diff options
Diffstat (limited to 'crypto/src/asn1/x509/X509Name.cs')
| -rw-r--r-- | crypto/src/asn1/x509/X509Name.cs | 501 |
1 files changed, 226 insertions, 275 deletions
diff --git a/crypto/src/asn1/x509/X509Name.cs b/crypto/src/asn1/x509/X509Name.cs index 3aa2f4e53..8fd564090 100644 --- a/crypto/src/asn1/x509/X509Name.cs +++ b/crypto/src/asn1/x509/X509Name.cs @@ -2,8 +2,10 @@ using System; using System.Collections.Generic; using System.IO; using System.Text; +using System.Threading; using Org.BouncyCastle.Asn1.Pkcs; +using Org.BouncyCastle.Asn1.X500.Style; using Org.BouncyCastle.Utilities.Collections; using Org.BouncyCastle.Utilities.Encoders; @@ -20,6 +22,7 @@ namespace Org.BouncyCastle.Asn1.X509 * value ANY } * </pre> */ + // TODO[api] sealed (and adjust protected constructors) public class X509Name : Asn1Encodable { @@ -80,58 +83,49 @@ namespace Org.BouncyCastle.Asn1.X509 /** * businessCategory - DirectoryString(SIZE(1..128) */ - public static readonly DerObjectIdentifier BusinessCategory = new DerObjectIdentifier( - "2.5.4.15"); + public static readonly DerObjectIdentifier BusinessCategory = new DerObjectIdentifier("2.5.4.15"); /** * postalCode - DirectoryString(SIZE(1..40) */ - public static readonly DerObjectIdentifier PostalCode = new DerObjectIdentifier( - "2.5.4.17"); + public static readonly DerObjectIdentifier PostalCode = new DerObjectIdentifier("2.5.4.17"); /** * dnQualifier - DirectoryString(SIZE(1..64) */ - public static readonly DerObjectIdentifier DnQualifier = new DerObjectIdentifier( - "2.5.4.46"); + public static readonly DerObjectIdentifier DnQualifier = new DerObjectIdentifier("2.5.4.46"); /** * RFC 3039 Pseudonym - DirectoryString(SIZE(1..64) */ - public static readonly DerObjectIdentifier Pseudonym = new DerObjectIdentifier( - "2.5.4.65"); + public static readonly DerObjectIdentifier Pseudonym = new DerObjectIdentifier("2.5.4.65"); /** * RFC 3039 DateOfBirth - GeneralizedTime - YYYYMMDD000000Z */ - public static readonly DerObjectIdentifier DateOfBirth = new DerObjectIdentifier( - "1.3.6.1.5.5.7.9.1"); + public static readonly DerObjectIdentifier DateOfBirth = new DerObjectIdentifier("1.3.6.1.5.5.7.9.1"); /** * RFC 3039 PlaceOfBirth - DirectoryString(SIZE(1..128) */ - public static readonly DerObjectIdentifier PlaceOfBirth = new DerObjectIdentifier( - "1.3.6.1.5.5.7.9.2"); + public static readonly DerObjectIdentifier PlaceOfBirth = new DerObjectIdentifier("1.3.6.1.5.5.7.9.2"); /** * RFC 3039 DateOfBirth - PrintableString (SIZE(1)) -- "M", "F", "m" or "f" */ - public static readonly DerObjectIdentifier Gender = new DerObjectIdentifier( - "1.3.6.1.5.5.7.9.3"); + public static readonly DerObjectIdentifier Gender = new DerObjectIdentifier("1.3.6.1.5.5.7.9.3"); /** * RFC 3039 CountryOfCitizenship - PrintableString (SIZE (2)) -- ISO 3166 * codes only */ - public static readonly DerObjectIdentifier CountryOfCitizenship = new DerObjectIdentifier( - "1.3.6.1.5.5.7.9.4"); + public static readonly DerObjectIdentifier CountryOfCitizenship = new DerObjectIdentifier("1.3.6.1.5.5.7.9.4"); /** * RFC 3039 CountryOfCitizenship - PrintableString (SIZE (2)) -- ISO 3166 * codes only */ - public static readonly DerObjectIdentifier CountryOfResidence = new DerObjectIdentifier( - "1.3.6.1.5.5.7.9.5"); + public static readonly DerObjectIdentifier CountryOfResidence = new DerObjectIdentifier("1.3.6.1.5.5.7.9.5"); /** * ISIS-MTT NameAtBirth - DirectoryString(SIZE(1..64) @@ -197,11 +191,11 @@ namespace Org.BouncyCastle.Asn1.X509 */ public static bool DefaultReverse { - get { lock (defaultReverse) return defaultReverse[0]; } - set { lock (defaultReverse) defaultReverse[0] = value; } + get { return Convert.ToBoolean(Interlocked.Read(ref defaultReverse)); } + set { Interlocked.Exchange(ref defaultReverse, Convert.ToInt64(value)); } } - private static readonly bool[] defaultReverse = { false }; + private static long defaultReverse = 0; /** * default look up table translating OID values into their common symbols following @@ -323,12 +317,14 @@ namespace Org.BouncyCastle.Asn1.X509 DefaultLookupInternal.Add("telephonenumber", TelephoneNumber); } - private readonly List<DerObjectIdentifier> ordering = new List<DerObjectIdentifier>(); - private readonly X509NameEntryConverter converter; - - private IList<string> values = new List<string>(); - private IList<bool> added = new List<bool>(); - private Asn1Sequence seq; + public static X509Name GetInstance(object obj) + { + if (obj == null) + return null; + if (obj is X509Name x509Name) + return x509Name; + return new X509Name(Asn1Sequence.GetInstance(obj)); + } /** * Return a X509Name based on the passed in tagged object. @@ -337,22 +333,15 @@ namespace Org.BouncyCastle.Asn1.X509 * @param explicitly true if explicitly tagged false otherwise. * @return the X509Name */ - public static X509Name GetInstance( - Asn1TaggedObject obj, - bool explicitly) - { - return GetInstance(Asn1Sequence.GetInstance(obj, explicitly)); - } + public static X509Name GetInstance(Asn1TaggedObject obj, bool explicitly) => + new X509Name(Asn1Sequence.GetInstance(obj, explicitly)); - public static X509Name GetInstance( - object obj) - { - if (obj is X509Name) - return (X509Name)obj; - if (obj == null) - return null; - return new X509Name(Asn1Sequence.GetInstance(obj)); - } + private readonly List<DerObjectIdentifier> m_ordering = new List<DerObjectIdentifier>(); + private readonly X509NameEntryConverter converter; + + private List<string> m_values = new List<string>(); + private List<bool> m_added = new List<bool>(); + private Asn1Sequence seq; protected X509Name() { @@ -365,38 +354,45 @@ namespace Org.BouncyCastle.Asn1.X509 */ protected X509Name(Asn1Sequence seq) { + // RDNSequence ::= SEQUENCE OF RelativeDistinguishedName this.seq = seq; foreach (Asn1Encodable asn1Obj in seq) { - Asn1Set asn1Set = Asn1Set.GetInstance(asn1Obj.ToAsn1Object()); + // RelativeDistinguishedName ::= SET SIZE(1..MAX) OF AttributeTypeAndValue + Asn1Set rdn = Asn1Set.GetInstance(asn1Obj.ToAsn1Object()); - for (int i = 0; i < asn1Set.Count; i++) + // TODO Apply this check? (Currently "breaks" CertificateTest.CheckDudCertificate) + //if (rdn.Count < 1) + // throw new ArgumentException("badly sized RelativeDistinguishedName"); + + for (int i = 0; i < rdn.Count; ++i) { - Asn1Sequence s = Asn1Sequence.GetInstance(asn1Set[i].ToAsn1Object()); + Asn1Sequence attributeTypeAndValue = Asn1Sequence.GetInstance(rdn[i].ToAsn1Object()); + if (attributeTypeAndValue.Count != 2) + throw new ArgumentException("badly sized AttributeTypeAndValue"); - if (s.Count != 2) - throw new ArgumentException("badly sized pair"); + var type = attributeTypeAndValue[0].ToAsn1Object(); + var value = attributeTypeAndValue[1].ToAsn1Object(); - ordering.Add(DerObjectIdentifier.GetInstance(s[0].ToAsn1Object())); + m_ordering.Add(DerObjectIdentifier.GetInstance(type)); - Asn1Object derValue = s[1].ToAsn1Object(); - if (derValue is IAsn1String && !(derValue is DerUniversalString)) + if (value is IAsn1String asn1String && !(value is DerUniversalString)) { - string v = ((IAsn1String)derValue).GetString(); + string v = asn1String.GetString(); if (v.StartsWith("#")) { v = "\\" + v; } - values.Add(v); + m_values.Add(v); } else { - values.Add("#" + Hex.ToHexString(derValue.GetEncoded())); + m_values.Add("#" + Hex.ToHexString(value.GetEncoded())); } - added.Add(i != 0); + m_added.Add(i != 0); } } } @@ -409,9 +405,7 @@ namespace Org.BouncyCastle.Asn1.X509 * construction process. The ordering ArrayList should contain the OIDs * in the order they are meant to be encoded or printed in ToString.</p> */ - public X509Name( - IList<DerObjectIdentifier> ordering, - IDictionary<DerObjectIdentifier, string> attributes) + public X509Name(IList<DerObjectIdentifier> ordering, IDictionary<DerObjectIdentifier, string> attributes) : this(ordering, attributes, new X509DefaultEntryConverter()) { } @@ -427,10 +421,8 @@ namespace Org.BouncyCastle.Asn1.X509 * The passed in converter will be used to convert the strings into their * ASN.1 counterparts.</p> */ - public X509Name( - IList<DerObjectIdentifier> ordering, - IDictionary<DerObjectIdentifier, string> attributes, - X509NameEntryConverter converter) + public X509Name(IList<DerObjectIdentifier> ordering, IDictionary<DerObjectIdentifier, string> attributes, + X509NameEntryConverter converter) { this.converter = converter; @@ -439,15 +431,9 @@ namespace Org.BouncyCastle.Asn1.X509 if (!attributes.TryGetValue(oid, out var attribute)) throw new ArgumentException("No attribute for object id - " + oid + " - passed to distinguished name"); - //object attribute = attributes[oid]; - //if (attribute == null) - //{ - // throw new ArgumentException("No attribute for object id - " + oid + " - passed to distinguished name"); - //} - - this.ordering.Add(oid); - this.added.Add(false); - this.values.Add(attribute); // copy the hash table + m_ordering.Add(oid); + m_values.Add(attribute); + m_added.Add(false); } } @@ -474,9 +460,9 @@ namespace Org.BouncyCastle.Asn1.X509 for (int i = 0; i < oids.Count; i++) { - this.ordering.Add(oids[i]); - this.values.Add(values[i]); - this.added.Add(false); + m_ordering.Add(oids[i]); + m_values.Add(values[i]); + m_added.Add(false); } } @@ -572,95 +558,55 @@ namespace Org.BouncyCastle.Asn1.X509 X509NameEntryConverter converter) { this.converter = converter; - X509NameTokenizer nTok = new X509NameTokenizer(dirName); - while (nTok.HasMoreTokens()) - { - string token = nTok.NextToken(); - int index = token.IndexOf('='); - - if (index == -1) - throw new ArgumentException("badly formated directory string"); + X509NameTokenizer nameTokenizer = new X509NameTokenizer(dirName); - string name = token.Substring(0, index); - string value = token.Substring(index + 1); - DerObjectIdentifier oid = DecodeOid(name, lookup); + while (nameTokenizer.HasMoreTokens()) + { + string rdn = NextToken(nameTokenizer); - if (value.IndexOf('+') > 0) - { - X509NameTokenizer vTok = new X509NameTokenizer(value, '+'); - string v = vTok.NextToken(); + X509NameTokenizer rdnTokenizer = new X509NameTokenizer(rdn, '+'); - this.ordering.Add(oid); - this.values.Add(v); - this.added.Add(false); + AddAttribute(lookup, NextToken(rdnTokenizer), false); - while (vTok.HasMoreTokens()) - { - string sv = vTok.NextToken(); - int ndx = sv.IndexOf('='); - - string nm = sv.Substring(0, ndx); - string vl = sv.Substring(ndx + 1); - this.ordering.Add(DecodeOid(nm, lookup)); - this.values.Add(vl); - this.added.Add(true); - } - } - else + while (rdnTokenizer.HasMoreTokens()) { - this.ordering.Add(oid); - this.values.Add(value); - this.added.Add(false); + AddAttribute(lookup, NextToken(rdnTokenizer), true); } } if (reverse) { -// this.ordering.Reverse(); -// this.values.Reverse(); -// this.added.Reverse(); var o = new List<DerObjectIdentifier>(); var v = new List<string>(); var a = new List<bool>(); int count = 1; - for (int i = 0; i < this.ordering.Count; i++) + for (int i = 0; i < m_ordering.Count; i++) { - if (!((bool) this.added[i])) - { - count = 0; - } - - int index = count++; - - o.Insert(index, this.ordering[i]); - v.Insert(index, this.values[i]); - a.Insert(index, this.added[i]); + count &= m_added[i] ? -1 : 0; + o.Insert(count, m_ordering[i]); + v.Insert(count, m_values[i]); + a.Insert(count, m_added[i]); + ++count; } - this.ordering = o; - this.values = v; - this.added = a; + m_ordering = o; + m_values = v; + m_added = a; } } /** * return an IList of the oids in the name, in the order they were found. */ - public IList<DerObjectIdentifier> GetOidList() - { - return new List<DerObjectIdentifier>(ordering); - } + public IList<DerObjectIdentifier> GetOidList() => new List<DerObjectIdentifier>(m_ordering); /** * return an IList of the values found in the name, in the order they * were found. */ - public IList<string> GetValueList() - { - return GetValueList(null); - } + public IList<string> GetValueList() => GetValueList(null); /** * return an IList of the values found in the name, in the order they @@ -669,17 +615,17 @@ namespace Org.BouncyCastle.Asn1.X509 public IList<string> GetValueList(DerObjectIdentifier oid) { var v = new List<string>(); - for (int i = 0; i != values.Count; i++) + for (int i = 0; i != m_values.Count; i++) { - if (null == oid || oid.Equals(ordering[i])) + if (null == oid || oid.Equals(m_ordering[i])) { - string val = (string)values[i]; - if (val.StartsWith("\\#")) + string value = m_values[i]; + if (value.StartsWith("\\#")) { - val = val.Substring(1); + value = value.Substring(1); } - v.Add(val); + v.Add(value); } } return v; @@ -691,34 +637,24 @@ namespace Org.BouncyCastle.Asn1.X509 { Asn1EncodableVector vec = new Asn1EncodableVector(); Asn1EncodableVector sVec = new Asn1EncodableVector(); - DerObjectIdentifier lstOid = null; + DerObjectIdentifier oid = null; - for (int i = 0; i != ordering.Count; i++) + for (int i = 0; i != m_ordering.Count; i++) { - DerObjectIdentifier oid = (DerObjectIdentifier)ordering[i]; - string str = (string)values[i]; - - if (lstOid == null - || ((bool)this.added[i])) - { - } - else + if (oid != null && !m_added[i]) { vec.Add(DerSet.FromVector(sVec)); sVec = new Asn1EncodableVector(); } - sVec.Add( - new DerSequence( - oid, - converter.GetConvertedValue(oid, str))); - - lstOid = oid; + oid = m_ordering[i]; + var convertedValue = converter.GetConvertedValue(oid, m_values[i]); + sVec.Add(new DerSequence(oid, convertedValue)); } vec.Add(DerSet.FromVector(sVec)); - seq = new DerSequence(vec); + this.seq = new DerSequence(vec); } return seq; @@ -727,9 +663,7 @@ namespace Org.BouncyCastle.Asn1.X509 /// <param name="other">The X509Name object to test equivalency against.</param> /// <param name="inOrder">If true, the order of elements must be the same, /// as well as the values associated with each element.</param> - public bool Equivalent( - X509Name other, - bool inOrder) + public bool Equivalent(X509Name other, bool inOrder) { if (!inOrder) return this.Equivalent(other); @@ -740,23 +674,23 @@ namespace Org.BouncyCastle.Asn1.X509 if (other == this) return true; - int orderingSize = ordering.Count; + int orderingSize = m_ordering.Count; - if (orderingSize != other.ordering.Count) + if (orderingSize != other.m_ordering.Count) return false; for (int i = 0; i < orderingSize; i++) { - DerObjectIdentifier oid = (DerObjectIdentifier) ordering[i]; - DerObjectIdentifier oOid = (DerObjectIdentifier) other.ordering[i]; + DerObjectIdentifier thisOid = m_ordering[i]; + DerObjectIdentifier thatOid = other.m_ordering[i]; - if (!oid.Equals(oOid)) + if (!thisOid.Equals(thatOid)) return false; - string val = (string) values[i]; - string oVal = (string) other.values[i]; + string thisValue = m_values[i]; + string thatValue = other.m_values[i]; - if (!EquivalentStrings(val, oVal)) + if (!EquivalentStrings(thisValue, thatValue)) return false; } @@ -766,8 +700,7 @@ namespace Org.BouncyCastle.Asn1.X509 /** * test for equivalence - note: case is ignored. */ - public bool Equivalent( - X509Name other) + public bool Equivalent(X509Name other) { if (other == null) return false; @@ -775,17 +708,14 @@ namespace Org.BouncyCastle.Asn1.X509 if (other == this) return true; - int orderingSize = ordering.Count; - - if (orderingSize != other.ordering.Count) - { + int orderingSize = m_ordering.Count; + if (orderingSize != other.m_ordering.Count) return false; - } bool[] indexes = new bool[orderingSize]; int start, end, delta; - if (ordering[0].Equals(other.ordering[0])) // guess forward + if (m_ordering[0].Equals(other.m_ordering[0])) // guess forward { start = 0; end = orderingSize; @@ -800,111 +730,105 @@ namespace Org.BouncyCastle.Asn1.X509 for (int i = start; i != end; i += delta) { - bool found = false; - DerObjectIdentifier oid = (DerObjectIdentifier)ordering[i]; - string value = (string)values[i]; + DerObjectIdentifier oid = m_ordering[i]; + string value = m_values[i]; + bool found = false; for (int j = 0; j < orderingSize; j++) { if (indexes[j]) - { continue; - } - - DerObjectIdentifier oOid = (DerObjectIdentifier)other.ordering[j]; - if (oid.Equals(oOid)) + if (oid.Equals(other.m_ordering[j])) { - string oValue = (string)other.values[j]; - - if (EquivalentStrings(value, oValue)) + if (EquivalentStrings(value, other.m_values[j])) { indexes[j] = true; - found = true; + found = true; break; } } } if (!found) - { return false; - } } return true; } - private static bool EquivalentStrings(string s1, string s2) + /** + * convert the structure to a string - if reverse is true the + * oids and values are listed out starting with the last element + * in the sequence (ala RFC 2253), otherwise the string will begin + * with the first element of the structure. If no string definition + * for the oid is found in oidSymbols the string value of the oid is + * added. Two standard symbol tables are provided DefaultSymbols, and + * RFC2253Symbols as part of this class. + * + * @param reverse if true start at the end of the sequence and work back. + * @param oidSymbols look up table strings for oids. + */ + public string ToString(bool reverse, IDictionary<DerObjectIdentifier, string> oidSymbols) { - string v1 = Canonicalize(s1); - string v2 = Canonicalize(s2); + var components = new List<StringBuilder>(); - if (!v1.Equals(v2)) - { - v1 = StripInternalSpaces(v1); - v2 = StripInternalSpaces(v2); + StringBuilder ava = null; - if (!v1.Equals(v2)) - return false; + for (int i = 0; i < m_ordering.Count; i++) + { + if (m_added[i]) + { + ava.Append('+'); + AppendValue(ava, oidSymbols, m_ordering[i], m_values[i]); + } + else + { + ava = new StringBuilder(); + AppendValue(ava, oidSymbols, m_ordering[i], m_values[i]); + components.Add(ava); + } } - return true; - } + if (reverse) + { + components.Reverse(); + } - private static string Canonicalize(string s) - { - string v = s.ToLowerInvariant().Trim(); + StringBuilder buf = new StringBuilder(); - if (v.StartsWith("#")) + if (components.Count > 0) { - Asn1Object obj = DecodeObject(v); - if (obj is IAsn1String str) + buf.Append(components[0].ToString()); + + for (int i = 1; i < components.Count; ++i) { - v = str.GetString().ToLowerInvariant().Trim(); + buf.Append(','); + buf.Append(components[i].ToString()); } } - return v; + return buf.ToString(); } - private static Asn1Object DecodeObject(string v) - { - try - { - return Asn1Object.FromByteArray(Hex.DecodeStrict(v, 1, v.Length - 1)); - } - catch (IOException e) - { - throw new InvalidOperationException("unknown encoding in name: " + e.Message, e); - } - } + public override string ToString() => ToString(DefaultReverse, DefaultSymbols); - private static string StripInternalSpaces(string str) + private void AddAttribute(IDictionary<string, DerObjectIdentifier> lookup, string token, bool added) { - StringBuilder res = new StringBuilder(); + X509NameTokenizer tokenizer = new X509NameTokenizer(token, '='); - if (str.Length != 0) - { - char c1 = str[0]; + string typeToken = NextToken(tokenizer, true); + string valueToken = NextToken(tokenizer, false); - res.Append(c1); + DerObjectIdentifier oid = DecodeOid(typeToken.Trim(), lookup); + string value = IetfUtilities.Unescape(valueToken); - for (int k = 1; k < str.Length; k++) - { - char c2 = str[k]; - if (!(c1 == ' ' && c2 == ' ')) - { - res.Append(c2); - } - c1 = c2; - } - } - - return res.ToString(); + m_ordering.Add(oid); + m_values.Add(value); + m_added.Add(added); } - private void AppendValue(StringBuilder buf, IDictionary<DerObjectIdentifier, string> oidSymbols, + private static void AppendValue(StringBuilder buf, IDictionary<DerObjectIdentifier, string> oidSymbols, DerObjectIdentifier oid, string val) { if (oidSymbols.TryGetValue(oid, out var sym)) @@ -948,63 +872,90 @@ namespace Org.BouncyCastle.Asn1.X509 } } - /** - * convert the structure to a string - if reverse is true the - * oids and values are listed out starting with the last element - * in the sequence (ala RFC 2253), otherwise the string will begin - * with the first element of the structure. If no string definition - * for the oid is found in oidSymbols the string value of the oid is - * added. Two standard symbol tables are provided DefaultSymbols, and - * RFC2253Symbols as part of this class. - * - * @param reverse if true start at the end of the sequence and work back. - * @param oidSymbols look up table strings for oids. - */ - public string ToString(bool reverse, IDictionary<DerObjectIdentifier, string> oidSymbols) + private static string Canonicalize(string s) { - var components = new List<StringBuilder>(); - - StringBuilder ava = null; + string v = s.ToLowerInvariant().Trim(); - for (int i = 0; i < ordering.Count; i++) + if (v.StartsWith("#")) { - if (added[i]) - { - ava.Append('+'); - AppendValue(ava, oidSymbols, ordering[i], values[i]); - } - else + Asn1Object obj = DecodeObject(v); + if (obj is IAsn1String str) { - ava = new StringBuilder(); - AppendValue(ava, oidSymbols, ordering[i], values[i]); - components.Add(ava); + v = str.GetString().ToLowerInvariant().Trim(); } } - if (reverse) + return v; + } + + private static Asn1Object DecodeObject(string v) + { + try { - components.Reverse(); + return Asn1Object.FromByteArray(Hex.DecodeStrict(v, 1, v.Length - 1)); } + catch (IOException e) + { + throw new InvalidOperationException("unknown encoding in name: " + e.Message, e); + } + } - StringBuilder buf = new StringBuilder(); - - if (components.Count > 0) + private static bool EquivalentStrings(string s1, string s2) + { + if (s1 != s2) { - buf.Append(components[0].ToString()); + string v1 = Canonicalize(s1); + string v2 = Canonicalize(s2); - for (int i = 1; i < components.Count; ++i) + if (v1 != v2) { - buf.Append(','); - buf.Append(components[i].ToString()); + v1 = StripInternalSpaces(v1); + v2 = StripInternalSpaces(v2); + + if (v1 != v2) + return false; } } - return buf.ToString(); + return true; } - public override string ToString() + private static string NextToken(X509NameTokenizer tokenizer) { - return ToString(DefaultReverse, DefaultSymbols); + return tokenizer.NextToken() ?? throw new ArgumentException("badly formatted directory string"); + } + + private static string NextToken(X509NameTokenizer tokenizer, bool expectMoreTokens) + { + string token = tokenizer.NextToken(); + if (token == null || tokenizer.HasMoreTokens() != expectMoreTokens) + throw new ArgumentException("badly formatted directory string"); + + return token; + } + + private static string StripInternalSpaces(string str) + { + StringBuilder res = new StringBuilder(); + + if (str.Length != 0) + { + char c1 = str[0]; + + res.Append(c1); + + for (int k = 1; k < str.Length; k++) + { + char c2 = str[k]; + if (!(c1 == ' ' && c2 == ' ')) + { + res.Append(c2); + } + c1 = c2; + } + } + + return res.ToString(); } } } |