134 lines
2.4 KiB
C++
134 lines
2.4 KiB
C++
#include "Base64.h"
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const char b64_alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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"abcdefghijklmnopqrstuvwxyz"
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"0123456789+/";
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/* 'Private' declarations */
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inline void a3_to_a4(unsigned char * a4, unsigned char * a3);
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inline void a4_to_a3(unsigned char * a3, unsigned char * a4);
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inline unsigned char b64_lookup(char c);
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int base64_encode(char *output, char *input, int inputLen) {
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int i = 0, j = 0;
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int encLen = 0;
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unsigned char a3[3];
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unsigned char a4[4];
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while(inputLen--) {
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a3[i++] = *(input++);
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if(i == 3) {
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a3_to_a4(a4, a3);
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for(i = 0; i < 4; i++) {
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output[encLen++] = b64_alphabet[a4[i]];
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}
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i = 0;
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}
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}
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if(i) {
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for(j = i; j < 3; j++) {
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a3[j] = '\0';
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}
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a3_to_a4(a4, a3);
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for(j = 0; j < i + 1; j++) {
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output[encLen++] = b64_alphabet[a4[j]];
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}
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while((i++ < 3)) {
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output[encLen++] = '=';
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}
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}
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output[encLen] = '\0';
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return encLen;
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}
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int base64_decode(char * output, char * input, int inputLen) {
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int i = 0, j = 0;
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int decLen = 0;
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unsigned char a3[3];
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unsigned char a4[4];
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while (inputLen--) {
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if(*input == '=') {
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break;
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}
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a4[i++] = *(input++);
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if (i == 4) {
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for (i = 0; i <4; i++) {
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a4[i] = b64_lookup(a4[i]);
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}
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a4_to_a3(a3,a4);
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for (i = 0; i < 3; i++) {
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output[decLen++] = a3[i];
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}
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i = 0;
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}
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}
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if (i) {
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for (j = i; j < 4; j++) {
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a4[j] = '\0';
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}
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for (j = 0; j <4; j++) {
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a4[j] = b64_lookup(a4[j]);
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}
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a4_to_a3(a3,a4);
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for (j = 0; j < i - 1; j++) {
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output[decLen++] = a3[j];
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}
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}
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output[decLen] = '\0';
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return decLen;
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}
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int base64_enc_len(int plainLen) {
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int n = plainLen;
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return (n + 2 - ((n + 2) % 3)) / 3 * 4;
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}
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int base64_dec_len(char * input, int inputLen) {
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int i = 0;
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int numEq = 0;
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for(i = inputLen - 1; input[i] == '='; i--) {
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numEq++;
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}
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return ((6 * inputLen) / 8) - numEq;
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}
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inline void a3_to_a4(unsigned char * a4, unsigned char * a3) {
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a4[0] = (a3[0] & 0xfc) >> 2;
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a4[1] = ((a3[0] & 0x03) << 4) + ((a3[1] & 0xf0) >> 4);
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a4[2] = ((a3[1] & 0x0f) << 2) + ((a3[2] & 0xc0) >> 6);
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a4[3] = (a3[2] & 0x3f);
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}
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inline void a4_to_a3(unsigned char * a3, unsigned char * a4) {
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a3[0] = (a4[0] << 2) + ((a4[1] & 0x30) >> 4);
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a3[1] = ((a4[1] & 0xf) << 4) + ((a4[2] & 0x3c) >> 2);
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a3[2] = ((a4[2] & 0x3) << 6) + a4[3];
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}
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inline unsigned char b64_lookup(char c) {
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int i;
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for(i = 0; i < 64; i++) {
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if(b64_alphabet[i] == c) {
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return i;
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}
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}
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return -1;
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}
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