TroubleWithNSScanner

Hi, I am trying to scan a text file using nsscanner. but it failed somehow and i don’t know why.

here is the file example :

v -0.38733 14.14545 -0.06502 v 0.19083 14.34016 -0.98115 v -0.50296 14.58355 -2.12632 v -2.12179 14.63222 -2.35535 v -2.69994 14.38883 -1.21019

vn -0.01873 -0.01664 -0.01477 vn -0.00510 -0.00352 -0.00479 vn -0.00198 -0.00065 -0.00220 vn -0.00568 -0.00643 -0.00543 vn -0.01920 -0.02015 -0.01348 vn -0.02511 -0.02719 -0.01687 vn -0.01049 0.00405 0.00145 vn -0.00699 0.00251 0.01230 vn 0.00175 0.00160 0.01005 vn -0.00874 -0.00243 -0.00257 g STEM f 3 2 1 f 2 4 1 f 4 5 1 f 6 1 5 f 5 7 6 f 7 6 8 f 8 9 6 f 8 10 9 f 10 11 9

and here is my code :

// this is the filename -> objFileName

General/NSString *objFile = General/[NSString stringWithContentsOfFile:objFileName]; General/NSScanner *scanner;

float x,y,z; scanner = General/[NSScanner scannerWithString:objFile];

while (![scanner isAtEnd]) { if ([scanner scanString:@”v” intoString:nil]) { [scanner scanFloat:&x]; [scanner scanFloat:&y]; [scanner scanFloat:&z]; } General/NSLog(@”x = %f , y = %f , z = %f”, x,y,z); }

this code end up with displaying all the “x = , y = , z = " but then my application freeze up. Thanks in advance - General/JuliusJuarsa

Where does it freeze?

I think it was right after the application displays all the v and then it try to scan the next line i guest; but then i try to add few of these line between the while iteration :

if ….. } else if ([scanner scanString:@”vn” intoString:nil]) { [scanner scanFloat:&x]; [scanner scanFloat:&y]; [scanner scanFloat:&z]; } General/NSLog(@”x = %f , y = %f , z = %f”, x,y,z); }

the run log window shows nothing T.T - General/JuliusJuarsa

“I think” is a bad thing here. Run your program in the debugger and find out exactly where it’s getting stuck.

thanks for the tip on using the debugger. Still my first time using it though but it’s proven to be usefull ^^, i’ve found the problem. it stuck because when the scanner didn’t find any of the ‘v’,’vn’ or ‘f’ i didn’t scan for the newLineCharacterSet. here is the final code :

General/NSString *objFile = General/[NSString stringWithContentsOfFile:objFileName];

General/NSScanner *scanner;
General/NSCharacterSet *newLineCharacterSet = General/[NSCharacterSet characterSetWithCharactersInString:@"\n"];
	
float x,y,z;
int jmhTitik = 0;
int jmhVn = 0;
int jmhF = 0;
scanner = General/[NSScanner scannerWithString:objFile];

while ([scanner isAtEnd] == NO)
{
	if ([scanner scanString:@"v " intoString:nil])
	{
		[scanner scanFloat:&x];
		[scanner scanFloat:&y];
		[scanner scanFloat:&z];

		jmhTitik++;
	} 
	else if ([scanner scanString:@"vn " intoString:nil])
	{
		[scanner scanFloat:&x];
		[scanner scanFloat:&y];
		[scanner scanFloat:&z];
		jmhVn++;
	}
	else if ([scanner scanString:@"f " intoString:nil])
	{
		[scanner scanInt:nil];
		[scanner scanInt:nil];
		[scanner scanInt:nil];
		jmhF++;
	} 
	else
	{
		[scanner scanUpToCharactersFromSet:newLineCharacterSet intoString:nil];
	}
}
	
General/NSLog(@"jumlah titik = %d ; jumlah vn = %d ; jumlah f = %d",jmhTitik,jmhVn,jmhF);

I am trying to use General/NSScanner on some malformed HTML but immediately ran into problems. Here is some General/SenTestingKit code to illustrate the problem.

@implementation General/MyScanner

(void)test_MyScanner { General/NSString *row = nil; General/NSScanner *html = General/[NSScanner scannerWithString:@”<html><body><tr><td>index 0</td></tr></body></html>”];

/* Capture @”<tr><td>index 0</td></tr>” in variable row */

[html scanUpToString:@”<tr>” intoString:nil]; General/STAssertTrue( ([html scanLocation] == 12), @”(1) scanner @ %d”, [html scanLocation] );

[html scanString:@”</tr>” intoString:&row]; General/STAssertTrue( ([html scanLocation] == 37), @”(2) scanner @ %d”, [html scanLocation] ); } @end

This code fails with the following assertion print.

error: -General/[MyScanner test_MyScanner]: "([html scanLocation] == 37)" should be true, (2) scanner @ 12

Repeating with the following also fails.

@implementation General/MyScanner

(void)test_MyScanner { General/NSString *row = nil; General/NSScanner *html = General/[NSScanner scannerWithString:@”<html><body><tr><td>index 0</td></tr></body></html>”];

/* Just try to advance the scanner to after </tr> */

[html scanString:@”</tr>” intoString:nil]; General/STAssertTrue( ([html scanLocation] == 37), @”(2) scanner @ %d”, [html scanLocation] ); } @end

This code fails with the following assertion print.

error: -General/[MyScanner test_MyScanner]: "([html scanLocation] == 37)" should be true, (2) scanner @ 0

Using only scanUpToString for both tags works but I can’t use the General/NSString* returned in the intoString argument. I have to use math to advance the cursor past the trailing tag and then an General/NSString method to actual extract the subrange. What am I missing? Why can’t I use the first code snippet?

Use both. scanUpToString: followed by scanString: for both tags. scanString: will not move the scan location, so the string you scan must be at the current location. Likewise, scanUpToString: will not move the location past the string, so you have to advance past it by actually scanning the string as well.

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