//prefixes assumes a \x00 delimited data with \x00 padding
func prefixes(idx *suffixarray.Index, data, q []byte) (keys [][]byte) {
for _, i := range idx.Lookup(q, -1) {
if data[i-1] == zero { //if previous byte is zero, it's a prefix
var l int
for l = i; data[l] != zero; l++ {
// iterating until end of word
}
k := data[i:l]
keys = append(keys, k)
}
}
return
}
func test_sa_speed(T int, // size of text
P int, // size of pattern.
N int, // number of occurrences of pattern in text
) (float64, float64) {
M := int(T / P)
fmt.Printf("Test suffix array speed: T=%v, P=%v, N=%v, M=%v\n",
T, P, N, M)
if M <= 0 {
panic("M must be greater than zero")
}
// text: String to be indexed and searched
// pattern: Substring to search for
pattern, text := make_pattern_text(T, P, N)
var (
count int
start time.Time
)
var text_index *suffixarray.Index
count = 0
for start = time.Now(); time.Since(start).Seconds() < MAX_TIME; {
text_index = suffixarray.New(text[:])
count++
}
if count < 1 {
panic("Count index")
}
duration_index := time.Since(start).Seconds() / float64(count)
// fmt.Printf(" count=%d,dt_index=%.1f,duration_index=%g\n",
// count, time.Since(start).Seconds(), duration_index)
// matches := []int{} // number of pattern matches
n_matches := 0
count = 0
for start = time.Now(); time.Since(start).Seconds() < MAX_TIME; {
offsets := text_index.Lookup(pattern, -1)
if len(offsets) != N {
panic(fmt.Sprintf("%d matched, expected %d, count=%d", len(offsets), N, count))
}
// matches = append(matches, len(offsets))
n_matches += N
count++
}
if count < 1 {
panic("Count lookup")
}
duration_lookup_total := time.Since(start).Seconds()
duration_lookup := duration_lookup_total / float64(count)
// fmt.Printf(" count=%d,dt_lookup=%.1f, duration_lookup=%g\n",
// count, duration_lookup_total, duration_lookup)
// n_matches := sum(matches)
// if n_matches < 1 {
// panic("matches")
// }
duration_match := duration_lookup_total / float64(n_matches) // Duration per pattern match
duration_char := duration_match / float64(P)
fmt.Printf(" %7d %e %e : %e %e\n", n_matches, duration_index, duration_lookup,
duration_match, duration_char)
return duration_index, duration_lookup
}