objCVCD

A VCD parser aiming to support IEEE 1364-1995.

Usage

Opening a document

To load an VCD file from local storage use

[VCD loadWithPath:filePath callback:^(VCD *vcd) {
	if(vcd == nil) {
		NSLog(@"VCD Parsing Error!");
		return;
	}
	
	// ...
}];

To load a VCD file from a web based location, use

[VCD loadWithURL:[NSURL URLWithString:@"http://your.location/test.vcd"] callback:^(VCD *vcd) {
	if(vcd == nil) {
		NSLog(@"VCD Parsing Error!");
		return;
	}
	
	// ...
}];

To simplify prototyping, we support a list of sample VCD files which can be accessed by this piece of code:

NSDictionary *samples = [VCD loadAvailableSamples];

for(NSString title in [samples allKeys]) {
	NSURL *url = [samples objectForKey:title];
	
	NSLog(@"Title: %@; URL: %@", title, url);
}

Please keep in mind, that loadAvailableSamples uses blocking I/O.

Elements of VCD:

• [VCD loadWithPath:path callback:^(VCD *vcd) { /* ... */}]: Loads VCD from NSString path and calls callback
• [VCD loadWithURL:url callback:^(VCD *vcd) { /* ... */}]: Loads VCD from NSURL and calls callback
• [VCD loadAvailableSamples]: Loads NSDictionary of samples of NSURLs and NSString as its key.
• [vcd signals]: returns NSDictionary of signals, identified by signal name
• [vcd timeScale]: returns int of timescale factor
• [vcd timeScaleUnit]: returns NSString of timescale unit (e.g. ns)
• [vcd date]: returns NSDate of creation
• [vcd version]: returns NSString version
• [vcd scope]: returns NSString scope

Accessing Signals

VCD *vcd = nil;

// Magically loading a VCD file
// ...

for(VCDSignal *signal in [[vcd signals] allValues]) {
	NSLog("Name of signal: %@", [signal name]);
}

Elements of VCDSignal:

• [signal name]: returns NSString name of signal
• [signal symbol]: returns NSString symbol of signal
• [signal symbol]: returns NSString symbol of signal
• [vcd valueAtTime:time]: returns value at specific time.

Accessing Signal Values

VCDSignal *signal = nil;

// Magically loads VCD Signal
// ...

// Access value at specific time.
// Please note, that valueAtTime does NOT respect the timescale!
VCDValue *v = [signal valueAtTime:500];

NSLog(@"First ValueChange at %d", [v time]);
// The VCDValue will be the very first value before the given time.
// Therefore, [v time] will be lesser equal 500.

// Iterate through values:
do {
	NSLog("ValueChange at: %d: newValue: %@", [v time], [v value]);
} while(v = [v next]);

// Or in short:
for(VCDValue *v = [signal valueAtTime:500]; v != nil; v = [v next]) {
	// ...
}