iPhone上读取ansi字符串的例子

iPhone的NSString并不支持ansi的字符串(比如咱们常用的gb2312), 因此如果要读取的话, 需要转换为UTF-8的

而iPhone上自带了libiconv库,于是这个转换变的就比较简单了

首先在工程的Framework部分加入/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.0.sdk/usr/lib/libiconv.dylib

当然,中间那个iPhoneOS3.0.sdk需要换成你当前使用的SDK版本

实际转换过程也就4步.

1,引入iconv库并添加头文件

2,利用iconv_open设置from和to的字符串编码

3,执行iconv进行转换

4,利用iconv_close关闭iconv_open创建的实例.

#include <iconv.h>
 
int code_convert(char *from_charset, char *to_charset, char *inbuf, size_t inlen, char *outbuf, size_t outlen) {
    iconv_t cd = NULL;
 
    cd = iconv_open(to_charset, from_charset);
    if(!cd)
        return -1;
 
    memset(outbuf, 0, outlen);
    if(iconv(cd, &inbuf, &inlen, &outbuf, &outlen) == -1)
        return -1;
 
    iconv_close(cd);
    return 0;
}
 
int u2g(char *inbuf, size_t inlen, char *outbuf, size_t outlen) {
    return code_convert("utf-8", "gb2312", inbuf, inlen, outbuf, outlen);
}
 
int g2u(char *inbuf, size_t inlen, char *outbuf,size_t outlen) {
    return code_convert("gb2312", "utf-8", inbuf, inlen, outbuf, outlen);
}

而在实际应用时, 无论从文件或者网络读取, 都要获取成NSData或者char *或void *, 至少不能是NSString, 因为NSString无法直接处理.以获取成NSData为例.

+ (NSString *)getANSIString:(NSData *)ansiData {
    char *ansiString = [ansiData bytes];
    int ansiLen = [ansiData length];
    int utf8Len = ansiLen * 2; //其实*1.5基本就够了
    char *utf8String = (char *)malloc(utf8Len);
    memset(utf8String, 0, utf8Len); //虽然code_convert中也memset了, 但还是自己分配后就set一次比较好
    int result = code_convert("gb2312", "utf-8", ansiString, ansiLen, utf8String, utf8Len);
    if(result == -1) {
        free(utf8String);
        return nil;
    }
    NSString *retString = [NSString stringWithUTF8String:utf8String];
    free(utf8String);
    return retString;
}

下面方法也可行：

NSStringEncoding myEncoding = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
    NSString* postStr = [NSString stringWithFormat:@"isbn=%@",ISBNStr];
    NSData* postData = [postStr dataUsingEncoding:myEncoding];