exifdata.cpp

Prints Exif metadata in different formats in an image.

// ***************************************************************** -*- 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 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 {
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;
}