| | 1 | .\" -*-nroff-*- |
| | 2 | .TH base64 3 "20 June 1999" "Straylight/Edgeware" "mLib utilities library" |
| | 3 | .SH NAME |
| | 4 | base64, base32, hex \- obsolete binary encoding functions |
| | 5 | .\" @base64_encode |
| | 6 | .\" @base64_decode |
| | 7 | .\" @base64_init |
| | 8 | .\" @base32_encode |
| | 9 | .\" @base32_decode |
| | 10 | .\" @base32_init |
| | 11 | .\" @hex_encode |
| | 12 | .\" @hex_decode |
| | 13 | .\" @hex_init |
| | 14 | .SH SYNOPSIS |
| | 15 | .nf |
| | 16 | .B "#include <mLib/base64.h>" |
| | 17 | .B "#include <mLib/base32.h>" |
| | 18 | .B "#include <mLib/hex.h>" |
| | 19 | |
| | 20 | .BI "void base64_encode(base64_ctx *" ctx , |
| | 21 | .BI " const void *" p ", size_t " sz , |
| | 22 | .BI " dstr *" d ); |
| | 23 | .BI "void base64_decode(base64_ctx *" ctx , |
| | 24 | .BI " const void *" p ", size_t " sz , |
| | 25 | .BI " dstr *" d ); |
| | 26 | .BI "void base64_init(base64_ctx *" ctx ); |
| | 27 | |
| | 28 | .BI "void base32_encode(base32_ctx *" ctx , |
| | 29 | .BI " const void *" p ", size_t " sz , |
| | 30 | .BI " dstr *" d ); |
| | 31 | .BI "void base32_decode(base32_ctx *" ctx , |
| | 32 | .BI " const void *" p ", size_t " sz , |
| | 33 | .BI " dstr *" d ); |
| | 34 | .BI "void base32_init(base32_ctx *" ctx ); |
| | 35 | |
| | 36 | .BI "void hex_encode(hex_ctx *" ctx , |
| | 37 | .BI " const void *" p ", size_t " sz , |
| | 38 | .BI " dstr *" d ); |
| | 39 | .BI "void hex_decode(hex_ctx *" ctx , |
| | 40 | .BI " const void *" p ", size_t " sz , |
| | 41 | .BI " dstr *" d ); |
| | 42 | .BI "void hex_init(hex_ctx *" ctx ); |
| | 43 | .fi |
| | 44 | .SH DESCRIPTION |
| | 45 | The |
| | 46 | .BR base64 , |
| | 47 | .B base32 |
| | 48 | and |
| | 49 | .B hex |
| | 50 | functions perform encoding and decoding of arbitrary binary strings, as |
| | 51 | defined by RFC4648, but without error reporting. These functions are |
| | 52 | obsolete, and new applications should use the |
| | 53 | .BR codec (3) |
| | 54 | interface, which provides more encoding and decoding options, and proper |
| | 55 | error detection. |
| | 56 | .PP |
| | 57 | The interfaces to these sets of functions is very similar: in |
| | 58 | the following description, |
| | 59 | .I prefix |
| | 60 | stands for one of |
| | 61 | .BR base64 , |
| | 62 | .BR base32 , |
| | 63 | or |
| | 64 | .BR hex . |
| | 65 | .PP |
| | 66 | Before encoding or decoding a string, a |
| | 67 | .I context |
| | 68 | (of type |
| | 69 | .IB prefix _ctx \fR) |
| | 70 | must be initialized, by passing it to |
| | 71 | .IB prefix _init \fR. |
| | 72 | The context contains data which must be retained between calls to encode |
| | 73 | or decode substrings. The |
| | 74 | .IB prefix _init |
| | 75 | function sets up initial values for the data, and sets up defaults for |
| | 76 | the output formatting settings (see below). |
| | 77 | .PP |
| | 78 | Encoding of a string is performed by the |
| | 79 | .IB prefix _encode |
| | 80 | function. It is passed a pointer to a context block |
| | 81 | .IR ctx , |
| | 82 | the input substring to encode passed by address |
| | 83 | .I p |
| | 84 | and length |
| | 85 | .IR sz , |
| | 86 | and a pointer to a dynamic string |
| | 87 | .I d |
| | 88 | in which to write its output (see |
| | 89 | .BR dstr (3) |
| | 90 | for details on dynamic strings). Once all the input data has been |
| | 91 | passed through |
| | 92 | .IB prefix _encode |
| | 93 | it is necessary to flush the final few bytes of output. This is |
| | 94 | achieved by passing |
| | 95 | .I prefix _encode |
| | 96 | a null pointer as its source argument. It is an error to attempt to |
| | 97 | continue encoding after flushing output. |
| | 98 | .PP |
| | 99 | The output of the |
| | 100 | .IB prefix _encode |
| | 101 | function is formatted into lines using values from the context |
| | 102 | structure. The |
| | 103 | .B indent |
| | 104 | member is a pointer to a null-terminated string which is used to |
| | 105 | separate the output lines. The default indent string contains only a |
| | 106 | newline character. The |
| | 107 | .B maxline |
| | 108 | member gives the maximum length of line that |
| | 109 | .IB prefix _encode |
| | 110 | is allowed to produce. If this is not a multiple of 4, it is rounded |
| | 111 | up to the next highest multiple of four before use. A value of zero |
| | 112 | instructs |
| | 113 | .IB prefix _encode |
| | 114 | not to perform line splitting: the output will be a single (possibly |
| | 115 | very long) output line. The default maximum line length is 72 |
| | 116 | characters. You may set these parameters by direct assignment to the |
| | 117 | context structure once it has been initialized. |
| | 118 | .PP |
| | 119 | Decoding is performed similarly by the |
| | 120 | .IB prefix _decode |
| | 121 | function. The comments above about flushing output apply equally to |
| | 122 | decoding. |
| | 123 | .PP |
| | 124 | Decoding ignores all errors. In particular, whitespace is ignored, and |
| | 125 | in the case of Base64 and Base32 encodings, it also ignores |
| | 126 | .RB ` = ' |
| | 127 | characters in the string. |
| | 128 | .SH "SEE ALSO" |
| | 129 | .BR codec (3), |
| | 130 | .BR dstr (3), |
| | 131 | .BR mLib (3). |
| | 132 | .SH AUTHOR |
| | 133 | Mark Wooding, <mdw@distorted.org.uk> |
~mdw / mLib / blame_incremental