mirror of
https://github.com/Ed94/Odin.git
synced 2026-06-17 19:32:23 -07:00
Zoltán Kéri
336 lines
8.6 KiB
Odin
336 lines
8.6 KiB
Odin
package encoding_base32
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import "core:testing"
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import "core:bytes"
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// @note(zh): Encoding utility for Base32
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// A secondary param can be used to supply a custom alphabet to
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// @link(encode) and a matching decoding table to @link(decode).
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// If none is supplied it just uses the standard Base32 alphabet.
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// Incase your specific version does not use padding, you may
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// truncate it from the encoded output.
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// Error represents errors that can occur during base32 decoding operations.
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// See RFC 4648 sections 3.2, 4 and 6.
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Error :: enum {
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None,
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Invalid_Character, // Input contains characters outside of base32 alphabet (A-Z, 2-7)
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Invalid_Length, // Input length is not valid for base32 (must be a multiple of 8 with proper padding)
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Malformed_Input, // Input has improper structure (wrong padding position or incomplete groups)
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}
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ENC_TABLE := [32]byte {
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
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'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
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'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
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'Y', 'Z', '2', '3', '4', '5', '6', '7',
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}
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PADDING :: '='
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DEC_TABLE := [?]u8 {
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 26, 27, 28, 29, 30, 31, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0,
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0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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}
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REQUIRED_PADDING := map[int]int{
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2 = 6, // 2 chars need 6 padding chars
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4 = 4, // 4 chars need 4 padding chars
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5 = 3, // 5 chars need 3 padding chars
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7 = 1, // 7 chars need 1 padding char
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}
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encode :: proc(data: []byte, ENC_TBL := ENC_TABLE, allocator := context.allocator) -> string {
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out_length := (len(data) + 4) / 5 * 8
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out := make([]byte, out_length, allocator)
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defer delete(out)
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_encode(out, data)
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return string(out[:])
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}
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@private
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_encode :: proc(out, data: []byte, ENC_TBL := ENC_TABLE, allocator := context.allocator) {
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out := out
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data := data
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for len(data) > 0 {
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carry: byte
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switch len(data) {
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case:
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out[7] = ENC_TABLE[data[4] & 0x1f]
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carry = data[4] >> 5
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fallthrough
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case 4:
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out[6] = ENC_TABLE[carry | (data[3] << 3) & 0x1f]
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out[5] = ENC_TABLE[(data[3] >> 2) & 0x1f]
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carry = data[3] >> 7
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fallthrough
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case 3:
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out[4] = ENC_TABLE[carry | (data[2] << 1) & 0x1f]
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carry = (data[2] >> 4) & 0x1f
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fallthrough
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case 2:
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out[3] = ENC_TABLE[carry | (data[1] << 4) & 0x1f]
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out[2] = ENC_TABLE[(data[1] >> 1) & 0x1f]
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carry = (data[1] >> 6) & 0x1f
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fallthrough
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case 1:
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out[1] = ENC_TABLE[carry | (data[0] << 2) & 0x1f]
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out[0] = ENC_TABLE[data[0] >> 3]
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}
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if len(data) < 5 {
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out[7] = byte(PADDING)
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if len(data) < 4 {
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out[6] = byte(PADDING)
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out[5] = byte(PADDING)
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if len(data) < 3 {
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out[4] = byte(PADDING)
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if len(data) < 2 {
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out[3] = byte(PADDING)
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out[2] = byte(PADDING)
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}
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}
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}
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break
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}
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data = data[5:]
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out = out[8:]
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}
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}
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@(optimization_mode="favor_size")
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decode :: proc(data: string, DEC_TBL := DEC_TABLE, allocator := context.allocator) -> (out: []byte, err: Error) {
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if len(data) == 0 {
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return nil, .None
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}
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// Check minimum length requirement first
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if len(data) < 2 {
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return nil, .Invalid_Length
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}
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// Validate characters - only A-Z and 2-7 allowed before padding
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for i := 0; i < len(data); i += 1 {
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c := data[i]
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if c == byte(PADDING) {
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break
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}
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if !((c >= 'A' && c <= 'Z') || (c >= '2' && c <= '7')) {
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return nil, .Invalid_Character
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}
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}
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// Validate padding and length
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data_len := len(data)
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padding_count := 0
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for i := data_len - 1; i >= 0; i -= 1 {
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if data[i] != byte(PADDING) {
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break
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}
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padding_count += 1
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}
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// Check for proper padding and length combinations
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if padding_count > 0 {
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// Verify no padding in the middle
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for i := 0; i < data_len - padding_count; i += 1 {
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if data[i] == byte(PADDING) {
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return nil, .Malformed_Input
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}
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}
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content_len := data_len - padding_count
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mod8 := content_len % 8
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if req_pad, ok := REQUIRED_PADDING[mod8]; ok {
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if padding_count != req_pad {
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return nil, .Malformed_Input
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}
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} else if mod8 != 0 {
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return nil, .Malformed_Input
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}
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} else {
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// No padding - must be multiple of 8
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if data_len % 8 != 0 {
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return nil, .Malformed_Input
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}
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}
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// Calculate decoded length: 5 bytes for every 8 input chars
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input_chars := data_len - padding_count
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out_len := input_chars * 5 / 8
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out = make([]byte, out_len, allocator)
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defer if err != .None {
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delete(out)
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}
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// Process input in 8-byte blocks
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outi := 0
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for i := 0; i < input_chars; i += 8 {
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buf: [8]byte
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block_size := min(8, input_chars - i)
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// Decode block
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for j := 0; j < block_size; j += 1 {
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buf[j] = DEC_TBL[data[i + j]]
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}
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// Convert to output bytes based on block size
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bytes_to_write := block_size * 5 / 8
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switch block_size {
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case 8:
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out[outi + 4] = (buf[6] << 5) | buf[7]
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fallthrough
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case 7:
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out[outi + 3] = (buf[4] << 7) | (buf[5] << 2) | (buf[6] >> 3)
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fallthrough
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case 5:
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out[outi + 2] = (buf[3] << 4) | (buf[4] >> 1)
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fallthrough
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case 4:
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out[outi + 1] = (buf[1] << 6) | (buf[2] << 1) | (buf[3] >> 4)
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fallthrough
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case 2:
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out[outi] = (buf[0] << 3) | (buf[1] >> 2)
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}
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outi += bytes_to_write
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}
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return
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}
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@(test)
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test_base32_decode_valid :: proc(t: ^testing.T) {
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// RFC 4648 Section 10 - Test vectors
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cases := [?]struct {
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input, expected: string,
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}{
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{"", ""},
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{"MY======", "f"},
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{"MZXQ====", "fo"},
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{"MZXW6===", "foo"},
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{"MZXW6YQ=", "foob"},
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{"MZXW6YTB", "fooba"},
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{"MZXW6YTBOI======", "foobar"},
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}
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for c in cases {
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output, err := decode(c.input)
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if output != nil {
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defer delete(output)
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}
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testing.expect_value(t, err, Error.None)
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expected := transmute([]u8)c.expected
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if output != nil {
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testing.expect(t, bytes.equal(output, expected))
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} else {
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testing.expect(t, len(c.expected) == 0)
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}
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}
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}
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@(test)
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test_base32_encode :: proc(t: ^testing.T) {
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// RFC 4648 Section 10 - Test vectors
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cases := [?]struct {
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input, expected: string,
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}{
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{"", ""},
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{"f", "MY======"},
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{"fo", "MZXQ===="},
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{"foo", "MZXW6==="},
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{"foob", "MZXW6YQ="},
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{"fooba", "MZXW6YTB"},
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{"foobar", "MZXW6YTBOI======"},
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}
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for c in cases {
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output := encode(transmute([]byte)c.input)
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testing.expect(t, output == c.expected)
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}
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}
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@(test)
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test_base32_decode_invalid :: proc(t: ^testing.T) {
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// Section 3.2 - Alphabet check
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{
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// Characters outside alphabet
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input := "MZ1W6YTB" // '1' not in alphabet (A-Z, 2-7)
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output, err := decode(input)
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if output != nil {
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defer delete(output)
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}
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testing.expect_value(t, err, Error.Invalid_Character)
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}
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{
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// Lowercase not allowed
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input := "mzxq===="
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output, err := decode(input)
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if output != nil {
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defer delete(output)
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}
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testing.expect_value(t, err, Error.Invalid_Character)
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}
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// Section 4 - Padding requirements
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{
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// Padding must only be at end
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input := "MZ=Q===="
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output, err := decode(input)
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if output != nil {
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defer delete(output)
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}
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testing.expect_value(t, err, Error.Malformed_Input)
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}
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{
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// Missing padding
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input := "MZXQ" // Should be MZXQ====
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output, err := decode(input)
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if output != nil {
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defer delete(output)
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}
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testing.expect_value(t, err, Error.Malformed_Input)
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}
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{
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// Incorrect padding length
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input := "MZXQ=" // Needs 4 padding chars
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output, err := decode(input)
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if output != nil {
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defer delete(output)
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}
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testing.expect_value(t, err, Error.Malformed_Input)
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}
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{
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// Too much padding
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input := "MY=========" // Extra padding chars
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output, err := decode(input)
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if output != nil {
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defer delete(output)
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}
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testing.expect_value(t, err, Error.Malformed_Input)
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}
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// Section 6 - Block size requirements
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{
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// Single character (invalid block)
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input := "M"
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output, err := decode(input)
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if output != nil {
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defer delete(output)
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}
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testing.expect_value(t, err, Error.Invalid_Length)
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}
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}
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