std/base64 (original) (raw)
This module implements a base64 encoder and decoder.
Unstable API.
Base64 is an encoding and decoding technique used to convert binary data to an ASCII string format. Each Base64 digit represents exactly 6 bits of data. Three 8-bit bytes (i.e., a total of 24 bits) can therefore be represented by four 6-bit Base64 digits.
Basic usage
Encoding data
Example:
import std/base64 let encoded = encode("Hello World") assert encoded == "SGVsbG8gV29ybGQ="
Apart from strings you can also encode lists of integers or characters:
Example:
import std/base64 let encodedInts = encode([1'u8,2,3]) assert encodedInts == "AQID" let encodedChars = encode(['h','e','y']) assert encodedChars == "aGV5"
Decoding data
Example:
import std/base64 let decoded = decode("SGVsbG8gV29ybGQ=") assert decoded == "Hello World"
URL Safe Base64
Example:
import std/base64 assert encode("c\xf7>", safe = true) == "Y_c-" assert encode("c\xf7>", safe = false) == "Y/c+"
See also
- hashes module for efficient computations of hash values for diverse Nim types
- md5 module for the MD5 checksum algorithm
- sha1 module for the SHA-1 checksum algorithm
Procs
proc decode(s: string): string {....raises: [ValueError], tags: [], forbids: [].}
Decodes string s in base64 representation back into its original form. The initial whitespace is skipped.
See also:
- encode proc for encoding an openarray
Example:
assert decode("SGVsbG8gV29ybGQ=") == "Hello World" assert decode(" SGVsbG8gV29ybGQ=") == "Hello World"
proc encodeMime(s: string; lineLen = 75.Positive; newLine = "\r\n"; safe = false): string {. ...raises: [], tags: [], forbids: [].}
Encodes s into base64 representation as lines. Used in email MIME format, use lineLen and newline.
This procedure encodes a string according to MIME spec.
If safe is true then it will encode using the URL-Safe and Filesystem-safe standard alphabet characters, which substitutes - instead of + and _ instead of /.
See also:
- encode proc for encoding an openArray
- decode proc for decoding a string
Example:
assert encodeMime("Hello World", 4, "\n") == "SGVs\nbG8g\nV29y\nbGQ="