diff --git a/src/util/base64.h b/src/util/base64.h new file mode 100644 index 0000000..7cb310b --- /dev/null +++ b/src/util/base64.h @@ -0,0 +1,80 @@ +// https://en.wikibooks.org/wiki/Algorithm_Implementation/Miscellaneous/Base64 + +#include +#include + +// TODO: split on header and implementation +static int base64encode(const void* data_buf, size_t dataLength, char* result, size_t resultSize) +{ + const char base64chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; + const uint8_t *data = (const uint8_t *)data_buf; + size_t resultIndex = 0; + size_t x; + uint32_t n = 0; + int padCount = dataLength % 3; + uint8_t n0, n1, n2, n3; + + /* increment over the length of the string, three characters at a time */ + for (x = 0; x < dataLength; x += 3) + { + /* these three 8-bit (ASCII) characters become one 24-bit number */ + n = ((uint32_t)data[x]) << 16; //parenthesis needed, compiler depending on flags can do the shifting before conversion to uint32_t, resulting to 0 + + if((x+1) < dataLength) + n += ((uint32_t)data[x+1]) << 8;//parenthesis needed, compiler depending on flags can do the shifting before conversion to uint32_t, resulting to 0 + + if((x+2) < dataLength) + n += data[x+2]; + + /* this 24-bit number gets separated into four 6-bit numbers */ + n0 = (uint8_t)(n >> 18) & 63; + n1 = (uint8_t)(n >> 12) & 63; + n2 = (uint8_t)(n >> 6) & 63; + n3 = (uint8_t)n & 63; + + /* + * if we have one byte available, then its encoding is spread + * out over two characters + */ + if(resultIndex >= resultSize) return 1; /* indicate failure: buffer too small */ + result[resultIndex++] = base64chars[n0]; + if(resultIndex >= resultSize) return 1; /* indicate failure: buffer too small */ + result[resultIndex++] = base64chars[n1]; + + /* + * if we have only two bytes available, then their encoding is + * spread out over three chars + */ + if((x+1) < dataLength) + { + if(resultIndex >= resultSize) return 1; /* indicate failure: buffer too small */ + result[resultIndex++] = base64chars[n2]; + } + + /* + * if we have all three bytes available, then their encoding is spread + * out over four characters + */ + if((x+2) < dataLength) + { + if(resultIndex >= resultSize) return 1; /* indicate failure: buffer too small */ + result[resultIndex++] = base64chars[n3]; + } + } + + /* + * create and add padding that is required if we did not have a multiple of 3 + * number of characters available + */ + if (padCount > 0) + { + for (; padCount < 3; padCount++) + { + if(resultIndex >= resultSize) return 1; /* indicate failure: buffer too small */ + result[resultIndex++] = '='; + } + } + if(resultIndex >= resultSize) return 1; /* indicate failure: buffer too small */ + result[resultIndex] = 0; + return 0; /* indicate success */ +}