1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
| using System;
using System.Diagnostics.Contracts;
using System.Linq;
namespace MySplit
{
class Program
{
static void Main(string[] args)
{
string[] result = split("we are families.",
new char[] { 'e', 'a', 'e' },
2,
StringSplitOptions.RemoveEmptyEntries);
result.ToList().ForEach(s => Console.Write("[{0}] ", s));
}
static string[] split(
string str,
char[] separator,
int? count = Int32.MaxValue,
StringSplitOptions options = StringSplitOptions.None)
{
return splitInternal(str, separator, count.Value, options);
}
static string[] splitInternal(
string str,
char[] separator,
int count,
StringSplitOptions options)
{
if (count < 0)
throw new ArgumentOutOfRangeException("count");
bool omitEmptyEntries = (options == StringSplitOptions.RemoveEmptyEntries);
if (count == 0 || str.Length == 0)
{
return new string[0];
}
int[] sepList = new int[str.Length];
int numReplaces = makeSeparatorList(str, separator, ref sepList);
if (0 == numReplaces || count == 1)
{
return new string[] { str };
}
if (omitEmptyEntries)
{
return internalSplitOmitEmptyEntries(str, sepList, null, numReplaces, count);
}
else
{
return internalSplitKeepEmptyEntries(str, sepList, null, numReplaces, count);
}
}
static int makeSeparatorList(string str, char[] separator, ref int[] sepList)
{
int foundCount = 0;
if (separator == null || separator.Length == 0)
{
for (int i = 0; i < str.Length && foundCount < separator.Length; i++)
{
if (Char.IsWhiteSpace(str[i]))
{
sepList[foundCount++] = i;
}
}
}
else
{
int sepListCount = sepList.Length;
int sepCount = separator.Length;
for (int i = 0; i < str.Length && foundCount < sepListCount; i++)
{
for (int j = 0; j < sepCount; j++)
{
if (str[i] == separator[j])
{
sepList[foundCount++] = i;
}
}
}
}
return foundCount;
}
static string[] internalSplitOmitEmptyEntries(
string str,
int[] sepList,
int[] lengthList,
int numReplaces,
int count)
{
Contract.Requires(numReplaces >= 0);
Contract.Requires(count >= 2);
Contract.Ensures(Contract.Result<string[]>() != null);
int maxItems = (numReplaces < count) ? (numReplaces + 1) : count;
string[] splitStrings = new string[maxItems];
int currentIndex = 0;
int arrIndex = 0;
for (int i = 0; i < numReplaces && currentIndex < str.Length; i++)
{
if (sepList[i] - currentIndex > 0)
{
splitStrings[arrIndex++] =
str.Substring(currentIndex, sepList[i] - currentIndex);
}
currentIndex = sepList[i] + ((lengthList == null) ? 1 : lengthList[i]);
if (arrIndex == count - 1)
{
while (i < numReplaces - 1 && currentIndex == sepList[++i])
{
currentIndex += ((lengthList == null) ? 1 : lengthList[i]);
}
break;
}
}
Contract.Assert(arrIndex < maxItems);
if (currentIndex < str.Length)
{
splitStrings[arrIndex++] = str.Substring(currentIndex);
}
string[] stringArray = splitStrings;
if (arrIndex != maxItems)
{
stringArray = new string[arrIndex];
for (int j = 0; j < arrIndex; j++)
stringArray[j] = splitStrings[j];
}
return stringArray;
}
static string[] internalSplitKeepEmptyEntries(
string str,
int[] sepList,
int[] lengthList,
int numReplacese,
int count)
{
Contract.Requires(numReplacese >= 0);
Contract.Requires(count >= 2);
Contract.Ensures(Contract.Result<string[]>() != null);
return null;
}
}
}
|