BITTER

Section: User Commands (1)
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NAME

bitter, sweet --- code-generators for packing bits

SYNOPSIS

bitter < input > output
sweet < input > output

DESCRIPTION

Bitter and sweet are two filters which turn a description of the form

        name    number-of-bits
        name    number-of-bits
        ...
into code.

Bitter generates code that packs the specified bits from their
variables into an array of unsigned char referenced by an
advancing pointer c.

Sweet generates code that unpacks the specified bits from an array
of unsigned char referenced by a mutable pointer c into the
named variables.

EXAMPLES

% cat in
amaretto 1
banana 2
cherry 3
strawberry 4
vanilla 15
walnut 15

% bitter < in
        *c++ =   ((amaretto & 0x1) << 7)
               | ((banana & 0x3) << 5)
               | ((cherry & 0x7) << 2)
               | ((strawberry >> 2) & 0x3);
        *c++ =   ((strawberry & 0x3) << 6)
               | ((vanilla >> 9) & 0x3F);
        *c++ =   ((vanilla >> 1) & 0xFF);
        *c++ =   ((vanilla & 0x1) << 7)
               | ((walnut >> 8) & 0x7F);
        *c++ =   walnut & 0xFF;

% sweet < in
        amaretto  = (*c >> 7) & 0x1;
        banana  = (*c >> 5) & 0x3;
        cherry  = (*c >> 2) & 0x7;
        strawberry  = (*c++ & 0x3) << 2;
        strawberry |= (*c >> 6) & 0x3;
        vanilla  = (*c++ & 0x3F) << 9;
        vanilla |= (*c++ & 0xFF) << 1;
        vanilla |= (*c >> 7) & 0x1;
        walnut  = (*c++ & 0x7F) << 8;
        walnut |= *c++;

NOTES

This is a quick hack for the gsm_encode() and gsm_decode() routines.

BUGS

Please direct bug reports to toast@tub.cs.tu-berlin.de.

This document was created by man2html, using the manual pages.
Time: 12:37:50 GMT, July 10, 2022