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Playing with NSPropertyListSerialization
#import <Foundation/Foundation.h>
// clang -g -Wall -fobjc-arc -framework Foundation -o serial serial.m
static id makePlistObjects (void) {
NSMutableDictionary *top = [NSMutableDictionary dictionary];
[top setObject: @"Hi I'm a string" forKey: @"string"];
[top setObject: [NSNumber numberWithInt: 23] forKey: @"number"];
[top setObject: [NSNumber numberWithBool: YES] forKey: @"boolean"];
[top setObject: [NSDate date] forKey: @"date"];
[top setObject: [NSData dataWithBytes: "badger" length: 7] forKey: @"data"];
NSArray *array =
[NSArray arrayWithObjects: @"I", @"seem", @"to", @"be", @"a", @"verb", nil];
[top setObject: array forKey: @"array"];
NSDictionary *dict =
[NSDictionary dictionaryWithObjectsAndKeys:
@"Ack", @"Oop",
@"Bill the Cat", @"It's", nil];
[top setObject: dict forKey: @"dictionary"];
return top;
} // makePlistObjects
// --------------------------------------------------
// Writing and reading property list objects
static void saveAsOpenStep (id plist) {
if (![NSPropertyListSerialization
propertyList: plist
isValidForFormat: kCFPropertyListOpenStepFormat]) {
NSLog (@"can't save as open step");
return;
}
// Turns out you can't save as open step any more - just read them. Bummer.
} // saveAsOpenStep
static void saveAsXML (id plist) {
if (![NSPropertyListSerialization
propertyList: plist
isValidForFormat: kCFPropertyListXMLFormat_v1_0]) {
NSLog (@"can't save as XML");
return;
}
NSError *error;
NSData *data =
[NSPropertyListSerialization dataWithPropertyList: plist
format: kCFPropertyListXMLFormat_v1_0
options: 0
error: &error];
if (data == nil) {
NSLog (@"error serializing to xml: %@", error);
return;
}
BOOL writeStatus = [data writeToFile: @"plist.xml"
options: NSDataWritingAtomic
error: &error];
if (!writeStatus) {
NSLog (@"error writing to file: %@", error);
return;
}
} // saveAsXML
static void saveAsBinary (id plist) {
if (![NSPropertyListSerialization
propertyList: plist
isValidForFormat: kCFPropertyListBinaryFormat_v1_0]) {
NSLog (@"can't save as binary");
return;
}
NSError *error;
NSData *data =
[NSPropertyListSerialization dataWithPropertyList: plist
format: kCFPropertyListBinaryFormat_v1_0
options: 0
error: &error];
if (data == nil) {
NSLog (@"error serializing to xml: %@", error);
return;
}
BOOL writeStatus = [data writeToFile: @"plist.bin"
options: NSDataWritingAtomic
error: &error];
if (!writeStatus) {
NSLog (@"error writing to file: %@", error);
return;
}
} // saveAsBinary
static id readFromFile (NSString *path) {
NSError *error;
NSData *data = [NSData dataWithContentsOfFile: path
options: 0
error: &error];
if (data == nil) {
NSLog (@"error reading %@: %@", path, error);
return nil;
}
NSPropertyListFormat format;
id plist = [NSPropertyListSerialization propertyListWithData: data
options: NSPropertyListImmutable
format: &format
error: &error];
if (plist == nil) {
NSLog (@"could not deserialize %@: %@", path, error);
} else {
NSString *formatDescription;
switch (format) {
case NSPropertyListOpenStepFormat:
formatDescription = @"openstep";
break;
case NSPropertyListXMLFormat_v1_0:
formatDescription = @"xml";
break;
case NSPropertyListBinaryFormat_v1_0:
formatDescription = @"binary";
break;
default:
formatDescription = @"unknown";
break;
}
NSLog (@"%@ was in %@ format", path, formatDescription);
}
return plist;
} // readFromFile
// --------------------------------------------------
// Writing and reading JSON
static void saveAsJSON (id plist) {
if (![NSJSONSerialization isValidJSONObject: plist]) {
NSLog (@"can't save as JSON");
return;
}
NSError *error;
NSData *data =
[NSJSONSerialization dataWithJSONObject: plist
options: 0 // NSJSONWritingPrettyPrinted
error: &error];
if (data == nil) {
NSLog (@"error serializing to json: %@", error);
return;
}
BOOL writeStatus = [data writeToFile: @"plist.json"
options: NSDataWritingAtomic
error: &error];
if (!writeStatus) {
NSLog (@"error writing to file: %@", error);
return;
}
} // saveAsJSON
static id readFromJSONFile (NSString *path) {
NSError *error;
NSData *data = [NSData dataWithContentsOfFile: path
options: 0
error: &error];
if (data == nil) {
NSLog (@"error reading %@: %@", path, error);
return nil;
}
id plist = [NSJSONSerialization JSONObjectWithData: data
options: 0
error: &error];
if (plist == nil) {
NSLog (@"could not deserialize %@: %@", path, error);
}
return plist;
} // readFromJSONFile
int main (void) {
@autoreleasepool {
id plist = makePlistObjects ();
NSLog (@"original plist %@", plist);
saveAsOpenStep (plist);
saveAsXML (plist);
saveAsBinary (plist);
id plist2 = readFromFile (@"plist.bin");
NSLog (@"read plist: %@", plist2);
// Make JSON-happy. Can't store dates, but we can store NULLs.
[plist removeObjectForKey: @"date"];
[plist setObject: [NSNull null] forKey: @"null"];
saveAsJSON (plist);
id plist3 = readFromJSONFile (@"plist.json");
NSLog (@"read JSON: %@", plist3);
}
return 0;
} // main
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