這幾天在處理一個登入介面
不過傳送密碼時碰到問題了
由於密碼中有特殊字元,諸如 @+等字元
而這些字元在 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding 中並不會被編碼
所以 server 端收到後,會有處理上的問題
因此必須強制編碼
http://stackoverflow.com/questions/3423545/objective-c-iphone-percent-encode-a-string
上面的連結提供了一個不錯的方式處理
其他相關的知識
cocoa coding
http://secondflush2.blog.fc2.com/blog-entry-62.html
http://stackoverflow.com/questions/2467844/convert-utf-8-encoded-nsdata-to-nsstring
字串非 null-terminated
NSString* newStr = [[[NSString alloc] initWithData:theData
encoding:NSUTF8StringEncoding] autorelease];
null terminated 時,使用 stringWithUTF8String 避免結尾的 \0 產生多餘字元
If the data is null-terminated, you should instead use -stringWithUTF8String: to avoid the extra \0 at the end.
NSString* newStr = [NSString stringWithUTF8String:[theData bytes]];
將 NSString to ASCII 轉成 ASCII
NSString *string = @"2";
int asciiCode = [string characterAtIndex:0]; //50
base64-utf8编码的NSString转化为NSString
http://blog.csdn.net/chenghxc/article/details/8618580
1、NSData+Base64.h
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- #import <Foundation/Foundation.h>
- void *NewBase64Decode(
- const char *inputBuffer,
- size_t length,
- size_t *outputLength);
- char *NewBase64Encode(
- const void *inputBuffer,
- size_t length,
- bool separateLines,
- size_t *outputLength);
- @interface NSData (Base64)
- + (NSData *)dataFromBase64String:(NSString *)aString;
- - (NSString *)base64EncodedString;
- @end
2、NSData+Base64.m
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- #import "NSData+Base64.h"
- //
- // Mapping from 6 bit pattern to ASCII character.
- //
- static unsigned char base64EncodeLookup[65] =
- "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
- //
- // Definition for "masked-out" areas of the base64DecodeLookup mapping
- //
- #define xx 65
- //
- // Mapping from ASCII character to 6 bit pattern.
- //
- static unsigned char base64DecodeLookup[256] =
- {
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 62, xx, xx, xx, 63,
- 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, xx, xx, xx, xx, xx, xx,
- xx, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
- 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, xx, xx, xx, xx, xx,
- xx, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
- 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
- };
- //
- // Fundamental sizes of the binary and base64 encode/decode units in bytes
- //
- #define BINARY_UNIT_SIZE 3
- #define BASE64_UNIT_SIZE 4
- //
- // NewBase64Decode
- //
- // Decodes the base64 ASCII string in the inputBuffer to a newly malloced
- // output buffer.
- //
- // inputBuffer - the source ASCII string for the decode
- // length - the length of the string or -1 (to specify strlen should be used)
- // outputLength - if not-NULL, on output will contain the decoded length
- //
- // returns the decoded buffer. Must be free'd by caller. Length is given by
- // outputLength.
- //
- void *NewBase64Decode(
- const char *inputBuffer,
- size_t length,
- size_t *outputLength)
- {
- if (length == -1)
- {
- length = strlen(inputBuffer);
- }
- size_t outputBufferSize =
- ((length+BASE64_UNIT_SIZE-1) / BASE64_UNIT_SIZE) * BINARY_UNIT_SIZE;
- unsigned char *outputBuffer = (unsigned char *)malloc(outputBufferSize);
- size_t i = 0;
- size_t j = 0;
- while (i < length)
- {
- //
- // Accumulate 4 valid characters (ignore everything else)
- //
- unsigned char accumulated[BASE64_UNIT_SIZE];
- size_t accumulateIndex = 0;
- while (i < length)
- {
- unsigned char decode = base64DecodeLookup[inputBuffer[i++]];
- if (decode != xx)
- {
- accumulated[accumulateIndex] = decode;
- accumulateIndex++;
- if (accumulateIndex == BASE64_UNIT_SIZE)
- {
- break;
- }
- }
- }
- //
- // Store the 6 bits from each of the 4 characters as 3 bytes
- //
- // (Uses improved bounds checking suggested by Alexandre Colucci)
- //
- if(accumulateIndex >= 2)
- outputBuffer[j] = (accumulated[0] << 2) | (accumulated[1] >> 4);
- if(accumulateIndex >= 3)
- outputBuffer[j + 1] = (accumulated[1] << 4) | (accumulated[2] >> 2);
- if(accumulateIndex >= 4)
- outputBuffer[j + 2] = (accumulated[2] << 6) | accumulated[3];
- j += accumulateIndex - 1;
- }
- if (outputLength)
- {
- *outputLength = j;
- }
- return outputBuffer;
- }
- //
- // NewBase64Encode
- //
- // Encodes the arbitrary data in the inputBuffer as base64 into a newly malloced
- // output buffer.
- //
- // inputBuffer - the source data for the encode
- // length - the length of the input in bytes
- // separateLines - if zero, no CR/LF characters will be added. Otherwise
- // a CR/LF pair will be added every 64 encoded chars.
- // outputLength - if not-NULL, on output will contain the encoded length
- // (not including terminating 0 char)
- //
- // returns the encoded buffer. Must be free'd by caller. Length is given by
- // outputLength.
- //
- char *NewBase64Encode(
- const void *buffer,
- size_t length,
- bool separateLines,
- size_t *outputLength)
- {
- const unsigned char *inputBuffer = (const unsigned char *)buffer;
- #define MAX_NUM_PADDING_CHARS 2
- #define OUTPUT_LINE_LENGTH 64
- #define INPUT_LINE_LENGTH ((OUTPUT_LINE_LENGTH / BASE64_UNIT_SIZE) * BINARY_UNIT_SIZE)
- #define CR_LF_SIZE 2
- //
- // Byte accurate calculation of final buffer size
- //
- size_t outputBufferSize =
- ((length / BINARY_UNIT_SIZE)
- + ((length % BINARY_UNIT_SIZE) ? 1 : 0))
- * BASE64_UNIT_SIZE;
- if (separateLines)
- {
- outputBufferSize +=
- (outputBufferSize / OUTPUT_LINE_LENGTH) * CR_LF_SIZE;
- }
- //
- // Include space for a terminating zero
- //
- outputBufferSize += 1;
- //
- // Allocate the output buffer
- //
- char *outputBuffer = (char *)malloc(outputBufferSize);
- if (!outputBuffer)
- {
- return NULL;
- }
- size_t i = 0;
- size_t j = 0;
- const size_t lineLength = separateLines ? INPUT_LINE_LENGTH : length;
- size_t lineEnd = lineLength;
- while (true)
- {
- if (lineEnd > length)
- {
- lineEnd = length;
- }
- for (; i + BINARY_UNIT_SIZE - 1 < lineEnd; i += BINARY_UNIT_SIZE)
- {
- //
- // Inner loop: turn 48 bytes into 64 base64 characters
- //
- outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
- outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i] & 0x03) << 4)
- | ((inputBuffer[i + 1] & 0xF0) >> 4)];
- outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i + 1] & 0x0F) << 2)
- | ((inputBuffer[i + 2] & 0xC0) >> 6)];
- outputBuffer[j++] = base64EncodeLookup[inputBuffer[i + 2] & 0x3F];
- }
- if (lineEnd == length)
- {
- break;
- }
- //
- // Add the newline
- //
- outputBuffer[j++] = '\r';
- outputBuffer[j++] = '\n';
- lineEnd += lineLength;
- }
- if (i + 1 < length)
- {
- //
- // Handle the single '=' case
- //
- outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
- outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i] & 0x03) << 4)
- | ((inputBuffer[i + 1] & 0xF0) >> 4)];
- outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i + 1] & 0x0F) << 2];
- outputBuffer[j++] = '=';
- }
- else if (i < length)
- {
- //
- // Handle the double '=' case
- //
- outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
- outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0x03) << 4];
- outputBuffer[j++] = '=';
- outputBuffer[j++] = '=';
- }
- outputBuffer[j] = 0;
- //
- // Set the output length and return the buffer
- //
- if (outputLength)
- {
- *outputLength = j;
- }
- return outputBuffer;
- }
- @implementation NSData (Base64)
- //
- // dataFromBase64String:
- //
- // Creates an NSData object containing the base64 decoded representation of
- // the base64 string 'aString'
- //
- // Parameters:
- // aString - the base64 string to decode
- //
- // returns the autoreleased NSData representation of the base64 string
- //
- + (NSData *)dataFromBase64String:(NSString *)aString
- {
- NSData *data = [aString dataUsingEncoding:NSASCIIStringEncoding];
- size_t outputLength;
- void *outputBuffer = NewBase64Decode([data bytes], [data length], &outputLength);
- NSData *result = [NSData dataWithBytes:outputBuffer length:outputLength];
- free(outputBuffer);
- return result;
- }
- //
- // base64EncodedString
- //
- // Creates an NSString object that contains the base 64 encoding of the
- // receiver's data. Lines are broken at 64 characters long.
- //
- // returns an autoreleased NSString being the base 64 representation of the
- // receiver.
- //
- - (NSString *)base64EncodedString
- {
- size_t outputLength;
- char *outputBuffer =
- NewBase64Encode([self bytes], [self length], true, &outputLength);
- NSString *result =
- [[[NSString alloc]
- initWithBytes:outputBuffer
- length:outputLength
- encoding:NSASCIIStringEncoding]
- autorelease];
- free(outputBuffer);
- return result;
- }
- @end
3、NSString+Base64.h
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- #import <Foundation/Foundation.h>
- @interface NSString (Base64)
- + (NSString *)base64Encode:(NSString *)plainText;
- + (NSString *)base64Decode:(NSString *)base64String;
- @end
4、NSString+Base64.m
[plain] view plaincopyprint?
- #import "NSString+Base64.h"
- #import "NSData+Base64.h"
- @implementation NSString (Base64)
- + (NSString *)base64Encode:(NSString *)plainText
- {
- NSData *plainTextData = [plainText dataUsingEncoding:NSUTF8StringEncoding];
- NSString *base64String = [plainTextData base64EncodedString];
- return base64String;
- }
- + (NSString *)base64Decode:(NSString *)base64String
- {
- NSData *plainTextData = [NSData dataFromBase64String:base64String];
- NSString *plainText = [[NSString alloc] initWithData:plainTextData encoding:NSUTF8StringEncoding];
- return plainText;
- }
- @end
5、实例代码:
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- #import "AppDelegate.h"
- #import "NSString+Base64.h"
- @implementation AppDelegate
- @synthesize window = _window;
- - (void)dealloc
- {
- [super dealloc];
- }
- - (void)applicationDidFinishLaunching:(NSNotification *)aNotification
- {
- NSString *str = @"未加密字符串";
- NSLog(@"nsstring: %@",str);
- NSString *base64utf8 = [NSString base64Encode:str];
- NSLog(@"base64utf8: %@",base64utf8);
- NSLog(@"nsstring: %@",[NSString base64Decode:base64utf8]);
- }
- @end
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