JavaScriptString.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / Orcas / RTM / ndp / fx / src / xsp / System / Web / Extensions / Script / Serialization / JavaScriptString.cs / 1 / JavaScriptString.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.Script.Serialization { 
    using System; 
    using System.Diagnostics.CodeAnalysis;
    using System.Globalization; 
    using System.Text;

    internal class JavaScriptString {
        private string _s; 
        private int _index;
 
        internal JavaScriptString(string s) { 
            _s = s;
        } 

        internal Nullable GetNextNonEmptyChar() {
            while (_s.Length > _index) {
                char c = _s[_index++]; 
                if (!Char.IsWhiteSpace(c)) {
                    return c; 
                } 
            }
 
            return null;
        }

        internal Nullable MoveNext() { 
            if (_s.Length > _index) {
                return _s[_index++]; 
            } 

            return null; 
        }

        internal string MoveNext(int count) {
            if (_s.Length >= _index + count) { 
                string result = _s.Substring(_index, count);
                _index += count; 
 
                return result;
            } 

            return null;
        }
 
        internal void MovePrev() {
            if (_index > 0) { 
                _index--; 
            }
        } 

        internal void MovePrev(int count) {
            while (_index > 0 && count > 0) {
                _index--; 
                count--;
            } 
        } 

        private static void AppendCharAsUnicode(StringBuilder builder, char c) { 
            builder.Append("\\u");
            builder.AppendFormat(CultureInfo.InvariantCulture, "{0:x4}", (int)c);
        }
 
        [SuppressMessage("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity",
            Justification="Method would be more complex if split into separate pieces.")] 
        internal static string QuoteString(string value) { 
            StringBuilder b = null;
 
            if (String.IsNullOrEmpty(value)) {
                return String.Empty;
            }
 
            int startIndex = 0;
            int count = 0; 
            for (int i = 0; i < value.Length; i++) { 
                char c = value[i];
 
                // Append the unhandled characters (that do not require special treament)
                // to the string builder when special characters are detected.
                if (c == '\r' || c == '\t' || c == '\"' || c == '\'' || c == '<' || c == '>' ||
                    c == '\\' || c == '\n' || c == '\b' || c == '\f' || c < ' ') { 
                    if (b == null) {
                        b = new StringBuilder(value.Length + 5); 
                    } 

                    if (count > 0) { 
                        b.Append(value, startIndex, count);
                    }

                    startIndex = i+1; 
                    count = 0;
                } 
 
                switch (c) {
                case '\r': 
                    b.Append("\\r");
                    break;
                case '\t':
                    b.Append("\\t"); 
                    break;
                case '\"': 
                    b.Append("\\\""); 
                    break;
                case '\\': 
                    b.Append("\\\\");
                    break;
                case '\n':
                    b.Append("\\n"); 
                    break;
                case '\b': 
                    b.Append("\\b"); 
                    break;
                case '\f': 
                    b.Append("\\f");
                    break;
                case '\'':
                case '>': 
                case '<':
                    AppendCharAsUnicode(b, c); 
                    break; 
                default:
                    if (c < ' ') { 
                        AppendCharAsUnicode(b, c);
                    } else {
                        count++;
                    } 
                    break;
                } 
            } 

            if (b == null) { 
                return value;
            }

            if (count > 0) { 
                b.Append(value, startIndex, count);
            } 
 
            return b.ToString();
        } 

        internal static string QuoteString(string value, bool addQuotes) {
            string s = QuoteString(value);
            if (addQuotes) { 
                s = "\"" + s + "\"";
            } 
            return s; 
        }
 
        public override string ToString() {
            if (_s.Length > _index) {
                return _s.Substring(_index);
            } 

            return String.Empty; 
        } 

        internal string GetDebugString(string message) { 
            return message + " (" + _index + "): " + _s;
        }
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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