exif.cpp

/*
 * Copyright 2015 by Philip N. Garner
 *
 * See the file COPYING for the licence associated with this software.
 *
 * Author(s):
 *   Phil Garner, September 2015
 */

#include "exif.h"

EXIF::EXIF(var iPath)
{
    mData = 0;
    load(iPath);
}

EXIF::EXIF(const unsigned char *iData, unsigned int iSize)
{
    mData = 0;
    load(iData, iSize);
}

EXIF::~EXIF()
{
    if (mData)
        exif_data_free(mData);
    mData = 0;
}

void EXIF::load(var iPath)
{
    if (mData)
        exif_data_free(mData);
    mData = exif_data_new_from_file(iPath.str());
    if (mData)
        // I'm not sure this is necessary, but it feels good
        exif_data_fix(mData);
}

void EXIF::load(const unsigned char *iData, unsigned int iSize)
{
    if (mData)
        exif_data_free(mData);
    mData = exif_data_new_from_data(iData, iSize);
    if (mData)
        // Ditto...
        exif_data_fix(mData);
}

void EXIF::dump()
{
    if (valid())
        exif_data_dump(mData);
}

var EXIF::entry(ExifTag iTag)
{
    if (!valid())
        throw lube::error("EXIF class invalid");
    var r;
    ExifEntry* e = exif_data_get_entry(mData, iTag);
    if (!e)
        return r;
    // Debuggin'
    //exif_entry_dump(e, 2);

    switch (e->format)
    {
    case EXIF_FORMAT_ASCII:
        r = var(e->components, (const char*)e->data);
        break;
    default:
        throw lube::error("EXIF::entry: Unknown format");
    }
    return r;
}

/**
 * Helper function to return the date as an array of strings
 */
var EXIF::date()
{
    if (!valid())
        throw lube::error("EXIF class invalid");

    // Try for the DATE_TIME EXIF tag, then DATE_TIME_ORIGINAL
    var r = entry(EXIF_TAG_DATE_TIME);
    if (!r)
        r = entry(EXIF_TAG_DATE_TIME_ORIGINAL);
    if (!r)
        return lube::nil;

    // Parse it to get at least the ISO date and the month
    //   iPhone has format 2015:01:01 17:31:46
    //   Old Nokia has     2010:06:09 12:22:02
    //   Old Samsung has   2012-12-02 04:08:18
    //   Dropbox files are 2012-12-02 04.08.18
    //   ISO format is     2012-12-02T04:08:18Z
    //              or     20121202T040818Z
    // So we need to get rid of at least ':', '-' and '.', and the ISO tags.
    // Actually, geeqie fails on that Samsung format
    r.replace("[-:.TZ]", " ");
    var s = r.strip().split(" ");
    if (s[0].size() != 4) return lube::nil;
    if (s[1].size() != 2) return lube::nil;
    if (s[2].size() != 2) return lube::nil;
    return s;
}