//========= Copyright Valve Corporation ============//
#include "strtools_public.h"
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

//-----------------------------------------------------------------------------
// Purpose:
//-----------------------------------------------------------------------------
bool StringHasPrefix( const std::string & sString, const std::string & sPrefix )
{
       return 0 == strnicmp( sString.c_str(), sPrefix.c_str(), sPrefix.length() );
}

bool StringHasPrefixCaseSensitive( const std::string & sString, const std::string & sPrefix )
{
       return 0 == strncmp( sString.c_str(), sPrefix.c_str(), sPrefix.length() );
}


bool StringHasSuffix( const std::string &sString, const std::string &sSuffix )
{
       size_t cStrLen = sString.length();
       size_t cSuffixLen = sSuffix.length();

       if ( cSuffixLen > cStrLen )
              return false;

       std::string sStringSuffix = sString.substr( cStrLen - cSuffixLen, cSuffixLen );

       return 0 == stricmp( sStringSuffix.c_str(), sSuffix.c_str() );
}

bool StringHasSuffixCaseSensitive( const std::string &sString, const std::string &sSuffix )
{
       size_t cStrLen = sString.length();
       size_t cSuffixLen = sSuffix.length();

       if ( cSuffixLen > cStrLen )
              return false;

       std::string sStringSuffix = sString.substr( cStrLen - cSuffixLen, cSuffixLen );

       return 0 == strncmp( sStringSuffix.c_str(), sSuffix.c_str(),cSuffixLen );
}

//-----------------------------------------------------------------------------
// Purpose:
//-----------------------------------------------------------------------------
std::string UTF16to8(const wchar_t * in)
{
       std::string out;
       unsigned int codepoint = 0;
       for ( ; in && *in != 0; ++in )
       {
              if (*in >= 0xd800 && *in <= 0xdbff)
                     codepoint = ((*in - 0xd800) << 10) + 0x10000;
              else
              {
                     if (*in >= 0xdc00 && *in <= 0xdfff)
                            codepoint |= *in - 0xdc00;
                     else
                            codepoint = *in;

                     if (codepoint <= 0x7f)
                            out.append(1, static_cast<char>(codepoint));
                     else if (codepoint <= 0x7ff)
                     {
                            out.append(1, static_cast<char>(0xc0 | ((codepoint >> 6) & 0x1f)));
                            out.append(1, static_cast<char>(0x80 | (codepoint & 0x3f)));
                     }
                     else if (codepoint <= 0xffff)
                     {
                            out.append(1, static_cast<char>(0xe0 | ((codepoint >> 12) & 0x0f)));
                            out.append(1, static_cast<char>(0x80 | ((codepoint >> 6) & 0x3f)));
                            out.append(1, static_cast<char>(0x80 | (codepoint & 0x3f)));
                     }
                     else
                     {
                            out.append(1, static_cast<char>(0xf0 | ((codepoint >> 18) & 0x07)));
                            out.append(1, static_cast<char>(0x80 | ((codepoint >> 12) & 0x3f)));
                            out.append(1, static_cast<char>(0x80 | ((codepoint >> 6) & 0x3f)));
                            out.append(1, static_cast<char>(0x80 | (codepoint & 0x3f)));
                     }
                     codepoint = 0;
              }
       }
       return out;
}

std::wstring UTF8to16(const char * in)
{
       std::wstring out;
       unsigned int codepoint = 0;
       int following = 0;
       for ( ; in && *in != 0; ++in )
       {
              unsigned char ch = *in;
              if (ch <= 0x7f)
              {
                     codepoint = ch;
                     following = 0;
              }
              else if (ch <= 0xbf)
              {
                     if (following > 0)
                     {
                            codepoint = (codepoint << 6) | (ch & 0x3f);
                            --following;
                     }
              }
              else if (ch <= 0xdf)
              {
                     codepoint = ch & 0x1f;
                     following = 1;
              }
              else if (ch <= 0xef)
              {
                     codepoint = ch & 0x0f;
                     following = 2;
              }
              else
              {
                     codepoint = ch & 0x07;
                     following = 3;
              }
              if (following == 0)
              {
                     if (codepoint > 0xffff)
                     {
                            out.append(1, static_cast<wchar_t>(0xd800 + (codepoint >> 10)));
                            out.append(1, static_cast<wchar_t>(0xdc00 + (codepoint & 0x03ff)));
                     }
                     else
                            out.append(1, static_cast<wchar_t>(codepoint));
                     codepoint = 0;
              }
       }
       return out;
}


void strcpy_safe( char *pchBuffer, size_t unBufferSizeBytes, const char *pchSource )
{
       pchBuffer[ unBufferSizeBytes - 1 ] = '\0';
       strncpy( pchBuffer, pchSource, unBufferSizeBytes - 1 );
}


// --------------------------------------------------------------------
// Purpose: converts a string to upper case
// --------------------------------------------------------------------
std::string StringToUpper( const std::string & sString )
{
       std::string sOut;
       sOut.reserve( sString.size() + 1 );
       for( std::string::const_iterator i = sString.begin(); i != sString.end(); i++ )
       {
              sOut.push_back( (char)toupper( *i ) );
       }

       return sOut;
}


// --------------------------------------------------------------------
// Purpose: converts a string to lower case
// --------------------------------------------------------------------
std::string StringToLower( const std::string & sString )
{
       std::string sOut;
       sOut.reserve( sString.size() + 1 );
       for( std::string::const_iterator i = sString.begin(); i != sString.end(); i++ )
       {
              sOut.push_back( (char)tolower( *i ) );
       }

       return sOut;
}


uint32_t ReturnStdString( const std::string & sValue, char *pchBuffer, uint32_t unBufferLen )
{
       uint32_t unLen = (uint32_t)sValue.length() + 1;
       if( !pchBuffer || !unBufferLen )
              return unLen;

       if( unBufferLen < unLen )
       {
              pchBuffer[0] = '\0';
       }
       else
       {
              memcpy( pchBuffer, sValue.c_str(), unLen );
       }

       return unLen;
}

void BufferToStdString( std::string & sDest, const char *pchBuffer, uint32_t unBufferLen )
{
       sDest.resize( unBufferLen + 1 );
       memcpy( const_cast< char* >( sDest.c_str() ), pchBuffer, unBufferLen );
       const_cast< char* >( sDest.c_str() )[ unBufferLen ] = '\0';
}

/** Returns a std::string from a uint64_t */
std::string Uint64ToString( uint64_t ulValue )
{
       char buf[ 22 ];
#if defined( _WIN32 )
       sprintf_s( buf, "%llu", ulValue );
#else
    snprintf( buf, sizeof( buf ), "%llu", (long long unsigned int ) ulValue );
#endif
       return buf;
}


/** returns a uint64_t from a string */
uint64_t StringToUint64( const std::string & sValue )
{
       return strtoull( sValue.c_str(), NULL, 0 );
}

//-----------------------------------------------------------------------------
// Purpose: Helper for converting a numeric value to a hex digit, value should be 0-15.
//-----------------------------------------------------------------------------
char cIntToHexDigit( int nValue )
{
       //Assert( nValue >= 0 && nValue <= 15 );
       return "0123456789ABCDEF"[ nValue & 15 ];
}

//-----------------------------------------------------------------------------
// Purpose: Helper for converting a hex char value to numeric, return -1 if the char
//          is not a valid hex digit.
//-----------------------------------------------------------------------------
int iHexCharToInt( char cValue )
{
       int32_t iValue = cValue;
       if ( (uint32_t)( iValue - '0' ) < 10 )
              return iValue - '0';

       iValue |= 0x20;
       if ( (uint32_t)( iValue - 'a' ) < 6 )
              return iValue - 'a' + 10;

       return -1;
}

//-----------------------------------------------------------------------------
// Purpose: Internal implementation of encode, works in the strict RFC manner, or
//          with spaces turned to + like HTML form encoding.
//-----------------------------------------------------------------------------
void V_URLEncodeInternal( char *pchDest, int nDestLen, const char *pchSource, int nSourceLen, bool bUsePlusForSpace )
{
       //AssertMsg( nDestLen > 3*nSourceLen, "Target buffer for V_URLEncode should be 3x source length, plus one for terminating null\n" );
       
       int iDestPos = 0;
       for ( int i=0; i < nSourceLen; ++i )
       {
              // worst case we need 3 additional chars
              if( (iDestPos+3) > nDestLen  )
              {
                     pchDest[0] = '\0';
//                     AssertMsg( false, "Target buffer too short\n" );
                     return;
              }

              // We allow only a-z, A-Z, 0-9, period, underscore, and hyphen to pass through unescaped.
              // These are the characters allowed by both the original RFC 1738 and the latest RFC 3986.
              // Current specs also allow '~', but that is forbidden under original RFC 1738.
              if ( !( pchSource[i] >= 'a' && pchSource[i] <= 'z' ) && !( pchSource[i] >= 'A' && pchSource[i] <= 'Z' ) && !(pchSource[i] >= '0' && pchSource[i] <= '9' )
                      && pchSource[i] != '-' && pchSource[i] != '_' && pchSource[i] != '.'       
              )
              {
                     if ( bUsePlusForSpace && pchSource[i] == ' ' )
                     {
                            pchDest[iDestPos++] = '+';
                     }
                     else
                     {
                            pchDest[iDestPos++] = '%';
                            uint8_t iValue = pchSource[i];
                            if ( iValue == 0 )
                            {
                                   pchDest[iDestPos++] = '0';
                                   pchDest[iDestPos++] = '0';
                            }
                            else
                            {
                                   char cHexDigit1 = cIntToHexDigit( iValue % 16 );
                                   iValue /= 16;
                                   char cHexDigit2 = cIntToHexDigit( iValue );
                                   pchDest[iDestPos++] = cHexDigit2;
                                   pchDest[iDestPos++] = cHexDigit1;
                            }
                     }
              }
              else
              {
                     pchDest[iDestPos++] = pchSource[i];
              }
       }

       if( (iDestPos+1) > nDestLen )
       {
              pchDest[0] = '\0';
              //AssertMsg( false, "Target buffer too short to terminate\n" );
              return;
       }

       // Null terminate
       pchDest[iDestPos++] = 0;
}


//-----------------------------------------------------------------------------
// Purpose: Internal implementation of decode, works in the strict RFC manner, or
//          with spaces turned to + like HTML form encoding.
//
//                     Returns the amount of space used in the output buffer.
//-----------------------------------------------------------------------------
size_t V_URLDecodeInternal( char *pchDecodeDest, int nDecodeDestLen, const char *pchEncodedSource, int nEncodedSourceLen, bool bUsePlusForSpace )
{
       if ( nDecodeDestLen < nEncodedSourceLen )
       {
              //AssertMsg( false, "V_URLDecode needs a dest buffer at least as large as the source" );
              return 0;
       }

       int iDestPos = 0;
       for( int i=0; i < nEncodedSourceLen; ++i )
       {
              if ( bUsePlusForSpace && pchEncodedSource[i] == '+' )
              {
                     pchDecodeDest[ iDestPos++ ] = ' ';
              }
              else if ( pchEncodedSource[i] == '%' )
              {
                     // Percent signifies an encoded value, look ahead for the hex code, convert to numeric, and use that

                     // First make sure we have 2 more chars
                     if ( i < nEncodedSourceLen - 2 )
                     {
                            char cHexDigit1 = pchEncodedSource[i+1];
                            char cHexDigit2 = pchEncodedSource[i+2];

                            // Turn the chars into a hex value, if they are not valid, then we'll
                            // just place the % and the following two chars direct into the string,
                            // even though this really shouldn't happen, who knows what bad clients
                            // may do with encoding.
                            bool bValid = false;
                            int iValue = iHexCharToInt( cHexDigit1 );
                            if ( iValue != -1 )
                            {
                                   iValue *= 16;
                                   int iValue2 = iHexCharToInt( cHexDigit2 );
                                   if ( iValue2 != -1 )
                                   {
                                          iValue += iValue2;
                                          pchDecodeDest[ iDestPos++ ] = (char)iValue;
                                          bValid = true;
                                   }
                            }

                            if ( !bValid )
                            {
                                   pchDecodeDest[ iDestPos++ ] = '%';
                                   pchDecodeDest[ iDestPos++ ] = cHexDigit1;
                                   pchDecodeDest[ iDestPos++ ] = cHexDigit2;
                            }
                     }

                     // Skip ahead
                     i += 2;
              }
              else
              {
                     pchDecodeDest[ iDestPos++ ] = pchEncodedSource[i];
              }
       }

       // We may not have extra room to NULL terminate, since this can be used on raw data, but if we do
       // go ahead and do it as this can avoid bugs.
       if ( iDestPos < nDecodeDestLen )
       {
              pchDecodeDest[iDestPos] = 0;
       }

       return (size_t)iDestPos;
}

//-----------------------------------------------------------------------------
// Purpose: Encodes a string (or binary data) from URL encoding format, see rfc1738 section 2.2.  
//          This version of the call isn't a strict RFC implementation, but uses + for space as is
//          the standard in HTML form encoding, despite it not being part of the RFC.
//
//          Dest buffer should be at least as large as source buffer to guarantee room for decode.
//-----------------------------------------------------------------------------
void V_URLEncode( char *pchDest, int nDestLen, const char *pchSource, int nSourceLen )
{
       return V_URLEncodeInternal( pchDest, nDestLen, pchSource, nSourceLen, true );
}


//-----------------------------------------------------------------------------
// Purpose: Decodes a string (or binary data) from URL encoding format, see rfc1738 section 2.2.  
//          This version of the call isn't a strict RFC implementation, but uses + for space as is
//          the standard in HTML form encoding, despite it not being part of the RFC.
//
//          Dest buffer should be at least as large as source buffer to guarantee room for decode.
//                     Dest buffer being the same as the source buffer (decode in-place) is explicitly allowed.
//-----------------------------------------------------------------------------
size_t V_URLDecode( char *pchDecodeDest, int nDecodeDestLen, const char *pchEncodedSource, int nEncodedSourceLen )
{
       return V_URLDecodeInternal( pchDecodeDest, nDecodeDestLen, pchEncodedSource, nEncodedSourceLen, true );
}

//-----------------------------------------------------------------------------
void V_StripExtension( std::string &in )
{
       // Find the last dot. If it's followed by a dot or a slash, then it's part of a 
       // directory specifier like ../../somedir/./blah.
       std::string::size_type test = in.rfind( '.' );
       if ( test != std::string::npos )
       {
              // This handles things like ".\blah" or "c:\my@email.com\abc\def\geh"
              // Which would otherwise wind up with "" and "c:\my@email", respectively.
              if ( in.rfind( '\\' ) < test && in.rfind( '/' ) < test )
              {
                     in.resize( test );
              }
       }
}