diff --git a/src/utils.c b/src/utils.c
new file mode 100644
index 0000000..0a1e33c
--- /dev/null
+++ b/src/utils.c
@@ -0,0 +1,211 @@
+#include "utils.h"
+#include "base.h"
+#include <stdio.h>
+
+/** CRC32 code derived from work by Gary S. Brown.
+ *  http://web.mit.edu/freebsd/head/sys/libkern/crc32.c
+ *
+ *  COPYRIGHT (C) 1986 Gary S. Brown.  You may use this program, or
+ *  code or tables extracted from it, as desired without restriction.
+ *
+ */
+static uint32_t crc32_tab[] = {
+    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+    0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+    0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+    0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+    0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+    0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
+    0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+    0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+    0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
+    0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+    0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+    0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+    0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+    0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+    0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+    0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+    0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+    0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+    0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+    0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+    0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+    0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+    0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+    0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+    0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+    0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+    0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+    0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+    0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+    0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+    0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+    0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+    0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d};
+
+/* 0x07(polynomial: x8+x2+x1+1)
+ */
+static const uint8_t crc8_table[] = {
+    0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15, 0x38, 0x3f, 0x36, 0x31,
+    0x24, 0x23, 0x2a, 0x2d, 0x70, 0x77, 0x7e, 0x79, 0x6c, 0x6b, 0x62, 0x65,
+    0x48, 0x4f, 0x46, 0x41, 0x54, 0x53, 0x5a, 0x5d, 0xe0, 0xe7, 0xee, 0xe9,
+    0xfc, 0xfb, 0xf2, 0xf5, 0xd8, 0xdf, 0xd6, 0xd1, 0xc4, 0xc3, 0xca, 0xcd,
+    0x90, 0x97, 0x9e, 0x99, 0x8c, 0x8b, 0x82, 0x85, 0xa8, 0xaf, 0xa6, 0xa1,
+    0xb4, 0xb3, 0xba, 0xbd, 0xc7, 0xc0, 0xc9, 0xce, 0xdb, 0xdc, 0xd5, 0xd2,
+    0xff, 0xf8, 0xf1, 0xf6, 0xe3, 0xe4, 0xed, 0xea, 0xb7, 0xb0, 0xb9, 0xbe,
+    0xab, 0xac, 0xa5, 0xa2, 0x8f, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9d, 0x9a,
+    0x27, 0x20, 0x29, 0x2e, 0x3b, 0x3c, 0x35, 0x32, 0x1f, 0x18, 0x11, 0x16,
+    0x03, 0x04, 0x0d, 0x0a, 0x57, 0x50, 0x59, 0x5e, 0x4b, 0x4c, 0x45, 0x42,
+    0x6f, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7d, 0x7a, 0x89, 0x8e, 0x87, 0x80,
+    0x95, 0x92, 0x9b, 0x9c, 0xb1, 0xb6, 0xbf, 0xb8, 0xad, 0xaa, 0xa3, 0xa4,
+    0xf9, 0xfe, 0xf7, 0xf0, 0xe5, 0xe2, 0xeb, 0xec, 0xc1, 0xc6, 0xcf, 0xc8,
+    0xdd, 0xda, 0xd3, 0xd4, 0x69, 0x6e, 0x67, 0x60, 0x75, 0x72, 0x7b, 0x7c,
+    0x51, 0x56, 0x5f, 0x58, 0x4d, 0x4a, 0x43, 0x44, 0x19, 0x1e, 0x17, 0x10,
+    0x05, 0x02, 0x0b, 0x0c, 0x21, 0x26, 0x2f, 0x28, 0x3d, 0x3a, 0x33, 0x34,
+    0x4e, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5c, 0x5b, 0x76, 0x71, 0x78, 0x7f,
+    0x6a, 0x6d, 0x64, 0x63, 0x3e, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2c, 0x2b,
+    0x06, 0x01, 0x08, 0x0f, 0x1a, 0x1d, 0x14, 0x13, 0xae, 0xa9, 0xa0, 0xa7,
+    0xb2, 0xb5, 0xbc, 0xbb, 0x96, 0x91, 0x98, 0x9f, 0x8a, 0x8d, 0x84, 0x83,
+    0xde, 0xd9, 0xd0, 0xd7, 0xc2, 0xc5, 0xcc, 0xcb, 0xe6, 0xe1, 0xe8, 0xef,
+    0xfa, 0xfd, 0xf4, 0xf3};
+
+uint32_t crc32(const void *data, size_t size)
+{
+	const uint8_t *p = data;
+	uint32_t crc = ~0U;
+	while (size--)
+		crc = crc32_tab[(crc ^ *p++) & 0xff] ^ (crc >> 8);
+	return crc ^ ~0U;
+}
+
+uint8_t crc8(const void *data, size_t size)
+{
+	const uint8_t *p = data;
+	uint8_t crc = 0x00;
+	while (size--)
+		crc = crc8_table[crc ^ *p++];
+	return crc;
+}
+
+static int print_version_field(uint8_t bcd, char *buffer, size_t buffer_size)
+{
+	int v;
+	if (bcd == 0xff)
+		return 0;
+	if ((bcd & 0xf0) == 0xf0) {
+		v = bcd & 0x0f;
+		return snprintf(buffer, buffer_size, "%d", v);
+	}
+	v = ((bcd >> 4) * 10) + (bcd & 0x0f);
+	return snprintf(buffer, buffer_size, "%02d", v);
+}
+
+#define POINTER_MOVE(rc, buffer, buffer_size, original_size)                   \
+	do {                                                                   \
+		if (rc < 0)                                                    \
+			return rc;                                             \
+		if ((size_t)rc >= buffer_size)                                 \
+			return original_size - 1;                              \
+		buffer += rc;                                                  \
+		buffer_size -= rc;                                             \
+	} while (0)
+
+int ver2str(const ver32_t *version, char *buffer, size_t buffer_size)
+{
+	int rc;
+	size_t original_size = buffer_size;
+	rc = print_version_field(version->major, buffer, buffer_size);
+	POINTER_MOVE(rc, buffer, buffer_size, original_size);
+	rc = snprintf(buffer, buffer_size, ".");
+	POINTER_MOVE(rc, buffer, buffer_size, original_size);
+	rc = print_version_field(version->minor, buffer, buffer_size);
+	POINTER_MOVE(rc, buffer, buffer_size, original_size);
+	if (version->update != 0xff) {
+		rc = snprintf(buffer, buffer_size, ".");
+		POINTER_MOVE(rc, buffer, buffer_size, original_size);
+		rc = print_version_field(version->update, buffer, buffer_size);
+		POINTER_MOVE(rc, buffer, buffer_size, original_size);
+	}
+	if (version->alpha != 0) {
+		rc = snprintf(buffer, buffer_size, "%c", version->alpha);
+		POINTER_MOVE(rc, buffer, buffer_size, original_size);
+	}
+	return original_size - buffer_size;
+}
+
+uint8_t bcd2dec8(uint8_t bcd)
+{
+	uint8_t dec = (bcd >> 4) * 10 + (bcd & 0x0f);
+	return dec;
+}
+
+uint8_t dec2bcd8(uint8_t dec)
+{
+	uint8_t bcd = (dec % 10) | (dec / 10) << 4;
+	return bcd;
+}
+
+uint16_t bcd2dec16(uint16_t bcd)
+{
+	return bcd2dec8(bcd >> 8) * 100 + bcd2dec8(bcd & 0xff);
+}
+
+uint16_t dec2bcd16(uint16_t dec)
+{
+	return dec2bcd8(dec % 100) | dec2bcd8(dec / 100) << 8;
+}
+
+uint32_t bcd2dec32(uint32_t bcd)
+{
+	return bcd2dec16(bcd >> 16) * 10000 + bcd2dec16(bcd & 0xffff);
+}
+
+uint32_t dec2bcd32(uint32_t dec)
+{
+	return dec2bcd16(dec % 10000) | dec2bcd16(dec / 10000) << 16;
+}
+
+bool is_time_legal(uint8_t seconds, uint8_t minutes, uint8_t hours, uint8_t day,
+		   uint8_t month, uint16_t year)
+{
+	if (month < 1 || month > 12) {
+		return false;
+	}
+	static const int days[13] = {0,	 31, 28, 31, 30, 31, 30,
+				     31, 31, 30, 31, 30, 31};
+	int rday = days[month];
+	if (month == 2 &&
+	    ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))) {
+		rday += 1;
+	}
+	if (year < 1970 || day < 1 || day > rday || seconds > 59 ||
+	    minutes > 59 || hours > 23) {
+		return false;
+	}
+	return true;
+}
+
+bool is_transfer_flag_valid(uint8_t transfer_flag)
+{
+	switch (transfer_flag) {
+	case PLDM_START:
+	case PLDM_MIDDLE:
+	case PLDM_END:
+	case PLDM_START_AND_END:
+		return true;
+
+	default:
+		return false;
+	}
+}