#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include "random.h"
#include "tv.h"

Include dependency graph for random.c:

Macros
#define	_CRT_RAND_S

Functions
double	ug_drand ()

uint32_t	ug_rand (void)

void	ug_rand_init (void)

Detailed Description

Author: Martin Pulec marti.nosp@m.n.pu.nosp@m.lec@c.nosp@m.esne.nosp@m.t.cz

Note

Remarks (possible improvements):

lbl_random reads from '/dev/urandom' instead if available (so Linux only) and HAVE_DEV_URANDOM defined (which isn't)
init_rng() in rtp.c used also hostname for seeding (but there may not be reasonable value, eg. '::1' if no host given to rcvr)

Definition in file random.c.

Macro Definition Documentation

◆ _CRT_RAND_S

#define _CRT_RAND_S

Definition at line 51 of file random.c.

Function Documentation

◆ ug_drand()

double ug_drand ( void )

Behaves similarly to drand48()

uses only 2^32 values from the interval (drand48 may use 48 bits)

Returns: val in interval [0.0, 1.0)

Remarks: thread-safe

Definition at line 111 of file random.c.

{
        return ug_rand() / (UINT32_MAX + 1.0);
}

References ug_rand().

Referenced by filter(), and rtcp_interval().

Here is the call graph for this function:

◆ ug_rand()

uint32_t ug_rand ( void )

Returns: pseudorandom number in interval [0, 2^32-1]

Remarks: thread-safe

Definition at line 88 of file random.c.

{
#ifdef _WIN32
        uint32_t ret = 0;
        rand_s(&ret);
#else
        uint32_t ret = (uint32_t) random() << 1;
        ret |= random() & 0x1;
#endif
        return ret;
}

Referenced by get_std_audio_local_mediatime(), get_std_video_local_mediatime(), init_first(), rtp_init_if(), rtp_init_with_udp_socket(), rtp_send_bye_now(), send_rtcp(), tx_init(), and ug_drand().

◆ ug_rand_init()

void ug_rand_init ( void )

Note: Windows rand_s() is not supposed to be seeded

Remarks: thread-safe

Definition at line 64 of file random.c.

{
#ifndef _WIN32
        unsigned seed =
            (getpid() * 42) ^ (unsigned) get_time_in_ns() ^ (unsigned) clock();
        FILE *dev_r = fopen("/dev/random", "rb");
        if (dev_r != NULL) {
                unsigned seed_dev_r = 0;
                if (fread(&seed_dev_r, sizeof seed_dev_r, 1, dev_r) == 1) {
                        seed ^= seed_dev_r;
                }
                fclose(dev_r);
        }
        srandom(seed);
#endif
}

References get_time_in_ns().

Referenced by common_preinit().