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-rw-r--r--include/axolotl/base64.hh35
-rw-r--r--src/base64.cpp118
-rw-r--r--tests/test_base64.cpp38
3 files changed, 191 insertions, 0 deletions
diff --git a/include/axolotl/base64.hh b/include/axolotl/base64.hh
new file mode 100644
index 0000000..c322640
--- /dev/null
+++ b/include/axolotl/base64.hh
@@ -0,0 +1,35 @@
+#ifndef AXOLOLT_BASE64_HH_
+#define AXOLOLT_BASE64_HH_
+
+#include <cstddef>
+#include <cstdint>
+
+namespace axolotl {
+
+
+std::size_t encode_base64_length(
+ std::size_t input_length
+);
+
+
+void encode_base64(
+ std::uint8_t const * input, std::size_t input_length,
+ std::uint8_t * output
+);
+
+
+std::size_t decode_base64_length(
+ std::size_t input_length
+);
+
+
+void decode_base64(
+ std::uint8_t const * input, std::size_t input_length,
+ std::uint8_t * output
+);
+
+
+} // namespace axolotl
+
+
+#endif /* AXOLOLT_BASE64_HH_ */
diff --git a/src/base64.cpp b/src/base64.cpp
new file mode 100644
index 0000000..6428424
--- /dev/null
+++ b/src/base64.cpp
@@ -0,0 +1,118 @@
+#include "axolotl/base64.hh"
+
+
+namespace {
+
+static const std::uint8_t ENCODE_BASE64[64] = {
+ 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
+ 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
+ 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
+ 0x59, 0x5A, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
+ 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E,
+ 0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76,
+ 0x77, 0x78, 0x79, 0x7A, 0x30, 0x31, 0x32, 0x33,
+ 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x2B, 0x2F,
+};
+
+static const std::uint8_t E = -1;
+
+static const std::uint8_t DECODE_BASE64[128] = {
+/* 0x0 0x1 0x2 0x3 0x4 0x5 0x6 0x7 0x8 0x9 0xA 0xB 0xC 0xD 0xE 0xF */
+ E, E, E, E, E, E, E, E, E, E, E, E, E, E, E, E,
+ E, E, E, E, E, E, E, E, E, E, E, E, E, E, E, E,
+ E, E, E, E, E, E, E, E, E, E, E, 62, E, E, E, 63,
+ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, E, E, E, E, E, E,
+ E, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
+ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, E, E, E, E, E,
+ E, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, E, E, E, E, E,
+};
+
+} // namespace
+
+
+std::size_t axolotl::encode_base64_length(
+ std::size_t input_length
+) {
+ return 4 * ((input_length + 2) / 3) + (input_length + 2) % 3 - 2;
+}
+
+
+void axolotl::encode_base64(
+ std::uint8_t const * input, std::size_t input_length,
+ std::uint8_t * output
+) {
+ std::uint8_t const * end = input + (input_length / 3) * 3;
+ std::uint8_t const * pos = input;
+ while (pos != end) {
+ unsigned value = pos[0];
+ value <<= 8; value |= pos[1];
+ value <<= 8; value |= pos[2];
+ pos += 3;
+ output[3] = ENCODE_BASE64[value & 0x3F];
+ value >>= 6; output[2] = ENCODE_BASE64[value & 0x3F];
+ value >>= 6; output[1] = ENCODE_BASE64[value & 0x3F];
+ value >>= 6; output[0] = ENCODE_BASE64[value];
+ output += 4;
+ }
+ unsigned remainder = input + input_length - pos;
+ if (remainder) {
+ unsigned value = pos[0];
+ if (remainder == 2) {
+ value <<= 8; value |= pos[1];
+ value <<= 2;
+ output[2] = ENCODE_BASE64[value & 0x3F];
+ value >>= 6;
+ } else {
+ value <<= 4;
+ }
+ output[1] = ENCODE_BASE64[value & 0x3F];
+ value >>= 6;
+ output[0] = ENCODE_BASE64[value];
+ }
+}
+
+
+std::size_t axolotl::decode_base64_length(
+ std::size_t input_length
+) {
+ if (input_length % 4 == 1) {
+ return std::size_t(-1);
+ } else {
+ return 3 * ((input_length + 2) / 4) + (input_length + 2) % 4 - 2;
+ }
+}
+
+
+void axolotl::decode_base64(
+ std::uint8_t const * input, std::size_t input_length,
+ std::uint8_t * output
+) {
+ std::uint8_t const * end = input + (input_length / 4) * 4;
+ std::uint8_t const * pos = input;
+ while (pos != end) {
+ unsigned value = DECODE_BASE64[pos[0] & 0x7F];
+ value <<= 6; value |= DECODE_BASE64[pos[1] & 0x7F];
+ value <<= 6; value |= DECODE_BASE64[pos[2] & 0x7F];
+ value <<= 6; value |= DECODE_BASE64[pos[3] & 0x7F];
+ pos += 4;
+ output[2] = value;
+ value >>= 8; output[1] = value;
+ value >>= 8; output[0] = value;
+ output += 3;
+ }
+ unsigned remainder = input + input_length - pos;
+ if (remainder) {
+ unsigned value = DECODE_BASE64[pos[0] & 0x7F];
+ value <<= 6; value |= DECODE_BASE64[pos[1] & 0x7F];
+ if (remainder == 3) {
+ value <<= 6; value |= DECODE_BASE64[pos[2] & 0x7F];
+ value >>= 2;
+ output[1] = value;
+ value >>= 8;
+ } else {
+ value >>= 4;
+ }
+ output[0] = value;
+ }
+}
diff --git a/tests/test_base64.cpp b/tests/test_base64.cpp
new file mode 100644
index 0000000..2340656
--- /dev/null
+++ b/tests/test_base64.cpp
@@ -0,0 +1,38 @@
+
+#include "axolotl/base64.hh"
+#include "unittest.hh"
+
+int main() {
+
+{ /* Base64 encode test */
+TestCase test_case("Base64 encode test");
+
+std::uint8_t input[] = "Hello World";
+std::uint8_t expected_output[] = "SGVsbG8gV29ybGQ";
+std::size_t input_length = sizeof(input) - 1;
+
+std::size_t output_length = axolotl::encode_base64_length(input_length);
+assert_equals(std::size_t(15), output_length);
+
+std::uint8_t output[output_length];
+axolotl::encode_base64(input, input_length, output);
+assert_equals(expected_output, output, output_length);
+}
+
+{ /* Base64 decode test */
+TestCase test_case("Base64 decode test");
+
+std::uint8_t input[] = "SGVsbG8gV29ybGQ";
+std::uint8_t expected_output[] = "Hello World";
+std::size_t input_length = sizeof(input) - 1;
+
+std::size_t output_length = axolotl::decode_base64_length(input_length);
+assert_equals(std::size_t(11), output_length);
+
+std::uint8_t output[output_length];
+axolotl::decode_base64(input, input_length, output);
+assert_equals(expected_output, output, output_length);
+}
+
+
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-02 21:17:01 +0000