C# Url编码解码

代码是从 System.Web中提取出来的，保留备用。

Encoder：

public class UrlEncoder { public static string Encode(string str) { if (str == null) { return null; } return Encode(str, Encoding.UTF8); } public static string Encode(string str, Encoding e) { if (str == null) { return null; } return Encoding.ASCII.GetString(UrlEncodeToBytes(str, e)); } internal static byte[] UrlEncodeToBytes(string str, Encoding e) { if (str == null) { return null; } byte[] bytes = e.GetBytes(str); return Encode(bytes, 0, bytes.Length, false); } internal static byte[] Encode(byte[] bytes, int offset, int count, bool alwaysCreateNewReturnValue) { byte[] buffer = Encode(bytes, offset, count); if ((alwaysCreateNewReturnValue && (buffer != null)) && (buffer == bytes)) { return (byte[])buffer.Clone(); } return buffer; } internal static byte[] Encode(byte[] bytes, int offset, int count) { if (!ValidateUrlEncodingParameters(bytes, offset, count)) { return null; } int num = 0; int num2 = 0; for (int i = 0; i < count; i++) { char ch = (char)bytes[offset + i]; if (ch == ' ') { num++; } else if (!IsUrlSafeChar(ch)) { num2++; } } if ((num == 0) && (num2 == 0)) { return bytes; } byte[] buffer = new byte[count + (num2 * 2)]; int num4 = 0; for (int j = 0; j < count; j++) { byte num6 = bytes[offset + j]; char ch2 = (char)num6; if (IsUrlSafeChar(ch2)) { buffer[num4++] = num6; } else if (ch2 == ' ') { buffer[num4++] = 0x2b; } else { buffer[num4++] = 0x25; buffer[num4++] = (byte)IntToHex((num6 >> 4) & 15); buffer[num4++] = (byte)IntToHex(num6 & 15); } } return buffer; } internal static bool ValidateUrlEncodingParameters(byte[] bytes, int offset, int count) { if ((bytes == null) && (count == 0)) { return false; } if (bytes == null) { throw new ArgumentNullException("bytes"); } if ((offset < 0) || (offset > bytes.Length)) { throw new ArgumentOutOfRangeException("offset"); } if ((count < 0) || ((offset + count) > bytes.Length)) { throw new ArgumentOutOfRangeException("count"); } return true; } public static bool IsUrlSafeChar(char ch) { if ((((ch >= 'a') && (ch <= 'z')) || ((ch >= 'A') && (ch <= 'Z'))) || ((ch >= '0') && (ch <= '9'))) { return true; } switch (ch) { case '(': case ')': case '*': case '-': case '.': case '_': case '!': return true; } return false; } public static char IntToHex(int n) { if (n <= 9) { return (char)(n + 0x30); } return (char)((n - 10) + 0x61); } }

 

Decoder：

  public class UrlDecoder { // Fields private int _bufferSize; private byte[] _byteBuffer; private char[] _charBuffer; private Encoding _encoding; private int _numBytes; private int _numChars; // Methods internal UrlDecoder(int bufferSize, Encoding encoding) { this._bufferSize = bufferSize; this._encoding = encoding; this._charBuffer = new char[bufferSize]; } internal void AddByte(byte b) { if (this._byteBuffer == null) { this._byteBuffer = new byte[this._bufferSize]; } this._byteBuffer[this._numBytes++] = b; } internal void AddChar(char ch) { if (this._numBytes > 0) { this.FlushBytes(); } this._charBuffer[this._numChars++] = ch; } private void FlushBytes() { if (this._numBytes > 0) { this._numChars += this._encoding.GetChars(this._byteBuffer, 0, this._numBytes, this._charBuffer, this._numChars); this._numBytes = 0; } } internal string GetString() { if (this._numBytes > 0) { this.FlushBytes(); } if (this._numChars > 0) { return new string(this._charBuffer, 0, this._numChars); } return string.Empty; } public static int HexToInt(char h) { if ((h >= '0') && (h <= '9')) { return (h - '0'); } if ((h >= 'a') && (h <= 'f')) { return ((h - 'a') + 10); } if ((h >= 'A') && (h <= 'F')) { return ((h - 'A') + 10); } return -1; } public static string UrlDecode(string value, Encoding encoding) { if (value == null) { return null; } int length = value.Length; UrlDecoder decoder = new UrlDecoder(length, encoding); for (int i = 0; i < length; i++) { char ch = value[i]; if (ch == '+') { ch = ' '; } else if ((ch == '%') && (i < (length - 2))) { if ((value[i + 1] == 'u') && (i < (length - 5))) { int num3 = HexToInt(value[i + 2]); int num4 = HexToInt(value[i + 3]); int num5 = HexToInt(value[i + 4]); int num6 = HexToInt(value[i + 5]); if (((num3 < 0) || (num4 < 0)) || ((num5 < 0) || (num6 < 0))) { goto Label_010B; } ch = (char)((((num3 << 12) | (num4 << 8)) | (num5 << 4)) | num6); i += 5; decoder.AddChar(ch); continue; } int num7 = HexToInt(value[i + 1]); int num8 = HexToInt(value[i + 2]); if ((num7 >= 0) && (num8 >= 0)) { byte b = (byte)((num7 << 4) | num8); i += 2; decoder.AddByte(b); continue; } } Label_010B: if ((ch & 0xff80) == 0) { decoder.AddByte((byte)ch); } else { decoder.AddChar(ch); } } return decoder.GetString(); } }