--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tool/cmd_alias.cpp	Mon Jul 21 22:20:23 2008 +0000
@@ -0,0 +1,181 @@
+/*****************************************************************************
+ *
+ * $Id$
+ *
+ ****************************************************************************/
+
+#include <iostream>
+#include <iomanip>
+#include <sstream>
+using namespace std;
+
+#include "globals.h"
+
+/*****************************************************************************/
+
+const char *help_alias =
+    "[OPTIONS] <ALIAS>\n"
+    "\n"
+    "Write the secondary slave address (alias) for either\n"
+    "one or for multiple slaves.\n"
+    "\n"
+    "Arguments:\n"
+    "  ALIAS must be a 16 bit unsigned integer, specified\n"
+    "        either in decimal (no prefix), octal (prefix '0')\n"
+    "        or hexadecimal (prefix '0x').\n"
+    "\n"
+    "Command-specific options:\n"
+    "  -s <SLAVE>  Write the alias of the slave with the given\n"
+    "              ring position. If this option is not\n"
+    "              specified, the alias of all slaves is set.\n"
+    "              The --force option is required in this\n"
+    "              case.\n";
+
+/*****************************************************************************/
+
+void writeSlaveAlias(uint16_t, uint16_t);
+
+/*****************************************************************************/
+
+/** Writes the Secondary slave address (alias) to the slave's SII.
+ */
+void command_alias(void)
+{
+    uint16_t alias;
+    stringstream err, strAlias;
+    int number;
+    unsigned int numSlaves, i;
+
+    if (commandArgs.size() != 1) {
+        err << "'" << command << "' takes exactly one argument!";
+        throw InvalidUsageException(err);
+    }
+
+    strAlias << commandArgs[0];
+    strAlias
+        >> resetiosflags(ios::basefield) // guess base from prefix
+        >> number;
+    if (strAlias.fail() || number < 0x0000 || number > 0xffff) {
+        err << "Invalid alias '" << commandArgs[0] << "'!";
+        throw InvalidUsageException(err);
+    }
+    alias = number;
+
+    if (slavePosition == -1) {
+        if (!force) {
+            err << "This will write the alias addresses of all slaves to "
+                << alias << "! Please specify --force to proceed.";
+            throw ExecutionFailureException(err);
+        }
+
+        masterDev.open(MasterDevice::ReadWrite);
+        numSlaves = masterDev.slaveCount();
+
+        for (i = 0; i < numSlaves; i++) {
+            writeSlaveAlias(i, alias);
+        }
+    } else {
+        masterDev.open(MasterDevice::ReadWrite);
+        writeSlaveAlias(slavePosition, alias);
+    }
+}
+
+/*****************************************************************************/
+
+/** Calculates the SII checksum field.
+ *
+ * The checksum is generated with the polynom x^8+x^2+x+1 (0x07) and an
+ * initial value of 0xff (see IEC 61158-6-12 ch. 5.4).
+ *
+ * The below code was originally generated with PYCRC
+ * http://www.tty1.net/pycrc
+ *
+ * ./pycrc.py --width=8 --poly=0x07 --reflect-in=0 --xor-in=0xff
+ *   --reflect-out=0 --xor-out=0 --generate c --algorithm=bit-by-bit
+ *
+ * \return CRC8
+ */
+uint8_t calcSiiCrc(
+        const uint8_t *data, /**< pointer to data */
+        size_t length /**< number of bytes in \a data */
+        )
+{
+    unsigned int i;
+    uint8_t bit, byte, crc = 0x48;
+
+    while (length--) {
+        byte = *data++;
+        for (i = 0; i < 8; i++) {
+            bit = crc & 0x80;
+            crc = (crc << 1) | ((byte >> (7 - i)) & 0x01);
+            if (bit) crc ^= 0x07;
+        }
+    }
+
+    for (i = 0; i < 8; i++) {
+        bit = crc & 0x80;
+        crc <<= 1;
+        if (bit) crc ^= 0x07;
+    }
+
+    return crc;
+}
+
+/*****************************************************************************/
+
+/** Writes the Secondary slave address (alias) to the slave's SII.
+ */
+void writeSlaveAlias(
+        uint16_t slavePosition,
+        uint16_t alias
+        )
+{
+    ec_ioctl_slave_sii_t data;
+    ec_ioctl_slave_t slave;
+    stringstream err;
+    uint8_t crc;
+
+    masterDev.getSlave(&slave, slavePosition);
+
+    if (slave.sii_nwords < 8) {
+        err << "Current SII contents are too small to set an alias "
+            << "(" << slave.sii_nwords << " words)!";
+        throw ExecutionFailureException(err);
+    }
+
+    // read first 8 SII words
+    data.slave_position = slavePosition;
+    data.offset = 0;
+    data.nwords = 8;
+    data.words = new uint16_t[data.nwords];
+
+    try {
+        masterDev.readSii(&data);
+    } catch (MasterDeviceException &e) {
+        delete [] data.words;
+        err << "Failed to read SII: " << e.what();
+        throw ExecutionFailureException(err);
+    }
+
+    // write new alias address in word 4
+    data.words[4] = cputole16(alias);
+
+    // calculate checksum over words 0 to 6
+    crc = calcSiiCrc((const uint8_t *) data.words, 14);
+
+    // write new checksum into first byte of word 7
+    *(uint8_t *) (data.words + 7) = crc;
+
+    // write first 8 words with new alias and checksum
+    try {
+        masterDev.writeSii(&data);
+    } catch (MasterDeviceException &e) {
+        delete [] data.words;
+        err << "Failed to read SII: " << e.what();
+        throw ExecutionFailureException(err);
+    }
+
+    delete [] data.words;
+}
+
+/*****************************************************************************/