+ dst[length * 2] = 0;
+ return length * 2;
+}
+
+int b64decode(const char *src, char *dst, int length) {
+ int i;
+ uint32_t triplet = 0;
+ unsigned char *udst = (unsigned char *)dst;
+
+ for(i = 0; i < length / 3 * 4 && src[i]; i++) {
+ triplet |= charb64decode(src[i]) << (6 * (i & 3));
+ if((i & 3) == 3) {
+ udst[0] = triplet & 0xff; triplet >>= 8;
+ udst[1] = triplet & 0xff; triplet >>= 8;
+ udst[2] = triplet;
+ triplet = 0;
+ udst += 3;
+ }
+ }
+ if((i & 3) == 3) {
+ udst[0] = triplet & 0xff; triplet >>= 8;
+ udst[1] = triplet & 0xff;
+ return i / 4 * 3 + 2;
+ } else if((i & 3) == 2) {
+ udst[0] = triplet & 0xff;
+ return i / 4 * 3 + 1;
+ } else {
+ return i / 4 * 3;
+ }
+}
+
+int b64encode(const char *src, char *dst, int length) {
+ uint32_t triplet;
+ const unsigned char *usrc = (unsigned char *)src;
+ int si = length / 3 * 3;
+ int di = length / 3 * 4;
+
+ switch(length % 3) {
+ case 2:
+ triplet = usrc[si] | usrc[si + 1] << 8;
+ dst[di] = base64imals[triplet & 63]; triplet >>= 6;
+ dst[di + 1] = base64imals[triplet & 63]; triplet >>= 6;
+ dst[di + 2] = base64imals[triplet];
+ dst[di + 3] = 0;
+ length = di + 2;
+ break;
+ case 1:
+ triplet = usrc[si];
+ dst[di] = base64imals[triplet & 63]; triplet >>= 6;
+ dst[di + 1] = base64imals[triplet];
+ dst[di + 2] = 0;
+ length = di + 1;
+ break;
+ default:
+ dst[di] = 0;
+ length = di;
+ break;
+ }
+
+ while(si > 0) {
+ di -= 4;
+ si -= 3;
+ triplet = usrc[si] | usrc[si + 1] << 8 | usrc[si + 2] << 16;
+ dst[di] = base64imals[triplet & 63]; triplet >>= 6;
+ dst[di + 1] = base64imals[triplet & 63]; triplet >>= 6;
+ dst[di + 2] = base64imals[triplet & 63]; triplet >>= 6;
+ dst[di + 3] = base64imals[triplet];
+ }
+
+ return length;