309 lines
10 KiB
V
309 lines
10 KiB
V
// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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// Based off: https://github.com/golang/go/blob/master/src/encoding/base64/base64.go
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// Last commit: https://github.com/golang/go/commit/9a93baf4d7d13d7d5c67388c93960d78abc8e11e
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module base64
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const (
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index = [0, 0, 0, 0, 0, 0, 0, 0, 0, 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, 0, 0, 62, 63, 62, 62, 63, 52, 53, 54, 55,
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56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
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13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 63, 0, 26, 27, 28, 29,
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30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51]!
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ending_table = [0, 2, 1]!
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enc_table = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
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)
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union B64_64_datablock {
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mut:
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data u64
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data_byte [8]byte
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}
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union B64_32_datablock {
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mut:
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data u32
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data_byte [4]byte
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}
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// decode decodes the base64 encoded `string` value passed in `data`.
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// Please note: If you need to decode many strings repeatedly, take a look at `decode_in_buffer`.
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// Example: assert base64.decode('ViBpbiBiYXNlIDY0') == 'V in base 64'
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pub fn decode(data string) []byte {
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mut size := i64(data.len) * 3 / 4
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if size <= 0 || data.len % 4 != 0 {
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return []
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}
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size = (size + 3) & ~0x03 // round to the next multiple of 4 (the decoding loop writes multiples of 4 bytes)
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unsafe {
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buffer := malloc(int(size))
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n := decode_in_buffer(data, buffer)
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return buffer.vbytes(n)
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}
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}
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// decode_str is the string variant of decode
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pub fn decode_str(data string) string {
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size := data.len * 3 / 4
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if size <= 0 || data.len % 4 != 0 {
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return ''
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}
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unsafe {
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buffer := malloc_noscan(size + 1)
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buffer[size] = 0
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return tos(buffer, decode_in_buffer(data, buffer))
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}
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}
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// encode encodes the `[]byte` value passed in `data` to base64.
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// Please note: base64 encoding returns a `string` that is ~ 4/3 larger than the input.
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// Please note: If you need to encode many strings repeatedly, take a look at `encode_in_buffer`.
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// Example: assert base64.encode('V in base 64') == 'ViBpbiBiYXNlIDY0'
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pub fn encode(data []byte) string {
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return alloc_and_encode(data.data, data.len)
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}
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// encode_str is the string variant of encode
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pub fn encode_str(data string) string {
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return alloc_and_encode(data.str, data.len)
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}
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// alloc_and_encode is a private function that allocates and encodes data into a string
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// Used by encode and encode_str
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fn alloc_and_encode(src &byte, len int) string {
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size := 4 * ((len + 2) / 3)
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if size <= 0 {
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return ''
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}
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unsafe {
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buffer := malloc_noscan(size + 1)
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buffer[size] = 0
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return tos(buffer, encode_from_buffer(buffer, src, len))
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}
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}
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// url_decode returns a decoded URL `string` version of
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// the a base64 url encoded `string` passed in `data`.
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pub fn url_decode(data string) []byte {
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mut result := data.replace_each(['-', '+', '_', '/'])
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match result.len % 4 {
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// Pad with trailing '='s
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2 { result += '==' } // 2 pad chars
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3 { result += '=' } // 1 pad char
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else {} // no padding
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}
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return decode(result)
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}
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// url_decode_str is the string variant of url_decode
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pub fn url_decode_str(data string) string {
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mut result := data.replace_each(['-', '+', '_', '/'])
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match result.len % 4 {
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// Pad with trailing '='s
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2 { result += '==' } // 2 pad chars
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3 { result += '=' } // 1 pad char
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else {} // no padding
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}
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return decode_str(result)
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}
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// url_encode returns a base64 URL encoded `string` version
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// of the value passed in `data`.
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pub fn url_encode(data []byte) string {
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return encode(data).replace_each(['+', '-', '/', '_', '=', ''])
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}
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// url_encode_str is the string variant of url_encode
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pub fn url_encode_str(data string) string {
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return encode_str(data).replace_each(['+', '-', '/', '_', '=', ''])
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}
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// assemble64 assembles 8 base64 digits into 6 bytes.
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// Each digit comes from the decode map.
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// Please note: Invalid base64 digits are not expected and not handled.
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fn assemble64(n1 byte, n2 byte, n3 byte, n4 byte, n5 byte, n6 byte, n7 byte, n8 byte) u64 {
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return u64(n1) << 58 | u64(n2) << 52 | u64(n3) << 46 | u64(n4) << 40 | u64(n5) << 34 | u64(n6) << 28 | u64(n7) << 22 | u64(n8) << 16
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}
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// assemble32 assembles 4 base64 digits into 3 bytes.
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// Each digit comes from the decode map.
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// Please note: Invalid base64 digits are not expected and not handled.
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fn assemble32(n1 byte, n2 byte, n3 byte, n4 byte) u32 {
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return u32(n1) << 26 | u32(n2) << 20 | u32(n3) << 14 | u32(n4) << 8
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}
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// decode_in_buffer decodes the base64 encoded `string` reference passed in `data` into `buffer`.
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// decode_in_buffer returns the size of the decoded data in the buffer.
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// Please note: The `buffer` should be large enough (i.e. 3/4 of the data.len, or larger)
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// to hold the decoded data.
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// Please note: This function does NOT allocate new memory, and is thus suitable for handling very large strings.
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pub fn decode_in_buffer(data &string, buffer &byte) int {
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return decode_from_buffer(buffer, data.str, data.len)
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}
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// decode_from_buffer decodes the base64 encoded ASCII bytes from `data` into `buffer`.
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// decode_from_buffer returns the size of the decoded data in the buffer.
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// Please note: The `buffer` should be large enough (i.e. 3/4 of the data.len, or larger)
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// to hold the decoded data.
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// Please note: This function does NOT allocate new memory, and is thus suitable for handling very large strings.
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pub fn decode_in_buffer_bytes(data []byte, buffer &byte) int {
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return decode_from_buffer(buffer, data.data, data.len)
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}
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// decode_from_buffer decodes the base64 encoded ASCII bytes from `src` into `dest`.
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// decode_from_buffer returns the size of the decoded data in the buffer.
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// Please note: The `dest` buffer should be large enough (i.e. 3/4 of the `src_len`, or larger)
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// to hold the decoded data.
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// Please note: This function does NOT allocate new memory, and is thus suitable for handling very large strings.
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// Please note: This function is for internal base64 decoding
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fn decode_from_buffer(dest &byte, src &byte, src_len int) int {
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if src_len < 4 {
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return 0
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}
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mut padding := 0
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if unsafe { src[src_len - 1] == `=` } {
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if unsafe { src[src_len - 2] == `=` } {
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padding = 2
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} else {
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padding = 1
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}
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}
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mut d := unsafe { src }
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mut b := unsafe { dest }
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unsafe {
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mut n_decoded_bytes := 0 // padding bytes are also counted towards this.
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mut si := 0
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mut datablock_64 := B64_64_datablock{
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data: 0
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}
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mut datablock_32 := B64_32_datablock{
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data: 0
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}
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for src_len - si >= 8 {
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// Converting 8 bytes of input into 6 bytes of output. Storing these in the upper bytes of an u64.
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datablock_64.data = assemble64(byte(base64.index[d[si + 0]]), byte(base64.index[d[si + 1]]),
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byte(base64.index[d[si + 2]]), byte(base64.index[d[si + 3]]), byte(base64.index[d[
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si + 4]]), byte(base64.index[d[si + 5]]), byte(base64.index[d[si + 6]]),
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byte(base64.index[d[si + 7]]))
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// Reading out the individual bytes from the u64. Watch out with endianess.
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$if little_endian {
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b[n_decoded_bytes + 0] = datablock_64.data_byte[7]
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b[n_decoded_bytes + 1] = datablock_64.data_byte[6]
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b[n_decoded_bytes + 2] = datablock_64.data_byte[5]
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b[n_decoded_bytes + 3] = datablock_64.data_byte[4]
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b[n_decoded_bytes + 4] = datablock_64.data_byte[3]
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b[n_decoded_bytes + 5] = datablock_64.data_byte[2]
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} $else {
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b[n_decoded_bytes + 0] = datablock_64.data_byte[0]
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b[n_decoded_bytes + 1] = datablock_64.data_byte[1]
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b[n_decoded_bytes + 2] = datablock_64.data_byte[2]
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b[n_decoded_bytes + 3] = datablock_64.data_byte[3]
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b[n_decoded_bytes + 4] = datablock_64.data_byte[4]
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b[n_decoded_bytes + 5] = datablock_64.data_byte[5]
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}
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n_decoded_bytes += 6
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si += 8
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}
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for src_len - si >= 4 {
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datablock_32.data = assemble32(byte(base64.index[d[si + 0]]), byte(base64.index[d[si + 1]]),
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byte(base64.index[d[si + 2]]), byte(base64.index[d[si + 3]]))
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$if little_endian {
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b[n_decoded_bytes + 0] = datablock_32.data_byte[3]
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b[n_decoded_bytes + 1] = datablock_32.data_byte[2]
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b[n_decoded_bytes + 2] = datablock_32.data_byte[1]
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b[n_decoded_bytes + 3] = datablock_32.data_byte[0]
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} $else {
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b[n_decoded_bytes + 0] = datablock_32.data_byte[0]
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b[n_decoded_bytes + 1] = datablock_32.data_byte[1]
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b[n_decoded_bytes + 2] = datablock_32.data_byte[2]
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b[n_decoded_bytes + 3] = datablock_32.data_byte[3]
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}
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n_decoded_bytes += 3
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si += 4
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}
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return n_decoded_bytes - padding
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}
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}
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// encode_in_buffer base64 encodes the `[]byte` passed in `data` into `buffer`.
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// encode_in_buffer returns the size of the encoded data in the buffer.
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// Please note: The buffer should be large enough (i.e. 4/3 of the data.len, or larger) to hold the encoded data.
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// Please note: The function does NOT allocate new memory, and is suitable for handling very large strings.
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pub fn encode_in_buffer(data []byte, buffer &byte) int {
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return encode_from_buffer(buffer, data.data, data.len)
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}
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// encode_from_buffer will perform encoding from any type of src buffer
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// and write the bytes into `dest`.
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// Please note: The `dest` buffer should be large enough (i.e. 4/3 of the src_len, or larger) to hold the encoded data.
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// Please note: This function is for internal base64 encoding
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fn encode_from_buffer(dest &byte, src &byte, src_len int) int {
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if src_len == 0 {
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return 0
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}
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output_length := 4 * ((src_len + 2) / 3)
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mut d := unsafe { src }
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mut b := unsafe { dest }
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etable := base64.enc_table.str
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mut di := 0
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mut si := 0
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n := (src_len / 3) * 3
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for si < n {
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// Convert 3x 8bit source bytes into 4 bytes
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unsafe {
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val := u32(d[si + 0]) << 16 | u32(d[si + 1]) << 8 | u32(d[si + 2])
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b[di + 0] = etable[val >> 18 & 0x3F]
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b[di + 1] = etable[val >> 12 & 0x3F]
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b[di + 2] = etable[val >> 6 & 0x3F]
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b[di + 3] = etable[val & 0x3F]
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}
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si += 3
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di += 4
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}
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remain := src_len - si
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if remain == 0 {
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return output_length
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}
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// Add the remaining small block and padding
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unsafe {
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mut val := u32(d[si + 0]) << 16
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if remain == 2 {
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val |= u32(d[si + 1]) << 8
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}
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b[di + 0] = etable[val >> 18 & 0x3F]
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b[di + 1] = etable[val >> 12 & 0x3F]
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match remain {
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2 {
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b[di + 2] = etable[val >> 6 & 0x3F]
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b[di + 3] = byte(`=`)
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}
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1 {
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b[di + 2] = byte(`=`)
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b[di + 3] = byte(`=`)
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}
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else {
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panic('base64: This case should never occur.')
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}
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}
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}
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return output_length
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}
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