在 ios 下实现 DataOutputStream 和 DataInputStream

       我们在java通讯，常用 DataOutputStream 和 DataInputStream 这两个数据流，客户端是android和j2me 的话没有什么大问题，如果是iphone和bada就比较麻烦了。为解决这问题我在ios下封装了 DataOutputStream 和 DataInputStream 这两个类，提供大家参考。

////  DataOutputStream.h//  DataStream////  Created by wangzhongbin on 11-8-16.//  Copyright 2011 wangzhongbin. All rights reserved.//#import <Foundation/Foundation.h>// 数据输出流允许应用程序以适当方式将基本数据类型写入输出流中@interface DataOutputStream : NSObject {NSMutableData *data;NSInteger length;}// 将一个 char 值以 1-byte 值形式写入基础输出流中，先写入高字节。- (void)writeChar:(int8_t)v;//将一个 short 值以 2-byte 值形式写入基础输出流中，先写入高字节。- (void)writeShort:(int16_t)v;//将一个 int 值以 4-byte 值形式写入基础输出流中，先写入高字节。- (void)writeInt:(int32_t)v;//将一个 long 值以 8-byte 值形式写入基础输出流中，先写入高字节。- (void)writeLong:(int64_t)v;//以与机器无关方式使用 UTF-8 修改版编码将一个字符串写入基础输出流。- (void)writeUTF:(NSString *)v;//将一个 NSData byte数组写入输出流中，先写入高字节。- (void)writeBytes:(NSData *)v;//将此转换为 byte 序列。- (NSData *)toByteArray;@end

////  DataOutputStream.m//  DataStream////  Created by wangzhongbin on 11-8-16.//  Copyright 2011 wangzhongbin. All rights reserved.//#import "DataOutputStream.h"@implementation DataOutputStream- (id)init{    self = [super init];if(self != nil){data = [[NSMutableData alloc] init];length = 0;}return self;}- (void)writeChar:(int8_t)v {int8_t ch[1];ch[0] = (v & 0x0ff);[data appendBytes:ch length:1];length++;}- (void)writeShort:(int16_t)v {int8_t ch[2];ch[0] = (v & 0x0ff00)>>8;ch[1] = (v & 0x0ff);[data appendBytes:ch length:2];length = length + 2;}- (void)writeInt:(int32_t)v {int8_t ch[4];for(int32_t i = 0;i<4;i++){ch[i] = ((v >> ((3 - i)*8)) & 0x0ff);}[data appendBytes:ch length:4];length = length + 4;}- (void)writeLong:(int64_t)v {int8_t ch[8];for(int32_t i = 0;i<8;i++){ch[i] = ((v >> ((7 - i)*8)) & 0x0ff);}[data appendBytes:ch length:8];length = length + 8;}- (void)writeUTF:(NSString *)v {NSData *d = [v dataUsingEncoding:NSUTF8StringEncoding];NSInteger len = [d length];[self writeShort:len];[data appendData:d];length = length + len;}- (void)writeBytes:(NSData *)v {[data appendData:v];NSInteger len = [v length];length = length + len;}- (NSData *)toByteArray{return [[[NSData alloc] initWithData:data] autorelease];}- (void)dealloc{[data release];[super dealloc];}@end

////  DataInputStream.h//  DataStream////  Created by  wangzhongbin on 11-8-15.//  Copyright 2011年 wangzhongbin. All rights reserved.//#import <Foundation/Foundation.h>// 从输入流读取基本数据类型的方法，以便解组自定义值类型@interface DataInputStream : NSObject {NSData *data;NSInteger length;}//- (id)initWithData:(NSData *)data;//+ (id)dataInputStreamWithData:(NSData *)aData;// 从输入流读取 char 值。- (int8_t)readChar;//从输入流读取 short 值。- (int16_t)readShort;//从输入流读取 int 值。- (int32_t)readInt;//从输入流读取 long 值。- (int64_t)readLong;//从输入流读取 NSString 字符串。- (NSString *)readUTF;@end

////  DataInputStream.m//  DataStream////  Created by  wangzhongbin on 11-8-15.//  Copyright 2011年 wangzhongbin. All rights reserved.//#import "DataInputStream.h"@interface DataInputStream (PrivateMethods)- (int32_t)read;@end@implementation DataInputStream- (id)initWithData:(NSData *)aData {    self = [self init];if(self != nil){        data = [[NSData alloc] initWithData:aData];}return self;}- (id)init{    self = [super init];if(self != nil){length = 0;}return self;}+ (id)dataInputStreamWithData:(NSData *)aData {    DataInputStream *dataInputStream = [[self alloc] initWithData:aData];    return [dataInputStream autorelease];}- (int32_t)read{    int8_t v;    [data getBytes:&v range:NSMakeRange(length,1)];    length++;    return ((int32_t)v & 0x0ff);}- (int8_t)readChar {    int8_t v;    [data getBytes:&v range:NSMakeRange(length,1)];    length++;    return (v & 0x0ff);}- (int16_t)readShort {    int32_t ch1 = [self read];    int32_t ch2 = [self read];    if ((ch1 | ch2) < 0){@throw [NSException exceptionWithName:@"Exception" reason:@"EOFException" userInfo:nil];    }    return (int16_t)((ch1 << 8) + (ch2 << 0));    }- (int32_t)readInt {    int32_t ch1 = [self read];    int32_t ch2 = [self read];    int32_t ch3 = [self read];    int32_t ch4 = [self read];    if ((ch1 | ch2 | ch3 | ch4) < 0){@throw [NSException exceptionWithName:@"Exception" reason:@"EOFException" userInfo:nil];    }    return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));}- (int64_t)readLong {    int8_t ch[8];    [data getBytes:&ch range:NSMakeRange(length,8)];    length = length + 8;    return (((int64_t)ch[0] << 56) +            ((int64_t)(ch[1] & 255) << 48) +            ((int64_t)(ch[2] & 255) << 40) +            ((int64_t)(ch[3] & 255) << 32) +            ((int64_t)(ch[4] & 255) << 24) +            ((ch[5] & 255) << 16) +            ((ch[6] & 255) <<  8) +            ((ch[7] & 255) <<  0));}- (NSString *)readUTF {    short utfLength = [self readShort];    NSData *d = [data subdataWithRange:NSMakeRange(length,utfLength)];    NSString *str = [[[NSString alloc] initWithData:d encoding:NSUTF8StringEncoding] autorelease];    length = length + utfLength;return str;}- (void)dealloc{[data release];[super dealloc];}@end