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ADD: add base64 encoding.
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‎Encoding/NSData+Base64.h

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//
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// NSData+Base64.h
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// base64
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//
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// Created by Matt Gallagher on 2009/06/03.
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// Copyright 2009 Matt Gallagher. All rights reserved.
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//
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// This software is provided 'as-is', without any express or implied
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// warranty. In no event will the authors be held liable for any damages
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// arising from the use of this software. Permission is granted to anyone to
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// use this software for any purpose, including commercial applications, and to
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// alter it and redistribute it freely, subject to the following restrictions:
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//
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// 1. The origin of this software must not be misrepresented; you must not
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// claim that you wrote the original software. If you use this software
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// in a product, an acknowledgment in the product documentation would be
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// appreciated but is not required.
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// 2. Altered source versions must be plainly marked as such, and must not be
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// misrepresented as being the original software.
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// 3. This notice may not be removed or altered from any source
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// distribution.
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//
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#import <Foundation/Foundation.h>
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void *NewBase64Decode(
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const char *inputBuffer,
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size_t length,
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size_t *outputLength);
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char *NewBase64Encode(
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const void *inputBuffer,
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size_t length,
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bool separateLines,
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size_t *outputLength);
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@interface NSData (Base64)
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+ (NSData *)dataFromBase64String:(NSString *)aString;
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- (NSString *)base64EncodedString;
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@end

‎Encoding/NSData+Base64.m

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//
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// NSData+Base64.m
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// base64
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//
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// Created by Matt Gallagher on 2009/06/03.
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// Copyright 2009 Matt Gallagher. All rights reserved.
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//
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// This software is provided 'as-is', without any express or implied
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// warranty. In no event will the authors be held liable for any damages
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// arising from the use of this software. Permission is granted to anyone to
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// use this software for any purpose, including commercial applications, and to
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// alter it and redistribute it freely, subject to the following restrictions:
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//
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// 1. The origin of this software must not be misrepresented; you must not
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// claim that you wrote the original software. If you use this software
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// in a product, an acknowledgment in the product documentation would be
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// appreciated but is not required.
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// 2. Altered source versions must be plainly marked as such, and must not be
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// misrepresented as being the original software.
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// 3. This notice may not be removed or altered from any source
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// distribution.
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//
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#import "NSData+Base64.h"
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//
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// Mapping from 6 bit pattern to ASCII character.
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//
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static unsigned char base64EncodeLookup[65] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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//
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// Definition for "masked-out" areas of the base64DecodeLookup mapping
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//
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#define xx 65
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//
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// Mapping from ASCII character to 6 bit pattern.
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//
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static unsigned char base64DecodeLookup[256] =
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{
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 62, xx, xx, xx, 63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, xx, xx, xx, xx, xx, xx,
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xx, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, xx, xx, xx, xx, xx,
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xx, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
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};
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//
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// Fundamental sizes of the binary and base64 encode/decode units in bytes
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//
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#define BINARY_UNIT_SIZE 3
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#define BASE64_UNIT_SIZE 4
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//
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// NewBase64Decode
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//
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// Decodes the base64 ASCII string in the inputBuffer to a newly malloced
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// output buffer.
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//
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// inputBuffer - the source ASCII string for the decode
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// length - the length of the string or -1 (to specify strlen should be used)
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// outputLength - if not-NULL, on output will contain the decoded length
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//
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// returns the decoded buffer. Must be free'd by caller. Length is given by
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// outputLength.
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//
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void *NewBase64Decode(
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const char *inputBuffer,
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size_t length,
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size_t *outputLength)
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{
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if (length == -1)
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{
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length = strlen(inputBuffer);
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}
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size_t outputBufferSize =
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((length+BASE64_UNIT_SIZE-1) / BASE64_UNIT_SIZE) * BINARY_UNIT_SIZE;
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unsigned char *outputBuffer = (unsigned char *)malloc(outputBufferSize);
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size_t i = 0;
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size_t j = 0;
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while (i < length)
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{
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//
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// Accumulate 4 valid characters (ignore everything else)
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//
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unsigned char accumulated[BASE64_UNIT_SIZE];
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size_t accumulateIndex = 0;
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while (i < length)
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{
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unsigned char decode = base64DecodeLookup[inputBuffer[i++]];
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if (decode != xx)
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{
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accumulated[accumulateIndex] = decode;
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accumulateIndex++;
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if (accumulateIndex == BASE64_UNIT_SIZE)
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{
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break;
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}
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}
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}
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//
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// Store the 6 bits from each of the 4 characters as 3 bytes
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//
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// (Uses improved bounds checking suggested by Alexandre Colucci)
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//
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if(accumulateIndex >= 2)
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outputBuffer[j] = (accumulated[0] << 2) | (accumulated[1] >> 4);
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if(accumulateIndex >= 3)
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outputBuffer[j + 1] = (accumulated[1] << 4) | (accumulated[2] >> 2);
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if(accumulateIndex >= 4)
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outputBuffer[j + 2] = (accumulated[2] << 6) | accumulated[3];
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j += accumulateIndex - 1;
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}
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if (outputLength)
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{
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*outputLength = j;
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}
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return outputBuffer;
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}
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//
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// NewBase64Encode
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//
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// Encodes the arbitrary data in the inputBuffer as base64 into a newly malloced
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// output buffer.
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//
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// inputBuffer - the source data for the encode
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// length - the length of the input in bytes
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// separateLines - if zero, no CR/LF characters will be added. Otherwise
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// a CR/LF pair will be added every 64 encoded chars.
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// outputLength - if not-NULL, on output will contain the encoded length
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// (not including terminating 0 char)
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//
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// returns the encoded buffer. Must be free'd by caller. Length is given by
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// outputLength.
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//
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char *NewBase64Encode(
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const void *buffer,
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size_t length,
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bool separateLines,
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size_t *outputLength)
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{
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const unsigned char *inputBuffer = (const unsigned char *)buffer;
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#define MAX_NUM_PADDING_CHARS 2
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#define OUTPUT_LINE_LENGTH 64
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#define INPUT_LINE_LENGTH ((OUTPUT_LINE_LENGTH / BASE64_UNIT_SIZE) * BINARY_UNIT_SIZE)
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#define CR_LF_SIZE 2
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//
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// Byte accurate calculation of final buffer size
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//
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size_t outputBufferSize =
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((length / BINARY_UNIT_SIZE)
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+ ((length % BINARY_UNIT_SIZE) ? 1 : 0))
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* BASE64_UNIT_SIZE;
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if (separateLines)
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{
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outputBufferSize +=
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(outputBufferSize / OUTPUT_LINE_LENGTH) * CR_LF_SIZE;
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}
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//
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// Include space for a terminating zero
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//
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outputBufferSize += 1;
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//
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// Allocate the output buffer
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//
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char *outputBuffer = (char *)malloc(outputBufferSize);
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if (!outputBuffer)
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{
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return NULL;
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}
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size_t i = 0;
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size_t j = 0;
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const size_t lineLength = separateLines ? INPUT_LINE_LENGTH : length;
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size_t lineEnd = lineLength;
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while (true)
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{
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if (lineEnd > length)
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{
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lineEnd = length;
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}
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for (; i + BINARY_UNIT_SIZE - 1 < lineEnd; i += BINARY_UNIT_SIZE)
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{
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//
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// Inner loop: turn 48 bytes into 64 base64 characters
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//
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outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
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outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i] & 0x03) << 4)
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| ((inputBuffer[i + 1] & 0xF0) >> 4)];
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outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i + 1] & 0x0F) << 2)
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| ((inputBuffer[i + 2] & 0xC0) >> 6)];
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outputBuffer[j++] = base64EncodeLookup[inputBuffer[i + 2] & 0x3F];
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}
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if (lineEnd == length)
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{
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break;
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}
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//
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// Add the newline
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//
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outputBuffer[j++] = '\r';
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outputBuffer[j++] = '\n';
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lineEnd += lineLength;
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}
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if (i + 1 < length)
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{
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//
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// Handle the single '=' case
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//
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outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
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outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i] & 0x03) << 4)
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| ((inputBuffer[i + 1] & 0xF0) >> 4)];
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outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i + 1] & 0x0F) << 2];
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outputBuffer[j++] = '=';
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}
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else if (i < length)
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{
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//
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// Handle the double '=' case
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//
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outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
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outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0x03) << 4];
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outputBuffer[j++] = '=';
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outputBuffer[j++] = '=';
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}
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outputBuffer[j] = 0;
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//
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// Set the output length and return the buffer
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//
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if (outputLength)
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{
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*outputLength = j;
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}
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return outputBuffer;
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}
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@implementation NSData (Base64)
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//
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// dataFromBase64String:
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//
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// Creates an NSData object containing the base64 decoded representation of
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// the base64 string 'aString'
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//
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// Parameters:
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// aString - the base64 string to decode
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//
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// returns the autoreleased NSData representation of the base64 string
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//
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+ (NSData *)dataFromBase64String:(NSString *)aString
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{
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NSData *data = [aString dataUsingEncoding:NSASCIIStringEncoding];
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size_t outputLength;
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void *outputBuffer = NewBase64Decode([data bytes], [data length], &outputLength);
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NSData *result = [NSData dataWithBytes:outputBuffer length:outputLength];
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free(outputBuffer);
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return result;
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}
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//
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// base64EncodedString
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//
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// Creates an NSString object that contains the base 64 encoding of the
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// receiver's data. Lines are broken at 64 characters long.
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//
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// returns an autoreleased NSString being the base 64 representation of the
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// receiver.
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//
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- (NSString *)base64EncodedString
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{
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size_t outputLength;
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char *outputBuffer =
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NewBase64Encode([self bytes], [self length], true, &outputLength);
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NSString *result =
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[[[NSString alloc]
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initWithBytes:outputBuffer
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length:outputLength
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encoding:NSASCIIStringEncoding]
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autorelease];
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free(outputBuffer);
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return result;
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}
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@end

‎README.markdown

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@@ -30,3 +30,8 @@ NSString Wrapper is a wrapper class to decorate NSString methods to java String
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1. VersionCompare.h Macros used for version comparison.
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2. MacroUtils.h Macros used for debuging and I18N.
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3. UIContants.h Macros used for UI.
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####5. Encoding Utils
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1. Base64 The author is Matt Gallagher. I got the code from <http://cocoawithlove.com/2009/06/base64-encoding-options-on-mac-and.html> . The copyright info is in the header of the relevant source file.
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