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| #include <stdio.h>
| #include <stdlib.h>
|
| const static char* b64 =
| "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
| // maps A=>0,B=>1..
| const static unsigned char unb64[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //10
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //20
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //30
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //40
| 0, 0, 0, 62, 0, 0, 0, 63, 52, 53, //50
| 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, //60
| 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, //70
| 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, //80
| 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, //90
| 25, 0, 0, 0, 0, 0, 0, 26, 27, 28, //100
| 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, //110
| 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, //120
| 49, 50, 51, 0, 0, 0, 0, 0, 0, 0, //130
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //140
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //150
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //160
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //170
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //180
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //190
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //200
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //210
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //220
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //230
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //240
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, //250
| 0, 0, 0, 0, 0, 0, }; // This array has 255 elements
|
| //review api
| char* base64(const void* binaryData, int len, int *flen) {
| const unsigned char* bin = (const unsigned char*) binaryData;
| char* res;
|
| int rc = 0; // result counter
| int byteNo; // I need this after the loop
|
| int modulusLen = len % 3;
| int pad = ((modulusLen & 1) << 1) + ((modulusLen & 2) >> 1); // 2 gives 1 and 1 gives 2, but 0 gives 0.
|
| *flen = 4 * (len + pad) / 3;
| res = (char*) malloc(*flen + 1); // and one for the null
| if (!res) {
| puts("ERROR: base64 could not allocate enough memory.");
| puts("I must stop because I could not get enough");
| return 0;
| }
|
| for (byteNo = 0; byteNo <= len - 3; byteNo += 3) {
| unsigned char BYTE0 = bin[byteNo];
| unsigned char BYTE1 = bin[byteNo + 1];
| unsigned char BYTE2 = bin[byteNo + 2];
| res[rc++] = b64[BYTE0 >> 2];
| res[rc++] = b64[((0x3 & BYTE0) << 4) + (BYTE1 >> 4)];
| res[rc++] = b64[((0x0f & BYTE1) << 2) + (BYTE2 >> 6)];
| res[rc++] = b64[0x3f & BYTE2];
| }
|
| if (pad == 2) {
| res[rc++] = b64[bin[byteNo] >> 2];
| res[rc++] = b64[(0x3 & bin[byteNo]) << 4];
| res[rc++] = '=';
| res[rc++] = '=';
| } else if (pad == 1) {
| res[rc++] = b64[bin[byteNo] >> 2];
| res[rc++] = b64[((0x3 & bin[byteNo]) << 4) + (bin[byteNo + 1] >> 4)];
| res[rc++] = b64[(0x0f & bin[byteNo + 1]) << 2];
| res[rc++] = '=';
| }
|
| res[rc] = 0; // NULL TERMINATOR! ;)
| return res;
| }
|
| unsigned char* unbase64(const char* ascii, int len, int *flen) {
| const unsigned char *safeAsciiPtr = (const unsigned char*) ascii;
| unsigned char *bin;
| int cb = 0;
| int charNo;
| int pad = 0;
|
| if (len < 2) { // 2 accesses below would be OOB.
| // catch empty string, return NULL as result.
| puts(
| "ERROR: You passed an invalid base64 string (too short). You get NULL back.");
| *flen = 0;
| return 0;
| }
| if (safeAsciiPtr[len - 1] == '=')
| ++pad;
| if (safeAsciiPtr[len - 2] == '=')
| ++pad;
|
| *flen = 3 * len / 4 - pad;
| bin = (unsigned char*) malloc(*flen);
| if (!bin) {
| puts("ERROR: unbase64 could not allocate enough memory.");
| puts("I must stop because I could not get enough");
| return 0;
| }
|
| for (charNo = 0; charNo <= len - 4 - pad; charNo += 4) {
| int A = unb64[safeAsciiPtr[charNo]];
| int B = unb64[safeAsciiPtr[charNo + 1]];
| int C = unb64[safeAsciiPtr[charNo + 2]];
| int D = unb64[safeAsciiPtr[charNo + 3]];
|
| bin[cb++] = (A << 2) | (B >> 4);
| bin[cb++] = (B << 4) | (C >> 2);
| bin[cb++] = (C << 6) | (D);
| }
|
| if (pad == 1) {
| int A = unb64[safeAsciiPtr[charNo]];
| int B = unb64[safeAsciiPtr[charNo + 1]];
| int C = unb64[safeAsciiPtr[charNo + 2]];
|
| bin[cb++] = (A << 2) | (B >> 4);
| bin[cb++] = (B << 4) | (C >> 2);
| } else if (pad == 2) {
| int A = unb64[safeAsciiPtr[charNo]];
| int B = unb64[safeAsciiPtr[charNo + 1]];
|
| bin[cb++] = (A << 2) | (B >> 4);
| }
|
| return bin;
| }
|
|
