wen-long · September 3, 2015 16:30 · May 14, 2012
diff --git a/serial.m b/serial.m
@@ -0,0 +1,225 @@
+#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