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string.c (mrb_memsearch): move simple search from mrb_memsearch_qs()

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This commit is contained in:
Yukihiro "Matz" Matsumoto
2024-01-19 15:21:43 +09:00
parent 6f0c34e04e
commit 69cf074778
1 changed files with 30 additions and 31 deletions
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src/string.c
+30 -31
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@@ -454,39 +454,23 @@ str_index_str_by_char(mrb_state *mrb, mrb_value str, mrb_value sub, mrb_int pos)
static inline mrb_int
mrb_memsearch_qs(const unsigned char *xs, mrb_int m, const unsigned char *ys, mrb_int n)
{
if (n + m < MRB_QS_SHORT_STRING_LENGTH) {
const unsigned char *y = ys;
const unsigned char *ye = ys+n-m+1;
const unsigned char *y = ys;
ptrdiff_t qstable[256];
for (;;) {
y = (const unsigned char*)memchr(y, xs[0], (size_t)(ye-y));
if (y == NULL) return -1;
if (memcmp(xs, y, m) == 0) {
return (mrb_int)(y - ys);
}
y++;
}
return -1;
}
else {
const unsigned char *y = ys;
ptrdiff_t qstable[256];
/* Preprocessing */
for (int i = 0; i < 256; i++)
qstable[i] = m + 1;
const unsigned char *x = xs, *xe = xs + m;
for (; x < xe; x++)
qstable[*x] = xe - x;
/* Searching */
for (; y + m <= ys + n; y += qstable[y[m]]) {
if (*xs == *y && memcmp(xs, y, m) == 0)
return (mrb_int)(y - ys);
}
return -1;
/* Preprocessing */
for (int i = 0; i < 256; i++)
qstable[i] = m + 1;
const unsigned char *x = xs, *xe = xs + m;
for (; x < xe; x++)
qstable[*x] = xe - x;
/* Searching */
for (; y + m <= ys + n; y += qstable[y[m]]) {
if (*xs == *y && memcmp(xs, y, m) == 0)
return (mrb_int)(y - ys);
}
return -1;
}
static mrb_int
@@ -509,6 +493,21 @@ mrb_memsearch(const void *x0, mrb_int m, const void *y0, mrb_int n)
else
return -1;
}
if (n + m < MRB_QS_SHORT_STRING_LENGTH) {
const unsigned char *ys = y0;
const unsigned char *y = ys;
const unsigned char *ye = y0+n-m+1;
for (;;) {
y = (const unsigned char*)memchr(y, x[0], (size_t)(ye-ys));
if (y == NULL) return -1;
if (memcmp(x, y, m) == 0) {
return (mrb_int)(y - ys);
}
y++;
}
return -1;
}
return mrb_memsearch_qs((const unsigned char*)x0, m, (const unsigned char*)y0, n);
}