NetType.cpp

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/*
 * SPDX-FileCopyrightText: 2006-2021 Istituto Italiano di Tecnologia (IIT)
 * SPDX-FileCopyrightText: 2006-2010 RobotCub Consortium
 * SPDX-License-Identifier: BSD-3-Clause
 */
 
#include <yarp/os/NetType.h>
 
#include <yarp/os/ManagedBytes.h>
#include <yarp/os/impl/LogComponent.h>
 
#include <clocale>
#include <cstdlib>
#include <cstring>
#include <limits>
 
 
 
 
using namespace yarp::os::impl;
using namespace yarp::os;
 
namespace {
YARP_OS_LOG_COMPONENT(NETTYPE, "yarp.os.NetType")
} // namespace
 
int NetType::netInt(const yarp::os::Bytes& code)
{
    yCAssert(NETTYPE, code.length() == sizeof(NetInt32));
    NetInt32 tmp;
    memcpy((char*)(&tmp), code.get(), code.length());
    return tmp;
}
 
bool NetType::netInt(int data, yarp::os::Bytes& code)
{
    NetInt32 i = data;
    yarp::os::Bytes b((char*)(&i), sizeof(i));
    if (code.length() != sizeof(i)) {
        yCError(NETTYPE, "not enough room for integer");
        return false;
    }
    memcpy(code.get(), b.get(), code.length());
    return true;
}
 
/*
  PNG's nice and simple CRC code
  (from http://www.w3.org/TR/PNG-CRCAppendix.html)
*/
 
/* Table of CRCs of all 8-bit messages. */
static unsigned long crc_table[256];
 
/* Flag: has the table been computed? Initially false. */
static int crc_table_computed = 0;
 
/* Make the table for a fast CRC. */
static void make_crc_table()
{
    unsigned long c;
    int n;
    int k;
 
    for (n = 0; n < 256; n++) {
        c = (unsigned long)n;
        for (k = 0; k < 8; k++) {
            if ((c & 1) != 0) {
                c = 0xedb88320L ^ (c >> 1);
            } else {
                c = c >> 1;
            }
        }
        crc_table[n] = c;
    }
    crc_table_computed = 1;
}
 
/* Update a running CRC with the bytes buf[0..len-1]--the CRC
   should be initialized to all 1's, and the transmitted value
   is the 1's complement of the final running CRC (see the
   crc() routine below)). */
 
static unsigned long update_crc(unsigned long crc, unsigned char* buf, size_t len)
{
 
    unsigned long c = crc;
    size_t n;
 
    if (crc_table_computed == 0) {
        make_crc_table();
    }
    for (n = 0; n < len; n++) {
        c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
    }
    return c;
}
 
/* Return the CRC of the bytes buf[0..len-1]. */
unsigned long NetType::getCrc(char* buf, size_t len)
{
    return update_crc(0xffffffffL, (unsigned char*)buf, len) ^ 0xffffffffL;
}