Saturday, June 16, 2012

NSString (1)



Test harness:

// clang strings1.m -o prog -framework Foundation -fobjc-gc-only
#include <Foundation/Foundation.h>

int main(int argc, char * argv[]) {

    // ..code here..

    return 0;
}

NSString *s;
    NSMutableArray *ma = [NSMutableArray arrayWithCapacity:10];

    char *cstr = "abc";   // real C string w/ "\0" also works
    uint ascii = NSASCIIStringEncoding;
    uint utf8 = NSUTF8StringEncoding;
    [ma addObject:[NSString stringWithCString:cstr encoding:ascii]];
    [ma addObject:[NSString stringWithCString:cstr encoding:utf8]];
    [ma addObject:[NSString stringWithUTF8String:cstr]];
    NSMutableString *ms = [[NSMutableString alloc] init];
    [ms appendString:@"abde"];
    [ms insertString:@"c" atIndex:2];
    [ma addObject:[ms copy]];  // otherwise code below will alter
    [ms appendString:@"fghij"];
    [ms replaceOccurrencesOfString:@"B"
                        withString:@"*"
                           options:NSCaseInsensitiveSearch
                             range:NSMakeRange(0,2) ];
    [ma addObject:ms];
    for (id obj in ma) { NSLog(@"%@ %@", obj, [obj class]); }
    [ma removeAllObjects];
    printf("-----------------\n");



> ./prog
2012-05-29 16:45:03.624 prog[444:707] abc __NSCFString
2012-05-29 16:45:03.626 prog[444:707] abc __NSCFString
2012-05-29 16:45:03.627 prog[444:707] abc __NSCFString
2012-05-29 16:45:03.627 prog[444:707] abcde __NSCFString
2012-05-29 16:45:03.628 prog[444:707] a*cdefghij __NSCFString
-----------------

[ma addObject:[NSString stringWithFormat:@"abcd"]];
    [ma addObject:[NSString stringWithFormat:@"ab%@", @"cd" @"ef"]];
    [ma addObject:[NSString stringWithFormat:@"a%C%C", 0x62, 0x63]];
    char b[] = { 0x61, 0x62, 0x63, 0x64, 0x65 };
    NSData *d = [NSData dataWithBytes:b length:5];
    s = [[NSString alloc] initWithData:d encoding:utf8];
    [ma addObject:s];
    for (id obj in ma) { NSLog(@"%@ %@", obj, [obj class]); }
    printf("-----------------\n");

2012-05-29 16:45:03.629 prog[444:707] abcd __NSCFString
2012-05-29 16:45:03.629 prog[444:707] abcdef __NSCFString
2012-05-29 16:45:03.630 prog[444:707] abc __NSCFString
2012-05-29 16:45:03.630 prog[444:707] abcde __NSCFString
-----------------

d = [NSData dataWithBytes:b length:5];
    [d writeToFile:@"x" atomically:YES];
    NSError *err = nil;
    NSStringEncoding enc = NSUTF8StringEncoding;
    s = [NSString stringWithContentsOfFile:@"x" 
                              usedEncoding:&enc
                                     error:&err];
    if (err != nil) { NSLog(@"%@", [err userInfo]); }
    else {  NSLog(@"%@", s );  }

    b[4] = 0xff;
    d = [NSData dataWithBytes:b length:5];
    [d writeToFile:@"x" atomically:YES];
    s = [NSString stringWithContentsOfFile:@"x" 
                              usedEncoding:&enc 
                                     error:&err];
    if (err != nil) { NSLog(@"%@", [err localizedDescription]); } 
    else {  NSLog(@"%@", s );  }

2012-05-29 16:45:03.641 prog[444:707] abcde
2012-05-29 16:45:03.658 prog[444:707] The file “x” couldn’t be opened because the text encoding of its contents can’t be determined.


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