// - UTF8
 #[allow(clippy::missing_errors_doc)]
 pub fn rndstr_alphanum(db: &Connection) -> Result<(), Error> {
   db.create_scalar_function(
     "randomstr",
     1,
@@ -64,10 +68,14 @@
 ///   id   INTEGER PRIMARY KEY,
 ///   salt TEXT NOT NULL DEFAULT (randomstr(8, "abcdefABCD123456"))
 /// );
 /// "#, []);
 /// ```
+///
+/// ## SQLite function properties
+/// - Innocuous
+/// - UTF8
 #[allow(clippy::missing_errors_doc)]
 pub fn rndstr(db: &Connection) -> Result<(), Error> {
   db.create_scalar_function(
     "randomstr",
     2,
@@ -102,10 +110,15 @@
 ///   name TEXT UNIQUE NOT NULL,
 ///   CHECK (isobjname(name) == 1)
 /// );
 /// "#, []);
 /// ```
+///
+/// ## SQLite function properties
+/// - Deterministic
+/// - Innocuous
+/// - UTF8
 ///
 /// # Panics
 /// The number of input parameters must be exactly 1.
 #[allow(clippy::missing_errors_doc)]
 pub fn isobjname(conn: &Connection) -> Result<(), Error> {

ADDED   src/transcode.rs
Index: src/transcode.rs
==================================================================
--- /dev/null
+++ src/transcode.rs
@@ -0,0 +1,47 @@
+//! Functions for transcoding data.
+
+use rusqlite::{Connection, Error, functions::FunctionFlags};
+
+/// Decode a hex encoded string
+///
+/// The SQL function `dehex()` takes a single argument:
+/// 1. The input hex string.
+///
+/// Its output will be a blob of the decoded data.
+///
+/// ```
+/// use rusqlite::Connection;
+/// use sqlfuncs::transcode::dehex;
+///
+/// let conn = Connection::open_in_memory().unwrap();
+/// dehex(&conn).unwrap();
+/// let instr = "48656c6c6f20776f726c6421";
+/// let buf: Vec<u8> = conn.query_row_and_then(
+///   "SELECT dehex(?);", [instr], |row| {
+///     row.get(0)
+///   }).unwrap();
+/// assert_eq!(buf, "Hello world!".to_owned().into_bytes());
+/// ```
+///
+/// ## SQLite function properties
+/// - Deterministic
+/// - Innocuous
+/// - UTF8
+#[allow(clippy::missing_errors_doc)]
+pub fn dehex(db: &Connection) -> Result<(), Error> {
+  db.create_scalar_function(
+    "dehex",
+    1,
+    FunctionFlags::SQLITE_UTF8
+      | FunctionFlags::SQLITE_INNOCUOUS
+      | FunctionFlags::SQLITE_DETERMINISTIC,
+    move |ctx| {
+      let hex_input = ctx.get::<String>(0)?;
+      let buf = hex::decode(hex_input)
+        .map_err(|_| Error::UserFunctionError("Invalid hex".into()))?;
+      Ok(buf)
+    }
+  )
+}
+
+// vim: set ft=rust et sw=2 ts=2 sts=2 cinoptions=2 tw=79 :

Index: www/changelog.md
==================================================================
--- www/changelog.md
+++ www/changelog.md
@@ -3,10 +3,12 @@
 ## [Unreleased]
 
 [Details](/vdiff?from=sqlfuncs-0.1.0&to=trunk)
 
 ### Added
+
+- Add `transcode` module with `dehex()` sql function.
 
 ### Changed
 
 ### Removed