#include <cstring>
#include "replace.h"

int Replace::run (
    std::string& buffer,
    const std::string& find,
    const std::string& replace,
    bool matchCase )
{
    if ( buffer.empty() || find.empty() )
        return 0;

    std::string output;
    size_t capacity = buffer.size();
    int diff = replace.size() - find.size();
    if ( diff > 0 )
        capacity += diff * BUFSIZ;

    output.reserve ( capacity );
    size_t findLength = find.size();
    int matchCount = 0;

    // comparison function pointer
    int ( *comp ) ( const char *, const char *, size_t ) =
#ifdef __WXMSW__
        ( matchCase ) ? strncmp : strnicmp;
#else
        ( matchCase ) ? strncmp : strncasecmp;
#endif

    char *bufferPtr;
    const char *findPtr, *replacePtr;
    bufferPtr = ( char * ) buffer.c_str();
    findPtr = find.c_str();
    replacePtr = replace.c_str();

    while ( *bufferPtr )
    {
        if ( !comp ( ( const char * ) bufferPtr, findPtr, findLength ) )
        {
            ++matchCount;
            output += replacePtr;
            bufferPtr += findLength;
        }
        else
        {
            output += *bufferPtr;
            ++bufferPtr;
        }
    }
    if ( !matchCount )
        return 0;
    buffer = output;
    return matchCount;
}