From 45609cdcc415a847558e31fb383ac1258a3e71af Mon Sep 17 00:00:00 2001
From: Hayleigh Thompson <me@hayleigh.dev>
Date: Sat, 25 Jul 2026 22:55:01 +0200
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20Add=20a=20'validate'=20function=20t?=
 =?UTF-8?q?o=20check=20if=20an=20input=20string=20is=20valid=20base32.?=
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---
 src/at/internal/base32.gleam | 60 ++++++++++++++++++++++++++++++++++--
 1 file changed, 58 insertions(+), 2 deletions(-)

diff --git a/src/at/internal/base32.gleam b/src/at/internal/base32.gleam
index 1b26c0e..ff58316 100644
--- a/src/at/internal/base32.gleam
+++ b/src/at/internal/base32.gleam
@@ -1,5 +1,7 @@
-// DECODING --------------------------------------------------------------------
+// CONSTRUCTORS ----------------------------------------------------------------
 
+///
+/// 
 pub fn decode(value: String) -> Result(BitArray, Nil) {
   do_decode(value, <<>>, 0)
 }
@@ -82,7 +84,61 @@ fn finish_decode_base32(
   }
 }
 
-// ENCODING --------------------------------------------------------------------
+// QUERIES ---------------------------------------------------------------------
+
+/// 
+/// 
+pub fn validate(input: String) -> Bool {
+  case input {
+    "a" <> rest
+    | "b" <> rest
+    | "c" <> rest
+    | "d" <> rest
+    | "e" <> rest
+    | "f" <> rest
+    | "g" <> rest
+    | "h" <> rest
+    | "i" <> rest
+    | "j" <> rest
+    | "k" <> rest
+    | "l" <> rest
+    | "m" <> rest
+    | "n" <> rest
+    | "o" <> rest
+    | "p" <> rest
+    | "q" <> rest
+    | "r" <> rest
+    | "s" <> rest
+    | "t" <> rest
+    | "u" <> rest
+    | "v" <> rest
+    | "w" <> rest
+    | "x" <> rest
+    | "y" <> rest
+    | "z" <> rest
+    | "2" <> rest
+    | "3" <> rest
+    | "4" <> rest
+    | "5" <> rest
+    | "6" <> rest
+    | "7" <> rest -> validate(rest)
+
+    "=" <> rest -> validate_padding(rest)
+    "" -> True
+
+    _ -> False
+  }
+}
+
+fn validate_padding(input: String) -> Bool {
+  case input {
+    "" -> True
+    "=" <> rest -> validate_padding(rest)
+    _ -> False
+  }
+}
+
+// CONVERSIONS -----------------------------------------------------------------
 
 pub fn encode(bits: BitArray, pad: Bool) -> String {
   do_encode(bits, "", 0, pad)
-- 
2.51.2