當C++遇到iOS應用開發---字符串處理

在Object-c中，字符串處理通常使用NSString，NSMutableString這兩個類，前者用於定長字符串，後者用於可變長度字符串的操作。盡量其提供的方法很豐富，但一用起來後就讓人感到很難受，比如其超長的方法名稱（如stringByReplacingPercentEscapesUsingEncoding），再加上嵌套“[]”式的調用方式，讓人很快就會產生"[]"匹配綜合症。

即使xcode提供了自動配對“[]”號的功能，但一閱讀起源代碼後依舊讓人心生厭惡。給人一種“強迫打字綜合症”的感覺。所以我在NSMutableString基礎上用C++進行了封裝，特別是對於一些常用方法的使用，在使用時會非常方便，與C#沒太大差別。

首先看一下String類的源碼（說明：因為C++中有std::string這個類，為了與其區別，這裡使用了首字母大寫）。

1. #import "RegexKitLite.h"
3. #define RELEASE_SAFELY(__POINTER) { [__POINTER release]; __POINTER = nil; }
5. class String {
6. private:
8. NSMutableString *temp;
10. static inline NSMutableString* ToMutableString(NSString *str){
11. return [[NSMutableString stringWithString:(NSString *)str] autorelease];
12. }
14. public :
15. String(){
16. temp = ToMutableString(@"");
17. }
19. String(NSString *str){
20. temp = ToMutableString(str);
21. }
23. String(int value){
24. temp = ToMutableString([NSString stringWithFormat:@"%d", value]);
25. }
27. String(float value){
28. temp = ToMutableString([NSString stringWithFormat:@"%f", value]);
29. }
31. String(std::string str){
32. temp = ToMutableString(toNSString(str));
33. }
35. String(const char* str){
36. temp = ToMutableString(toNSString(str));
37. }
39. ~String(){
40. RELEASE_SAFELY(temp);
41. }
43. NSString * toString(){
44. return temp;
45. }
47. const std::string toStdString(){
48. return [temp UTF8String];
49. }
51. NSString * toLower(){
52. return [temp lowercaseString];
53. }
55. NSString* toUpper(){
56. return [temp uppercaseString];
57. }
59. int length(){
60. return temp.length;
61. }
63. bool contains(NSString *search){
64. return [temp rangeOfString:search].location != NSNotFound;
65. }
67. //不考慮大小寫
68. static BOOL stringEquals(NSString* str1, NSString* str2)
69. {
70. if ( str1 == nil || str2 == nil ) {
71. return NO;
72. }
73. return [str1 compare:str2 options:NSCaseInsensitiveSearch] == NSOrderedSame;
74. }
76. //區分大小寫
77. static BOOL caseEquals(NSString* str1, NSString* str2)
78. {
79. return (str1 == nil || str2 == nil) ? NO : [str1 isEqualToString:str2];
80. }
82. bool operator==( NSString *str)
83. {
84. return caseEquals(this->toString(), str);
85. }
87. bool operator==( String *str)
88. {
89. return caseEquals(this->toString(), str->toString());
90. }
92. //區分大小寫
93. BOOL startWith(NSString *prefix){
94. if ( temp != nil && prefix != nil ){
95. if ( prefix.length > temp.length ) {
96. return NO;
97. }
98. if ([temp hasPrefix:prefix]){
99. return YES;
100. }
101. }
102. return NO;
103. }
105. //區分大小寫
106. BOOL endWith(NSString* suffix){
107. if ( temp != nil && suffix != nil ){
108. if ( [suffix length] > [temp length] ) {
109. return NO;
110. }
111. if ([temp hasSuffix:suffix]){
112. return YES;
113. }
114. }
115. return NO;
116. }
119. String& operator=( NSString *str)
120. {
121. temp = ToMutableString(str);
122. return (*this);
123. }
125. String& operator=( std::string str)
126. {
127. temp = ToMutableString(toNSString(str));
128. return (*this);
129. }
131. String& operator=( Json::Value value)
132. {
133. temp = ToMutableString(toNSString(value.asString()));
134. return (*this);
135. }
138. //不區別大小寫
139. BOOL isURL(){
140. if ( [temp length] > 6 ) {
141. NSString* prefix = [temp substringToIndex:6];
142. if (stringEquals(prefix, @"http:/") || stringEquals(prefix, @"https:") ) {
143. return YES;
144. } else if (stringEquals(prefix, @"local:")){
145. return YES;
146. }
147. }
148. if (startWith(@"/")){
149. return YES;
150. }
151. return NO;
152. }
154. int toInt(){
155. return [temp intValue];
156. }
158. int toFloat(){
159. return [temp floatValue];
160. }
162. NSDate* toDate(NSString* fmt){
163. return stringToDate(temp, fmt);
164. }
167. NSArray* split(NSString *schar){
168. return [temp componentsSeparatedByString:schar];
169. }
171. String& trim(){
172. temp = ToMutableString([temp stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceAndNewlineCharacterSet]]);
173. return (*this);
174. }
176. String& append(NSString *appstr){
177. [temp appendString:appstr];
178. return *this;
179. }
182. BOOL isEmpty(){
183. return temp == nil || [temp length] == 0;
184. }
187. String& appendFormat(NSString* formatStr, ...){
188. va_list arglist;
189. va_start(arglist, formatStr);
190. id statement = [[NSString alloc] initWithFormat:formatStr arguments:arglist];
191. va_end(arglist);
192. [temp appendString:statement];
193. [statement release];
194. return *this;
195. }
197. String& replace(NSString *oldStr, NSString *newStr){
198. [temp replaceOccurrencesOfString:oldStr
199. withString:newStr
200. options:0 range:NSMakeRange(0, [temp length])];
201. return *this;
202. }
204. String& regexReplace(NSString *regex, NSString *newStr){
205. NSString *tempstr = temp;
206. temp = ToMutableString([tempstr stringByReplacingOccurrencesOfRegex:regex withString:newStr]);
207. return *this;
208. }
210. NSArray* regexMatchs(NSString *regex){
211. return [temp componentsMatchedByRegex:regex];
212. }
214. NSArray* regexMatchs(NSString *regex, int capture){
215. return [temp componentsMatchedByRegex:regex capture:capture];
216. }
218. BOOL regexIsMatch(NSString *regex){
219. return [temp isMatchedByRegex:regex];
220. }
224. NSString * encodeUrl(){
225. NSString *resultStr = temp;
227. CFStringRef originalString = (CFStringRef) temp;
228. CFStringRef leaveUnescaped = CFSTR(" ");
229. CFStringRef forceEscaped = CFSTR("!*'();:@&=+$,/?%#[]");
231. CFStringRef escapedStr;
232. escapedStr = CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
233. originalString,
234. leaveUnescaped,
235. forceEscaped,
236. kCFStringEncodingUTF8);
238. if(escapedStr)
239. {
240. NSMutableString *mutableStr = [NSMutableString stringWithString:(NSString *)escapedStr];
241. CFRelease(escapedStr);
242. if (!mutableStr || [mutableStr isKindOfClass:[NSNull class]] || mutableStr.length <= 0) {
243. return resultStr;
244. }
246. // replace spaces with plusses
247. [mutableStr replaceOccurrencesOfString:@" "
248. withString:@"%20"
249. options:0
250. range:NSMakeRange(0, [mutableStr length])];
251. resultStr = mutableStr;
252. }
254. return resultStr;
255. }
257. NSString * decodeUrl(){
258. return [temp stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
259. }
261. NSString * toGBK(){
262. NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
263. NSData *data = [temp dataUsingEncoding:NSUTF8StringEncoding];
264. return [[[NSString alloc] initWithData:data encoding:enc] autorelease];
265. }
267. NSString * toUTF8(){
268. return [DZUtils urlEncode:temp stringEncode:NSUTF8StringEncoding];
269. }
271. NSData * toNSData(){
272. return [temp dataUsingEncoding:NSUTF8StringEncoding];
273. }
275. NSString* subString(int start/*start from 0*/, int count){
276. if(start + count <= temp.length)
277. return [temp substringWithRange:NSMakeRange(start, count)];
278. return nil;
279. }
281. NSString* subString(int count){
282. if(count <= temp.length)
283. return [temp substringToIndex: count];
284. return nil;
285. }
287. static NSDate* stringToDate(NSString * string, NSString* fmt){
288. NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
289. [formatter setTimeZone:[NSTimeZone defaultTimeZone]];
290. NSString* format = fmt == nil ? @"yyyy-MM-dd'T'HH:mm:ss'Z'" : fmt;
291. [formatter setDateFormat:format];
292. NSDate *date = [formatter dateFromString:string];
293. [formatter release];
294. return date;
295. }
297. static NSString* dateToString(NSDate* date, NSString* fmt){
298. NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
299. [formatter setTimeZone:[NSTimeZone defaultTimeZone]];
300. NSString* format = fmt == nil ? @"yyyy-MM-dd'T'HH:mm:ss'Z'" : fmt;
301. [formatter setDateFormat:format];
302. NSString* dateStr = [formatter stringFromDate:date];
303. [formatter release];
304. return dateStr;
305. }
307. static NSString* format(NSString* formatStr, ...){
308. va_list arglist;
309. va_start(arglist, formatStr);
310. id statement = [[[NSString alloc] initWithFormat:formatStr arguments:arglist] autorelease];
311. va_end(arglist);
312. return statement;
313. }
315. static NSString* toNSString(std::string str){
316. return toNSString(str.c_str());
317. }
319. static NSString* toNSString(const char* str){
320. return [NSString stringWithUTF8String:str];
321. }
323. static NSString* toNSString(Json::Value value){
324. return toNSString(value.asString());
325. }
327. static String Create(Json::Value value){
328. String str(toNSString(value));
329. return str;
330. }
331. };