uint8_t c1 = c[1];
const uint8_t *end = s + n - 1;
- while (s < end)
+ do
{
+ /* Here s < end.
+ Test whether s[0..1] == { c0, c1 }. */
uint8_t s1 = s[1];
if (s1 == c1)
{
if (*s == c0)
return (uint8_t *) s;
else
+ /* Skip the search at s + 1, because s[1] = c1 < c0. */
s += 2;
}
else
if (s1 == c0)
s++;
else
+ /* Skip the search at s + 1, because s[1] != c0. */
s += 2;
}
}
+ while (s < end);
break;
}
else
skip = 3;
- while (s < end)
+ do
{
+ /* Here s < end.
+ Test whether s[0..2] == { c0, c1, c2 }. */
uint8_t s2 = s[2];
if (s2 == c2)
{
if (s[1] == c1 && *s == c0)
return (uint8_t *) s;
else
+ /* If c2 != c1:
+ Skip the search at s + 1, because s[2] == c2 != c1.
+ Skip the search at s + 2, because s[2] == c2 < c0. */
s += skip;
}
else
if (s2 == c1)
s++;
else if (s2 == c0)
+ /* Skip the search at s + 1, because s[2] != c1. */
s += 2;
else
+ /* Skip the search at s + 1, because s[2] != c1.
+ Skip the search at s + 2, because s[2] != c0. */
s += 3;
}
}
+ while (s < end);
break;
}
else
skip = 4;
- while (s < end)
+ do
{
+ /* Here s < end.
+ Test whether s[0..3] == { c0, c1, c2, c3 }. */
uint8_t s3 = s[3];
if (s3 == c3)
{
if (s[2] == c2 && s[1] == c1 && *s == c0)
return (uint8_t *) s;
else
+ /* If c3 != c2:
+ Skip the search at s + 1, because s[3] == c3 != c2.
+ If c3 != c1:
+ Skip the search at s + 2, because s[3] == c3 != c1.
+ Skip the search at s + 3, because s[3] == c3 < c0. */
s += skip;
}
else
if (s3 == c2)
s++;
else if (s3 == c1)
+ /* Skip the search at s + 1, because s[3] != c2. */
s += 2;
else if (s3 == c0)
+ /* Skip the search at s + 1, because s[3] != c2.
+ Skip the search at s + 2, because s[3] != c1. */
s += 3;
else
+ /* Skip the search at s + 1, because s[3] != c2.
+ Skip the search at s + 2, because s[3] != c1.
+ Skip the search at s + 3, because s[3] != c0. */
s += 4;
}
}
+ while (s < end);
break;
}
}