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using Apewer.Internals;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
namespace Apewer
{
/// <summary>文本实用工具。</summary>
public static class TextUtility
{
const string BlankChars = "  \n\r\t\f\b\a"; // 在 IsBlank 和 Trim 中视为空白的字符。
const string LineFeed = "\r\n"; // 换行符,由 ASCII 13 和 ASCII 10 组成。
const string SpaceDbc = " ";
const string SpaceSbc = " ";
const string LucidChars = "3456789acefhknpstwxyz";
const string KeyChars = "0123456789abcdefghijklmnopqrstuvwxyz";
const string HexChars = "0123456789abcdef";
const string NumericChars = "0123456789";
const string LowerChars = "abcdefghijklmnopqrstuvwxyz";
const string UpperChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const string LetterChars = LowerChars + UpperChars;
/// <summary>UTF-8 BOM。</summary>
public static byte[] Bom { get => new byte[] { 0xEF, 0xBB, 0xBF }; }
/// <summary>CRLF。</summary>
public const string CRLF = "\r\n";
/// <summary>LF。</summary>
public const string LF = "\n";
/// <summary>空文本。</summary>
public const string Empty = "";
/// <summary>返回表示指定对象的字符串。</summary>
public static string Text(object value)
{
if (value is string str) return str;
if (value == null) return null;
if (value.Equals(DBNull.Value)) return null;
if (value is Type t) return t.Name;
if (value is char[] chars) return new string(chars);
var type = value.GetType();
var toString = type.GetMethod(nameof(object.ToString), Type.EmptyTypes);
if (toString.DeclaringType.Equals(type))
{
try { return value.ToString(); }
catch { return null; }
}
return "<" + type.Name + ">";
}
/// <summary>字符串为空。</summary>
public static bool IsEmpty(string text) => text == null || text == Empty;
/// <summary>字符串不为空。</summary>
public static bool NotEmpty(string text) => text != null && text != Empty;
/// <summary>字符串为空,或只含有空白字符。</summary>
public static bool IsBlank(string text)
{
if (IsEmpty(text)) return true;
var length = text.Length;
var bcs = BlankChars.ToCharArray();
var bcl = bcs.Length;
bool b;
char c;
for (var i = 0; i < length; i++)
{
c = text[i];
b = false;
for (var j = 0; j < bcl; j++)
{
if (c == bcs[j])
{
b = true;
break;
}
}
if (!b) return false;
}
return true;
}
/// <summary>字符串不为空,切含有非空白字符。</summary>
public static bool NotBlank(string text) => !IsBlank(text);
/// <summary>获取文本的 Int32 哈希。</summary>
private static int HashCode(string text)
{
if (text == null) return 0;
int hash = 0;
var length = text.Length;
for (int i = 0; i < length; i++)
{
hash = 31 * hash + text[i];
}
return hash;
}
private static string PrivateJoin(string separator, IEnumerable cells)
{
if (cells == null) return Empty;
if (cells is string str) return str ?? "";
var sb = new StringBuilder();
var first = true;
var hasSeparator = !string.IsNullOrEmpty(separator);
foreach (var cell in cells)
{
if (cell == null) continue;
var text = null as string;
if (cell is string) text = cell as string;
else if (cell is Type type) text = type.Name;
else cell.ToString();
if (string.IsNullOrEmpty(text)) continue;
if (!first && hasSeparator) sb.Append(separator);
first = false;
sb.Append(text);
}
var result = sb.ToString();
return result;
}
/// <summary>合并为字符串。</summary>
public static string Merge(params object[] cells) => Join(null, cells);
/// <summary>合并为字符串。</summary>
public static string Join(string separator, params object[] cells)
{
if (cells == null) return Empty;
while (cells.Length == 1)
{
var first = cells[0];
if (first.IsNull()) return Empty;
if (first is string str) return str ?? Empty;
if (first is IEnumerable<char> chars)
{
var list = new List<char>();
foreach (var @char in chars) list.Add(@char);
return new string(list.ToArray());
}
if (!first.GetType().IsValueType && first is IEnumerable enumerable)
{
var list = new List<object>();
foreach (var item in enumerable) list.Add(item);
cells = list.ToArray();
continue;
}
break;
}
{
var sb = new StringBuilder();
var first = true;
var hasSeparator = !string.IsNullOrEmpty(separator);
foreach (var cell in cells)
{
if (cell.IsNull()) continue;
var text = null as string;
if (cell is string str) text = str;
else if (cell is char[] chars) text = new string(chars);
else text = Text(cell);
if (string.IsNullOrEmpty(text)) continue;
if (hasSeparator)
{
if (first) first = false;
else sb.Append(separator);
}
sb.Append(text);
}
var result = sb.ToString();
return result;
}
}
/// <summary>重复指定字符,直到达到指定长度。</summary>
/// <param name="cell">要重复的字符。</param>
/// <param name="count">重复的次数。</param>
public static string Duplicate(char cell, int count)
{
if (count < 1) return Empty;
var chars = new char[count];
for (var i = 0; i < count; i++) chars[i] = cell;
return new string(chars);
}
/// <summary>重复指定字符串,直到达到指定长度。</summary>
/// <param name="cell">要重复的字符串。</param>
/// <param name="count">重复的次数。</param>
public static string Duplicate(string cell, int count)
{
if (IsEmpty(cell) || count < 1) return Empty;
var length = cell.Length;
var total = length * count;
var output = new char[total];
var input = cell.ToCharArray();
for (var i = 0; i < count; i++)
{
Array.Copy(input, 0, output, length * i, length);
}
return new string(output);
}
/// <summary>获取指定长的的空格。</summary>
public static string Space(int length) => Duplicate(' ', length);
/// <summary>将文本以转换为字节数组。默认 Encoding 为 UTF-8。</summary>
public static byte[] Bytes(string text, Encoding encoding = null)
{
if (text == null || text == Empty) return BytesUtility.Empty;
try { return (encoding ?? Encoding.UTF8).GetBytes(text); }
catch { return BytesUtility.Empty; }
}
/// <summary>将字节数组转换为文本。默认 Encoding 为 UTF-8。</summary>
public static string FromBytes(byte[] bytes, Encoding encoding = null)
{
if (bytes == null || bytes.LongLength < 1L) return Empty;
try { return (encoding ?? Encoding.UTF8).GetString(bytes); }
catch { return Empty; }
}
/// <summary>将明文文本以 UTF-8 转换为 Base64 文本。</summary>
public static string ToBase64(string plain)
{
if (plain == null || plain == Empty) return Empty;
return BytesUtility.ToBase64(Bytes(plain));
}
/// <summary>将 Base64 文本以 UTF-8 转换为明文文本。</summary>
public static string FromBase64(string cipher)
{
if (cipher == null || cipher == Empty) return Empty;
return FromBytes(BytesUtility.FromBase64(cipher));
}
/// <summary>从字符串中删除子字符串。</summary>
/// <param name="text">要查询的字符串。</param>
/// <param name="sub">子字符串。</param>
/// <param name="ignoreCase">是否忽略大小写。</param>
/// <returns>删除子字符串后的父字符串。</returns>
private static string Exlude(string text, string sub, bool ignoreCase = false)
{
if (string.IsNullOrEmpty(text)) return "";
if (string.IsNullOrEmpty(sub)) return text;
try
{
string vp = text;
string vs = sub;
string vr = "";
int vl;
int vi;
if (ignoreCase)
{
vp = TextHelper.LCase(vp);
vs = TextHelper.LCase(vs);
}
vl = vs.Length;
vi = 1;
while (vi <= (vp.Length - vl + 1))
{
if (TextHelper.Middle(vp, vi, vl) == vs)
{
vi = vi + vl;
}
else
{
vr = vr + TextHelper.Middle(text, vi, 1);
vi = vi + 1;
}
}
return vr;
}
catch { return text; }
}
/// <summary>替换字符串中的子字符串。</summary>
/// <param name="text">要查询的字符串。</param>
/// <param name="new">新子字符串,保留大小写。</param>
/// <param name="old">原子字符串。</param>
/// <param name="ignoreCase">查找时是否忽略父字符串和原子字符串大小写。</param>
/// <returns>替换后的父字符串。</returns>
private static string Replace(string text, string old, string @new, bool ignoreCase = false)
{
if (string.IsNullOrEmpty(text)) return "";
if (string.IsNullOrEmpty(old)) return text;
if (string.IsNullOrEmpty(@new)) return Exlude(text, old, ignoreCase);
if (TextHelper.Len(text) < TextHelper.Len(old)) return text;
if (ignoreCase)
{
try
{
string p = TextHelper.LCase(text);
string o = TextHelper.LCase(old);
int vil = TextHelper.Len(old);
int viv = 1;
int vend = TextHelper.Len(text) - vil + 1;
string vcell;
string vresult = "";
while (viv <= vend)
{
vcell = TextHelper.Middle(p, viv, vil);
if (vcell == o)
{
vresult = vresult + @new;
viv = viv + vil;
}
else
{
vresult = vresult + TextHelper.Middle(text, viv, 1);
viv = viv + 1;
}
}
return vresult;
}
catch { return text; }
}
else
{
try
{
string vresult = text.Replace(old, @new);
return vresult;
}
catch { return ""; }
}
}
/// <summary>修复文本前缀。</summary>
/// <param name="text">原文本。</param>
/// <param name="include">TRUE:追加指定缀;FALSE:去除指定缀。</param>
/// <param name="head">前缀文本。</param>
public static string AssureStarts(string text, string head, bool include = true)
{
if (string.IsNullOrEmpty(text)) return Empty;
if (string.IsNullOrEmpty(head)) return text;
if (include)
{
return text.StartsWith(head) ? text : (head + text);
}
else
{
var headLength = head.Length;
if (!text.StartsWith(head)) return text;
var result = text;
while (true)
{
result = result.Substring(headLength);
if (!result.StartsWith(head)) return result;
}
}
}
/// <summary>修复文本后缀。</summary>
/// <param name="text">原文本。</param>
/// <param name="include">TRUE:追加指定后缀;FALSE:去除指定后缀。</param>
/// <param name="foot">后缀文本。</param>
public static string AssureEnds(string text, string foot, bool include = true)
{
if (string.IsNullOrEmpty(text)) return Empty;
if (string.IsNullOrEmpty(foot)) return text;
if (include == true)
{
return text.EndsWith(foot) ? text : (text + foot);
}
else
{
var footLength = foot.Length;
if (!text.EndsWith(foot)) return text;
var result = text;
while (true)
{
result = result.Substring(0, result.Length - footLength);
if (!result.EndsWith(foot)) return result;
}
}
}
/// <summary>用单字符作为分隔符拆分文本。</summary>
public static string[] Split(string text, char separator)
{
if (text == null) return new string[0];
if (text.Length < 1) return new string[] { "" };
if ((object)separator == null) return new string[] { text };
return text.Split(separator);
}
/// <summary>用字符串作为分隔符拆分文本。</summary>
public static string[] Split(string text, string separator)
{
if (text == null) return new string[0];
if (text.Length < 1) return new string[] { "" };
if (string.IsNullOrEmpty(separator)) return new string[] { text };
if (separator.Length > text.Length) return new string[] { text };
var list = new List<string>();
var position = 0;
var total = text.Length;
var length = separator.Length;
var cell = new StringBuilder();
while (position < total)
{
var read = null as string;
if (position + length < total) read = text.Substring(position, length);
else read = text.Substring(position);
if (read == separator)
{
if (cell.Length > 0)
{
list.Add(cell.ToString());
// cell.Clear();
cell = new StringBuilder();
}
else
{
list.Add("");
}
position += length;
}
else
{
cell.Append((char)text[position]);
position += 1;
}
if (position >= total)
{
list.Add(cell.ToString());
}
}
var array = list.ToArray();
return array;
}
/// <summary>用多个分隔符拆分文本。</summary>
public static string[] Split(string text, params char[] separators)
{
if (text == null) return new string[0];
if (text.Length < 1) return new string[] { "" };
if (separators == null || separators.Length < 1) return new string[] { text };
if (separators.Length == 1) return Split(text, separators[0]);
var list = new List<string>();
var separatorsText = new string(separators);
var sb = new StringBuilder();
foreach (var c in text)
{
if (separatorsText.IndexOf(c) >= 0)
{
list.Add(sb.ToString());
//sb.Clear();
sb = new StringBuilder();
continue;
}
sb.Append(c);
}
list.Add(sb.ToString());
#if !NET20
sb.Clear();
#endif
return list.ToArray();
}
/// <summary>移除字符串前后的空字符。</summary>
/// <param name="text">原始字符串。</param>
/// <param name="trimBlank">移除空格、全角空格、换行符、回车符、制表符和换页符。</param>
public static string Trim(string text, bool trimBlank = false)
{
if (text == null || text == Empty) return Empty;
if (!trimBlank) return Trim(text, ' ');
return Trim(text, BlankChars.ToCharArray());
}
/// <summary>移除字符串前后的指定字符。</summary>
/// <param name="text">原始字符串。</param>
/// <param name="chars">要移除的字符。</param>
public static string Trim(string text, params char[] chars)
{
if (text == null || text == Empty) return Empty;
if (chars == null || chars.Length < 1) return text;
var length = text.Length;
var charsLength = chars.Length;
var starts = 0;
var offset = 0;
while (true)
{
if (offset >= length) break;
var c = text[offset];
var trim = false;
for (var i = 0; i < charsLength; i++)
{
if (c == chars[i])
{
starts += 1;
offset += 1;
trim = true;
break;
}
}
if (trim) continue; else break;
}
var ends = 0;
if (starts < length)
{
offset = length - 1;
while (true)
{
if (offset <= starts) break;
var c = text[offset];
var trim = false;
for (var i = 0; i < charsLength; i++)
{
if (c == chars[i])
{
ends += 1;
offset -= 1;
trim = true;
break;
}
}
if (trim) continue; else break;
}
}
if (starts == 0 && ends == 0) return text;
return text.Substring(starts, length - starts - ends);
}
/// <summary>修剪字符串数组,修剪元素,并去除空字符串。</summary>
public static string[] Trim(this IEnumerable<string> strings)
{
var ab = new ArrayBuilder<string>();
if (strings == null) return ab.Export();
foreach (var str in strings)
{
var trim = Trim(str);
if (string.IsNullOrEmpty(trim)) continue;
ab.Add(trim);
}
var array = ab.Export();
return array;
}
/// <summary>剪取文本内容,若指定头部为空则从原文本首部起,若指定尾部为空则至原文本末尾。</summary>
/// <returns>剪取后的内容,不包含 head 和 foot。</returns>
public static string Cut(string text, string head = null, string foot = null)
{
if (IsEmpty(text)) return Empty;
int start, length;
if (IsEmpty(head))
{
// none
if (IsEmpty(foot)) return Empty;
// foot
length = text.IndexOf(foot);
if (length < 1) return text;
return text.Substring(0, length);
}
else
{
if (IsEmpty(foot))
{
// head
start = text.IndexOf(head);
if (start < 0) return text;
start += head.Length;
return text.Substring(start);
}
// both
start = text.IndexOf(head);
if (start < 0) start = 0;
else start += head.Length;
var temp = start == 0 ? text : text.Substring(start);
length = temp.IndexOf(foot);
if (length < 0) return temp;
if (length == 0) return Empty;
return temp.Substring(0, length);
}
}
/// <summary>比较两个字符串的相似度。返回值大于 0,小于等于 1。</summary>
/// <param name="arg1"></param>
/// <param name="arg2"></param>
/// <returns></returns>
public static double Similarity(string arg1, string arg2) => Levenshtein.Compute(arg1, arg2).Rate;
/// <summary>生成新的 GUID。</summary>
public static string Guid(bool hyphenation = true, bool lower = true)
{
var guid = System.Guid.NewGuid();
var str = hyphenation ? guid.ToString() : guid.ToString("n");
if (!lower) str = str.ToUpper();
return str;
}
/// <summary>生成新主键。</summary>
public static string Key() => System.Guid.NewGuid().ToString("n");
/// <summary>生成随机字符串,出现的字符由字符池指定,默认池包含数字和字母。</summary>
/// <param name="length">随机字符串的长度。</param>
/// <param name="pool">字符池,字符池中每个字符在随机字符串中出现的概率约等。</param>
public static string Random(int length, string pool = "0123456789abcdefghijklmnopqrstuvwxyz")
{
if (length < 1) return Empty;
if (IsEmpty(pool)) return Duplicate(SpaceDbc, length);
var array = new char[length];
var max = pool.Length - 1;
for (var i = 0; i < length; i++) array[i] = pool[NumberUtility.Random(0, max)];
return new string(array);
}
/// <summary>对字符串列表去重。指定 valid 参数时将去除无效字符串。</summary>
public static List<string> Distinct(IEnumerable<string> strings, bool valid = false)
{
if (strings == null) return new List<string>();
const string space = " ";
var count = strings.Count();
var array = new string[count];
var added = 0;
var hasNull = false;
var hasEmpty = false;
var hasSpace = false;
foreach (var s in strings)
{
if (s == null)
{
if (valid) continue;
if (hasNull) continue;
hasNull = true;
array[added] = s;
added += 1;
continue;
}
if (s == Empty)
{
if (valid) continue;
if (hasEmpty) continue;
hasEmpty = true;
array[added] = s;
added += 1;
continue;
}
if (s == space)
{
if (valid) continue;
if (hasSpace) continue;
hasSpace = true;
array[added] = s;
added += 1;
continue;
}
var exist = false;
for (var i = 0; i < added; i++)
{
if (array[i] == s)
{
exist = true;
break;
}
}
if (exist) continue;
array[added] = s;
added += 1;
}
if (added < 1) return new List<string>();
var list = new List<string>(added);
for (var i = 0; i < added; i++) list.Add(array[i]);
return list;
}
/// <summary>约束字符串中的字符,只包含指定的字符。</summary>
public static string Restrict(string text, char[] chars)
{
if (IsEmpty(text)) return Empty;
if (chars == null || chars.Length < 1) return Empty;
var total = text.Length;
var count = chars.Length;
var array = new char[total];
var added = 0;
for (var i = 0; i < total; i++)
{
var c = text[i];
for (var j = 0; j < count; j++)
{
if (c == chars[j])
{
array[added] = c;
added += 1;
break;
}
}
}
if (added < 1) return Empty;
return new string(array, 0, added);
}
/// <summary>约束字符串中的字符,只包含指定的字符。</summary>
public static string Restrict(string text, string chars) => IsEmpty(text) || IsEmpty(chars) ? Empty : Restrict(text, chars.ToCharArray());
/// <summary>约束字符串中的字符,只包含字母。</summary>
public static string RestrictLetters(string text) => Restrict(text, LetterChars.ToCharArray());
/// <summary>约束字符串中的字符,只包含数字。</summary>
public static string RestrictNumeric(string text) => Restrict(text, NumericChars.ToCharArray());
/// <summary>返回此字符串的安全键副本,只保留数据记录主键中可能出现的字符,默认限制长度为 255 字符。</summary>
public static string SafeKey(string text, int maxLength = 255)
{
if (string.IsNullOrEmpty(text)) return Empty;
var input = text;
var max = maxLength;
if (max < 1 || max > input.Length) max = input.Length;
// 允许用于主键值的字符。
const string KeyCollection = "-_0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
var sb = new StringBuilder();
var total = input.Length;
var length = 0;
for (var i = 0; i < total; i++)
{
var c = input[i];
if (KeyCollection.IndexOf(c) < 0) continue;
sb.Append(c);
length += 1;
if (length >= max) break;
}
var result = sb.ToString();
if (result.Length > max) result = result.Substring(0, max);
return result;
}
/// <summary>追加字符串。</summary>
public static StringBuilder Append(StringBuilder builder, params object[] cells)
{
if (builder != null) builder.Append(Join(null, cells));
return builder;
}
/// <summary>对 URL 编码。</summary>
public static string EncodeUrl(string plain)
{
return UrlEncoding.Encode(plain);
}
/// <summary>对 URL 解码。</summary>
public static string DecodeUrl(string escaped)
{
return UrlEncoding.Decode(escaped);
}
/// <summary>返回此字符串转换为小写形式的副本。</summary>
public static string Lower(string text)
{
if (text == null) return null;
else if (text.Length < 1) return Empty;
else return text.ToLower();
}
/// <summary>返回此字符串转换为大写形式的副本。</summary>
public static string Upper(string text)
{
if (text == null) return null;
else if (text.Length < 1) return Empty;
else return text.ToUpper();
}
/// <summary>检查中国手机号码,包含 13x、14x、15x、16x、17x、18x 和 19x 号段。</summary>
public static bool IsPhone(string phone)
{
if (string.IsNullOrEmpty(phone)) return false;
var regex = new Regex(@"^(13|14|15|16|17|18|19)\d{9}$", RegexOptions.None);
var match = regex.Match(phone);
return match.Success;
}
/// <summary>渲染 Markdown 文本为 HTML 文本。</summary>
public static string RenderMarkdown(string markdown) => MarkdownSharp.Demo.ToHtml(markdown);
/// <summary>合并用于启动进程的参数。</summary>
public static string MergeProcessArgument(params object[] args)
{
// var special = " \"\n\r\b\t\f";
var list = new List<string>();
if (args != null)
{
foreach (var i in args)
{
var arg = null as string;
if (i != null)
{
if (i is string) arg = i as string;
else arg = i.ToString();
}
if (string.IsNullOrEmpty(arg))
{
list.Add("\"\"");
continue;
}
if (arg.Contains(" ") || arg.Contains("\""))
{
list.Add(Merge("\"", arg.Replace("\"", "\\\""), "\""));
continue;
}
list.Add(arg);
}
}
var result = Join(" ", list.ToArray());
return result;
}
/// <summary>合并用于启动进程的参数。</summary>
private static string MergeProcessArgument_2(params object[] args)
{
if (args == null) return "";
if (args.Length < 1) return "";
var sb = new StringBuilder();
for (var i = 0; i < args.Length; i++)
{
if (i > 0) sb.Append(" ");
var arg = null as string;
if (args[i] != null)
{
if (args[i] is string) arg = args[i] as string;
else arg = args[i].ToString();
}
if (arg.IsEmpty())
{
sb.Append("\"\"");
continue;
}
// var special = " \"\n\r\b\t\f";
var special = " \"";
if (arg.IndexOfAny(special.ToCharArray()) < 0)
{
sb.Append(arg);
}
else
{
sb.Append("\"");
if (arg.NotEmpty())
{
foreach (var c in arg)
{
switch (c)
{
case '"':
sb.Append("\\\"");
break;
// case '\n':
// sb.Append("\\n");
// break;
// case '\r':
// sb.Append("\\r");
// break;
// case '\b':
// sb.Append("\\b");
// break;
// case '\t':
// sb.Append("\\t");
// break;
default:
sb.Append(c);
break;
}
}
}
sb.Append("\"");
}
}
var result = sb.ToString();
return result;
}
/// <summary>字符串仅使用英文。可指定空字符串的返回值。</summary>
public static bool IsEnglish(string text, bool ifEmpty = true)
{
if (string.IsNullOrEmpty(text)) return ifEmpty;
var trim = text.Trim();
if (string.IsNullOrEmpty(trim)) return ifEmpty;
return Regex.IsMatch(trim, "(^[0-9a-zA-Z_ -;:,~!@#%&=<>~\\(\\)\\.\\$\\^\\`\\'\\\"\\&\\{\\}\\[\\]\\|\\*\\+\\?]{0,80}$)");
}
/// <summary>转换文本为驼峰形式。</summary>
public static string Camel(string text)
{
if (string.IsNullOrEmpty(text) || !char.IsUpper(text[0])) return text;
var chars = text.ToCharArray();
for (int i = 0; i < chars.Length; i++)
{
if (i == 1 && !char.IsUpper(chars[i])) break;
bool hasNext = (i + 1) < chars.Length;
if (i > 0 && hasNext)
{
var nextChar = chars[i + 1];
if (!char.IsUpper(nextChar))
{
if (char.IsSeparator(nextChar)) chars[i] = char.ToLowerInvariant(chars[i]);
break;
}
}
chars[i] = char.ToLowerInvariant(chars[i]);
}
return new string(chars);
}
/// <summary>移除参数 chars 中的每一个字符。</summary>
public static string RemoveChars(string text, string chars)
{
if (IsEmpty(text)) return Empty;
if (IsEmpty(chars)) return text;
return RemoveChar(text, chars.ToCharArray());
}
/// <summary>移除指定的一个或多个字符。</summary>
public static string RemoveChar(string text, params char[] chars)
{
if (IsEmpty(text)) return Empty;
if (chars == null || chars.Length < 1) return text;
var length = text.Length;
var array = new char[length];
var count = chars.Length;
var added = 0;
for (var i = 0; i < length; i++)
{
var c = text[i];
var removed = false;
for (var j = 0; j < count; j++)
{
if (c == chars[j])
{
removed = true;
break;
}
}
if (removed) continue;
array[added] = c;
added += 1;
}
if (added < 1) return Empty;
return new string(array, 0, added);
}
/// <summary>防注入,去除常见的功能符号。可限定字符串长度。</summary>
public static string AntiInject(string text, int length = -1, string chars = "\"'`\b\f\n\r\t\\/:*?<>|@")
{
if (IsEmpty(text) || length == 0) return Empty;
var t = Trim(text);
t = RemoveChars(t, chars);
if (length > 0 && t.Length > length) t = t.Substring(0, length);
return t;
}
/// <summary>获取指定长度的字符串片段,可指定 trim 参数对片段再次修剪。</summary>
public static string Left(string text, int maxLength, bool trim = false, bool trimBlank = false)
{
if (IsEmpty(text)) return Empty;
if (maxLength > 0 && text.Length > maxLength)
{
var left = text.Substring(0, maxLength);
return trim ? Trim(left, trimBlank) : left;
}
else return trim ? Trim(text, trimBlank) : text;
}
/// <summary>获取指定长度的字符串片段,可指定 trim 参数对片段再次修剪。</summary>
public static string Right(string text, int maxLength, bool trim = false, bool trimBlank = false)
{
if (IsEmpty(text)) return Empty;
if (maxLength > 0 && text.Length > maxLength)
{
var left = text.Substring(text.Length - maxLength);
return trim ? Trim(left, trimBlank) : left;
}
else return trim ? Trim(text, trimBlank) : text;
}
/// <summary>获取字符串片段,起始位置从 0 开始,可指定 trim 参数对片段再次修剪。</summary>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public static string Middle(string text, int startIndex, int maxLength = -1, bool trim = false, bool trimBlank = false)
{
if (IsEmpty(text) || maxLength == 0) return Empty;
var total = text.Length;
var start = startIndex;
var length = maxLength;
if (start < 0)
{
length = length + start;
start = 0;
}
if (maxLength < 0) length = total;
if (start + length > total) length = total - start;
if (start == 0 && length == total) return trim ? Trim(text, trimBlank) : text;
var middle = text.Substring(start, length);
return trim ? Trim(middle, trimBlank) : middle;
}
#region Lock
static Locker _locker = new Locker();
/// <summary>锁定文本,在锁中执行函数。</summary>
/// <param name="text">要锁定的文本。</param>
/// <param name="inLock">要在锁中执行的函数。</param>
/// <exception cref="ArgumentNullException"></exception>
public static T Lock<T>(this string text, Func<T> inLock)
{
if (inLock == null) throw new ArgumentNullException(nameof(inLock));
return _locker.InLock(text, inLock);
}
/// <summary>锁定文本,在锁中执行函数。</summary>
/// <param name="text">要锁定的文本。</param>
/// <param name="inLock">要在锁中执行的函数。</param>
/// <exception cref="ArgumentNullException"></exception>
public static void Lock<T>(this string text, Action inLock)
{
if (inLock == null) throw new ArgumentNullException(nameof(inLock));
_locker.InLock(text, inLock);
}
#endregion
#region encoding
/// <summary>检查字节数组包含 UTF-8 BOM 头。</summary>
public static bool ContainsBOM(byte[] bytes)
{
if (bytes == null) return false;
if (bytes.LongLength < 3L) return false;
return bytes[0L] == 0xEF && bytes[1L] == 0xBB && bytes[2L] == 0xBF;
}
/// <summary>检查字节数组是 UTF-8 文本。可指定检查的最大字节长度。</summary>
/// <param name="bytes">要检查的字节数组。</param>
/// <param name="offset">已检查的偏移量。</param>
/// <param name="checkLength">检查的最大字节长度。</param>
public static bool IsUTF8(byte[] bytes, Class<int> offset, int checkLength = 1048576)
{
return IsUTF8(bytes, offset, checkLength);
}
/// <summary>检查字节数组是 UTF-8 文本,默认最多检测 1MB 数据。</summary>
/// <param name="bytes">要检查的字节数组。</param>
/// <param name="checkLength">检查的最大字节长度,指定为 0 将不限制检查长度。</param>
/// <param name="offset">已检查的偏移量,用于调试。</param>
public static bool IsUTF8(byte[] bytes, int checkLength = 1048576, Class<int> offset = null)
{
// UTF8在Unicode的基础上制定了这样一套规则:
// 1.对于单字节字符,比特位的最高位为0;
// 2.对于多字节字符,第一个字节的比特位中,最高位有n个1,剩下的n - 1个字节的比特位中,最高位都是10。
// 好了,我知道你一定看不懂,那就先来看看下面例子后,再去看上面定义吧。
// 比如一个字符(“A”),它在UTF8中的编码为(用二进制表示):01000001。由于比特位的最高位是0,表示它是单字节,它只需要1个字节就可以表示。
// 再比如一个字符(“判”),它在UTF8中的编码为(用二进制表示):11100101 10001000 10100100。由于在第一个字节中,比特位最高位有3个1,说明这个字符总共需要3个字节来表示,且后3 - 1 = 2位字节中,比特位的最高位为10。
if (bytes == null) return false;
var length = bytes.LongLength;
// 检查 BOM 头。
if (ContainsBOM(bytes)) return true;
var hasOffset = offset != null;
var append = 0;
if (hasOffset) offset.Value = 0;
for (int i = 0; i < length; i++)
{
if (checkLength > 0 && i >= checkLength) break;
var b = bytes[i];
if (hasOffset) offset.Value = i;
// 追加字节最高位为 0。
if (append > 0)
{
if (b >> 6 != 2) return false;
append -= 1;
continue;
}
// ASCII 字符。
if (b < 128) continue;
// 2 字节 UTF-8。
if (b >= 0xC0 && b <= 0xDF)
{
append = 1;
continue;
}
// 3 字节 UTF-8 字符。
if (b >= 0xE0 && b <= 0xEF)
{
append = 2;
continue;
}
// 4 字节 UTF-8 字符。
if (b >= 0xF0 && b <= 0xF7)
{
append = 3;
continue;
}
// 5 字节 UTF-8 字符。
if (b >= 0xF8 && b <= 0xFB)
{
append = 4;
continue;
}
// 6 字节 UTF-8 字符。
if (b >= 0xFC && b <= 0xFD)
{
append = 5;
continue;
}
// 未知字节,非 UTF-8 定义。
return false;
}
return true;
}
/// <summary>解析编码名称。</summary>
/// <returns>解析失败时,返回 NULL 值。</returns>
private static Encoding ParseEncoding(string encoding)
{
if (encoding.IsEmpty()) return null;
var lower = encoding.Lower();
var nick = lower.Replace("-", "");
switch (nick)
{
case "ascii":
return Encoding.ASCII;
case "bigendia":
case "bigendianunicode":
return Encoding.BigEndianUnicode;
case "utf7":
return Encoding.UTF7;
case "utf8":
return Encoding.UTF8;
case "utf16":
case "unicode":
return Encoding.Unicode;
case "utf32":
return Encoding.UTF7;
case "default":
return Encoding.Default;
case "ansi":
case "gb2312":
case "gb18030":
return Encoding.Default;
}
return null;
}
#endregion
}
}