src/common/uri.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        src/common/uri.cpp
// Purpose:     Implementation of a URI parser
// Author:      Ryan Norton,
//              Vadim Zeitlin (UTF-8 URI support, many other changes)
// Created:     10/26/04
// Copyright:   (c) 2004 Ryan Norton,
//                  2008 Vadim Zeitlin
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// ===========================================================================
// declarations
// ===========================================================================

// ---------------------------------------------------------------------------
// headers
// ---------------------------------------------------------------------------

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

#ifndef WX_PRECOMP
    #include "wx/crt.h"
#endif

#include "wx/uri.h"

// ---------------------------------------------------------------------------
// definitions
// ---------------------------------------------------------------------------

IMPLEMENT_CLASS(wxURI, wxObject)

// ===========================================================================
// wxURI implementation
// ===========================================================================

// ---------------------------------------------------------------------------
// Constructors and cleanup
// ---------------------------------------------------------------------------

wxURI::wxURI()
     : m_hostType(wxURI_REGNAME),
       m_fields(0)
{
}

wxURI::wxURI(const wxString& uri)
     : m_hostType(wxURI_REGNAME),
       m_fields(0)
{
    Create(uri);
}

bool wxURI::Create(const wxString& uri)
{
    if (m_fields)
        Clear();

    return Parse(uri.utf8_str());
}

void wxURI::Clear()
{
    m_scheme =
    m_userinfo =
    m_server =
    m_port =
    m_path =
    m_query =
    m_fragment = wxEmptyString;

    m_hostType = wxURI_REGNAME;

    m_fields = 0;
}

// ---------------------------------------------------------------------------
// Escaped characters handling
// ---------------------------------------------------------------------------

// Converts a character into a numeric hexadecimal value, or -1 if the passed
// in character is not a valid hex character

/* static */
int wxURI::CharToHex(char c)
{
    if ((c >= 'A') && (c <= 'Z'))
        return c - 'A' + 10;
    if ((c >= 'a') && (c <= 'z'))
        return c - 'a' + 10;
    if ((c >= '0') && (c <= '9'))
        return c - '0';

    return -1;
}

int wxURI::DecodeEscape(wxString::const_iterator& i)
{
    int hi = CharToHex(*++i);
    if ( hi == -1 )
        return -1;

    int lo = CharToHex(*++i);
    if ( lo == -1 )
        return -1;

    return (hi << 4) | lo;
}

/* static */
wxString wxURI::Unescape(const wxString& uri)
{
    // the unescaped version can't be longer than the original one
    wxCharBuffer buf(uri.length());
    char *p = buf.data();

    for ( wxString::const_iterator i = uri.begin(); i != uri.end(); ++i, ++p )
    {
        char c = *i;
        if ( c == '%' )
        {
            int n = wxURI::DecodeEscape(i);
            if ( n == -1 )
                return wxString();

            wxASSERT_MSG( n >= 0 && n <= 0xff, "unexpected character value" );

            c = static_cast<char>(n);
        }

        *p = c;
    }

    *p = '\0';

    // by default assume that the URI is in UTF-8, this is the most common
    // practice
    wxString s = wxString::FromUTF8(buf);
    if ( s.empty() )
    {
        // if it isn't, use latin-1 as a fallback -- at least this always
        // succeeds
        s = wxCSConv(wxFONTENCODING_ISO8859_1).cMB2WC(buf);
    }

    return s;
}

void wxURI::AppendNextEscaped(wxString& s, const char *& p)
{
    // check for an already encoded character:
    //
    // pct-encoded   = "%" HEXDIG HEXDIG
    if ( p[0] == '%' && IsHex(p[1]) && IsHex(p[2]) )
    {
        s += *p++;
        s += *p++;
        s += *p++;
    }
    else // really needs escaping
    {
        static const char* hexDigits = "0123456789abcdef";

        const char c = *p++;

        s += '%';
        s += hexDigits[(c >> 4) & 15];
        s += hexDigits[c & 15];
    }
}

// ---------------------------------------------------------------------------
// GetUser
// GetPassword
//
// Gets the username and password via the old URL method.
// ---------------------------------------------------------------------------
wxString wxURI::GetUser() const
{
    // if there is no colon at all, find() returns npos and this method returns
    // the entire string which is correct as it means that password was omitted
    return m_userinfo(0, m_userinfo.find(':'));
}

wxString wxURI::GetPassword() const
{
      size_t posColon = m_userinfo.find(':');

      if ( posColon == wxString::npos )
          return "";

      return m_userinfo(posColon + 1, wxString::npos);
}

// combine all URI fields in a single string, applying funcDecode to each
// component which it may make sense to decode (i.e. "unescape")
wxString wxURI::DoBuildURI(wxString (*funcDecode)(const wxString&)) const
{
    wxString ret;

    if (HasScheme())
        ret += m_scheme + ":";

    if (HasServer())
    {
        ret += "//";

        if (HasUserInfo())
            ret += funcDecode(m_userinfo) + "@";

        if (m_hostType == wxURI_REGNAME)
            ret += funcDecode(m_server);
        else
            ret += m_server;

        if (HasPort())
            ret += ":" + m_port;
    }

    ret += funcDecode(m_path);

    if (HasQuery())
        ret += "?" + funcDecode(m_query);

    if (HasFragment())
        ret += "#" + funcDecode(m_fragment);

    return ret;
}

// ---------------------------------------------------------------------------
// Comparison
// ---------------------------------------------------------------------------

bool wxURI::operator==(const wxURI& uri) const
{
    if (HasScheme())
    {
        if(m_scheme != uri.m_scheme)
            return false;
    }
    else if (uri.HasScheme())
        return false;


    if (HasServer())
    {
        if (HasUserInfo())
        {
            if (m_userinfo != uri.m_userinfo)
                return false;
        }
        else if (uri.HasUserInfo())
            return false;

        if (m_server != uri.m_server ||
            m_hostType != uri.m_hostType)
            return false;

        if (HasPort())
        {
            if(m_port != uri.m_port)
                return false;
        }
        else if (uri.HasPort())
            return false;
    }
    else if (uri.HasServer())
        return false;


    if (HasPath())
    {
        if(m_path != uri.m_path)
            return false;
    }
    else if (uri.HasPath())
        return false;

    if (HasQuery())
    {
        if (m_query != uri.m_query)
            return false;
    }
    else if (uri.HasQuery())
        return false;

    if (HasFragment())
    {
        if (m_fragment != uri.m_fragment)
            return false;
    }
    else if (uri.HasFragment())
        return false;

    return true;
}

// ---------------------------------------------------------------------------
// IsReference
//
// if there is no authority or scheme, it is a reference
// ---------------------------------------------------------------------------

bool wxURI::IsReference() const
{
    return !HasScheme() || !HasServer();
}

// ---------------------------------------------------------------------------
// Parse
//
// Master URI parsing method.  Just calls the individual parsing methods
//
// URI = scheme ":" hier-part [ "?" query ] [ "#" fragment ]
// URI-reference = URI / relative
// ---------------------------------------------------------------------------

bool wxURI::Parse(const char *uri)
{
    uri = ParseScheme(uri);
    if ( uri )
        uri = ParseAuthority(uri);
    if ( uri )
        uri = ParsePath(uri);
    if ( uri )
        uri = ParseQuery(uri);
    if ( uri )
        uri = ParseFragment(uri);

    // we only succeed if we parsed the entire string
    return uri && *uri == '\0';
}

const char* wxURI::ParseScheme(const char *uri)
{
    const char * const start = uri;

    // assume that we have a scheme if we have the valid start of it
    if ( IsAlpha(*uri) )
    {
        m_scheme += *uri++;

        //scheme        = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
        while (IsAlpha(*uri) || IsDigit(*uri) ||
               *uri == '+'   ||
               *uri == '-'   ||
               *uri == '.')
        {
            m_scheme += *uri++;
        }

        //valid scheme?
        if (*uri == ':')
        {
            //mark the scheme as valid
            m_fields |= wxURI_SCHEME;

            //move reference point up to input buffer
            ++uri;
        }
        else // no valid scheme finally
        {
            uri = start; // rewind
            m_scheme.clear();
        }
    }
    //else: can't have schema, possible a relative URI

    return uri;
}

const char* wxURI::ParseAuthority(const char* uri)
{
    // authority     = [ userinfo "@" ] host [ ":" port ]
    if ( uri[0] == '/' && uri[1] == '/' )
    {
        //skip past the two slashes
        uri += 2;

        // ############# DEVIATION FROM RFC #########################
        // Don't parse the server component for file URIs
        if(m_scheme != "file")
        {
            //normal way
            uri = ParseUserInfo(uri);
            uri = ParseServer(uri);
            return ParsePort(uri);
        }
    }

    return uri;
}

const char* wxURI::ParseUserInfo(const char* uri)
{
    const char * const start = uri;

    // userinfo      = *( unreserved / pct-encoded / sub-delims / ":" )
    while ( *uri && *uri != '@' && *uri != '/' && *uri != '#' && *uri != '?' )
    {
        if ( IsUnreserved(*uri) || IsSubDelim(*uri) || *uri == ':' )
            m_userinfo += *uri++;
        else
            AppendNextEscaped(m_userinfo, uri);
    }

    if ( *uri++ == '@' )
    {
        // valid userinfo
        m_fields |= wxURI_USERINFO;
    }
    else
    {
        uri = start; // rewind
        m_userinfo.clear();
    }

    return uri;
}

const char* wxURI::ParseServer(const char* uri)
{
    const char * const start = uri;

    // host          = IP-literal / IPv4address / reg-name
    // IP-literal    = "[" ( IPv6address / IPvFuture  ) "]"
    if (*uri == '[')
    {
        ++uri;
        if (ParseIPv6address(uri) && *uri == ']')
        {
            m_hostType = wxURI_IPV6ADDRESS;

            m_server.assign(start + 1, uri - start - 1);
            ++uri;
        }
        else
        {
            uri = start + 1; // skip the leading '[' again

            if (ParseIPvFuture(uri) && *uri == ']')
            {
                m_hostType = wxURI_IPVFUTURE;

                m_server.assign(start + 1, uri - start - 1);
                ++uri;
            }
            else // unrecognized IP literal
            {
                uri = start;
            }
        }
    }
    else // IPv4 or a reg-name
    {
        if (ParseIPv4address(uri))
        {
            m_hostType = wxURI_IPV4ADDRESS;

            m_server.assign(start, uri - start);
        }
        else
        {
            uri = start;
        }
    }

    if ( m_hostType == wxURI_REGNAME )
    {
        uri = start;
        // reg-name      = *( unreserved / pct-encoded / sub-delims )
        while ( *uri && *uri != '/' && *uri != ':' && *uri != '#' && *uri != '?' )
        {
            if ( IsUnreserved(*uri) || IsSubDelim(*uri) )
                m_server += *uri++;
            else
                AppendNextEscaped(m_server, uri);
        }
    }

    m_fields |= wxURI_SERVER;

    return uri;
}


const char* wxURI::ParsePort(const char* uri)
{
    // port          = *DIGIT
    if( *uri == ':' )
    {
        ++uri;
        while ( IsDigit(*uri) )
        {
            m_port += *uri++;
        }

        m_fields |= wxURI_PORT;
    }

    return uri;
}

const char* wxURI::ParsePath(const char* uri)
{
    /// hier-part     = "//" authority path-abempty
    ///               / path-absolute
    ///               / path-rootless
    ///               / path-empty
    ///
    /// relative-part = "//" authority path-abempty
    ///               / path-absolute
    ///               / path-noscheme
    ///               / path-empty
    ///
    /// path-abempty  = *( "/" segment )
    /// path-absolute = "/" [ segment-nz *( "/" segment ) ]
    /// path-noscheme = segment-nz-nc *( "/" segment )
    /// path-rootless = segment-nz *( "/" segment )
    /// path-empty    = 0<pchar>
    ///
    /// segment       = *pchar
    /// segment-nz    = 1*pchar
    /// segment-nz-nc = 1*( unreserved / pct-encoded / sub-delims / "@" )
    ///               ; non-zero-length segment without any colon ":"
    ///
    /// pchar         = unreserved / pct-encoded / sub-delims / ":" / "@"

    if ( IsEndPath(*uri) )
        return uri;

    const bool isAbs = *uri == '/';
    if ( isAbs )
        m_path += *uri++;

    wxArrayString segments;
    wxString segment;
    for ( ;; )
    {
        const bool endPath = IsEndPath(*uri);
        if ( endPath || *uri == '/' )
        {
            // end of a segment, look at what we got
            if ( segment == ".." )
            {
                if ( !segments.empty() && *segments.rbegin() != ".." )
                    segments.pop_back();
                else if ( !isAbs )
                    segments.push_back("..");
            }
            else if ( segment == "." )
            {
                // normally we ignore "." but the last one should be taken into
                // account as "path/." is the same as "path/" and not just "path"
                if ( endPath )
                    segments.push_back("");
            }
            else // normal segment
            {
                segments.push_back(segment);
            }

            if ( endPath )
                break;

            segment.clear();
            ++uri;
            continue;
        }

        if ( IsUnreserved(*uri) || IsSubDelim(*uri) || *uri == ':' || *uri == '@' )
            segment += *uri++;
        else
            AppendNextEscaped(segment, uri);
    }

    m_path += wxJoin(segments, '/', '\0');
    m_fields |= wxURI_PATH;

    return uri;
}


const char* wxURI::ParseQuery(const char* uri)
{
    // query         = *( pchar / "/" / "?" )
    if ( *uri == '?' )
    {
        ++uri;
        while ( *uri && *uri != '#' )
        {
            if ( IsUnreserved(*uri) || IsSubDelim(*uri) ||
                    *uri == ':' || *uri == '@' || *uri == '/' || *uri == '?' )
                m_query += *uri++;
            else
                AppendNextEscaped(m_query, uri);
        }

        m_fields |= wxURI_QUERY;
    }

    return uri;
}


const char* wxURI::ParseFragment(const char* uri)
{
    // fragment      = *( pchar / "/" / "?" )
    if ( *uri == '#' )
    {
        ++uri;
        while ( *uri )
        {
            if ( IsUnreserved(*uri) || IsSubDelim(*uri) ||
                    *uri == ':' || *uri == '@' || *uri == '/' || *uri == '?')
                m_fragment += *uri++;
            else
                AppendNextEscaped(m_fragment, uri);
        }

        m_fields |= wxURI_FRAGMENT;
    }

    return uri;
}

// ---------------------------------------------------------------------------
// Resolve
//
// Builds missing components of this uri from a base uri
//
// A version of the algorithm outlined in the RFC is used here
// (it is shown in comments)
//
// Note that an empty URI inherits all components
// ---------------------------------------------------------------------------

/* static */
wxArrayString wxURI::SplitInSegments(const wxString& path)
{
    return wxSplit(path, '/', '\0' /* no escape character */);
}

void wxURI::Resolve(const wxURI& base, int flags)
{
    wxASSERT_MSG(!base.IsReference(),
                "wxURI to inherit from must not be a reference!");

    // If we aren't being strict, enable the older (pre-RFC2396) loophole that
    // allows this uri to inherit other properties from the base uri - even if
    // the scheme is defined
    if ( !(flags & wxURI_STRICT) &&
            HasScheme() && base.HasScheme() &&
                m_scheme == base.m_scheme )
    {
        m_fields -= wxURI_SCHEME;
    }


    // Do nothing if this is an absolute wxURI
    //    if defined(R.scheme) then
    //       T.scheme    = R.scheme;
    //       T.authority = R.authority;
    //       T.path      = remove_dot_segments(R.path);
    //       T.query     = R.query;
    if (HasScheme())
        return;

    //No scheme - inherit
    m_scheme = base.m_scheme;
    m_fields |= wxURI_SCHEME;

    // All we need to do for relative URIs with an
    // authority component is just inherit the scheme
    //       if defined(R.authority) then
    //          T.authority = R.authority;
    //          T.path      = remove_dot_segments(R.path);
    //          T.query     = R.query;
    if (HasServer())
        return;

    //No authority - inherit
    if (base.HasUserInfo())
    {
        m_userinfo = base.m_userinfo;
        m_fields |= wxURI_USERINFO;
    }

    m_server = base.m_server;
    m_hostType = base.m_hostType;
    m_fields |= wxURI_SERVER;

    if (base.HasPort())
    {
        m_port = base.m_port;
        m_fields |= wxURI_PORT;
    }


    // Simple path inheritance from base
    if (!HasPath())
    {
        //             T.path = Base.path;
        m_path = base.m_path;
        m_fields |= wxURI_PATH;


        //             if defined(R.query) then
        //                T.query = R.query;
        //             else
        //                T.query = Base.query;
        //             endif;
        if (!HasQuery())
        {
            m_query = base.m_query;
            m_fields |= wxURI_QUERY;
        }
    }
    else if ( m_path.empty() || m_path[0u] != '/' )
    {
        //             if (R.path starts-with "/") then
        //                T.path = remove_dot_segments(R.path);
        //             else
        //                T.path = merge(Base.path, R.path);
        //                T.path = remove_dot_segments(T.path);
        //             endif;
        //             T.query = R.query;
        //
        // So we don't do anything for absolute paths and implement merge for
        // the relative ones

        wxArrayString our(SplitInSegments(m_path)),
                      result(SplitInSegments(base.m_path));

        if ( !result.empty() )
            result.pop_back();

        if ( our.empty() )
        {
            // if we have an empty path it means we were constructed from a "."
            // string or something similar (e.g. "././././"), it should count
            // as (empty) segment
            our.push_back("");
        }

        const wxArrayString::const_iterator end = our.end();
        for ( wxArrayString::const_iterator i = our.begin(); i != end; ++i )
        {
            if ( i->empty() || *i == "." )
            {
                // as in ParsePath(), while normally we ignore the empty
                // segments, we need to take account of them at the end
                if ( i == end - 1 )
                    result.push_back("");
                continue;
            }

            if ( *i == ".." )
            {
                if ( !result.empty() )
                {
                    result.pop_back();

                    if ( i == end - 1 )
                        result.push_back("");
                }
                //else: just ignore, extra ".." don't accumulate
            }
            else
            {
                if ( result.empty() )
                {
                    // ensure that the resulting path will always be absolute
                    result.push_back("");
                }

                result.push_back(*i);
            }
        }

        m_path = wxJoin(result, '/', '\0');
    }

    //T.fragment = R.fragment;
}

// ---------------------------------------------------------------------------
// ParseH16
//
// Parses 1 to 4 hex values.  Returns true if the first character of the input
// string is a valid hex character.  It is the caller's responsibility to move
// the input string back to its original position on failure.
// ---------------------------------------------------------------------------

bool wxURI::ParseH16(const char*& uri)
{
    // h16           = 1*4HEXDIG
    if(!IsHex(*++uri))
        return false;

    if(IsHex(*++uri) && IsHex(*++uri) && IsHex(*++uri))
        ++uri;

    return true;
}

// ---------------------------------------------------------------------------
// ParseIPXXX
//
// Parses a certain version of an IP address and moves the input string past
// it.  Returns true if the input  string contains the proper version of an ip
// address.  It is the caller's responsibility to move the input string back
// to its original position on failure.
// ---------------------------------------------------------------------------

bool wxURI::ParseIPv4address(const char*& uri)
{
    //IPv4address   = dec-octet "." dec-octet "." dec-octet "." dec-octet
    //
    //dec-octet     =      DIGIT                    ; 0-9
    //                / %x31-39 DIGIT               ; 10-99
    //                / "1" 2DIGIT                  ; 100-199
    //                / "2" %x30-34 DIGIT           ; 200-249
    //                / "25" %x30-35                ; 250-255
    size_t iIPv4 = 0;
    if (IsDigit(*uri))
    {
        ++iIPv4;


        //each ip part must be between 0-255 (dupe of version in for loop)
        if( IsDigit(*++uri) && IsDigit(*++uri) &&
           //100 or less  (note !)
           !( (*(uri-2) < '2') ||
           //240 or less
             (*(uri-2) == '2' &&
               (*(uri-1) < '5' || (*(uri-1) == '5' && *uri <= '5'))
             )
            )
          )
        {
            return false;
        }

        if(IsDigit(*uri))++uri;

        //compilers should unroll this loop
        for(; iIPv4 < 4; ++iIPv4)
        {
            if (*uri != '.' || !IsDigit(*++uri))
                break;

            //each ip part must be between 0-255
            if( IsDigit(*++uri) && IsDigit(*++uri) &&
               //100 or less  (note !)
               !( (*(uri-2) < '2') ||
               //240 or less
                 (*(uri-2) == '2' &&
                   (*(uri-1) < '5' || (*(uri-1) == '5' && *uri <= '5'))
                 )
                )
              )
            {
                return false;
            }
            if(IsDigit(*uri))++uri;
        }
    }
    return iIPv4 == 4;
}

bool wxURI::ParseIPv6address(const char*& uri)
{
    // IPv6address   =                            6( h16 ":" ) ls32
    //               /                       "::" 5( h16 ":" ) ls32
    //               / [               h16 ] "::" 4( h16 ":" ) ls32
    //               / [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32
    //               / [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32
    //               / [ *3( h16 ":" ) h16 ] "::"    h16 ":"   ls32
    //               / [ *4( h16 ":" ) h16 ] "::"              ls32
    //               / [ *5( h16 ":" ) h16 ] "::"              h16
    //               / [ *6( h16 ":" ) h16 ] "::"

    size_t numPrefix = 0,
              maxPostfix;

    bool bEndHex = false;

    for( ; numPrefix < 6; ++numPrefix)
    {
        if(!ParseH16(uri))
        {
            --uri;
            bEndHex = true;
            break;
        }

        if(*uri != ':')
        {
            break;
        }
    }

    if(!bEndHex && !ParseH16(uri))
    {
        --uri;

        if (numPrefix)
            return false;

        if (*uri == ':')
        {
            if (*++uri != ':')
                return false;

            maxPostfix = 5;
        }
        else
            maxPostfix = 6;
    }
    else
    {
        if (*uri != ':' || *(uri+1) != ':')
        {
            if (numPrefix != 6)
                return false;

            while (*--uri != ':') {}
            ++uri;

            const char * const start = uri;
            //parse ls32
            // ls32          = ( h16 ":" h16 ) / IPv4address
            if (ParseH16(uri) && *uri == ':' && ParseH16(uri))
                return true;

            uri = start;

            if (ParseIPv4address(uri))
                return true;
            else
                return false;
        }
        else
        {
            uri += 2;

            if (numPrefix > 3)
                maxPostfix = 0;
            else
                maxPostfix = 4 - numPrefix;
        }
    }

    bool bAllowAltEnding = maxPostfix == 0;

    for(; maxPostfix != 0; --maxPostfix)
    {
        if(!ParseH16(uri) || *uri != ':')
            return false;
    }

    if(numPrefix <= 4)
    {
        const char * const start = uri;
        //parse ls32
        // ls32          = ( h16 ":" h16 ) / IPv4address
        if (ParseH16(uri) && *uri == ':' && ParseH16(uri))
            return true;

        uri = start;

        if (ParseIPv4address(uri))
            return true;

        uri = start;

        if (!bAllowAltEnding)
            return false;
    }

    if(numPrefix <= 5 && ParseH16(uri))
        return true;

    return true;
}

bool wxURI::ParseIPvFuture(const char*& uri)
{
    // IPvFuture     = "v" 1*HEXDIG "." 1*( unreserved / sub-delims / ":" )
    if (*++uri != 'v' || !IsHex(*++uri))
        return false;

    while (IsHex(*++uri))
        ;

    if (*uri != '.' || !(IsUnreserved(*++uri) || IsSubDelim(*uri) || *uri == ':'))
        return false;

    while(IsUnreserved(*++uri) || IsSubDelim(*uri) || *uri == ':') {}

    return true;
}


// ---------------------------------------------------------------------------
// IsXXX
//
// Returns true if the passed in character meets the criteria of the method
// ---------------------------------------------------------------------------

// unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
bool wxURI::IsUnreserved(char c)
{
    return IsAlpha(c) ||
           IsDigit(c) ||
           c == '-' ||
           c == '.' ||
           c == '_' ||
           c == '~'
           ;
}

bool wxURI::IsReserved(char c)
{
    return IsGenDelim(c) || IsSubDelim(c);
}

// gen-delims    = ":" / "/" / "?" / "#" / "[" / "]" / "@"
bool wxURI::IsGenDelim(char c)
{
    return c == ':' ||
           c == '/' ||
           c == '?' ||
           c == '#' ||
           c == '[' ||
           c == ']' ||
           c == '@';
}

// sub-delims    = "!" / "$" / "&" / "'" / "(" / ")"
//               / "*" / "+" / "," / ";" / "="
bool wxURI::IsSubDelim(char c)
{
    return c == '!' ||
           c == '$' ||
           c == '&' ||
           c == '\'' ||
           c == '(' ||
           c == ')' ||
           c == '*' ||
           c == '+' ||
           c == ',' ||
           c == ';' ||
           c == '='
           ;
}

bool wxURI::IsHex(char c)
{
    return IsDigit(c) ||
           (c >= 'a' && c <= 'f') ||
           (c >= 'A' && c <= 'F');
}

bool wxURI::IsAlpha(char c)
{
    return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
}

bool wxURI::IsDigit(char c)
{
    return c >= '0' && c <= '9';
}

bool wxURI::IsEndPath(char c)
{
    return c == '\0' || c == '#' || c == '?';
}