library/cpp/html/escape/escape.cpp


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#include "escape.h"

#include <util/generic/array_size.h>
#include <util/generic/strbuf.h>

namespace NHtml {
    namespace { 
        struct TReplace { 
            char Char; 
            bool ForText; 
            TStringBuf Entity; 
        }; 

        TReplace Escapable[] = {
            {'"', false, TStringBuf("&quot;")},
            {'&', true, TStringBuf("&amp;")},
            {'<', true, TStringBuf("&lt;")},
            {'>', true, TStringBuf("&gt;")},
        }; 

        TString EscapeImpl(const TString& value, bool isText) {
            auto ci = value.begin(); 
            // Looking for escapable characters. 
            for (; ci != value.end(); ++ci) { 
                for (size_t i = (isText ? 1 : 0); i < Y_ARRAY_SIZE(Escapable); ++i) { 
                    if (*ci == Escapable[i].Char) { 
                        goto escape; 
                    } 
                } 
            }

            // There is no escapable characters, so return original value. 
            return value; 

        escape: 
            TString tmp = TString(value.begin(), ci); 

            for (; ci != value.end(); ++ci) { 
                size_t i = (isText ? 1 : 0); 

                for (; i < Y_ARRAY_SIZE(Escapable); ++i) { 
                    if (*ci == Escapable[i].Char) { 
                        tmp += Escapable[i].Entity; 
                        break; 
                    } 
                } 
 
                if (i == Y_ARRAY_SIZE(Escapable)) { 
                    tmp += *ci; 
                } 
            }
 
            return tmp; 
        }

    }

    TString EscapeAttributeValue(const TString& value) { 
        return EscapeImpl(value, false); 
    } 

    TString EscapeText(const TString& value) { 
        return EscapeImpl(value, true); 
    } 

}