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/Elixir 1.5

Base

This module provides data encoding and decoding functions according to RFC 4648.

This document defines the commonly used base 16, base 32, and base 64 encoding schemes.

Base 16 alphabet

| Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding |
|------:|---------:|------:|---------:|------:|---------:|------:|---------:|
|      0|         0|      4|         4|      8|         8|     12|         C|
|      1|         1|      5|         5|      9|         9|     13|         D|
|      2|         2|      6|         6|     10|         A|     14|         E|
|      3|         3|      7|         7|     11|         B|     15|         F|

Base 32 alphabet

| Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding |
|------:|---------:|------:|---------:|------:|---------:|------:|---------:|
|      0|         A|      9|         J|     18|         S|     27|         3|
|      1|         B|     10|         K|     19|         T|     28|         4|
|      2|         C|     11|         L|     20|         U|     29|         5|
|      3|         D|     12|         M|     21|         V|     30|         6|
|      4|         E|     13|         N|     22|         W|     31|         7|
|      5|         F|     14|         O|     23|         X|       |          |
|      6|         G|     15|         P|     24|         Y|  (pad)|         =|
|      7|         H|     16|         Q|     25|         Z|       |          |
|      8|         I|     17|         R|     26|         2|       |          |

Base 32 (extended hex) alphabet

| Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding |
|------:|---------:|------:|---------:|------:|---------:|------:|---------:|
|      0|         0|      9|         9|     18|         I|     27|         R|
|      1|         1|     10|         A|     19|         J|     28|         S|
|      2|         2|     11|         B|     20|         K|     29|         T|
|      3|         3|     12|         C|     21|         L|     30|         U|
|      4|         4|     13|         D|     22|         M|     31|         V|
|      5|         5|     14|         E|     23|         N|       |          |
|      6|         6|     15|         F|     24|         O|  (pad)|         =|
|      7|         7|     16|         G|     25|         P|       |          |
|      8|         8|     17|         H|     26|         Q|       |          |

Base 64 alphabet

| Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding |
|------:|---------:|------:|---------:|------:|---------:|------:|---------:|
|      0|         A|     17|         R|     34|         i|     51|         z|
|      1|         B|     18|         S|     35|         j|     52|         0|
|      2|         C|     19|         T|     36|         k|     53|         1|
|      3|         D|     20|         U|     37|         l|     54|         2|
|      4|         E|     21|         V|     38|         m|     55|         3|
|      5|         F|     22|         W|     39|         n|     56|         4|
|      6|         G|     23|         X|     40|         o|     57|         5|
|      7|         H|     24|         Y|     41|         p|     58|         6|
|      8|         I|     25|         Z|     42|         q|     59|         7|
|      9|         J|     26|         a|     43|         r|     60|         8|
|     10|         K|     27|         b|     44|         s|     61|         9|
|     11|         L|     28|         c|     45|         t|     62|         +|
|     12|         M|     29|         d|     46|         u|     63|         /|
|     13|         N|     30|         e|     47|         v|       |          |
|     14|         O|     31|         f|     48|         w|  (pad)|         =|
|     15|         P|     32|         g|     49|         x|       |          |
|     16|         Q|     33|         h|     50|         y|       |          |

Base 64 (URL and filename safe) alphabet

| Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding |
|------:|---------:|------:|---------:|------:|---------:|------:|---------:|
|      0|         A|     17|         R|     34|         i|     51|         z|
|      1|         B|     18|         S|     35|         j|     52|         0|
|      2|         C|     19|         T|     36|         k|     53|         1|
|      3|         D|     20|         U|     37|         l|     54|         2|
|      4|         E|     21|         V|     38|         m|     55|         3|
|      5|         F|     22|         W|     39|         n|     56|         4|
|      6|         G|     23|         X|     40|         o|     57|         5|
|      7|         H|     24|         Y|     41|         p|     58|         6|
|      8|         I|     25|         Z|     42|         q|     59|         7|
|      9|         J|     26|         a|     43|         r|     60|         8|
|     10|         K|     27|         b|     44|         s|     61|         9|
|     11|         L|     28|         c|     45|         t|     62|         -|
|     12|         M|     29|         d|     46|         u|     63|         _|
|     13|         N|     30|         e|     47|         v|       |          |
|     14|         O|     31|         f|     48|         w|  (pad)|         =|
|     15|         P|     32|         g|     49|         x|       |          |
|     16|         Q|     33|         h|     50|         y|       |          |

Summary

Functions

decode16(string, opts \\ [])

Decodes a base 16 encoded string into a binary string

decode16!(string, opts \\ [])

Decodes a base 16 encoded string into a binary string

decode32(string, opts \\ [])

Decodes a base 32 encoded string into a binary string

decode32!(string, opts \\ [])

Decodes a base 32 encoded string into a binary string

decode64(string, opts \\ [])

Decodes a base 64 encoded string into a binary string

decode64!(string, opts \\ [])

Decodes a base 64 encoded string into a binary string

encode16(data, opts \\ [])

Encodes a binary string into a base 16 encoded string

encode32(data, opts \\ [])

Encodes a binary string into a base 32 encoded string

encode64(data, opts \\ [])

Encodes a binary string into a base 64 encoded string

hex_decode32(string, opts \\ [])

Decodes a base 32 encoded string with extended hexadecimal alphabet into a binary string

hex_decode32!(string, opts \\ [])

Decodes a base 32 encoded string with extended hexadecimal alphabet into a binary string

hex_encode32(data, opts \\ [])

Encodes a binary string into a base 32 encoded string with an extended hexadecimal alphabet

url_decode64(string, opts \\ [])

Decodes a base 64 encoded string with URL and filename safe alphabet into a binary string

url_decode64!(string, opts \\ [])

Decodes a base 64 encoded string with URL and filename safe alphabet into a binary string

url_encode64(data, opts \\ [])

Encodes a binary string into a base 64 encoded string with URL and filename safe alphabet

Functions

decode16(string, opts \\ [])

decode16(binary, keyword) :: {:ok, binary} | :error

Decodes a base 16 encoded string into a binary string.

Options

The accepted options are:

  • :case - specifies the character case to accept when decoding

The values for :case can be:

  • :upper - only allows upper case characters (default)
  • :lower - only allows lower case characters
  • :mixed - allows mixed case characters

Examples

iex> Base.decode16("666F6F626172")
{:ok, "foobar"}

iex> Base.decode16("666f6f626172", case: :lower)
{:ok, "foobar"}

iex> Base.decode16("666f6F626172", case: :mixed)
{:ok, "foobar"}

decode16!(string, opts \\ [])

decode16!(binary, keyword) :: binary

Decodes a base 16 encoded string into a binary string.

Options

The accepted options are:

  • :case - specifies the character case to accept when decoding

The values for :case can be:

  • :upper - only allows upper case characters (default)
  • :lower - only allows lower case characters
  • :mixed - allows mixed case characters

An ArgumentError exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

Examples

iex> Base.decode16!("666F6F626172")
"foobar"

iex> Base.decode16!("666f6f626172", case: :lower)
"foobar"

iex> Base.decode16!("666f6F626172", case: :mixed)
"foobar"

decode32(string, opts \\ [])

decode32(binary, keyword) :: {:ok, binary} | :error

Decodes a base 32 encoded string into a binary string.

Options

The accepted options are:

  • :case - specifies the character case to accept when decoding
  • :padding - specifies whether to require padding

The values for :case can be:

  • :upper - only allows upper case characters (default)
  • :lower - only allows lower case characters
  • :mixed - allows mixed case characters

The values for :padding can be:

  • true - requires the input string to be padded to the nearest multiple of 8 (default)
  • false - ignores padding from the input string

Examples

iex> Base.decode32("MZXW6YTBOI======")
{:ok, "foobar"}

iex> Base.decode32("mzxw6ytboi======", case: :lower)
{:ok, "foobar"}

iex> Base.decode32("mzXW6ytBOi======", case: :mixed)
{:ok, "foobar"}

iex> Base.decode32("MZXW6YTBOI", padding: false)
{:ok, "foobar"}

decode32!(string, opts \\ [])

decode32!(binary, keyword) :: binary

Decodes a base 32 encoded string into a binary string.

An ArgumentError exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

Options

The accepted options are:

  • :case - specifies the character case to accept when decoding
  • :padding - specifies whether to require padding

The values for :case can be:

  • :upper - only allows upper case characters (default)
  • :lower - only allows lower case characters
  • :mixed - allows mixed case characters

The values for :padding can be:

  • true - requires the input string to be padded to the nearest multiple of 8 (default)
  • false - ignores padding from the input string

Examples

iex> Base.decode32!("MZXW6YTBOI======")
"foobar"

iex> Base.decode32!("mzxw6ytboi======", case: :lower)
"foobar"

iex> Base.decode32!("mzXW6ytBOi======", case: :mixed)
"foobar"

iex> Base.decode32!("MZXW6YTBOI", padding: false)
"foobar"

decode64(string, opts \\ [])

decode64(binary, keyword) :: {:ok, binary} | :error

Decodes a base 64 encoded string into a binary string.

Accepts ignore: :whitespace option which will ignore all the whitespace characters in the input string.

Accepts padding: false option which will ignore padding from the input string.

Examples

iex> Base.decode64("Zm9vYmFy")
{:ok, "foobar"}

iex> Base.decode64("Zm9vYmFy\n", ignore: :whitespace)
{:ok, "foobar"}

iex> Base.decode64("Zm9vYg==")
{:ok, "foob"}

iex> Base.decode64("Zm9vYg", padding: false)
{:ok, "foob"}

decode64!(string, opts \\ [])

decode64!(binary, keyword) :: binary

Decodes a base 64 encoded string into a binary string.

Accepts ignore: :whitespace option which will ignore all the whitespace characters in the input string.

Accepts padding: false option which will ignore padding from the input string.

An ArgumentError exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

Examples

iex> Base.decode64!("Zm9vYmFy")
"foobar"

iex> Base.decode64!("Zm9vYmFy\n", ignore: :whitespace)
"foobar"

iex> Base.decode64!("Zm9vYg==")
"foob"

iex> Base.decode64!("Zm9vYg", padding: false)
"foob"

encode16(data, opts \\ [])

encode16(binary, keyword) :: binary

Encodes a binary string into a base 16 encoded string.

Options

The accepted options are:

  • :case - specifies the character case to use when encoding

The values for :case can be:

  • :upper - uses upper case characters (default)
  • :lower - uses lower case characters

Examples

iex> Base.encode16("foobar")
"666F6F626172"

iex> Base.encode16("foobar", case: :lower)
"666f6f626172"

encode32(data, opts \\ [])

encode32(binary, keyword) :: binary

Encodes a binary string into a base 32 encoded string.

Options

The accepted options are:

  • :case - specifies the character case to use when encoding
  • :padding - specifies whether to apply padding

The values for :case can be:

  • :upper - uses upper case characters (default)
  • :lower - uses lower case characters

The values for :padding can be:

  • true - pad the output string to the nearest multiple of 8 (default)
  • false - omit padding from the output string

Examples

iex> Base.encode32("foobar")
"MZXW6YTBOI======"

iex> Base.encode32("foobar", case: :lower)
"mzxw6ytboi======"

iex> Base.encode32("foobar", padding: false)
"MZXW6YTBOI"

encode64(data, opts \\ [])

encode64(binary, keyword) :: binary

Encodes a binary string into a base 64 encoded string.

Accepts padding: false option which will omit padding from the output string.

Examples

iex> Base.encode64("foobar")
"Zm9vYmFy"

iex> Base.encode64("foob")
"Zm9vYg=="

iex> Base.encode64("foob", padding: false)
"Zm9vYg"

hex_decode32(string, opts \\ [])

hex_decode32(binary, keyword) :: {:ok, binary} | :error

Decodes a base 32 encoded string with extended hexadecimal alphabet into a binary string.

Options

The accepted options are:

  • :case - specifies the character case to accept when decoding
  • :padding - specifies whether to require padding

The values for :case can be:

  • :upper - only allows upper case characters (default)
  • :lower - only allows lower case characters
  • :mixed - allows mixed case characters

The values for :padding can be:

  • true - requires the input string to be padded to the nearest multiple of 8 (default)
  • false - ignores padding from the input string

Examples

iex> Base.hex_decode32("CPNMUOJ1E8======")
{:ok, "foobar"}

iex> Base.hex_decode32("cpnmuoj1e8======", case: :lower)
{:ok, "foobar"}

iex> Base.hex_decode32("cpnMuOJ1E8======", case: :mixed)
{:ok, "foobar"}

iex> Base.hex_decode32("CPNMUOJ1E8", padding: false)
{:ok, "foobar"}

hex_decode32!(string, opts \\ [])

hex_decode32!(binary, keyword) :: binary

Decodes a base 32 encoded string with extended hexadecimal alphabet into a binary string.

An ArgumentError exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

Options

The accepted options are:

  • :case - specifies the character case to accept when decoding
  • :padding - specifies whether to require padding

The values for :case can be:

  • :upper - only allows upper case characters (default)
  • :lower - only allows lower case characters
  • :mixed - allows mixed case characters

The values for :padding can be:

  • true - requires the input string to be padded to the nearest multiple of 8 (default)
  • false - ignores padding from the input string

Examples

iex> Base.hex_decode32!("CPNMUOJ1E8======")
"foobar"

iex> Base.hex_decode32!("cpnmuoj1e8======", case: :lower)
"foobar"

iex> Base.hex_decode32!("cpnMuOJ1E8======", case: :mixed)
"foobar"

iex> Base.hex_decode32!("CPNMUOJ1E8", padding: false)
"foobar"

hex_encode32(data, opts \\ [])

hex_encode32(binary, keyword) :: binary

Encodes a binary string into a base 32 encoded string with an extended hexadecimal alphabet.

Options

The accepted options are:

  • :case - specifies the character case to use when encoding
  • :padding - specifies whether to apply padding

The values for :case can be:

  • :upper - uses upper case characters (default)
  • :lower - uses lower case characters

The values for :padding can be:

  • true - pad the output string to the nearest multiple of 8 (default)
  • false - omit padding from the output string

Examples

iex> Base.hex_encode32("foobar")
"CPNMUOJ1E8======"

iex> Base.hex_encode32("foobar", case: :lower)
"cpnmuoj1e8======"

iex> Base.hex_encode32("foobar", padding: false)
"CPNMUOJ1E8"

url_decode64(string, opts \\ [])

url_decode64(binary, keyword) :: {:ok, binary} | :error

Decodes a base 64 encoded string with URL and filename safe alphabet into a binary string.

Accepts ignore: :whitespace option which will ignore all the whitespace characters in the input string.

Accepts padding: false option which will ignore padding from the input string.

Examples

iex> Base.url_decode64("_3_-_A==")
{:ok, <<255, 127, 254, 252>>}

iex> Base.url_decode64("_3_-_A==\n", ignore: :whitespace)
{:ok, <<255, 127, 254, 252>>}

iex> Base.url_decode64("_3_-_A", padding: false)
{:ok, <<255, 127, 254, 252>>}

url_decode64!(string, opts \\ [])

url_decode64!(binary, keyword) :: binary

Decodes a base 64 encoded string with URL and filename safe alphabet into a binary string.

Accepts ignore: :whitespace option which will ignore all the whitespace characters in the input string.

Accepts padding: false option which will ignore padding from the input string.

An ArgumentError exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

Examples

iex> Base.url_decode64!("_3_-_A==")
<<255, 127, 254, 252>>

iex> Base.url_decode64!("_3_-_A==\n", ignore: :whitespace)
<<255, 127, 254, 252>>

iex> Base.url_decode64!("_3_-_A", padding: false)
<<255, 127, 254, 252>>

url_encode64(data, opts \\ [])

url_encode64(binary, keyword) :: binary

Encodes a binary string into a base 64 encoded string with URL and filename safe alphabet.

Accepts padding: false option which will omit padding from the output string.

Examples

iex> Base.url_encode64(<<255, 127, 254, 252>>)
"_3_-_A=="

iex> Base.url_encode64(<<255, 127, 254, 252>>, padding: false)
"_3_-_A"

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Licensed under the Apache License, Version 2.0.
https://hexdocs.pm/elixir/1.5.0/Base.html