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+//
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+// GTMBase64.m
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+//
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+// Copyright 2006-2008 Google Inc.
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+//
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+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
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+// use this file except in compliance with the License. You may obtain a copy
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+// of the License at
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+//
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+// http://www.apache.org/licenses/LICENSE-2.0
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+//
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+// Unless required by applicable law or agreed to in writing, software
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+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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+// License for the specific language governing permissions and limitations under
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+// the License.
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+//
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+
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+#import "GTMBase64.h"
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+#import "GTMDefines.h"
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+
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+static const char *kBase64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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+static const char *kWebSafeBase64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
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+static const char kBase64PaddingChar = '=';
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+static const char kBase64InvalidChar = 99;
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+
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+static const char kBase64DecodeChars[] = {
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+ // This array was generated by the following code:
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+ // #include <sys/time.h>
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+ // #include <stdlib.h>
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+ // #include <string.h>
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+ // main()
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+ // {
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+ // static const char Base64[] =
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+ // "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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+ // char *pos;
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+ // int idx, i, j;
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+ // printf(" ");
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+ // for (i = 0; i < 255; i += 8) {
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+ // for (j = i; j < i + 8; j++) {
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+ // pos = strchr(Base64, j);
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+ // if ((pos == NULL) || (j == 0))
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+ // idx = 99;
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+ // else
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+ // idx = pos - Base64;
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+ // if (idx == 99)
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+ // printf(" %2d, ", idx);
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+ // else
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+ // printf(" %2d/*%c*/,", idx, j);
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+ // }
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+ // printf("\n ");
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+ // }
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+ // }
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 62/*+*/, 99, 99, 99, 63/*/ */,
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+ 52/*0*/, 53/*1*/, 54/*2*/, 55/*3*/, 56/*4*/, 57/*5*/, 58/*6*/, 59/*7*/,
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+ 60/*8*/, 61/*9*/, 99, 99, 99, 99, 99, 99,
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+ 99, 0/*A*/, 1/*B*/, 2/*C*/, 3/*D*/, 4/*E*/, 5/*F*/, 6/*G*/,
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+ 7/*H*/, 8/*I*/, 9/*J*/, 10/*K*/, 11/*L*/, 12/*M*/, 13/*N*/, 14/*O*/,
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+ 15/*P*/, 16/*Q*/, 17/*R*/, 18/*S*/, 19/*T*/, 20/*U*/, 21/*V*/, 22/*W*/,
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+ 23/*X*/, 24/*Y*/, 25/*Z*/, 99, 99, 99, 99, 99,
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+ 99, 26/*a*/, 27/*b*/, 28/*c*/, 29/*d*/, 30/*e*/, 31/*f*/, 32/*g*/,
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+ 33/*h*/, 34/*i*/, 35/*j*/, 36/*k*/, 37/*l*/, 38/*m*/, 39/*n*/, 40/*o*/,
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+ 41/*p*/, 42/*q*/, 43/*r*/, 44/*s*/, 45/*t*/, 46/*u*/, 47/*v*/, 48/*w*/,
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+ 49/*x*/, 50/*y*/, 51/*z*/, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99
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+};
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+
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+static const char kWebSafeBase64DecodeChars[] = {
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+ // This array was generated by the following code:
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+ // #include <sys/time.h>
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+ // #include <stdlib.h>
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+ // #include <string.h>
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+ // main()
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+ // {
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+ // static const char Base64[] =
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+ // "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
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+ // char *pos;
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+ // int idx, i, j;
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+ // printf(" ");
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+ // for (i = 0; i < 255; i += 8) {
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+ // for (j = i; j < i + 8; j++) {
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+ // pos = strchr(Base64, j);
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+ // if ((pos == NULL) || (j == 0))
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+ // idx = 99;
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+ // else
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+ // idx = pos - Base64;
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+ // if (idx == 99)
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+ // printf(" %2d, ", idx);
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+ // else
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+ // printf(" %2d/*%c*/,", idx, j);
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+ // }
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+ // printf("\n ");
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+ // }
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+ // }
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 62/*-*/, 99, 99,
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+ 52/*0*/, 53/*1*/, 54/*2*/, 55/*3*/, 56/*4*/, 57/*5*/, 58/*6*/, 59/*7*/,
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+ 60/*8*/, 61/*9*/, 99, 99, 99, 99, 99, 99,
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+ 99, 0/*A*/, 1/*B*/, 2/*C*/, 3/*D*/, 4/*E*/, 5/*F*/, 6/*G*/,
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+ 7/*H*/, 8/*I*/, 9/*J*/, 10/*K*/, 11/*L*/, 12/*M*/, 13/*N*/, 14/*O*/,
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+ 15/*P*/, 16/*Q*/, 17/*R*/, 18/*S*/, 19/*T*/, 20/*U*/, 21/*V*/, 22/*W*/,
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+ 23/*X*/, 24/*Y*/, 25/*Z*/, 99, 99, 99, 99, 63/*_*/,
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+ 99, 26/*a*/, 27/*b*/, 28/*c*/, 29/*d*/, 30/*e*/, 31/*f*/, 32/*g*/,
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+ 33/*h*/, 34/*i*/, 35/*j*/, 36/*k*/, 37/*l*/, 38/*m*/, 39/*n*/, 40/*o*/,
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+ 41/*p*/, 42/*q*/, 43/*r*/, 44/*s*/, 45/*t*/, 46/*u*/, 47/*v*/, 48/*w*/,
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+ 49/*x*/, 50/*y*/, 51/*z*/, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99,
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+ 99, 99, 99, 99, 99, 99, 99, 99
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+};
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+
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+
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+// Tests a charact to see if it's a whitespace character.
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+//
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+// Returns:
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+// YES if the character is a whitespace character.
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+// NO if the character is not a whitespace character.
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+//
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+FOUNDATION_STATIC_INLINE BOOL IsSpace(unsigned char c) {
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+ // we use our own mapping here because we don't want anything w/ locale
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+ // support.
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+ static BOOL kSpaces[256] = {
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, // 0-9
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+ 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 10-19
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 20-29
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+ 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, // 30-39
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 40-49
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 50-59
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 60-69
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 70-79
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 80-89
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 90-99
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 100-109
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 110-119
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 120-129
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 130-139
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 140-149
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 150-159
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+ 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 160-169
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 170-179
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 180-189
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 190-199
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 200-209
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 210-219
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 220-229
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 230-239
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+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 240-249
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+ 0, 0, 0, 0, 0, 1, // 250-255
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+ };
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+ return kSpaces[c];
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+}
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+
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+// Calculate how long the data will be once it's base64 encoded.
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+//
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+// Returns:
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+// The guessed encoded length for a source length
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+//
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+FOUNDATION_STATIC_INLINE NSUInteger CalcEncodedLength(NSUInteger srcLen,
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+ BOOL padded) {
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+ NSUInteger intermediate_result = 8 * srcLen + 5;
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+ NSUInteger len = intermediate_result / 6;
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+ if (padded) {
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+ len = ((len + 3) / 4) * 4;
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+ }
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+ return len;
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+}
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+
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+// Tries to calculate how long the data will be once it's base64 decoded.
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+// Unlinke the above, this is always an upperbound, since the source data
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+// could have spaces and might end with the padding characters on them.
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+//
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+// Returns:
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+// The guessed decoded length for a source length
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+//
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+FOUNDATION_STATIC_INLINE NSUInteger GuessDecodedLength(NSUInteger srcLen) {
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+ return (srcLen + 3) / 4 * 3;
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+}
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+
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+
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+@interface GTMBase64 (PrivateMethods)
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+
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++(NSData *)baseEncode:(const void *)bytes
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+ length:(NSUInteger)length
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+ charset:(const char *)charset
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+ padded:(BOOL)padded;
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+
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++(NSData *)baseDecode:(const void *)bytes
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+ length:(NSUInteger)length
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+ charset:(const char*)charset
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+ requirePadding:(BOOL)requirePadding;
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+
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++(NSUInteger)baseEncode:(const char *)srcBytes
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+ srcLen:(NSUInteger)srcLen
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+ destBytes:(char *)destBytes
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+ destLen:(NSUInteger)destLen
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+ charset:(const char *)charset
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+ padded:(BOOL)padded;
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+
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++(NSUInteger)baseDecode:(const char *)srcBytes
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+ srcLen:(NSUInteger)srcLen
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+ destBytes:(char *)destBytes
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+ destLen:(NSUInteger)destLen
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+ charset:(const char *)charset
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+ requirePadding:(BOOL)requirePadding;
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+
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+@end
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+
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+
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+@implementation GTMBase64
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+
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+//
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+// Standard Base64 (RFC) handling
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+//
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+
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++(NSData *)encodeData:(NSData *)data {
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+ return [self baseEncode:[data bytes]
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+ length:[data length]
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+ charset:kBase64EncodeChars
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+ padded:YES];
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+}
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+
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++(NSData *)decodeData:(NSData *)data {
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+ return [self baseDecode:[data bytes]
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+ length:[data length]
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+ charset:kBase64DecodeChars
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+ requirePadding:YES];
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+}
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+
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++(NSData *)encodeBytes:(const void *)bytes length:(NSUInteger)length {
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+ return [self baseEncode:bytes
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+ length:length
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+ charset:kBase64EncodeChars
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+ padded:YES];
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+}
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+
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++(NSData *)decodeBytes:(const void *)bytes length:(NSUInteger)length {
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+ return [self baseDecode:bytes
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+ length:length
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+ charset:kBase64DecodeChars
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+ requirePadding:YES];
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+}
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+
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++(NSString *)stringByEncodingData:(NSData *)data {
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+ NSString *result = nil;
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+ NSData *converted = [self baseEncode:[data bytes]
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+ length:[data length]
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+ charset:kBase64EncodeChars
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+ padded:YES];
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+ if (converted) {
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+ result = [[NSString alloc] initWithData:converted
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+ encoding:NSASCIIStringEncoding];
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+ }
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+ return result;
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+}
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+
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++(NSString *)stringByEncodingBytes:(const void *)bytes length:(NSUInteger)length {
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+ NSString *result = nil;
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+ NSData *converted = [self baseEncode:bytes
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+ length:length
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+ charset:kBase64EncodeChars
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+ padded:YES];
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+ if (converted) {
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+ result = [[NSString alloc] initWithData:converted
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+ encoding:NSASCIIStringEncoding];
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+ }
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+ return result;
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+}
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+
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++(NSData *)decodeString:(NSString *)string {
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+ NSData *result = nil;
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+ NSData *data = [string dataUsingEncoding:NSASCIIStringEncoding];
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+ if (data) {
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+ result = [self baseDecode:[data bytes]
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+ length:[data length]
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+ charset:kBase64DecodeChars
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+ requirePadding:YES];
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+ }
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+ return result;
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+}
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+
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+//
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+// Modified Base64 encoding so the results can go onto urls.
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+//
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+// The changes are in the characters generated and also the result isn't
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+// padded to a multiple of 4.
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+// Must use the matching call to encode/decode, won't interop with the
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+// RFC versions.
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+//
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+
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++(NSData *)webSafeEncodeData:(NSData *)data
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+ padded:(BOOL)padded {
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+ return [self baseEncode:[data bytes]
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+ length:[data length]
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+ charset:kWebSafeBase64EncodeChars
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+ padded:padded];
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+}
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+
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++(NSData *)webSafeDecodeData:(NSData *)data {
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+ return [self baseDecode:[data bytes]
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+ length:[data length]
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+ charset:kWebSafeBase64DecodeChars
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+ requirePadding:NO];
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+}
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+
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++(NSData *)webSafeEncodeBytes:(const void *)bytes
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+ length:(NSUInteger)length
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+ padded:(BOOL)padded {
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+ return [self baseEncode:bytes
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+ length:length
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+ charset:kWebSafeBase64EncodeChars
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+ padded:padded];
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+}
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+
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++(NSData *)webSafeDecodeBytes:(const void *)bytes length:(NSUInteger)length {
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+ return [self baseDecode:bytes
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+ length:length
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+ charset:kWebSafeBase64DecodeChars
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+ requirePadding:NO];
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+}
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+
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|
|
++(NSString *)stringByWebSafeEncodingData:(NSData *)data
|
|
|
+ padded:(BOOL)padded {
|
|
|
+ NSString *result = nil;
|
|
|
+ NSData *converted = [self baseEncode:[data bytes]
|
|
|
+ length:[data length]
|
|
|
+ charset:kWebSafeBase64EncodeChars
|
|
|
+ padded:padded];
|
|
|
+ if (converted) {
|
|
|
+ result = [[NSString alloc] initWithData:converted
|
|
|
+ encoding:NSASCIIStringEncoding];
|
|
|
+ }
|
|
|
+ return result;
|
|
|
+}
|
|
|
+
|
|
|
++(NSString *)stringByWebSafeEncodingBytes:(const void *)bytes
|
|
|
+ length:(NSUInteger)length
|
|
|
+ padded:(BOOL)padded {
|
|
|
+ NSString *result = nil;
|
|
|
+ NSData *converted = [self baseEncode:bytes
|
|
|
+ length:length
|
|
|
+ charset:kWebSafeBase64EncodeChars
|
|
|
+ padded:padded];
|
|
|
+ if (converted) {
|
|
|
+ result = [[NSString alloc] initWithData:converted
|
|
|
+ encoding:NSASCIIStringEncoding];
|
|
|
+ }
|
|
|
+ return result;
|
|
|
+}
|
|
|
+
|
|
|
++(NSData *)webSafeDecodeString:(NSString *)string {
|
|
|
+ NSData *result = nil;
|
|
|
+ NSData *data = [string dataUsingEncoding:NSASCIIStringEncoding];
|
|
|
+ if (data) {
|
|
|
+ result = [self baseDecode:[data bytes]
|
|
|
+ length:[data length]
|
|
|
+ charset:kWebSafeBase64DecodeChars
|
|
|
+ requirePadding:NO];
|
|
|
+ }
|
|
|
+ return result;
|
|
|
+}
|
|
|
+
|
|
|
+@end
|
|
|
+
|
|
|
+@implementation GTMBase64 (PrivateMethods)
|
|
|
+
|
|
|
+//
|
|
|
+// baseEncode:length:charset:padded:
|
|
|
+//
|
|
|
+// Does the common lifting of creating the dest NSData. it creates & sizes the
|
|
|
+// data for the results. |charset| is the characters to use for the encoding
|
|
|
+// of the data. |padding| controls if the encoded data should be padded to a
|
|
|
+// multiple of 4.
|
|
|
+//
|
|
|
+// Returns:
|
|
|
+// an autorelease NSData with the encoded data, nil if any error.
|
|
|
+//
|
|
|
++(NSData *)baseEncode:(const void *)bytes
|
|
|
+ length:(NSUInteger)length
|
|
|
+ charset:(const char *)charset
|
|
|
+ padded:(BOOL)padded {
|
|
|
+ // how big could it be?
|
|
|
+ NSUInteger maxLength = CalcEncodedLength(length, padded);
|
|
|
+ // make space
|
|
|
+ NSMutableData *result = [NSMutableData data];
|
|
|
+ [result setLength:maxLength];
|
|
|
+ // do it
|
|
|
+ NSUInteger finalLength = [self baseEncode:bytes
|
|
|
+ srcLen:length
|
|
|
+ destBytes:[result mutableBytes]
|
|
|
+ destLen:[result length]
|
|
|
+ charset:charset
|
|
|
+ padded:padded];
|
|
|
+ if (finalLength) {
|
|
|
+ _GTMDevAssert(finalLength == maxLength, @"how did we calc the length wrong?");
|
|
|
+ } else {
|
|
|
+ // shouldn't happen, this means we ran out of space
|
|
|
+ result = nil;
|
|
|
+ }
|
|
|
+ return result;
|
|
|
+}
|
|
|
+
|
|
|
+//
|
|
|
+// baseDecode:length:charset:requirePadding:
|
|
|
+//
|
|
|
+// Does the common lifting of creating the dest NSData. it creates & sizes the
|
|
|
+// data for the results. |charset| is the characters to use for the decoding
|
|
|
+// of the data.
|
|
|
+//
|
|
|
+// Returns:
|
|
|
+// an autorelease NSData with the decoded data, nil if any error.
|
|
|
+//
|
|
|
+//
|
|
|
++(NSData *)baseDecode:(const void *)bytes
|
|
|
+ length:(NSUInteger)length
|
|
|
+ charset:(const char *)charset
|
|
|
+ requirePadding:(BOOL)requirePadding {
|
|
|
+ // could try to calculate what it will end up as
|
|
|
+ NSUInteger maxLength = GuessDecodedLength(length);
|
|
|
+ // make space
|
|
|
+ NSMutableData *result = [NSMutableData data];
|
|
|
+ [result setLength:maxLength];
|
|
|
+ // do it
|
|
|
+ NSUInteger finalLength = [self baseDecode:bytes
|
|
|
+ srcLen:length
|
|
|
+ destBytes:[result mutableBytes]
|
|
|
+ destLen:[result length]
|
|
|
+ charset:charset
|
|
|
+ requirePadding:requirePadding];
|
|
|
+ if (finalLength) {
|
|
|
+ if (finalLength != maxLength) {
|
|
|
+ // resize down to how big it was
|
|
|
+ [result setLength:finalLength];
|
|
|
+ }
|
|
|
+ } else {
|
|
|
+ // either an error in the args, or we ran out of space
|
|
|
+ result = nil;
|
|
|
+ }
|
|
|
+ return result;
|
|
|
+}
|
|
|
+
|
|
|
+//
|
|
|
+// baseEncode:srcLen:destBytes:destLen:charset:padded:
|
|
|
+//
|
|
|
+// Encodes the buffer into the larger. returns the length of the encoded
|
|
|
+// data, or zero for an error.
|
|
|
+// |charset| is the characters to use for the encoding
|
|
|
+// |padded| tells if the result should be padded to a multiple of 4.
|
|
|
+//
|
|
|
+// Returns:
|
|
|
+// the length of the encoded data. zero if any error.
|
|
|
+//
|
|
|
++(NSUInteger)baseEncode:(const char *)srcBytes
|
|
|
+ srcLen:(NSUInteger)srcLen
|
|
|
+ destBytes:(char *)destBytes
|
|
|
+ destLen:(NSUInteger)destLen
|
|
|
+ charset:(const char *)charset
|
|
|
+ padded:(BOOL)padded {
|
|
|
+ if (!srcLen || !destLen || !srcBytes || !destBytes) {
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+
|
|
|
+ char *curDest = destBytes;
|
|
|
+ const unsigned char *curSrc = (const unsigned char *)(srcBytes);
|
|
|
+
|
|
|
+ // Three bytes of data encodes to four characters of cyphertext.
|
|
|
+ // So we can pump through three-byte chunks atomically.
|
|
|
+ while (srcLen > 2) {
|
|
|
+ // space?
|
|
|
+ _GTMDevAssert(destLen >= 4, @"our calc for encoded length was wrong");
|
|
|
+ curDest[0] = charset[curSrc[0] >> 2];
|
|
|
+ curDest[1] = charset[((curSrc[0] & 0x03) << 4) + (curSrc[1] >> 4)];
|
|
|
+ curDest[2] = charset[((curSrc[1] & 0x0f) << 2) + (curSrc[2] >> 6)];
|
|
|
+ curDest[3] = charset[curSrc[2] & 0x3f];
|
|
|
+
|
|
|
+ curDest += 4;
|
|
|
+ curSrc += 3;
|
|
|
+ srcLen -= 3;
|
|
|
+ destLen -= 4;
|
|
|
+ }
|
|
|
+
|
|
|
+ // now deal with the tail (<=2 bytes)
|
|
|
+ switch (srcLen) {
|
|
|
+ case 0:
|
|
|
+ // Nothing left; nothing more to do.
|
|
|
+ break;
|
|
|
+ case 1:
|
|
|
+ // One byte left: this encodes to two characters, and (optionally)
|
|
|
+ // two pad characters to round out the four-character cypherblock.
|
|
|
+ _GTMDevAssert(destLen >= 2, @"our calc for encoded length was wrong");
|
|
|
+ curDest[0] = charset[curSrc[0] >> 2];
|
|
|
+ curDest[1] = charset[(curSrc[0] & 0x03) << 4];
|
|
|
+ curDest += 2;
|
|
|
+ destLen -= 2;
|
|
|
+ if (padded) {
|
|
|
+ _GTMDevAssert(destLen >= 2, @"our calc for encoded length was wrong");
|
|
|
+ curDest[0] = kBase64PaddingChar;
|
|
|
+ curDest[1] = kBase64PaddingChar;
|
|
|
+ curDest += 2;
|
|
|
+ //destLen -= 2;
|
|
|
+ }
|
|
|
+ break;
|
|
|
+ case 2:
|
|
|
+ // Two bytes left: this encodes to three characters, and (optionally)
|
|
|
+ // one pad character to round out the four-character cypherblock.
|
|
|
+ _GTMDevAssert(destLen >= 3, @"our calc for encoded length was wrong");
|
|
|
+ curDest[0] = charset[curSrc[0] >> 2];
|
|
|
+ curDest[1] = charset[((curSrc[0] & 0x03) << 4) + (curSrc[1] >> 4)];
|
|
|
+ curDest[2] = charset[(curSrc[1] & 0x0f) << 2];
|
|
|
+ curDest += 3;
|
|
|
+ destLen -= 3;
|
|
|
+ if (padded) {
|
|
|
+ _GTMDevAssert(destLen >= 1, @"our calc for encoded length was wrong");
|
|
|
+ curDest[0] = kBase64PaddingChar;
|
|
|
+ curDest += 1;
|
|
|
+ //destLen -= 1;
|
|
|
+ }
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ // return the length
|
|
|
+ return (curDest - destBytes);
|
|
|
+}
|
|
|
+
|
|
|
+//
|
|
|
+// baseDecode:srcLen:destBytes:destLen:charset:requirePadding:
|
|
|
+//
|
|
|
+// Decodes the buffer into the larger. returns the length of the decoded
|
|
|
+// data, or zero for an error.
|
|
|
+// |charset| is the character decoding buffer to use
|
|
|
+//
|
|
|
+// Returns:
|
|
|
+// the length of the encoded data. zero if any error.
|
|
|
+//
|
|
|
++(NSUInteger)baseDecode:(const char *)srcBytes
|
|
|
+ srcLen:(NSUInteger)srcLen
|
|
|
+ destBytes:(char *)destBytes
|
|
|
+ destLen:(NSUInteger)destLen
|
|
|
+ charset:(const char *)charset
|
|
|
+ requirePadding:(BOOL)requirePadding {
|
|
|
+ if (!srcLen || !destLen || !srcBytes || !destBytes) {
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+
|
|
|
+ int decode;
|
|
|
+ NSUInteger destIndex = 0;
|
|
|
+ int state = 0;
|
|
|
+ char ch = 0;
|
|
|
+ while (srcLen-- && (ch = *srcBytes++) != 0) {
|
|
|
+ if (IsSpace(ch)) // Skip whitespace
|
|
|
+ continue;
|
|
|
+
|
|
|
+ if (ch == kBase64PaddingChar)
|
|
|
+ break;
|
|
|
+
|
|
|
+ decode = charset[(unsigned int)ch];
|
|
|
+ if (decode == kBase64InvalidChar)
|
|
|
+ return 0;
|
|
|
+
|
|
|
+ // Four cyphertext characters decode to three bytes.
|
|
|
+ // Therefore we can be in one of four states.
|
|
|
+ switch (state) {
|
|
|
+ case 0:
|
|
|
+ // We're at the beginning of a four-character cyphertext block.
|
|
|
+ // This sets the high six bits of the first byte of the
|
|
|
+ // plaintext block.
|
|
|
+ _GTMDevAssert(destIndex < destLen, @"our calc for decoded length was wrong");
|
|
|
+ destBytes[destIndex] = decode << 2;
|
|
|
+ state = 1;
|
|
|
+ break;
|
|
|
+ case 1:
|
|
|
+ // We're one character into a four-character cyphertext block.
|
|
|
+ // This sets the low two bits of the first plaintext byte,
|
|
|
+ // and the high four bits of the second plaintext byte.
|
|
|
+ _GTMDevAssert((destIndex+1) < destLen, @"our calc for decoded length was wrong");
|
|
|
+ destBytes[destIndex] |= decode >> 4;
|
|
|
+ destBytes[destIndex+1] = (decode & 0x0f) << 4;
|
|
|
+ destIndex++;
|
|
|
+ state = 2;
|
|
|
+ break;
|
|
|
+ case 2:
|
|
|
+ // We're two characters into a four-character cyphertext block.
|
|
|
+ // This sets the low four bits of the second plaintext
|
|
|
+ // byte, and the high two bits of the third plaintext byte.
|
|
|
+ // However, if this is the end of data, and those two
|
|
|
+ // bits are zero, it could be that those two bits are
|
|
|
+ // leftovers from the encoding of data that had a length
|
|
|
+ // of two mod three.
|
|
|
+ _GTMDevAssert((destIndex+1) < destLen, @"our calc for decoded length was wrong");
|
|
|
+ destBytes[destIndex] |= decode >> 2;
|
|
|
+ destBytes[destIndex+1] = (decode & 0x03) << 6;
|
|
|
+ destIndex++;
|
|
|
+ state = 3;
|
|
|
+ break;
|
|
|
+ case 3:
|
|
|
+ // We're at the last character of a four-character cyphertext block.
|
|
|
+ // This sets the low six bits of the third plaintext byte.
|
|
|
+ _GTMDevAssert(destIndex < destLen, @"our calc for decoded length was wrong");
|
|
|
+ destBytes[destIndex] |= decode;
|
|
|
+ destIndex++;
|
|
|
+ state = 0;
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ // We are done decoding Base-64 chars. Let's see if we ended
|
|
|
+ // on a byte boundary, and/or with erroneous trailing characters.
|
|
|
+ if (ch == kBase64PaddingChar) { // We got a pad char
|
|
|
+ if ((state == 0) || (state == 1)) {
|
|
|
+ return 0; // Invalid '=' in first or second position
|
|
|
+ }
|
|
|
+ if (srcLen == 0) {
|
|
|
+ if (state == 2) { // We run out of input but we still need another '='
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+ // Otherwise, we are in state 3 and only need this '='
|
|
|
+ } else {
|
|
|
+ if (state == 2) { // need another '='
|
|
|
+ while ((ch = *srcBytes++) && (srcLen-- > 0)) {
|
|
|
+ if (!IsSpace(ch))
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ if (ch != kBase64PaddingChar) {
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ // state = 1 or 2, check if all remain padding is space
|
|
|
+ while ((ch = *srcBytes++) && (srcLen-- > 0)) {
|
|
|
+ if (!IsSpace(ch)) {
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ }
|
|
|
+ } else {
|
|
|
+ // We ended by seeing the end of the string.
|
|
|
+
|
|
|
+ if (requirePadding) {
|
|
|
+ // If we require padding, then anything but state 0 is an error.
|
|
|
+ if (state != 0) {
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+ } else {
|
|
|
+ // Make sure we have no partial bytes lying around. Note that we do not
|
|
|
+ // require trailing '=', so states 2 and 3 are okay too.
|
|
|
+ if (state == 1) {
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ // If then next piece of output was valid and got written to it means we got a
|
|
|
+ // very carefully crafted input that appeared valid but contains some trailing
|
|
|
+ // bits past the real length, so just toss the thing.
|
|
|
+ if ((destIndex < destLen) &&
|
|
|
+ (destBytes[destIndex] != 0)) {
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+
|
|
|
+ return destIndex;
|
|
|
+}
|
|
|
+
|
|
|
+@end
|