/*      $NetBSD: smeartest.c,v 1.3 2024/08/18 20:47:27 christos Exp $   */

#include <config.h>

#include <ntp.h>
#include <ntp_fp.h>
#include <ntp_assert.h>

/*
* we want to test a refid format of:
* 254.x.y.x
*
* where x.y.z are 24 bits containing 2 (signed) integer bits
* and 22 fractional bits.
*
* we want functions to convert to/from this format, with unit tests.
*
* Interesting test cases include:
* 254.0.0.0
* 254.0.0.1
* 254.127.255.255
* 254.128.0.0
* 254.255.255.255
*/

char *progname = "";

l_fp convertRefIDToLFP(uint32_t r);
uint32_t convertLFPToRefID(l_fp num);


/*
* The smear data in the refid is the bottom 3 bytes of the refid,
* 2 bits of integer
* 22 bits of fraction
*/
l_fp
convertRefIDToLFP(uint32_t r)
{
       l_fp temp;

       r = ntohl(r);

       printf("%03d %08x: ", (r >> 24) & 0xFF, (r & 0x00FFFFFF) );

       temp.l_uf = (r << 10);  /* 22 fractional bits */

       temp.l_ui = (r >> 22) & 0x3;
       temp.l_ui |= ~(temp.l_ui & 2) + 1;

       return temp;
}


uint32_t
convertLFPToRefID(l_fp num)
{
       uint32_t temp;

       /* round the input with the highest bit to shift out from the
        * fraction, then keep just two bits from the integral part.
        *
        * TODO: check for overflows; should we clamp/saturate or just
        * complain?
        */
       L_ADDUF(&num, 0x200);
       num.l_ui &= 3;

       /* combine integral and fractional part to 24 bits */
       temp  = (num.l_ui << 22) | (num.l_uf >> 10);

       /* put in the leading 254.0.0.0 */
       temp |= UINT32_C(0xFE000000);

       printf("%03d %08x: ", (temp >> 24) & 0xFF, (temp & 0x00FFFFFF) );

       return htonl(temp);
}

/* Tests start here */

void rtol(uint32_t r);

void
rtol(uint32_t r)
{
       l_fp l;

       printf("rtol: ");

       l = convertRefIDToLFP(htonl(r));
       printf("refid %#x, smear %s\n", r, lfptoa(&l, 8));

       return;
}


void rtoltor(uint32_t r);

void
rtoltor(uint32_t r)
{
       l_fp l;

       printf("rtoltor: ");
       l = convertRefIDToLFP(htonl(r));

       r = convertLFPToRefID(l);
       printf("smear %s, refid %#.8x\n", lfptoa(&l, 8), ntohl(r));

       return;
}


void ltor(l_fp l);

void
ltor(l_fp l)
{
       uint32_t r;

       printf("ltor: ");

       r = convertLFPToRefID(l);
       printf("smear %s, refid %#.8x\n", lfptoa(&l, 8), ntohl(r));

       return;
}


int
main(void)
{
       l_fp l;
       int rc;

       init_lib();

       rtol(0xfe800000);
       rtol(0xfe800001);
       rtol(0xfe8ffffe);
       rtol(0xfe8fffff);
       rtol(0xfef00000);
       rtol(0xfef00001);
       rtol(0xfefffffe);
       rtol(0xfeffffff);

       rtol(0xfe000000);
       rtol(0xfe000001);
       rtol(0xfe6ffffe);
       rtol(0xfe6fffff);
       rtol(0xfe700000);
       rtol(0xfe700001);
       rtol(0xfe7ffffe);
       rtol(0xfe7fffff);

       rtoltor(0xfe800000);
       rtoltor(0xfe800001);
       rtoltor(0xfe8ffffe);
       rtoltor(0xfe8fffff);
       rtoltor(0xfef00000);
       rtoltor(0xfef00001);
       rtoltor(0xfefffffe);
       rtoltor(0xfeffffff);

       rtoltor(0xfe000000);
       rtoltor(0xfe000001);
       rtoltor(0xfe6ffffe);
       rtoltor(0xfe6fffff);
       rtoltor(0xfe700000);
       rtoltor(0xfe700001);
       rtoltor(0xfe7ffffe);
       rtoltor(0xfe7fffff);

       rc = atolfp("-.932087", &l);
       INSIST(1 == rc);

       ltor(l);
       rtol(0xfec458b0);
       printf("%x -> %d.%d.%d.%d\n",
               0xfec458b0,
               0xfe,
                 0xc4,
                   0x58,
                     0xb0);

       return 0;
}