File syn_random.c

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#include "syn_random.h"

#include "../port/syn_port_system.h"

#include <string.h>

SYN_Status syn_random_fill(void *buf, size_t len)
{
    if (!buf || len == 0)
        return SYN_OK;
    (void)memset(buf, 0, len);
    return syn_port_random_fill(buf, len);
}

uint32_t syn_random_u32(void)
{
    uint32_t val = 0;
    syn_random_fill(&val, sizeof(val));
    return val;
}

uint32_t syn_random_range(uint32_t min, uint32_t max)
{
    if (min >= max)
        return min;
    uint32_t range = max - min + 1;
    return min + (syn_random_u32() % range);
}

/* Weak fallback: NOT SECURE. Platform port must override this. */
SYN_WEAK SYN_Status syn_port_random_fill(void *buf, size_t len)
{
    return syn_random_fallback_fill(buf, len);
}

SYN_Status syn_random_fallback_fill(void *buf, size_t len)
{
    uint8_t *p = (uint8_t *)buf;
    static uint32_t state = 0x87654321;

    for (size_t i = 0; i < len; i++) {
        /* Simple XOR-shift for fallback */
        state ^= state << 13;
        state ^= state >> 17;
        state ^= state << 5;
        p[i] = (uint8_t)(state ^ syn_port_get_tick_ms());
    }

    return SYN_OK;
}