[PATCH v2 3/5] base64: Add decoder
Sebastian Huber
sebastian.huber at embedded-brains.de
Thu Jan 25 19:22:59 UTC 2024
From: Matthew Joyce <matthew.joyce at embedded-brains.de>
---
cpukit/base64/base64-decode.c | 165 ++++++++++++++++
cpukit/include/rtems/base64.h | 63 ++++++
spec/build/cpukit/librtemscpu.yml | 1 +
.../build/testsuites/unit/unit-no-clock-0.yml | 1 +
testsuites/unit/tc-base64-decode.c | 180 ++++++++++++++++++
5 files changed, 410 insertions(+)
create mode 100644 cpukit/base64/base64-decode.c
create mode 100644 testsuites/unit/tc-base64-decode.c
diff --git a/cpukit/base64/base64-decode.c b/cpukit/base64/base64-decode.c
new file mode 100644
index 0000000000..5739266528
--- /dev/null
+++ b/cpukit/base64/base64-decode.c
@@ -0,0 +1,165 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup RTEMSImplBase64
+ *
+ * @brief This source file contains the implementation of
+ * _Base64_Decode_initialize() and _Base64_Decode().
+ */
+
+/*
+ * Copyright (C) 2023 embedded brains GmbH & Co. KG
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <rtems/base64.h>
+
+#define SPACE 253
+
+#define PAD 254
+
+#define INVALID 255
+
+const uint8_t _Base64_Decoding[128] = {
+ ['A'] = 0, ['B'] = 1, ['C'] = 2, ['D'] = 3,
+ ['E'] = 4, ['F'] = 5, ['G'] = 6, ['H'] = 7,
+ ['I'] = 8, ['J'] = 9, ['K'] = 10, ['L'] = 11,
+ ['M'] = 12, ['N'] = 13, ['O'] = 14, ['P'] = 15,
+ ['Q'] = 16, ['R'] = 17, ['S'] = 18, ['T'] = 19,
+ ['U'] = 20, ['V'] = 21, ['W'] = 22, ['X'] = 23,
+ ['Y'] = 24, ['Z'] = 25, ['a'] = 26, ['b'] = 27,
+ ['c'] = 28, ['d'] = 29, ['e'] = 30, ['f'] = 31,
+ ['g'] = 32, ['h'] = 33, ['i'] = 34, ['j'] = 35,
+ ['k'] = 36, ['l'] = 37, ['m'] = 38, ['n'] = 39,
+ ['o'] = 40, ['p'] = 41, ['q'] = 42, ['r'] = 43,
+ ['s'] = 44, ['t'] = 45, ['u'] = 46, ['v'] = 47,
+ ['w'] = 48, ['x'] = 49, ['y'] = 50, ['z'] = 51,
+ ['0'] = 52, ['1'] = 53, ['2'] = 54, ['3'] = 55,
+ ['4'] = 56, ['5'] = 57, ['6'] = 58, ['7'] = 59,
+ ['8'] = 60, ['9'] = 61, ['+'] = 62, ['-'] = 62,
+ ['/'] = 63, ['_'] = 63, ['='] = PAD, [' '] = SPACE,
+ ['\t'] = SPACE, ['\n'] = SPACE, ['\v'] = SPACE, ['\f'] = SPACE,
+ ['\r'] = SPACE, [0] = INVALID, [1] = INVALID, [2] = INVALID,
+ [3] = INVALID, [4] = INVALID, [5] = INVALID, [6] = INVALID,
+ [7] = INVALID, [8] = INVALID, [14] = INVALID, [15] = INVALID,
+ [16] = INVALID, [17] = INVALID, [18] = INVALID, [19] = INVALID,
+ [20] = INVALID, [21] = INVALID, [22] = INVALID, [23] = INVALID,
+ [24] = INVALID, [25] = INVALID, [26] = INVALID, [27] = INVALID,
+ [28] = INVALID, [29] = INVALID, [30] = INVALID, [31] = INVALID,
+ [33] = INVALID, [34] = INVALID, [35] = INVALID, [36] = INVALID,
+ [37] = INVALID, [38] = INVALID, [39] = INVALID, [40] = INVALID,
+ [41] = INVALID, [42] = INVALID, [44] = INVALID, [46] = INVALID,
+ [58] = INVALID, [59] = INVALID, [60] = INVALID, [62] = INVALID,
+ [63] = INVALID, [64] = INVALID, [91] = INVALID, [92] = INVALID,
+ [93] = INVALID, [94] = INVALID, [96] = INVALID, [123] = INVALID,
+ [124] = INVALID, [125] = INVALID, [126] = INVALID, [127] = INVALID};
+
+void _Base64_Decode_initialize(Base64_Decode_control* self,
+ uint8_t* target,
+ size_t target_size) {
+ self->state = BASE64_DECODE_STATE_0;
+ self->target = target;
+ self->target_end = target + target_size;
+}
+
+Base64_Decode_status _Base64_Decode(Base64_Decode_control* self, char ch) {
+ uint8_t decoded_ch;
+ uint8_t next_ch;
+ uint8_t* target;
+ const uint8_t* target_end;
+ Base64_Decode_state next_state;
+
+ if ((unsigned char)ch >= 128) {
+ return BASE64_DECODE_INVALID_INPUT;
+ }
+
+ decoded_ch = _Base64_Decoding[(unsigned char)ch];
+
+ if (decoded_ch == SPACE) {
+ return BASE64_DECODE_SUCCESS;
+ }
+
+ target = self->target;
+
+ if (decoded_ch == PAD) {
+ self->target_end = target;
+ return BASE64_DECODE_SUCCESS;
+ }
+
+ if (decoded_ch == INVALID) {
+ return BASE64_DECODE_INVALID_INPUT;
+ }
+
+ target_end = self->target_end;
+
+ if (target == target_end) {
+ return BASE64_DECODE_OVERFLOW;
+ }
+
+ switch (self->state) {
+ case BASE64_DECODE_STATE_0:
+ *target = decoded_ch << 2;
+ next_state = BASE64_DECODE_STATE_1;
+ break;
+
+ case BASE64_DECODE_STATE_1:
+ *target |= decoded_ch >> 4;
+ next_ch = (decoded_ch & 0x0fU) << 4;
+ ++target;
+
+ if (target != target_end) {
+ *target = next_ch;
+ } else if (next_ch != 0) {
+ return BASE64_DECODE_OVERFLOW;
+ }
+
+ next_state = BASE64_DECODE_STATE_2;
+ break;
+
+ case BASE64_DECODE_STATE_2:
+ *target |= decoded_ch >> 2;
+ next_ch = (decoded_ch & 0x03U) << 6;
+ ++target;
+
+ if (target != target_end) {
+ *target = next_ch;
+ } else if (next_ch != 0) {
+ return BASE64_DECODE_OVERFLOW;
+ }
+
+ next_state = BASE64_DECODE_STATE_3;
+ break;
+
+ default: /* BASE64_DECODE_STATE_3 */
+ *target |= decoded_ch;
+ ++target;
+ next_state = BASE64_DECODE_STATE_0;
+ break;
+ }
+
+ self->state = next_state;
+ self->target = target;
+ return BASE64_DECODE_SUCCESS;
+}
diff --git a/cpukit/include/rtems/base64.h b/cpukit/include/rtems/base64.h
index b9d88f7818..58e48a8c33 100644
--- a/cpukit/include/rtems/base64.h
+++ b/cpukit/include/rtems/base64.h
@@ -126,6 +126,69 @@ int _Base64url_Encode(
int wordlen
);
+/**
+ * @brief Represents the base64 and base64url decoder state.
+ */
+typedef enum {
+ BASE64_DECODE_STATE_0,
+ BASE64_DECODE_STATE_1,
+ BASE64_DECODE_STATE_2,
+ BASE64_DECODE_STATE_3
+} Base64_Decode_state;
+
+/**
+ * @brief Contains the base64 and base64url decoder control.
+ */
+typedef struct {
+ Base64_Decode_state state;
+ uint8_t *target;
+ const uint8_t *target_end;
+} Base64_Decode_control;
+
+/**
+ * @brief Maps a 7-bit character to the associated 6-bit integer as defined by
+ * the base64 or base64url encoding or a special value.
+ */
+extern const uint8_t _Base64_Decoding[ 128 ];
+
+/**
+ * @brief Initializes the base64 decoder.
+ *
+ * @param[out] self is the base64 decoder control to initialize.
+ *
+ * @param[out] target is the base address of the target area for decoding.
+ *
+ * @param target_size is the size in bytes of the target area for decoding.
+ */
+void _Base64_Decode_initialize(
+ Base64_Decode_control *self,
+ uint8_t *target,
+ size_t target_size
+);
+
+/**
+ * @brief Represents the base64 and base64url decoder status.
+ */
+typedef enum {
+ BASE64_DECODE_SUCCESS,
+ BASE64_DECODE_OVERFLOW,
+ BASE64_DECODE_INVALID_INPUT
+} Base64_Decode_status;
+
+/**
+ * @brief Decodes the character.
+ *
+ * The decoder accepts base64 and base64url encodings. White space is ignored.
+ *
+ * @param[in, out] self is the base64 decoder control.
+ *
+ * @param ch is the character to decode.
+ */
+Base64_Decode_status _Base64_Decode(
+ Base64_Decode_control *self,
+ char ch
+);
+
/** @} */
#ifdef __cplusplus
diff --git a/spec/build/cpukit/librtemscpu.yml b/spec/build/cpukit/librtemscpu.yml
index 24b63af8de..45960099e8 100644
--- a/spec/build/cpukit/librtemscpu.yml
+++ b/spec/build/cpukit/librtemscpu.yml
@@ -529,6 +529,7 @@ source:
- cpukit/compression/xz/xz_dec_lzma2.c
- cpukit/compression/xz/xz_dec_stream.c
- cpukit/base64/base64-encode.c
+- cpukit/base64/base64-decode.c
- cpukit/dev/flash/flashdev.c
- cpukit/dev/i2c/eeprom.c
- cpukit/dev/i2c/fpga-i2c-slave.c
diff --git a/spec/build/testsuites/unit/unit-no-clock-0.yml b/spec/build/testsuites/unit/unit-no-clock-0.yml
index 5d15bf52b7..d61c570183 100644
--- a/spec/build/testsuites/unit/unit-no-clock-0.yml
+++ b/spec/build/testsuites/unit/unit-no-clock-0.yml
@@ -11,6 +11,7 @@ includes: []
ldflags: []
links: []
source:
+- testsuites/unit/tc-base64-decode.c
- testsuites/unit/tc-compiler-builtins.c
- testsuites/unit/tc-config.c
- testsuites/unit/tc-misaligned-builtin-memcpy.c
diff --git a/testsuites/unit/tc-base64-decode.c b/testsuites/unit/tc-base64-decode.c
new file mode 100644
index 0000000000..dd9d50b069
--- /dev/null
+++ b/testsuites/unit/tc-base64-decode.c
@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/*
+ * Copyright (C) 2023 embedded brains GmbH & Co. KG
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <rtems/base64.h>
+
+#include <rtems/test.h>
+
+typedef struct {
+ Base64_Decode_control base;
+ uint8_t buf[64];
+} test_control;
+
+static int test_run(test_control* self, const char* payload) {
+ size_t len = strlen(payload);
+
+ for (size_t i = 0; i < len; ++i) {
+ int rv = _Base64_Decode(&self->base, payload[i]);
+
+ if (rv != 0) {
+ return rv;
+ }
+ }
+
+ return 0;
+}
+
+static int test_payload(test_control* self, const char* payload) {
+ memset(self->buf, 0xff, sizeof(self->buf));
+ _Base64_Decode_initialize(&self->base, &self->buf[0], sizeof(self->buf));
+ return test_run(self, payload);
+}
+
+T_TEST_CASE(IOBase64Decode) {
+ int rv;
+ test_control instance;
+ test_control* self = &instance;
+
+ rv = test_payload(self, "POOL");
+ T_eq_int(rv, BASE64_DECODE_SUCCESS);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_0);
+ T_eq_ptr(self->base.target, &self->buf[3]);
+ const uint8_t expected1[] = {0x3c, 0xe3, 0x8b, 0xff};
+ T_eq_mem(&self->buf[0], expected1, sizeof(expected1));
+
+ rv = test_payload(self, "ABCDEFGH");
+ T_eq_int(rv, BASE64_DECODE_SUCCESS);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_0);
+ T_eq_ptr(self->base.target, &self->buf[6]);
+ const uint8_t expected2[] = {0x00, 0x10, 0x83, 0x10, 0x51, 0x87, 0xff};
+ T_eq_mem(&self->buf[0], expected2, sizeof(expected2));
+
+ /* Non-base64 character results in an error */
+ rv = test_payload(self, "PO*OL");
+ T_eq_int(rv, BASE64_DECODE_INVALID_INPUT);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_2);
+ T_eq_ptr(self->base.target, &self->buf[1]);
+ const uint8_t expected3[] = {0x3c};
+ T_eq_mem(&self->buf[0], expected3, sizeof(expected3));
+
+ /* Other non-base64 character results in an error */
+ rv = test_payload(self, "PO\x80OL");
+ T_eq_int(rv, BASE64_DECODE_INVALID_INPUT);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_2);
+ T_eq_ptr(self->base.target, &self->buf[1]);
+ T_eq_mem(&self->buf[0], expected3, sizeof(expected3));
+
+ /* Space characters should be ignored */
+ rv = test_payload(self, "P OOL");
+ T_eq_int(rv, BASE64_DECODE_SUCCESS);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_0);
+ T_eq_ptr(self->base.target, &self->buf[3]);
+ const uint8_t expected4[] = {0x3c, 0xe3, 0x8b, 0xff};
+ T_eq_mem(&self->buf[0], expected4, sizeof(expected4));
+
+ /* Handle pad characters */
+ rv = test_payload(self, "POOL==");
+ T_eq_int(rv, BASE64_DECODE_SUCCESS);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_0);
+ T_eq_ptr(self->base.target, &self->buf[3]);
+ T_eq_ptr(self->base.target, self->base.target_end);
+ const uint8_t expected5[] = {0x3c, 0xe3, 0x8b, 0xff};
+ T_eq_mem(&self->buf[0], expected5, sizeof(expected5));
+
+ /* If characters come after pad characters, an error results */
+ rv = test_payload(self, "POOL==xy");
+ T_eq_int(rv, BASE64_DECODE_OVERFLOW);
+ T_eq_int(self->base.state, BASE64_DECODE_SUCCESS);
+ T_eq_ptr(self->base.target, &self->buf[3]);
+ T_eq_ptr(self->base.target, self->base.target_end);
+ const uint8_t expected6[] = {0x3c, 0xe3, 0x8b, 0xff};
+ T_eq_mem(&self->buf[0], expected6, sizeof(expected6));
+
+ rv = test_payload(self, "POOLPOOL");
+ T_eq_int(rv, BASE64_DECODE_SUCCESS);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_0);
+ T_eq_ptr(self->base.target, &self->buf[6]);
+ const uint8_t expected7[] = {0x3c, 0xe3, 0x8b, 0x3c, 0xe3, 0x8b, 0xff};
+ T_eq_mem(&self->buf[0], expected7, sizeof(expected7));
+
+ /*
+ * Test valid payload with series of target sizes. All target sizes
+ * less than three are invalid for the given payload and will result
+ * in an error.
+ */
+ const uint8_t expected9[] = {0x3c, 0xe3, 0x8b, 0xff};
+
+ for (size_t i = 0; i < 4; ++i) {
+ memset(&self->buf[0], 0xff, sizeof(self->buf));
+ _Base64_Decode_initialize(&self->base, &self->buf[0], i);
+ rv = test_run(self, "POOL");
+
+ if (i < 3) {
+ T_eq_int(rv, BASE64_DECODE_OVERFLOW);
+ T_eq_int(self->base.state, i);
+ T_ne_ptr(self->base.target, &self->buf[3]);
+ T_ne_mem(&self->buf[0], expected9, sizeof(expected9));
+ } else {
+ T_eq_int(rv, BASE64_DECODE_SUCCESS);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_0);
+ T_eq_ptr(self->base.target, &self->buf[3]);
+ T_eq_mem(&self->buf[0], expected9, sizeof(expected9));
+ }
+ }
+
+ /* No overflow in state 1 */
+ memset(&self->buf[0], 0xff, sizeof(self->buf));
+ _Base64_Decode_initialize(&self->base, &self->buf[0], 1);
+ rv = test_run(self, "AA");
+ T_eq_int(rv, BASE64_DECODE_SUCCESS);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_2);
+ T_eq_ptr(self->base.target, &self->buf[1]);
+ const uint8_t expected10[] = {0x00, 0xff};
+ T_eq_mem(&self->buf[0], expected10, sizeof(expected10));
+
+ /* No overflow in state 2 */
+ memset(&self->buf[0], 0xff, sizeof(self->buf));
+ _Base64_Decode_initialize(&self->base, &self->buf[0], 2);
+ rv = test_run(self, "AAA");
+ T_eq_int(rv, BASE64_DECODE_SUCCESS);
+ T_eq_int(self->base.state, BASE64_DECODE_STATE_3);
+ T_eq_ptr(self->base.target, &self->buf[2]);
+ const uint8_t expected11[] = {0x00, 0x00, 0xff};
+ T_eq_mem(&self->buf[0], expected11, sizeof(expected11));
+}
+
+T_TEST_CASE(IOBase64DecodeInitialize) {
+ Base64_Decode_control instance;
+ Base64_Decode_control* self = &instance;
+ uint8_t buf[1];
+
+ memset(self, 0xff, sizeof(*self));
+ _Base64_Decode_initialize(self, buf, sizeof(buf));
+ T_eq_int(self->state, BASE64_DECODE_STATE_0);
+ T_eq_ptr(self->target, &buf[0]);
+ T_eq_ptr(self->target_end, &buf[1]);
+}
--
2.35.3
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