crc: Factor out CRC16 implementation from Modbus

[libsigrok.git] / src / modbus / modbus_serial_rtu.c

diff --git a/src/modbus/modbus_serial_rtu.c b/src/modbus/modbus_serial_rtu.c
index f7fee0abafec655ef221a2df335705f7f619dfa3..8d6978b1e0bf114f23ee578f329e2653f3161f8b 100644 (file)
--- a/src/modbus/modbus_serial_rtu.c
+++ b/src/modbus/modbus_serial_rtu.c
@@ -81,27 +81,6 @@ static int modbus_serial_rtu_source_remove(struct sr_session *session,
        return serial_source_remove(session, serial);
 }
 
-static uint16_t modbus_serial_rtu_crc(uint16_t crc,
-               const uint8_t *buffer, int len)
-{
-       int i;
-
-       if (!buffer || len < 0)
-               return crc;
-
-       while (len--) {
-               crc ^= *buffer++;
-               for (i = 0; i < 8; i++) {
-                       int carry = crc & 1;
-                       crc >>= 1;
-                       if (carry)
-                               crc ^= 0xA001;
-               }
-       }
-
-       return crc;
-}
-
 static int modbus_serial_rtu_send(void *priv,
                const uint8_t *buffer, int buffer_size)
 {
@@ -119,8 +98,8 @@ static int modbus_serial_rtu_send(void *priv,
        if (result < 0)
                return SR_ERR;
 
-       crc = modbus_serial_rtu_crc(0xFFFF, &slave_addr, sizeof(slave_addr));
-       crc = modbus_serial_rtu_crc(crc, buffer, buffer_size);
+       crc = sr_crc16(SR_CRC16_DEFAULT_INIT, &slave_addr, sizeof(slave_addr));
+       crc = sr_crc16(crc, buffer, buffer_size);
 
        result = serial_write_blocking(serial, &crc, sizeof(crc), 0);
        if (result < 0)
@@ -143,8 +122,8 @@ static int modbus_serial_rtu_read_begin(void *priv, uint8_t *function_code)
        if (ret != 1)
                return SR_ERR;
 
-       modbus->crc = modbus_serial_rtu_crc(0xFFFF, &slave_addr, sizeof(slave_addr));
-       modbus->crc = modbus_serial_rtu_crc(modbus->crc, function_code, 1);
+       modbus->crc = sr_crc16(SR_CRC16_DEFAULT_INIT, &slave_addr, sizeof(slave_addr));
+       modbus->crc = sr_crc16(modbus->crc, function_code, 1);
 
        return SR_OK;
 }
@@ -157,7 +136,7 @@ static int modbus_serial_rtu_read_data(void *priv, uint8_t *buf, int maxlen)
        ret = serial_read_nonblocking(modbus->serial, buf, maxlen);
        if (ret < 0)
                return ret;
-       modbus->crc = modbus_serial_rtu_crc(modbus->crc, buf, ret);
+       modbus->crc = sr_crc16(modbus->crc, buf, ret);
        return ret;
 }