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问题描述
下面是我实现BMH算法(它就像一个魅力)的:
公共静态的Int64的IndexOf(此字节[ ]值,字节[]模式) {如果(价值== NULL)抛出新的ArgumentNullException(值); 如果(模式== NULL)抛出新的ArgumentNullException(模式); 的Int64 valueLength = value.LongLength; 的Int64 patternLength = pattern.LongLength; 如果((valueLength == 0)||(patternLength == 0)||(patternLength> valueLength))返回-1; 的Int64 [] = badCharacters新的Int64 [256]; 为(Int64的I = 0; I< 256; ++ I) badCharacters [I] = patternLength; 的Int64 lastPatternByte = patternLength - 1; 为(Int64的I = 0; I< lastPatternByte ++ I) badCharacters [模式[我] = lastPatternByte - 我; //开始 的Int64指数= 0; ,而(指数< =(valueLength - patternLength)) {为(Int64的I = lastPatternByte;值[(索引+ 1)] ==模式[I] ; --i) {如果(我== 0)收益指数; } 指数+ = badCharacters [值[(+指数lastPatternByte)]; } 返回-1; }
我试图修改它以此来回报所有的比赛,而不是只第一个指标,但我得到IndexOutOfRangeException无处不在D:
很显然,我失去了一些东西重要还是我没有正确地理解它是如何工作。什么?我做错了。
公共静态列表<&的Int64 GT; IndexesOf(此字节]值,字节[]模式) {如果(价值== NULL)抛出新的ArgumentNullException(值); 如果(模式== NULL)抛出新的ArgumentNullException(模式); 的Int64 valueLength = value.LongLength; 的Int64 patternLength = pattern.LongLength; 如果((valueLength == 0)||(patternLength == 0)||(patternLength> valueLength))收益(新的List<&的Int64 GT;()); 的Int64 [] = badCharacters新的Int64 [256]; 为(Int64的I = 0; I< 256; ++ I) badCharacters [I] = patternLength; 的Int64 lastPatternByte = patternLength - 1; 为(Int64的I = 0; I< lastPatternByte ++ I) badCharacters [模式[我] = lastPatternByte - 我; //开始 的Int64指数= 0; 名单,LT; Int64的>指数=新的List<&的Int64 GT;(); ,而(指数< =(valueLength - patternLength)) {为(Int64的I = lastPatternByte;值[(索引+ 1)] ==模式[I] ; --i) {如果(我== 0) indexes.Add(指数); } 指数+ = badCharacters [值[(+指数lastPatternByte)]; } 收益指数; }解决方案
修改
如果(我== 0) indexes.Add(指数);
到
如果(我== 0) { indexes.Add(指数); 中断; }
Here is my implementation of BMH algorithm (it works like a charm):
public static Int64 IndexOf(this Byte[] value, Byte[] pattern) { if (value == null) throw new ArgumentNullException("value"); if (pattern == null) throw new ArgumentNullException("pattern"); Int64 valueLength = value.LongLength; Int64 patternLength = pattern.LongLength; if ((valueLength == 0) || (patternLength == 0) || (patternLength > valueLength)) return -1; Int64[] badCharacters = new Int64[256]; for (Int64 i = 0; i < 256; ++i) badCharacters[i] = patternLength; Int64 lastPatternByte = patternLength - 1; for (Int64 i = 0; i < lastPatternByte; ++i) badCharacters[pattern[i]] = lastPatternByte - i; // Beginning Int64 index = 0; while (index <= (valueLength - patternLength)) { for (Int64 i = lastPatternByte; value[(index + i)] == pattern[i]; --i) { if (i == 0) return index; } index += badCharacters[value[(index + lastPatternByte)]]; } return -1; }I tried to modify it in order to return all the matches instead of only the first index, but I'm getting IndexOutOfRangeException everywhere D:
Obviously I'm missing something important or I didn't properly understood how it works. What am I doing wrong?
public static List<Int64> IndexesOf(this Byte[] value, Byte[] pattern) { if (value == null) throw new ArgumentNullException("value"); if (pattern == null) throw new ArgumentNullException("pattern"); Int64 valueLength = value.LongLength; Int64 patternLength = pattern.LongLength; if ((valueLength == 0) || (patternLength == 0) || (patternLength > valueLength)) return (new List<Int64>()); Int64[] badCharacters = new Int64[256]; for (Int64 i = 0; i < 256; ++i) badCharacters[i] = patternLength; Int64 lastPatternByte = patternLength - 1; for (Int64 i = 0; i < lastPatternByte; ++i) badCharacters[pattern[i]] = lastPatternByte - i; // Beginning Int64 index = 0; List<Int64> indexes = new List<Int64>(); while (index <= (valueLength - patternLength)) { for (Int64 i = lastPatternByte; value[(index + i)] == pattern[i]; --i) { if (i == 0) indexes.Add(index); } index += badCharacters[value[(index + lastPatternByte)]]; } return indexes; }解决方案
Change
if (i == 0) indexes.Add(index);to
if (i == 0) { indexes.Add(index); break; }
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