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benchtests: Add difficult strstr needle for bruteforce algorithms

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Add another difficult needle to strstr that clearly shows the quadratic
complexity of bruteforce algorithms.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Wilco Dijkstra 2024-04-24 18:24:45 +01:00
parent 46c9997413
commit f262fce616
1 changed files with 27 additions and 0 deletions
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27
benchtests/bench-strstr.c
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@ -352,6 +352,33 @@ test_hard_needle (json_ctx_t *json_ctx, size_t ne_len, size_t hs_len)
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
/* Hard needle for bruteforce algorithms that match first few chars. */
{
memset (hs, 'a', hs_len);
for (int i = ne_len-1; i < hs_len; i += ne_len)
hs[i] = 'b';
hs[hs_len] = 0;
memset (ne, 'a', ne_len);
ne[ne_len] = 0;
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "len_haystack", hs_len);
json_attr_uint (json_ctx, "len_needle", ne_len);
json_attr_uint (json_ctx, "align_haystack", 0);
json_attr_uint (json_ctx, "align_needle", 0);
json_attr_uint (json_ctx, "fail", 1);
json_attr_string (json_ctx, "desc", "Difficult bruteforce needle");
json_array_begin (json_ctx, "timings");
FOR_EACH_IMPL (impl, 0)
do_one_test (json_ctx, impl, hs, ne, NULL);
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
}
static int