字符串搜索方法（記錄）

因爲需要字符串搜索功能所以寫了一個方法，我叫它影子搜索，因爲一直有個影子在前面“探路”，寫完後總覺得有點問題，但是隨便測試了幾個東西好像又沒有問題？先記錄把等以後發現問題再說（我沒有完整測試請不要隨便使用免得出問題），如果測試沒有問題，那麼至少比暴力搜索次數要少

 

context = b"ddcaddaabacabaabaaaadaabaaabaadaabaaaaaaaaaadaabaaaaaaaaaadaaa"
search = b"aaaadaab"

context_p = 0
search_p = 0
shadow_p = 1
shadow_next_p = 0

count = 0

while True:
    count += 1
    if shadow_p + shadow_next_p >= len(context) or shadow_next_p >= len(search):
        pass
    elif context[shadow_p + shadow_next_p] == search[shadow_next_p]:
        shadow_next_p += 1
    else:
        shadow_p += 1
        shadow_next_p = 0

    if context_p >= len(context) or search_p >= len(search):
        print("find: %s， for count: %d" % (str(context[context_p - search_p:context_p]), count))
        break
    elif context[context_p] == search[search_p]:
        context_p += 1
        search_p += 1
    else:
        context_p = shadow_p + shadow_next_p
        search_p = shadow_next_p
        shadow_p += 1
        shadow_next_p = 0