C# 字符串操作(部分重写，纯算法)
重写了一些.Net String提供的函数的功能 不过命名并不代表完全一样哦。
_find = 寻找文本
_rfind 倒找文本
_split 分割文本
_substr 取子字符串
_sub_replace 替换子文本
_replace 替换文本
_add strcat 链接字符串
_pad_left 左填充文本
_pad_right 右填充文本
_remove 删除字符串
_c_str 到C字符串
_data 到C+字符串
_size 取文本尺寸
_contains 文本是否存在
_equals 文本是否相同
using System; using System.Collections.Generic; public static class c_str { public static int _find(this string str, string value) { return _find(str, value, 0); } public static int _find(this string str, string value, int index) { if (str != null && value != null) { int i = index, len = str.Length, size = value.Length; if (i > -1 && len > 0 && size > 0) while (i < len) { int j = 0; if (i + size > len) break; while (j < size) { if (str[i + j] != value[j]) break; j++; } if (j == size) return i; i++; } } return -1; } public static int _rfind(this string str, string value) { if (str != null && value != null) { int len = str.Length; int size = value.Length; if (len > 0 && size > 0) { int i = len - size; while (i > -1) { int j = size - 1; while (j > -1) { if (str[i + j] != value[j]) break; j--; } if (j < 0) return i; i--; } } } return -1; } public static string[] _split(this string str, string value) { IList<int> finds = new List<int>(); int[] size = { str.Length, value.Length }; int i = _find(str, value, 0); while (i > -1) { finds.Add(i); i = _find(str, value, i + size[1]); } size[1] = finds.Count; bool begin = false, end = false; if (size[1] > 0) { int min = size[1] - 1; if (finds[min] < size[0]) { end = true; size[1]++; } if (finds[0] > 0) { begin = true; size[1]++; } } int len = finds.Count; // strtok string[] buffer = new string[size[1]]; if (len > 0) { int x, y; len--; for (i = 0; i <= len; i++) { int j = i; x = finds[i]; if (i >= len && end) j++; if (begin && end || begin) j++; y = i < len ? finds[i + 1] : y = x; buffer[j] = _substr(str, x + 1, y); } if (end) { i = size[1] - 2; x = finds[len] + 1; y = size[0]; buffer[i] = _substr(str, x, y); } if (begin) { x = 0; i = len + 1; y = finds[0]; buffer[0] = _substr(str, x, y); } } return buffer; } public static string _substr(string str, int start, int end) { if (str != null && str != string.Empty) { int len = str.Length; if (end > len || start > len) return string.Empty; if (start > end || start < 0 || end < 0) return string.Empty; char[] buffer = new char[end - start]; for (int i = start; i < end; i++) buffer[i - start] = str[i]; return new string(buffer); } return string.Empty; } public static string _add(this string str, string value) { if (str == null || str == string.Empty) return value; if (value == null || value == string.Empty) return str; int len = str.Length, size = value.Length; char[] buffer = new char[len + size]; for (int i = 0; i < len; i++) buffer[i] = str[i]; for (int i = 0; i < size; i++) { int j = i + len; buffer[j] = value[i]; } return new string(buffer); } public static string _replace(this string str, string oldValue, string newValue) { if (str == null || oldValue == null) return str; int i = _find(str, oldValue); if ((i ) > (-1)) { int len = str.Length; string beige = _substr(str, 0, i); string end = _substr(str, ++i, len); str = _add(beige, newValue); str = _add(str, end); } return str; } public static string _sub_replace(this string str, string oldValue, string newValue) { int i = -1; while ((i = _find(str, oldValue)) > -1) str = _replace(str, oldValue, newValue); return str; } public static string _pad_left(this string str, int totalWidth, char paddingValue) { return _add(new string(paddingValue, totalWidth), str); } public static string _pad_right(this string str, int totalWidth, char paddingValue) { return _add(str, new string(paddingValue, totalWidth)); } public static string _pad_left(this string str, int totalWidth) { return _pad_left(str, totalWidth, (char)32); } public static string _pad_right(this string str, int totalWidth) { return _pad_right(str, totalWidth, (char)32); } public static string _remove(this string str, int startIndex, int count) { if (str != null && str != string.Empty) { if (startIndex < 0) startIndex = str.Length + startIndex; string beige = _substr(str, 0, startIndex); int x = startIndex + count; int y = str.Length; string end = _substr(str, x, y); return _add(beige, end); } return string.Empty; } public static string _remove(this string str, int startIndex) { if (str != null && str != string.Empty) { int len = str.Length - startIndex; return _remove(str, startIndex, len); } return string.Empty; } public static char[] _data(this string str) { int len = str != null ? str.Length : 0; char[] buffer = new char[len]; for (int i = 0; i < len; i++) buffer[i] = str[i]; return buffer; } public static char[] _c_str(this string str) { int len = str != null ? str.Length : 0; char[] buffer = new char[len + 1]; for (int i = 0; i < len; i++) buffer[i] = str[i]; return buffer; } public static int _size(this string str) { if (str != null && str != string.Empty) return str.Length; return 0; } public static bool _contains(this string str, string value) { return _find(str, value) > -1; } public static bool _equals(this string str, object obj) { if (str != null && obj != null) return str.GetHashCode() == obj.GetHashCode(); return false; } public static bool _equals(this string str, string value) { if (str != null && value != null) { int x = 0, y = 0; int len = str.Length; for (int i = 0; i < len; i++) x ^= str[i]; len = value.Length; for (int i = 0; i < len; i++) y ^= value[i]; return x == y; } return false; } }