gusucode.com > vnt工具箱matlab源码程序 > vnt/vnt/+can/Utility.m
classdef (Hidden) Utility
% Utility Supporting functionality for toolbox operations.
%
% This class implements internal functionality required for toolbox
% operation. These methods are not intended for external use.
% Authors: JDP
% Copyright 2007-2015 The MathWorks, Inc.
methods (Static)
function dt = calculateInitialTimestamp(offset)
% calculateInitialTimestamp Makes a datetime out of a seconds offset.
%
% This function is used to convert the seconds offset from a channel
% start time as received from asyncio to a MATLAB datetime object of
% the current time and locale.
% Make a datetime object at the base time specified by the tamutil
% timestamp from asyncio.
dt = datetime(1970, 1, 1, 0, 0, 0);
dt.TimeZone = 'UTC';
% Add the time offset in seconds.
dt = dt + seconds(offset);
% Adjust the timezone of the object to the current time
% zone of the system.
dt.TimeZone = datetime().SystemTimeZone;
end
function key = deriveIDKey(message)
% deriveIDKey Makes a string key value from a message ID.
%
% This function is used to turn a numeric ID and Extended flag
% into a string value, generally use as a key value for maps. The
% string is the numeric ID with an 'x' on the end for extended
% identifiers.
% Turn the numeric ID into a string.
key = num2str(message.ID);
% Add the postfix onto the string if it is an extended ID.
if message.Extended
key = [key 'x'];
end
end
function [code, mask] = filterCalc(id, idType)
% filterCalc Calculates filter settings for a set of identifiers.
%
% This function is used interally to perform the calculations
% necessary to determine the CODE and MASK filter settings for
% a given ID or set of IDs of the specified IDTYPE.
% Cast the input IDs as uint32 for proper bit handling and to
% enable use of the MATLAB bit functions.
id = uint32(id);
% If only one ID is provided, the code and mask can be directly set.
% There is no need to calculate them. Just set them and return.
if numel(id) == 1
% For one ID, code is equal to the exact bit field of the ID.
code = id;
% For one ID, mask is simply all 1s to indicate that every bit
% of the field is relevant.
mask = uint32(hex2dec('FFFFFFFF'));
% Trim the unused bits.
zeroBits();
return;
end
% Bit complement the IDs. This is done to find the common
% positions in each ID where the values are 0.
idcmp = bitcmp(id);
% Calculating the code and mask for 2 or more IDs involves
% constantly ANDing each ID value together with the ongoing
% result. First, we do the AND on the first 2 IDs as well
% as AND the bit complement of the first 2 IDs together.
runningCode = bitand(id(1), id(2));
runningbandcmp = bitand(idcmp(1), idcmp(2));
% Loop through each remaining ID to AND it with the running
% result for the regular ID and bit complemented value too.
for ii = 3:numel(id)
runningCode = bitand(runningCode, id(ii));
runningbandcmp = bitand(runningbandcmp, idcmp(ii));
end
% Set the code.
code = runningCode;
% Calculate the mask by ORing together the code along with
% the ANDing of the one's complement of the IDs. This sets
% a 1 in every bit position of the mask where all IDs have
% either a 1 or a 0 in the same position.
mask = bitor(code, runningbandcmp);
% Trim the unused bits.
zeroBits();
function zeroBits()
% zeroBits Clears the unused bits from the code and mask.
%
% This function is used locally to zero out to preceding,
% unused bits of the code and mask that are still part of
% the uint32 bit field. For standard IDs, the function will
% zero the first 21 bits. For extended IDs, it will zero out
% just the first 3 bits.
% Adjust the code and mask values according to the type of ID for
% which the values are being calculated.
switch lower(idType)
case 'standard'
code = bitand(code, uint32(hex2dec('7FF')));
mask = bitand(mask, uint32(hex2dec('7FF')));
case 'extended'
code = bitand(code, uint32(hex2dec('1FFFFFFF')));
mask = bitand(mask, uint32(hex2dec('1FFFFFFF')));
end
end
end
function passed = validateCallbackFcn(func)
% validateCallbackFcn Validate a callback function.
%
% This method is used internally to validate an intended value
% for the message received callback functionality of the
% Channel class. Input may be a function handle, a string, or a
% cell array. In the case of a cell array, the first element in
% the array is expected to be a function handle.
% A valid callback value must either be a string, function
% handle, or cell array. If the type of func is none of
% these, then error.
if ~isempty(func) &&...
~ischar(func) &&...
~isa(func, 'function_handle') &&...
~iscell(func)
passed = false;
return;
end
% Extra validation is required for cell arrays.
if iscell(func)
% Check the type of the first element of the cell array.
% The first element must be a function handle.
if ~isa(func{1}, 'function_handle')
passed = false;
return;
end
end
% Return passed as true.
passed = true;
end
function executeCallbackFcn(func, channel)
% executeCallbackFcn Execute a callback function.
%
% This method is used internally to execute a set message
% received callback function. It activates the callback according
% to the type of value set to represent the callback.
% Check a string.
if ischar(func)
% Eval the string to execute it.
eval(func);
% Check for a function handle.
elseif isa(func, 'function_handle')
% Call the function directly.
feval(func, channel);
% Check a cell array.
elseif iscell(func)
% Set the function.
funcHandle = func{1};
% Extract the remainder of the cell array, exclusive of
% the first element, which was the function handle.
args = func(2:end);
% Invoke the callback function passing any extra arguments
% along with the call.
feval(funcHandle, channel, args{:});
end
end
function out = callbackFcnToString(func)
% callbackFcnToString Convert a callback function name to a string.
%
% This method is used internally to convert a callback function
% name to a string for used in screen displaying. It handles
% converting the name for types of empty, string, function
% handle, and cell array.
% Parse the func name to convert it properly.
if (isempty(func))
% When empty, return empty brackets.
out = '[]';
elseif (ischar(func))
% When a string type already, return it with quotes.
out = ['''' func ''''];
elseif (isa(func, 'function_handle'))
% When a function handle, convert with an @ symbol.
out = ['@' func2str(func)];
elseif (iscell(func))
% When a cell, obtain the size and class and return in curly braces.
out = ['{' num2str(size(func, 1)) 'x' num2str(size(func, 2)) ' ' class(func) '}'];
end
end
end
end