sp<ABuffer> decodeBase64(const AString &s) {
 size_t n = s.size();
 if ((n % 4) != 0) {
 return NULL;
 }

 size_t padding = 0;
 if (n >= 1 && s.c_str()[n - 1] == '=') {
        padding = 1;

 if (n >= 2 && s.c_str()[n - 2] == '=') {
            padding = 2;

 if (n >= 3 && s.c_str()[n - 3] == '=') {
                padding = 3;
 }
 }
 }

 size_t outLen = (n / 4) * 3 - padding;

    sp<ABuffer> buffer = new ABuffer(outLen);

 uint8_t *out = buffer->data();
 if (out == NULL || buffer->size() < outLen) {
 return NULL;
 }
 size_t j = 0;
 uint32_t accum = 0;
 for (size_t i = 0; i < n; ++i) {
 char c = s.c_str()[i];
 unsigned value;
 if (c >= 'A' && c <= 'Z') {
            value = c - 'A';
 } else if (c >= 'a' && c <= 'z') {
            value = 26 + c - 'a';
 } else if (c >= '0' && c <= '9') {
            value = 52 + c - '0';
 } else if (c == '+') {
            value = 62;
 } else if (c == '/') {
            value = 63;
 } else if (c != '=') {
 return NULL;
 } else {
 if (i < n - padding) {
 return NULL;
 }

            value = 0;
 }


         accum = (accum << 6) | value;
 
         if (((i + 1) % 4) == 0) {
            if (j < outLen) { out[j++] = (accum >> 16); }
             if (j < outLen) { out[j++] = (accum >> 8) & 0xff; }
             if (j < outLen) { out[j++] = accum & 0xff; }
 
            accum = 0;
 }
 }

 return buffer;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.