链接地址：http://qzc770707.blog.163.com/blog/static/34082753201022442356502/
UIImage 的字符串存储与读取
//
// NSDataAdditions.h
// IOSTestPro
//
// Created by infohold infohold_Mac3 on 13-2-22.
// Copyright (c) 2013年 infohold infohold_Mac3. All rights reserved.
//
#import <Foundation/Foundation.h>
@interface NSData (MBBase64)
//Get NSData from Base64 String
+ (id)dataWithBase64EncodedString:(NSString *)string;//Padding '=' characters are optional. Whitespace is ignored.
//Turn NSData into Base64 String
- (NSString *)base64Encoding;
@end
//实现文件
//
// NSDataAdditions.m
// IOSTestPro
//
// Created by infohold infohold_Mac3 on 13-2-22.
// Copyright (c) 2013年 infohold infohold_Mac3. All rights reserved.
//
#import "NSDataAdditions.h"
staticconstchar encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
//encodingTable.length = 64 = 26+26+10+2
@implementation NSData (MBBase64)
+ (NSData *) dataWithBase64EncodedString: (NSString *)string
{
// Create a memory buffer containing Base64 encoded string data
if (string == nil)
[NSExceptionraise:NSInvalidArgumentExceptionformat:nil];
if ([string length] == 0)
return [NSData data];
static char *decodingTable = NULL;
if (decodingTable == NULL)
{
decodingTable = malloc(256);
if (decodingTable == NULL)
return nil;
memset(decodingTable, CHAR_MAX, 256);
NSUInteger i;
for (i = 0; i < 64; i++)
decodingTable[(short)encodingTable[i]] = i;
}
constchar *characters = [string cStringUsingEncoding:NSASCIIStringEncoding];
if (characters == NULL) // Not an ASCII string!
return nil;
char *bytes = malloc((([string length] + 3) / 4) * 3);
if (bytes == NULL)
return nil;
NSUInteger length = 0;
NSUInteger i = 0;
while (YES)
{
char buffer[4];
short bufferLength;
for (bufferLength = 0; bufferLength < 4; i++)
{
if (characters[i] == '\0')
break;
if (isspace(characters[i]) || characters[i] == '=')
continue;
buffer[bufferLength] = decodingTable[(short)characters[i]];
if (buffer[bufferLength++] == CHAR_MAX) // Illegal character!
{
free(bytes);
return nil;
}
}
if (bufferLength == 0)
break;
if (bufferLength == 1) // At least two characters are needed to produce one byte!
{
free(bytes);
return nil;
}
// Decode the characters in the buffer to bytes.
bytes[length++] = (buffer[0] << 2) | (buffer[1] >> 4);
if (bufferLength > 2)
bytes[length++] = (buffer[1] << 4) | (buffer[2] >> 2);
if (bufferLength > 3)
bytes[length++] = (buffer[2] << 6) | buffer[3];
}
realloc(bytes, length);
return [NSDatadataWithBytesNoCopy:bytes length:length];
}
- (NSString *)base64Encoding;
{
if ([self length] == 0)
return @"";
char *characters = malloc((([self length] + 2) / 3) * 4);
if (characters == NULL)
return nil;
NSUInteger length = 0;
NSUInteger i = 0;
while (i < [self length])
{
char buffer[3] = {0,0,0};
short bufferLength = 0;
while (bufferLength < 3 && i < [self length])
buffer[bufferLength++] = ((char *)[self bytes])[i++];
// Encode the bytes in the buffer to four characters, including padding "=" characters if necessary.
characters[length++] = encodingTable[(buffer[0] & 0xFC) >> 2];
characters[length++] = encodingTable[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)];
if (bufferLength > 1)
characters[length++] = encodingTable[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)];
else characters[length++] = '=';
if (bufferLength > 2)
characters[length++] = encodingTable[buffer[2] & 0x3F];
else characters[length++] = '=';
}
return [[[NSStringalloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncodingfreeWhenDone:YES] autorelease];
}
@end
测试代码：
- (void)viewDidLoad
{
[superviewDidLoad];
UIImage *m_image = [UIImage imageNamed:@"pic_1.jpg"];
NSData *m_imageData = UIImageJPEGRepresentation(m_image, 1.0f);
NSString *m_Base64Str = [m_imageData base64Encoding];
NSData *m_imageDataFromString = [NSData dataWithBase64EncodedString:m_Base64Str];
UIImage *m_imageN = [UIImage imageWithData:m_imageDataFromString];
UIImageView *m_imageView =[[UIImageView alloc] initWithImage:m_imageN];
m_imageView.frame = CGRectMake(0, 0, 320, 460);
[self.view addSubview:m_imageView];
[m_imageView release];
}
THE END!
2013-02-22
