1#include <stdint.h>
2#include <string.h>
3
4static inline uint32_t swapc(uint32_t x, int c) {
5    return c ? x >> 24 | (x >> 8 & 0xff00) | (x << 8 & 0xff0000) | x << 24 : x;
6}
7
8const char* __mo_lookup(const void* p, size_t size, const char* s) {
9    const uint32_t* mo = p;
10    int sw = *mo - 0x950412de;
11    uint32_t b = 0, n = swapc(mo[2], sw);
12    uint32_t o = swapc(mo[3], sw);
13    uint32_t t = swapc(mo[4], sw);
14    if (n >= size / 4 || o >= size - 4 * n || t >= size - 4 * n || ((o | t) % 4))
15        return 0;
16    o /= 4;
17    t /= 4;
18    for (;;) {
19        uint32_t ol = swapc(mo[o + 2 * (b + n / 2)], sw);
20        uint32_t os = swapc(mo[o + 2 * (b + n / 2) + 1], sw);
21        if (os >= size || ol >= size - os || ((char*)p)[os + ol])
22            return 0;
23        int sign = strcmp(s, (char*)p + os);
24        if (!sign) {
25            uint32_t tl = swapc(mo[t + 2 * (b + n / 2)], sw);
26            uint32_t ts = swapc(mo[t + 2 * (b + n / 2) + 1], sw);
27            if (ts >= size || tl >= size - ts || ((char*)p)[ts + tl])
28                return 0;
29            return (char*)p + ts;
30        } else if (n == 1)
31            return 0;
32        else if (sign < 0)
33            n /= 2;
34        else {
35            b += n / 2;
36            n -= n / 2;
37        }
38    }
39    return 0;
40}
41