Boyer moore horspool algorithm implemented

Author: iamilyasedunov

algorithm/boyer_moore_horspool.py

@@ -0,0 +1,49 @@
+from collections import defaultdict
+from algorithm.base import Algorithm
+
+class BoyerMooreHorspool(Algorithm):
+
+    def __init__(self, reference):
+        spec_characters = '\tEmCGH7'
+        reference = reference.translate(reference.maketrans('', '', spec_characters))
+        self.reference = reference
+
+    @property
+    def name(self):
+        return 'Boyer-Moore-Horspool'
+
+    def set_candidate(self, candidate, **params):
+        self.candidate = candidate
+
+    def set_skip_table(self):
+        len_reference = len(self.reference)
+        len_candidate = len(self.candidate)
+        if len_candidate > len_reference:
+            print("Error: len candidate > len references {} > {}.".format(len_candidate, len_reference))
+            return -1
+
+        self.table_skip = defaultdict(lambda: len_candidate) 
+
+        for offset in range(len_candidate - 1):
+            self.table_skip[ord(self.candidate[offset])] = len_candidate - offset - 1
+        
+    def search(self, multiple_search=False) -> list:
+        self.set_skip_table()
+
+        len_reference = len(self.reference)
+        len_candidate = len(self.candidate)
+
+        offset_lst = []
+        offset = len_candidate - 1
+
+        while offset < len_reference:
+            j = len_candidate - 1
+            i = offset
+            while j >= 0 and self.reference[i] == self.candidate[j]:
+                j -= 1
+                i -= 1
+            if j == -1:
+                offset_lst.append(i + 1)
+            offset += self.table_skip[ord(self.reference[offset])]
+
+        return offset_lst