API_CHAR7.md

mulle_char7_t

This is a scheme that encodes strings contsisting only of 7 bit ASCII characters into integers. The string "VfL 1848" will be transformed into a 64 bit integer like this:

   ('8' << (7 * 7)) |
   ('4' << (6 * 7)) |
   ('8' << (5 * 7)) |
   ('1' << (4 * 7)) |
   (' ' << (3 * 7)) |
   ('L' << (2 * 7)) |
   ('f' << (1 * 7)) |
   ('V' << (0 * 7))

On 32 bit systems the maximum encodable string length is 4 on 64 bit systems it is 8.

Functions

mulle_char7_get

char  mulle_char7_get( mulle_char7_t value, unsigned int index);

Get character at index. If the index is out of range, the returned value is 0.

mulle_char7_strlen

size_t  mulle_char7_strlen( uintptr_t value)

Retrieve the string length of value.

mulle_char7_get_maxlength

size_t  mulle_char7_get_maxlength( void)

Retrieve the maximum string length for mulle_char7_t on your system.

mulle_char7_substring

mulle_char7_t  mulle_char7_substring( mulle_char7_t value, unsigned int location, unsigned int length)

Retrieve substring of length charactes of value starting at location. Range errors are ignored unless compiling with asserts enabled.

mulle_char7_is_char7string

int   mulle_char7_is_char7string( char *src, size_t len)

Check if string src of length len can be encoded as mulle_char7_t.

mulle_char7_encode

mulle_char7_t   mulle_char7_encode( char *src, size_t len)

Encode ASCII string src into len. '\0' will be ignored. When asserts are enabled, this function does some sanity checks, but it is the callers responsibility that character are 7 bit ASCII, that len is correct and that the string does not contain \0.

mulle_char7_decode

size_t  mulle_char7_decode( mulle_char7_t value, char *dst, size_t len)

Decode up to len characters of value into dst. The destination buffer must be large enough to hold len characters. Returns the actual number of characters. dst is not zero terminated!