Break picture handling code from C++ to C.

This commit breaks the loading of images that were done in the divelist
into smaller bits. A bit of code refactor was done in order to correct the
placement of a few methods.

ShiftTimesDialog::EpochFromExiv got moved to Exif::epoch dive_add_picture
is now used instead of add_event picture_load_exif_data got implemented
using the old listview code.  dive_set_geodata_from_picture got
implemented using the old listview code.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 587 insertions, 0 deletions

diff --git a/exif.cpp b/exif.cpp
new file mode 100644
index 000000000..0b1cda2bc
--- /dev/null
+++ b/exif.cpp
@@ -0,0 +1,587 @@
+#include <stdio.h>
+/**************************************************************************
+  exif.cpp  -- A simple ISO C++ library to parse basic EXIF
+	       information from a JPEG file.
+
+  Copyright (c) 2010-2013 Mayank Lahiri
+  mlahiri@gmail.com
+  All rights reserved (BSD License).
+
+  See exif.h for version history.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+  -- Redistributions of source code must retain the above copyright notice,
+     this list of conditions and the following disclaimer.
+  -- Redistributions in binary form must reproduce the above copyright notice,
+     this list of conditions and the following disclaimer in the documentation
+     and/or other materials provided with the distribution.
+
+     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY EXPRESS
+     OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+     OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
+     NO EVENT SHALL THE FREEBSD PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+     INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+     BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+     OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+#include <algorithm>
+#include "dive.h"
+#include "exif.h"
+
+using std::string;
+
+namespace {
+	// IF Entry
+	struct IFEntry {
+		// Raw fields
+		unsigned short tag;
+		unsigned short format;
+		unsigned data;
+		unsigned length;
+
+		// Parsed fields
+		string val_string;
+		unsigned short val_16;
+		unsigned val_32;
+		double val_rational;
+		unsigned char val_byte;
+	};
+
+	// Helper functions
+	unsigned int parse32(const unsigned char *buf, bool intel)
+	{
+		if (intel)
+			return ((unsigned)buf[3] << 24) |
+			       ((unsigned)buf[2] << 16) |
+			       ((unsigned)buf[1] << 8) |
+			       buf[0];
+
+		return ((unsigned)buf[0] << 24) |
+		       ((unsigned)buf[1] << 16) |
+		       ((unsigned)buf[2] << 8) |
+		       buf[3];
+	}
+
+	unsigned short parse16(const unsigned char *buf, bool intel)
+	{
+		if (intel)
+			return ((unsigned)buf[1] << 8) | buf[0];
+		return ((unsigned)buf[0] << 8) | buf[1];
+	}
+
+	string parseEXIFString(const unsigned char *buf,
+			       const unsigned num_components,
+			       const unsigned data,
+			       const unsigned base,
+			       const unsigned len)
+	{
+		string value;
+		if (num_components <= 4)
+			value.assign((const char *)&data, num_components);
+		else {
+			if (base + data + num_components <= len)
+				value.assign((const char *)(buf + base + data), num_components);
+		}
+		return value;
+	}
+
+	double parseEXIFRational(const unsigned char *buf, bool intel)
+	{
+		double numerator = 0;
+		double denominator = 1;
+
+		numerator = (double)parse32(buf, intel);
+		denominator = (double)parse32(buf + 4, intel);
+		if (denominator < 1e-20)
+			return 0;
+		return numerator / denominator;
+	}
+
+	IFEntry parseIFEntry(const unsigned char *buf,
+			     const unsigned offs,
+			     const bool alignIntel,
+			     const unsigned base,
+			     const unsigned len)
+	{
+		IFEntry result;
+
+		// Each directory entry is composed of:
+		// 2 bytes: tag number (data field)
+		// 2 bytes: data format
+		// 4 bytes: number of components
+		// 4 bytes: data value or offset to data value
+		result.tag = parse16(buf + offs, alignIntel);
+		result.format = parse16(buf + offs + 2, alignIntel);
+		result.length = parse32(buf + offs + 4, alignIntel);
+		result.data = parse32(buf + offs + 8, alignIntel);
+
+		// Parse value in specified format
+		switch (result.format) {
+		case 1:
+			result.val_byte = (unsigned char)*(buf + offs + 8);
+			break;
+		case 2:
+			result.val_string = parseEXIFString(buf, result.length, result.data, base, len);
+			break;
+		case 3:
+			result.val_16 = parse16((const unsigned char *)buf + offs + 8, alignIntel);
+			break;
+		case 4:
+			result.val_32 = result.data;
+			break;
+		case 5:
+			if (base + result.data + 8 <= len)
+				result.val_rational = parseEXIFRational(buf + base + result.data, alignIntel);
+			break;
+		case 7:
+		case 9:
+		case 10:
+			break;
+		default:
+			result.tag = 0xFF;
+		}
+		return result;
+	}
+}
+
+//
+// Locates the EXIF segment and parses it using parseFromEXIFSegment
+//
+int EXIFInfo::parseFrom(const unsigned char *buf, unsigned len)
+{
+	// Sanity check: all JPEG files start with 0xFFD8 and end with 0xFFD9
+	// This check also ensures that the user has supplied a correct value for len.
+	if (!buf || len < 4)
+		return PARSE_EXIF_ERROR_NO_EXIF;
+	if (buf[0] != 0xFF || buf[1] != 0xD8)
+		return PARSE_EXIF_ERROR_NO_JPEG;
+	if (buf[len - 2] != 0xFF || buf[len - 1] != 0xD9)
+		return PARSE_EXIF_ERROR_NO_JPEG;
+	clear();
+
+	// Scan for EXIF header (bytes 0xFF 0xE1) and do a sanity check by
+	// looking for bytes "Exif\0\0". The marker length data is in Motorola
+	// byte order, which results in the 'false' parameter to parse16().
+	// The marker has to contain at least the TIFF header, otherwise the
+	// EXIF data is corrupt. So the minimum length specified here has to be:
+	//   2 bytes: section size
+	//   6 bytes: "Exif\0\0" string
+	//   2 bytes: TIFF header (either "II" or "MM" string)
+	//   2 bytes: TIFF magic (short 0x2a00 in Motorola byte order)
+	//   4 bytes: Offset to first IFD
+	// =========
+	//  16 bytes
+	unsigned offs = 0; // current offset into buffer
+	for (offs = 0; offs < len - 1; offs++)
+		if (buf[offs] == 0xFF && buf[offs + 1] == 0xE1)
+			break;
+	if (offs + 4 > len)
+		return PARSE_EXIF_ERROR_NO_EXIF;
+	offs += 2;
+	unsigned short section_length = parse16(buf + offs, false);
+	if (offs + section_length > len || section_length < 16)
+		return PARSE_EXIF_ERROR_CORRUPT;
+	offs += 2;
+
+	return parseFromEXIFSegment(buf + offs, len - offs);
+}
+
+int EXIFInfo::parseFrom(const string &data)
+{
+	return parseFrom((const unsigned char *)data.data(), data.length());
+}
+
+//
+// Main parsing function for an EXIF segment.
+//
+// PARAM: 'buf' start of the EXIF TIFF, which must be the bytes "Exif\0\0".
+// PARAM: 'len' length of buffer
+//
+int EXIFInfo::parseFromEXIFSegment(const unsigned char *buf, unsigned len)
+{
+	bool alignIntel = true; // byte alignment (defined in EXIF header)
+	unsigned offs = 0;      // current offset into buffer
+	if (!buf || len < 6)
+		return PARSE_EXIF_ERROR_NO_EXIF;
+
+	if (!std::equal(buf, buf + 6, "Exif\0\0"))
+		return PARSE_EXIF_ERROR_NO_EXIF;
+	offs += 6;
+
+	// Now parsing the TIFF header. The first two bytes are either "II" or
+	// "MM" for Intel or Motorola byte alignment. Sanity check by parsing
+	// the unsigned short that follows, making sure it equals 0x2a. The
+	// last 4 bytes are an offset into the first IFD, which are added to
+	// the global offset counter. For this block, we expect the following
+	// minimum size:
+	//  2 bytes: 'II' or 'MM'
+	//  2 bytes: 0x002a
+	//  4 bytes: offset to first IDF
+	// -----------------------------
+	//  8 bytes
+	if (offs + 8 > len)
+		return PARSE_EXIF_ERROR_CORRUPT;
+	unsigned tiff_header_start = offs;
+	if (buf[offs] == 'I' && buf[offs + 1] == 'I')
+		alignIntel = true;
+	else {
+		if (buf[offs] == 'M' && buf[offs + 1] == 'M')
+			alignIntel = false;
+		else
+			return PARSE_EXIF_ERROR_UNKNOWN_BYTEALIGN;
+	}
+	this->ByteAlign = alignIntel;
+	offs += 2;
+	if (0x2a != parse16(buf + offs, alignIntel))
+		return PARSE_EXIF_ERROR_CORRUPT;
+	offs += 2;
+	unsigned first_ifd_offset = parse32(buf + offs, alignIntel);
+	offs += first_ifd_offset - 4;
+	if (offs >= len)
+		return PARSE_EXIF_ERROR_CORRUPT;
+
+	// Now parsing the first Image File Directory (IFD0, for the main image).
+	// An IFD consists of a variable number of 12-byte directory entries. The
+	// first two bytes of the IFD section contain the number of directory
+	// entries in the section. The last 4 bytes of the IFD contain an offset
+	// to the next IFD, which means this IFD must contain exactly 6 + 12 * num
+	// bytes of data.
+	if (offs + 2 > len)
+		return PARSE_EXIF_ERROR_CORRUPT;
+	int num_entries = parse16(buf + offs, alignIntel);
+	if (offs + 6 + 12 * num_entries > len)
+		return PARSE_EXIF_ERROR_CORRUPT;
+	offs += 2;
+	unsigned exif_sub_ifd_offset = len;
+	unsigned gps_sub_ifd_offset = len;
+	while (--num_entries >= 0) {
+		IFEntry result = parseIFEntry(buf, offs, alignIntel, tiff_header_start, len);
+		offs += 12;
+		switch (result.tag) {
+		case 0x102:
+			// Bits per sample
+			if (result.format == 3)
+				this->BitsPerSample = result.val_16;
+			break;
+
+		case 0x10E:
+			// Image description
+			if (result.format == 2)
+				this->ImageDescription = result.val_string;
+			break;
+
+		case 0x10F:
+			// Digicam make
+			if (result.format == 2)
+				this->Make = result.val_string;
+			break;
+
+		case 0x110:
+			// Digicam model
+			if (result.format == 2)
+				this->Model = result.val_string;
+			break;
+
+		case 0x112:
+			// Orientation of image
+			if (result.format == 3)
+				this->Orientation = result.val_16;
+			break;
+
+		case 0x131:
+			// Software used for image
+			if (result.format == 2)
+				this->Software = result.val_string;
+			break;
+
+		case 0x132:
+			// EXIF/TIFF date/time of image modification
+			if (result.format == 2)
+				this->DateTime = result.val_string;
+			break;
+
+		case 0x8298:
+			// Copyright information
+			if (result.format == 2)
+				this->Copyright = result.val_string;
+			break;
+
+		case 0x8825:
+			// GPS IFS offset
+			gps_sub_ifd_offset = tiff_header_start + result.data;
+			break;
+
+		case 0x8769:
+			// EXIF SubIFD offset
+			exif_sub_ifd_offset = tiff_header_start + result.data;
+			break;
+		}
+	}
+
+	// Jump to the EXIF SubIFD if it exists and parse all the information
+	// there. Note that it's possible that the EXIF SubIFD doesn't exist.
+	// The EXIF SubIFD contains most of the interesting information that a
+	// typical user might want.
+	if (exif_sub_ifd_offset + 4 <= len) {
+		offs = exif_sub_ifd_offset;
+		int num_entries = parse16(buf + offs, alignIntel);
+		if (offs + 6 + 12 * num_entries > len)
+			return PARSE_EXIF_ERROR_CORRUPT;
+		offs += 2;
+		while (--num_entries >= 0) {
+			IFEntry result = parseIFEntry(buf, offs, alignIntel, tiff_header_start, len);
+			switch (result.tag) {
+			case 0x829a:
+				// Exposure time in seconds
+				if (result.format == 5)
+					this->ExposureTime = result.val_rational;
+				break;
+
+			case 0x829d:
+				// FNumber
+				if (result.format == 5)
+					this->FNumber = result.val_rational;
+				break;
+
+			case 0x8827:
+				// ISO Speed Rating
+				if (result.format == 3)
+					this->ISOSpeedRatings = result.val_16;
+				break;
+
+			case 0x9003:
+				// Original date and time
+				if (result.format == 2)
+					this->DateTimeOriginal = result.val_string;
+				break;
+
+			case 0x9004:
+				// Digitization date and time
+				if (result.format == 2)
+					this->DateTimeDigitized = result.val_string;
+				break;
+
+			case 0x9201:
+				// Shutter speed value
+				if (result.format == 5)
+					this->ShutterSpeedValue = result.val_rational;
+				break;
+
+			case 0x9204:
+				// Exposure bias value
+				if (result.format == 5)
+					this->ExposureBiasValue = result.val_rational;
+				break;
+
+			case 0x9206:
+				// Subject distance
+				if (result.format == 5)
+					this->SubjectDistance = result.val_rational;
+				break;
+
+			case 0x9209:
+				// Flash used
+				if (result.format == 3)
+					this->Flash = result.data ? 1 : 0;
+				break;
+
+			case 0x920a:
+				// Focal length
+				if (result.format == 5)
+					this->FocalLength = result.val_rational;
+				break;
+
+			case 0x9207:
+				// Metering mode
+				if (result.format == 3)
+					this->MeteringMode = result.val_16;
+				break;
+
+			case 0x9291:
+				// Subsecond original time
+				if (result.format == 2)
+					this->SubSecTimeOriginal = result.val_string;
+				break;
+
+			case 0xa002:
+				// EXIF Image width
+				if (result.format == 4)
+					this->ImageWidth = result.val_32;
+				if (result.format == 3)
+					this->ImageWidth = result.val_16;
+				break;
+
+			case 0xa003:
+				// EXIF Image height
+				if (result.format == 4)
+					this->ImageHeight = result.val_32;
+				if (result.format == 3)
+					this->ImageHeight = result.val_16;
+				break;
+
+			case 0xa405:
+				// Focal length in 35mm film
+				if (result.format == 3)
+					this->FocalLengthIn35mm = result.val_16;
+				break;
+			}
+			offs += 12;
+		}
+	}
+
+	// Jump to the GPS SubIFD if it exists and parse all the information
+	// there. Note that it's possible that the GPS SubIFD doesn't exist.
+	if (gps_sub_ifd_offset + 4 <= len) {
+		offs = gps_sub_ifd_offset;
+		int num_entries = parse16(buf + offs, alignIntel);
+		if (offs + 6 + 12 * num_entries > len)
+			return PARSE_EXIF_ERROR_CORRUPT;
+		offs += 2;
+		while (--num_entries >= 0) {
+			unsigned short tag = parse16(buf + offs, alignIntel);
+			unsigned short format = parse16(buf + offs + 2, alignIntel);
+			unsigned length = parse32(buf + offs + 4, alignIntel);
+			unsigned data = parse32(buf + offs + 8, alignIntel);
+			switch (tag) {
+			case 1:
+				// GPS north or south
+				this->GeoLocation.LatComponents.direction = *(buf + offs + 8);
+				if ('S' == this->GeoLocation.LatComponents.direction)
+					this->GeoLocation.Latitude = -this->GeoLocation.Latitude;
+				break;
+
+			case 2:
+				// GPS latitude
+				if (format == 5 && length == 3) {
+					this->GeoLocation.LatComponents.degrees =
+						parseEXIFRational(buf + data + tiff_header_start, alignIntel);
+					this->GeoLocation.LatComponents.minutes =
+						parseEXIFRational(buf + data + tiff_header_start + 8, alignIntel);
+					this->GeoLocation.LatComponents.seconds =
+						parseEXIFRational(buf + data + tiff_header_start + 16, alignIntel);
+					this->GeoLocation.Latitude =
+						this->GeoLocation.LatComponents.degrees +
+						this->GeoLocation.LatComponents.minutes / 60 +
+						this->GeoLocation.LatComponents.seconds / 3600;
+					if ('S' == this->GeoLocation.LatComponents.direction)
+						this->GeoLocation.Latitude = -this->GeoLocation.Latitude;
+				}
+				break;
+
+			case 3:
+				// GPS east or west
+				this->GeoLocation.LonComponents.direction = *(buf + offs + 8);
+				if ('W' == this->GeoLocation.LonComponents.direction)
+					this->GeoLocation.Longitude = -this->GeoLocation.Longitude;
+				break;
+
+			case 4:
+				// GPS longitude
+				if (format == 5 && length == 3) {
+					this->GeoLocation.LonComponents.degrees =
+						parseEXIFRational(buf + data + tiff_header_start, alignIntel);
+					this->GeoLocation.LonComponents.minutes =
+						parseEXIFRational(buf + data + tiff_header_start + 8, alignIntel);
+					this->GeoLocation.LonComponents.seconds =
+						parseEXIFRational(buf + data + tiff_header_start + 16, alignIntel);
+					this->GeoLocation.Longitude =
+						this->GeoLocation.LonComponents.degrees +
+						this->GeoLocation.LonComponents.minutes / 60 +
+						this->GeoLocation.LonComponents.seconds / 3600;
+					if ('W' == this->GeoLocation.LonComponents.direction)
+						this->GeoLocation.Longitude = -this->GeoLocation.Longitude;
+				}
+				break;
+
+			case 5:
+				// GPS altitude reference (below or above sea level)
+				this->GeoLocation.AltitudeRef = *(buf + offs + 8);
+				if (1 == this->GeoLocation.AltitudeRef)
+					this->GeoLocation.Altitude = -this->GeoLocation.Altitude;
+				break;
+
+			case 6:
+				// GPS altitude reference
+				if (format == 5) {
+					this->GeoLocation.Altitude =
+						parseEXIFRational(buf + data + tiff_header_start, alignIntel);
+					if (1 == this->GeoLocation.AltitudeRef)
+						this->GeoLocation.Altitude = -this->GeoLocation.Altitude;
+				}
+				break;
+			}
+			offs += 12;
+		}
+	}
+
+	return PARSE_EXIF_SUCCESS;
+}
+
+void EXIFInfo::clear()
+{
+	// Strings
+	ImageDescription.clear();
+	Make.clear();
+	Model.clear();
+	Software.clear();
+	DateTime.clear();
+	DateTimeOriginal.clear();
+	DateTimeDigitized.clear();
+	SubSecTimeOriginal.clear();
+	Copyright.clear();
+
+	// Shorts / unsigned / double
+	ByteAlign = 0;
+	Orientation = 0;
+
+	BitsPerSample = 0;
+	ExposureTime = 0;
+	FNumber = 0;
+	ISOSpeedRatings = 0;
+	ShutterSpeedValue = 0;
+	ExposureBiasValue = 0;
+	SubjectDistance = 0;
+	FocalLength = 0;
+	FocalLengthIn35mm = 0;
+	Flash = 0;
+	MeteringMode = 0;
+	ImageWidth = 0;
+	ImageHeight = 0;
+
+	// Geolocation
+	GeoLocation.Latitude = 0;
+	GeoLocation.Longitude = 0;
+	GeoLocation.Altitude = 0;
+	GeoLocation.AltitudeRef = 0;
+	GeoLocation.LatComponents.degrees = 0;
+	GeoLocation.LatComponents.minutes = 0;
+	GeoLocation.LatComponents.seconds = 0;
+	GeoLocation.LatComponents.direction = 0;
+	GeoLocation.LonComponents.degrees = 0;
+	GeoLocation.LonComponents.minutes = 0;
+	GeoLocation.LonComponents.seconds = 0;
+	GeoLocation.LonComponents.direction = 0;
+}
+
+time_t EXIFInfo::epoch()
+{
+	struct tm tm;
+	int year, month, day, hour, min, sec;
+
+	if (DateTimeOriginal.size())
+		sscanf(DateTimeOriginal.c_str(), "%d:%d:%d %d:%d:%d", &year, &month, &day, &hour, &min, &sec);
+	else
+		sscanf(DateTime.c_str(), "%d:%d:%d %d:%d:%d", &year, &month, &day, &hour, &min, &sec);
+	tm.tm_year = year;
+	tm.tm_mon = month - 1;
+	tm.tm_mday = day;
+	tm.tm_hour = hour;
+	tm.tm_min = min;
+	tm.tm_sec = sec;
+	return (utc_mktime(&tm));
+}