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/*
* Copyright (c) 2011-2023, Shanghai Real-Thread Electronic Technology Co.,Ltd
*
* Change Logs:
* Date Author Notes
* 2020-12-18 quanzhao the first version
*/
#include <time.h>
#include <string.h>
#include <rtthread.h>
static struct rt_device random_dev;
static unsigned long seed;
static rt_uint16_t calc_random(void)
{
seed = 214013L * seed + 2531011L;
return (seed >> 16) & 0x7FFF; /* return bits 16~30 */
}
static rt_ssize_t random_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
{
rt_uint16_t rand;
ssize_t ret = 0;
while (size >= sizeof(rand))
{
/* update rand */
rand = calc_random();
*(rt_uint16_t *)buffer = rand;
buffer = (char *)buffer + sizeof(rand);
ret += sizeof(rand);
size -= sizeof(rand);
}
if (size)
{
rand = calc_random();
memcpy(buffer, &rand, size);
ret += size;
}
return ret;
}
static rt_ssize_t random_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
{
ssize_t ret = sizeof(seed) < size ? sizeof(seed) : size;
rt_memcpy(&seed, buffer, ret);
return ret;
}
static rt_err_t random_control(rt_device_t dev, int cmd, void *args)
{
return RT_EOK;
}
#ifdef RT_USING_DEVICE_OPS
const static struct rt_device_ops random_ops =
{
RT_NULL,
RT_NULL,
RT_NULL,
random_read,
random_write,
random_control
};
#endif
int random_device_init(void)
{
static rt_bool_t init_ok = RT_FALSE;
if (init_ok)
{
return 0;
}
RT_ASSERT(!rt_device_find("random"));
random_dev.type = RT_Device_Class_Miscellaneous;
#ifdef RT_USING_DEVICE_OPS
random_dev.ops = &random_ops;
#else
random_dev.init = RT_NULL;
random_dev.open = RT_NULL;
random_dev.close = RT_NULL;
random_dev.read = random_read;
random_dev.write = random_write;
random_dev.control = random_control;
#endif
/* no private */
random_dev.user_data = RT_NULL;
rt_device_register(&random_dev, "random", RT_DEVICE_FLAG_RDWR);
init_ok = RT_TRUE;
return 0;
}
INIT_DEVICE_EXPORT(random_device_init);
static struct rt_device urandom_dev;
static unsigned long useed;
static rt_uint16_t calc_urandom(void)
{
useed = 214013L * useed + 2531011L;
return (useed >> 16) & 0x7FFF; /* return bits 16~30 */
}
static rt_ssize_t random_uread(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
{
rt_uint16_t rand;
ssize_t ret = 0;
while (size >= sizeof(rand))
{
/* update rand */
rand = calc_urandom();
*(rt_uint16_t *)buffer = rand;
buffer = (char *)buffer + sizeof(rand);
ret += sizeof(rand);
size -= sizeof(rand);
}
if (size)
{
rand = calc_urandom();
memcpy(buffer, &rand, size);
ret += size;
}
return ret;
}
static rt_ssize_t random_uwrite(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
{
ssize_t ret = sizeof(useed) < size ? sizeof(useed) : size;
rt_memcpy(&useed, buffer, ret);
return ret;
}
static rt_err_t random_ucontrol(rt_device_t dev, int cmd, void *args)
{
return RT_EOK;
}
#ifdef RT_USING_DEVICE_OPS
const static struct rt_device_ops urandom_ops =
{
RT_NULL,
RT_NULL,
RT_NULL,
random_uread,
random_uwrite,
random_ucontrol
};
#endif
int urandom_device_init(void)
{
static rt_bool_t init_ok = RT_FALSE;
if (init_ok)
{
return 0;
}
RT_ASSERT(!rt_device_find("urandom"));
urandom_dev.type = RT_Device_Class_Miscellaneous;
#ifdef RT_USING_DEVICE_OPS
urandom_dev.ops = &urandom_ops;
#else
urandom_dev.init = RT_NULL;
urandom_dev.open = RT_NULL;
urandom_dev.close = RT_NULL;
urandom_dev.read = random_uread;
urandom_dev.write = random_uwrite;
urandom_dev.control = random_ucontrol;
#endif
/* no private */
urandom_dev.user_data = RT_NULL;
rt_device_register(&urandom_dev, "urandom", RT_DEVICE_FLAG_RDWR);
init_ok = RT_TRUE;
return 0;
}
INIT_DEVICE_EXPORT(urandom_device_init);
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