module base64 // encode_in_buffer base64 encodes the `[]byte` passed in `data` into `buffer`. // encode_in_buffer returns the size of the encoded data in the buffer. // Please note: The buffer should be large enough (i.e. 4/3 of the data.len, or larger) to hold the encoded data. // Please note: The function does NOT allocate new memory, and is suitable for handling very large strings. pub fn encode_in_buffer(data []byte, buffer &byte) int { return encode_from_buffer(buffer, data.data, data.len) } // encode_from_buffer will perform encoding from any type of src buffer // and write the bytes into `dest`. // Please note: The `dest` buffer should be large enough (i.e. 4/3 of the src_len, or larger) to hold the encoded data. // Please note: This function is for internal base64 encoding fn encode_from_buffer(dest &byte, src &byte, src_len int) int { if src_len == 0 { return 0 } output_length := 4 * ((src_len + 2) / 3) mut d := unsafe { src } mut b := unsafe { dest } etable := enc_table.str mut di := 0 mut si := 0 n := (src_len / 3) * 3 for si < n { // Convert 3x 8bit source bytes into 4 bytes unsafe { val := u32(d[si + 0]) << 16 | u32(d[si + 1]) << 8 | u32(d[si + 2]) b[di + 0] = etable[val >> 18 & 0x3F] b[di + 1] = etable[val >> 12 & 0x3F] b[di + 2] = etable[val >> 6 & 0x3F] b[di + 3] = etable[val & 0x3F] } si += 3 di += 4 } remain := src_len - si if remain == 0 { return output_length } // Add the remaining small block and padding unsafe { mut val := u32(d[si + 0]) << 16 if remain == 2 { val |= u32(d[si + 1]) << 8 } b[di + 0] = etable[val >> 18 & 0x3F] b[di + 1] = etable[val >> 12 & 0x3F] match remain { 2 { b[di + 2] = etable[val >> 6 & 0x3F] b[di + 3] = byte(`=`) } 1 { b[di + 2] = byte(`=`) b[di + 3] = byte(`=`) } else { panic('base64: This case should never occur.') } } } return output_length } // decode_in_buffer decodes the base64 encoded `string` reference passed in `data` into `buffer`. // decode_in_buffer returns the size of the decoded data in the buffer. // Please note: The `buffer` should be large enough (i.e. 3/4 of the data.len, or larger) // to hold the decoded data. // Please note: This function does NOT allocate new memory, and is thus suitable for handling very large strings. pub fn decode_in_buffer(data &string, buffer &byte) int { return decode_from_buffer(buffer, data.str, data.len) } // decode_from_buffer decodes the base64 encoded ASCII bytes from `data` into `buffer`. // decode_from_buffer returns the size of the decoded data in the buffer. // Please note: The `buffer` should be large enough (i.e. 3/4 of the data.len, or larger) // to hold the decoded data. // Please note: This function does NOT allocate new memory, and is thus suitable for handling very large strings. pub fn decode_in_buffer_bytes(data []byte, buffer &byte) int { return decode_from_buffer(buffer, data.data, data.len) } // decode_from_buffer decodes the base64 encoded ASCII bytes from `src` into `dest`. // decode_from_buffer returns the size of the decoded data in the buffer. // Please note: The `dest` buffer should be large enough (i.e. 3/4 of the `src_len`, or larger) // to hold the decoded data. // Please note: This function does NOT allocate new memory, and is thus suitable for handling very large strings. // Please note: This function is for internal base64 decoding fn decode_from_buffer(dest &byte, src &byte, src_len int) int { if src_len < 4 { return 0 } mut padding := 0 if unsafe { src[src_len - 1] == `=` } { if unsafe { src[src_len - 2] == `=` } { padding = 2 } else { padding = 1 } } mut d := unsafe { src } mut b := unsafe { dest } unsafe { mut n_decoded_bytes := 0 // padding bytes are also counted towards this. mut si := 0 mut datablock_64 := B64_64_datablock{ data: 0 } mut datablock_32 := B64_32_datablock{ data: 0 } for src_len - si >= 8 { // Converting 8 bytes of input into 6 bytes of output. Storing these in the upper bytes of an u64. datablock_64.data = assemble64(byte(index[d[si + 0]]), byte(index[d[si + 1]]), byte(index[d[si + 2]]), byte(index[d[si + 3]]), byte(index[d[si + 4]]), byte(index[d[si + 5]]), byte(index[d[si + 6]]), byte(index[d[si + 7]])) // Reading out the individual bytes from the u64. Watch out with endianess. $if little_endian { b[n_decoded_bytes + 0] = datablock_64.data_byte[7] b[n_decoded_bytes + 1] = datablock_64.data_byte[6] b[n_decoded_bytes + 2] = datablock_64.data_byte[5] b[n_decoded_bytes + 3] = datablock_64.data_byte[4] b[n_decoded_bytes + 4] = datablock_64.data_byte[3] b[n_decoded_bytes + 5] = datablock_64.data_byte[2] } $else { b[n_decoded_bytes + 0] = datablock_64.data_byte[0] b[n_decoded_bytes + 1] = datablock_64.data_byte[1] b[n_decoded_bytes + 2] = datablock_64.data_byte[2] b[n_decoded_bytes + 3] = datablock_64.data_byte[3] b[n_decoded_bytes + 4] = datablock_64.data_byte[4] b[n_decoded_bytes + 5] = datablock_64.data_byte[5] } n_decoded_bytes += 6 si += 8 } for src_len - si >= 4 { datablock_32.data = assemble32(byte(index[d[si + 0]]), byte(index[d[si + 1]]), byte(index[d[si + 2]]), byte(index[d[si + 3]])) $if little_endian { b[n_decoded_bytes + 0] = datablock_32.data_byte[3] b[n_decoded_bytes + 1] = datablock_32.data_byte[2] b[n_decoded_bytes + 2] = datablock_32.data_byte[1] b[n_decoded_bytes + 3] = datablock_32.data_byte[0] } $else { b[n_decoded_bytes + 0] = datablock_32.data_byte[0] b[n_decoded_bytes + 1] = datablock_32.data_byte[1] b[n_decoded_bytes + 2] = datablock_32.data_byte[2] b[n_decoded_bytes + 3] = datablock_32.data_byte[3] } n_decoded_bytes += 3 si += 4 } return n_decoded_bytes - padding } } union B64_64_datablock { mut: data u64 data_byte [8]byte } union B64_32_datablock { mut: data u32 data_byte [4]byte } // decode decodes the base64 encoded `string` value passed in `data`. // Please note: If you need to decode many strings repeatedly, take a look at `decode_in_buffer`. // Example: assert base64.decode('ViBpbiBiYXNlIDY0') == 'V in base 64' pub fn decode(data string) []byte { mut size := i64(data.len) * 3 / 4 if size <= 0 || data.len % 4 != 0 { return [] } size = (size + 3) & ~0x03 // round to the next multiple of 4 (the decoding loop writes multiples of 4 bytes) unsafe { buffer := malloc(int(size)) n := decode_in_buffer(data, buffer) return buffer.vbytes(n) } } // decode_str is the string variant of decode pub fn decode_str(data string) string { size := data.len * 3 / 4 if size <= 0 || data.len % 4 != 0 { return '' } unsafe { buffer := malloc_noscan(size + 1) buffer[size] = 0 blen := decode_in_buffer(data, buffer) return tos(buffer, blen) } } // encode encodes the `[]byte` value passed in `data` to base64. // Please note: base64 encoding returns a `string` that is ~ 4/3 larger than the input. // Please note: If you need to encode many strings repeatedly, take a look at `encode_in_buffer`. // Example: assert base64.encode('V in base 64') == 'ViBpbiBiYXNlIDY0' pub fn encode(data []byte) string { return alloc_and_encode(data.data, data.len) } // encode_str is the string variant of encode pub fn encode_str(data string) string { return alloc_and_encode(data.str, data.len) } // alloc_and_encode is a private function that allocates and encodes data into a string // Used by encode and encode_str fn alloc_and_encode(src &byte, len int) string { if len == 0 { return '' } size := 4 * ((len + 2) / 3) if size <= 0 { return '' } unsafe { buffer := malloc_noscan(size + 1) buffer[size] = 0 blen := encode_from_buffer(buffer, src, len) return tos(buffer, blen) } }