encoding/base32: Add custom validation support

Add support for custom alphabet validation through an optional validation
function parameter. The default validation follows RFC 4648 base32
alphabet rules (A-Z, 2-7).

This properly supports the documented ability to use custom alphabets.

1 files changed, 16 insertions, 5 deletions

diff --git a/core/encoding/base32/base32.odin b/core/encoding/base32/base32.odin
index 68b8b7a5e..7c70b7e9a 100644
--- a/core/encoding/base32/base32.odin
+++ b/core/encoding/base32/base32.odin
@@ -7,18 +7,25 @@ import "core:bytes"
 // A secondary param can be used to supply a custom alphabet to

 // @link(encode) and a matching decoding table to @link(decode).

 // If none is supplied it just uses the standard Base32 alphabet.

-// Incase your specific version does not use padding, you may

+// In case your specific version does not use padding, you may

 // truncate it from the encoded output.

 

 // Error represents errors that can occur during base32 decoding operations.

 // See RFC 4648 sections 3.2, 4 and 6.

 Error :: enum {

 	None,

-	Invalid_Character, // Input contains characters outside of base32 alphabet (A-Z, 2-7)

+	Invalid_Character, // Input contains characters outside the specified alphabet

 	Invalid_Length,    // Input length is not valid for base32 (must be a multiple of 8 with proper padding)

 	Malformed_Input,   // Input has improper structure (wrong padding position or incomplete groups)

 }

 

+Validate_Proc :: #type proc(c: byte) -> bool

+

+@private

+_validate_default :: proc(c: byte) -> bool {

+	return (c >= 'A' && c <= 'Z') || (c >= '2' && c <= '7')

+}

+

 ENC_TABLE := [32]byte {

 	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',

 	'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',

@@ -105,7 +112,11 @@ _encode :: proc(out, data: []byte, ENC_TBL := ENC_TABLE, allocator := context.al
 }

 

 @(optimization_mode="favor_size")

-decode :: proc(data: string, DEC_TBL := DEC_TABLE, allocator := context.allocator) -> (out: []byte, err: Error) {

+decode :: proc(

+  data: string,

+  DEC_TBL := DEC_TABLE,

+  validate: Validate_Proc = _validate_default,

+  allocator := context.allocator) -> (out: []byte, err: Error) {

 	if len(data) == 0 {

 		return nil, .None

 	}

@@ -115,13 +126,13 @@ decode :: proc(data: string, DEC_TBL := DEC_TABLE, allocator := context.allocato
 		return nil, .Invalid_Length

 	}

 

-	// Validate characters - only A-Z and 2-7 allowed before padding

+	// Validate characters using provided validation function

 	for i := 0; i < len(data); i += 1 {

 		c := data[i]

 		if c == byte(PADDING) {

 			break

 		}

-		if !((c >= 'A' && c <= 'Z') || (c >= '2' && c <= '7')) {

+		if !validate(c) {

 			return nil, .Invalid_Character

 		}

 	}