5 files changed, 143 insertions, 0 deletions
diff --git a/shared/bin.c b/shared/bin.c
new file mode 100644
index 0000000..a2c91a4
--- /dev/null
+++ b/shared/bin.c
@@ -0,0 +1,64 @@
+#include <stdlib.h>
+
+#include "bin.h"
+
+#define W2_ENDIAN_LITTLE (1)
+#define W2_ENDIAN_BIG (0)
+
+#define _SHIFT_0B (8 * 0)
+#define _SHIFT_1B (8 * 1)
+#define _SHIFT_2B (8 * 2)
+#define _SHIFT_3B (8 * 3)
+#define _BYTE_0 ((uint32_t)(0xff << (_SHIFT_0B)))
+#define _BYTE_1 ((uint32_t)(0xff << (_SHIFT_1B)))
+#define _BYTE_2 ((uint32_t)(0xff << (_SHIFT_2B)))
+#define _BYTE_3 ((uint32_t)(0xff << (_SHIFT_3B)))
+
+const uint8_t W2_STRUCT_T_SIZES[] = {sizeof(uint8_t), sizeof(uint16_t), sizeof(uint32_t)};
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wshift-count-overflow"
+w2_s_bin *w2_bin_from_uint8_t(uint8_t data) {
+	size_t size	  = 1;
+	w2_s_bin *ret = malloc(sizeof(w2_s_bin) + sizeof(uint8_t) * size);
+	ret->bytes	  = size;
+	ret->data[0]  = data;
+	return ret;
+}
+
+w2_s_bin *w2_bin_from_uint16_t(uint16_t data) {
+	size_t size	  = 2;
+	w2_s_bin *ret = malloc(sizeof(w2_s_bin) + sizeof(uint8_t) * size);
+	data		  = w2_bin_hton16(data);
+	ret->bytes	  = size;
+	ret->data[0]  = (data & _BYTE_1) >> _SHIFT_1B;
+	ret->data[1]  = (data & _BYTE_0) >> _SHIFT_0B;
+	return ret;
+}
+
+w2_s_bin *w2_bin_from_uint32_t(uint32_t data) {
+	size_t size	  = 4;
+	w2_s_bin *ret = malloc(sizeof(w2_s_bin) + sizeof(uint8_t) * size);
+	data		  = w2_bin_hton32(data);
+	ret->bytes	  = size;
+	ret->data[0]  = (data & _BYTE_3) >> _SHIFT_3B;
+	ret->data[1]  = (data & _BYTE_2) >> _SHIFT_2B;
+	ret->data[2]  = (data & _BYTE_1) >> _SHIFT_1B;
+	ret->data[3]  = (data & _BYTE_0) >> _SHIFT_0B;
+	return ret;
+}
+
+uint32_t w2_bin_hton32(uint32_t h32) {
+	if (g_w2_endianness == W2_ENDIAN_BIG) return h32;
+	return ((h32 & _BYTE_0) << _SHIFT_3B) | ((h32 & _BYTE_1) << _SHIFT_1B) |
+		   ((h32 & _BYTE_2) >> _SHIFT_1B) | ((h32 & _BYTE_3) >> _SHIFT_3B);
+}
+#pragma GCC diagnostic pop
+
+uint16_t w2_bin_hton16(uint16_t h16) {
+	if (g_w2_endianness == W2_ENDIAN_BIG) return h16;
+	return ((h16 & _BYTE_0) << _SHIFT_1B) | ((h16 & _BYTE_1) >> _SHIFT_1B);
+}
+
+uint32_t w2_bin_ntoh32(uint32_t n32) { return w2_bin_hton32(n32); }
+uint16_t w2_bin_ntoh16(uint16_t n16) { return w2_bin_hton16(n16); }
diff --git a/shared/bin.h b/shared/bin.h
new file mode 100644
index 0000000..1c9b951
--- /dev/null
+++ b/shared/bin.h
@@ -0,0 +1,52 @@
+#pragma once
+/**
+ * helper file for binary data
+ *
+ * - fix endianness with functions inspired by UNIX arpa/inet.h
+ * - convert uint16_t and uint32_t to w2_s_bin
+ */
+
+#include <stdint.h>
+
+extern uint8_t g_w2_endianness;
+
+#define W2_T_UINT8_T (0)
+#define W2_T_UINT16_T (1)
+#define W2_T_UINT32_T (2)
+
+enum w2_e_struct_types {
+	W2_ST_UINT8_T,
+	W2_ST_UINT16_T,
+	W2_ST_UINT32_T,
+};
+
+extern const uint8_t W2_STRUCT_T_SIZES[];
+
+typedef struct {
+	uint16_t bytes;
+	uint8_t data[];
+} w2_s_bin;
+
+typedef struct {
+	enum w2_e_struct_types type;
+	uint16_t length;
+	const uint8_t *data;
+} w2_s_struct_property;
+
+typedef struct {
+	uint16_t length;
+	w2_s_struct_property *properties[];
+} w2_s_property_list;
+
+w2_s_bin *w2_bin_from_uint8_t(uint8_t data);
+w2_s_bin *w2_bin_from_uint16_t(uint16_t data);
+w2_s_bin *w2_bin_from_uint32_t(uint32_t data);
+
+/** convert 32-bit value from host endian to network (big-endian) */
+uint32_t w2_bin_hton32(uint32_t h32);
+/** convert 16-bit value from host endian to network (big-endian) */
+uint16_t w2_bin_hton16(uint16_t h16);
+/** convert 32-bit value from network (big-endian) to host endian */
+uint32_t w2_bin_ntoh32(uint32_t n32);
+/** convert 16-bit value from network (big-endian) to host endian */
+uint16_t w2_bin_ntoh16(uint16_t n16);
diff --git a/shared/consts.h b/shared/consts.h
new file mode 100644
index 0000000..70efcac
--- /dev/null
+++ b/shared/consts.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#ifndef W2_BUILD_STR
+// is defined by CFLAGS += -DW2_BUILD_STR in makefile
+#define W2_BUILD_STR ("????????")
+#endif
+
+/** max logic module execution time in milliseconds */
+#define W2_MAX_MODULE_CYCLE_MS (20)
+/** serial baud rate (bit/s) */
+#define W2_SERIAL_BAUD (9600)
+/** size of the error handling buffer (in errors, not bytes) */
+#define W2_ERROR_BUFFER_SIZE (16)
+/** size of the serial communication buffer (in messages, not bytes) */
+#define W2_SERCOMM_BUFFER_SIZE (16)
+/** size of input (receive) buffer (in bytes) */
+#define W2_SERIAL_READ_BUFFER_SIZE (255)
diff --git a/shared/makefile b/shared/makefile
new file mode 100644
index 0000000..815d33c
--- /dev/null
+++ b/shared/makefile
@@ -0,0 +1,2 @@
+SOURCES += $(wildcard ../shared/*.c)
+HEADERS += $(wildcard ../shared/*.h)
diff --git a/shared/readme.md b/shared/readme.md
new file mode 100644
index 0000000..870f015
--- /dev/null
+++ b/shared/readme.md
@@ -0,0 +1,8 @@
+# shared code
+
+this is the subdirectory for all code that is shared between the robot code and
+the client code. to use these, include the .h files with a relative path (e.g.
+`#include "../shared/consts.h"`). makefiles should add `include
+../shared/makefile` to add the .c and .h files to `$SOURCES` and `$HEADERS` in
+the makefile targets (this is already done for the robot and client
+subdirectories).