DwightChan · October 14, 2016 12:35 · Jun 24, 2013 · Jun 24, 2013
diff --git a/NSString+Extensions.m b/NSString+Extensions.m
@@ -0,0 +1,57 @@
+#import "NSString+Extensions.h"
+#import <CommonCrypto/CommonDigest.h>
+
+
+@implementation NSString (Extensions)
+
++ (NSString*)stringToSha1:(NSString*)str {
+  const char *s = [str cStringUsingEncoding:NSUTF8StringEncoding];
+    NSData *keyData = [NSData dataWithBytes:s length:strlen(s)];
+
+    // This is the destination
+    uint8_t digest[CC_SHA1_DIGEST_LENGTH] = {0};
+    // This one function does an unkeyed SHA1 hash of your hash data
+    CC_SHA1(keyData.bytes, keyData.length, digest);
+
+    // Now convert to NSData structure to make it usable again
+    NSData *out = [NSData dataWithBytes:digest length:CC_SHA1_DIGEST_LENGTH];
+    NSString *hash = [out description];
+
+	NSCharacterSet *doNotWants = [NSCharacterSet characterSetWithCharactersInString:@"<> "];
+	hash = [[hash componentsSeparatedByCharactersInSet:doNotWants] componentsJoinedByString:@""];
+
+    return hash;
+}
+
+- (NSNumber*)stringToNSNumber {
+	NSNumberFormatter* tmpFormatter = [[NSNumberFormatter alloc] init];
+	[tmpFormatter setNumberStyle:NSNumberFormatterDecimalStyle];
+	NSNumber* theNumber = [tmpFormatter numberFromString:self];
+	return theNumber;
+}
+
+- (BOOL)isEmpty {
+    if ([self length] <= 0 || self == (id)[NSNull null] || self == nil) {
+        return YES;
+    } 
+    return NO;
+}
+
+- (BOOL)stringContainsSubString:(NSString *)subString {
+    NSRange aRange = [self rangeOfString:subString];
+    if (aRange.location == NSNotFound) {
+        return NO;
+    }
+
+    return YES;
+}
+
+- (NSString*)stringByReplacingStringsFromDictionary:(NSDictionary*)dict {
+    NSMutableString* string = [self mutableCopy];
+    for (NSString* target in dict) {
+        [string replaceOccurrencesOfString:target withString:[dict objectForKey:target] options:0 range:NSMakeRange(0, [string length])];
+    }
+    return string;
+}
+
+@end
diff --git a/NSString+Extensions.h b/NSString+Extensions.h
@@ -0,0 +1,13 @@
+#import <Foundation/Foundation.h>
+
+
+@interface NSString (Extensions) 
+
++ (NSString *)stringToSha1:(NSString *)str;
+- (NSNumber*)stringToNSNumber;
+- (BOOL)isEmpty;
+- (BOOL)stringContainsSubString:(NSString *)subString;
+- (NSString *)stringByReplacingStringsFromDictionary:(NSDictionary *)dict;
+
+
+@end