pub fn decode(decoder_with_ignore: *const Base64DecoderWithIgnore, dest: []u8, source: []const u8) Error!usizedecoder_with_ignore: *const Base64DecoderWithIgnoredest: []u8source: []const u8InvalidCharacterInvalidPaddingNoSpaceLeft331
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375 pub fn decode(decoder_with_ignore: *const Base64DecoderWithIgnore, dest: []u8, source: []const u8) Error!usize {
const decoder = &decoder_with_ignore.decoder;
var acc: u12 = 0;
var acc_len: u4 = 0;
var dest_idx: usize = 0;
var leftover_idx: ?usize = null;
for (source, 0..) |c, src_idx| {
if (decoder_with_ignore.char_is_ignored[c]) continue;
const d = decoder.char_to_index[c];
if (d == Base64Decoder.invalid_char) {
if (decoder.pad_char == null or c != decoder.pad_char.?) return error.InvalidCharacter;
leftover_idx = src_idx;
break;
}
acc = (acc << 6) + d;
acc_len += 6;
if (acc_len >= 8) {
if (dest_idx == dest.len) return error.NoSpaceLeft;
acc_len -= 8;
dest[dest_idx] = @as(u8, @truncate(acc >> acc_len));
dest_idx += 1;
}
}
if (acc_len > 4 or (acc & (@as(u12, 1) << acc_len) - 1) != 0) {
return error.InvalidPadding;
}
const padding_len = acc_len / 2;
if (leftover_idx == null) {
if (decoder.pad_char != null and padding_len != 0) return error.InvalidPadding;
return dest_idx;
}
const leftover = source[leftover_idx.?..];
if (decoder.pad_char) |pad_char| {
var padding_chars: usize = 0;
for (leftover) |c| {
if (decoder_with_ignore.char_is_ignored[c]) continue;
if (c != pad_char) {
return if (c == Base64Decoder.invalid_char) error.InvalidCharacter else error.InvalidPadding;
}
padding_chars += 1;
}
if (padding_chars != padding_len) return error.InvalidPadding;
}
return dest_idx;
}
Invalid characters that are not ignored result in error.InvalidCharacter. Invalid padding results in error.InvalidPadding. Decoding more data than can fit in dest results in error.NoSpaceLeft. See also ::calcSizeUpperBound. Returns the number of bytes written to dest.