exifdata.cpp

// ***************************************************************** -*- C++ -*-
// exifdata.cpp
// Sample program to format exif data in various external formats

#include <exiv2/exiv2.hpp>

#include <iostream>
#include <iomanip>
#include <cassert>
#include <string>

typedef std::map<std::string,int> format_t;
typedef format_t::const_iterator  format_i;
typedef enum  { wolf ,  csv , json , xml } format_e;

void syntax(const char* argv[],format_t& formats)
{
    std::cout << "Usage: " << argv[0] << " file format" << std::endl;
    int count = 0;
    std::cout << "formats: ";
    for ( format_i i = formats.begin() ; i != formats.end() ; ++i ) {
        std::cout << ( count++ ? " | " : "") << i->first ;
    }
    std::cout << std::endl;
}

size_t formatInit(Exiv2::ExifData& exifData)
{
    size_t result = 0;
    for (Exiv2::ExifData::const_iterator i = exifData.begin(); i != exifData.end() ; ++i) {
        result ++ ;
    }
    return result ;
}

///////////////////////////////////////////////////////////////////////
std::string escapeCSV(Exiv2::ExifData::const_iterator it,bool bValue)
{
    std::string   result ;

    std::ostringstream os;
    if ( bValue ) os << it->value() ; else os << it->key() ;

    std::string s = os.str();
    for ( size_t i = 0 ;i < s.length() ; i ++ ) {
        if ( s[i] == ',' ) result += '\\';
        result += s[i];
    }

    return result ;
}

std::string formatCSV(Exiv2::ExifData& exifData)
{
    size_t count  = 0;
    size_t length = formatInit(exifData);
    std::ostringstream result;

    for (Exiv2::ExifData::const_iterator i = exifData.begin(); count++ < length; ++i) {
        result << escapeCSV(i,false) << (count != length ? ", " : "" ) ;
    }
    result << std::endl;

    count = 0;
    for (Exiv2::ExifData::const_iterator i = exifData.begin(); count++ < length ; ++i) {
        result << escapeCSV(i,true) << (count != length ? ", " : "" ) ;
    }
    return result.str();
}

///////////////////////////////////////////////////////////////////////
std::string formatWolf(Exiv2::ExifData& exifData)
{
    size_t count  = 0;
    size_t length = formatInit(exifData);
    std::ostringstream result;

    result << "{ " << std::endl;
    for (Exiv2::ExifData::const_iterator i = exifData.begin(); count++ < length ; ++i) {
        result << "  " << i->key()  << " -> " << i->value()  << (count != length ? "," : "" ) << std::endl ;
    }
    result << "}";
    return result.str();
}

///////////////////////////////////////////////////////////////////////
std::string escapeJSON(Exiv2::ExifData::const_iterator it,bool bValue=true)
{
    std::string   result ;

    std::ostringstream os;
    if ( bValue ) os << it->value() ; else os << it->key() ;

    std::string s = os.str();
    for ( size_t i = 0 ;i < s.length() ; i ++ ) {
        if ( s[i] == '"' ) result += "\\\"";
        result += s[i];
    }

    std::string q = "\"";
    return q + result + q ;
}

std::string formatJSON(Exiv2::ExifData& exifData)
{
    size_t count  = 0;
    size_t length = formatInit(exifData);
    std::ostringstream result;

    result << "{" << std::endl ;
    for (Exiv2::ExifData::const_iterator i = exifData.begin(); count++ < length ; ++i) {
        result << "  " << escapeJSON(i,false)  << ":" << escapeJSON(i,true) << ( count != length ? "," : "" ) << std::endl ;
    }
    result << "}";
    return result.str();
}

///////////////////////////////////////////////////////////////////////
std::string escapeXML(Exiv2::ExifData::const_iterator it,bool bValue=true)
{
    std::string   result ;

    std::ostringstream os;
    if ( bValue ) os << it->value() ; else os << it->key() ;

    std::string s = os.str();
    for ( size_t i = 0 ;i < s.length() ; i ++ ) {
        if ( s[i] == '<' ) result += "&lg;";
        if ( s[i] == '>' ) result += "&gt;";
        result += s[i];
    }

    return result ;
}

std::string formatXML(Exiv2::ExifData& exifData)
{
    size_t count  = 0;
    size_t length = formatInit(exifData);
    std::ostringstream result;

    result << "<exif>" << std::endl;
    for (Exiv2::ExifData::const_iterator i = exifData.begin(); count++ < length ; ++i) {
        std::string key   = escapeXML(i,false);
        std::string value = escapeXML(i,true);
        result << "  <" << key << ">" << value << "<" << key << "/>" << std::endl ;
    }
    result << "</exif>" << std::endl;
    return result.str();
}

///////////////////////////////////////////////////////////////////////
int main(int argc,const char* argv[])
{
    format_t formats;
    formats["wolf"] = wolf;
    formats["csv" ] = csv ;
    formats["json"] = json;
    formats["xml" ] = xml ;

    int result = 0 ;
    if (argc != 3) {
        syntax(argv,formats) ;
        result = 1;
    }

    const char* file   = argv[1];
    const char* format = argv[2];

    if ( !result && formats.find(format) == formats.end() ) {
        std::cout << "Unrecognised format " << format << std::endl;
        syntax(argv,formats);
        result = 2;
	}

	if ( !result ) try {
		Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
		assert(image.get() != 0);
		image->readMetadata();
		Exiv2::ExifData &exifData = image->exifData();

		switch ( formats.find(format)->second ) {
			case wolf : std::cout << formatWolf(exifData) << std::endl; break;
			case csv  : std::cout << formatCSV (exifData) << std::endl; break;
			case json : std::cout << formatJSON(exifData) << std::endl; break;
			case xml  : std::cout << formatXML (exifData) << std::endl; break;

			default   : std::cout << "*** error: format not implemented yet: " << format << " ***" << std::endl;
			            result = 3;
			break;
		}
	} catch (Exiv2::AnyError& e) {
    	std::cerr << "*** error exiv2 exception '" << e << "' ***" << std::endl;
    	result = 4;
	} catch ( ... ) {
    	std::cerr << "*** error exception" << std::endl;
    	result = 5;
	}

    return result;
}