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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2020, Google Inc.
*
* exif.cpp - EXIF tag creation using libexif
*/
#include "exif.h"
#include <cmath>
#include <iomanip>
#include <map>
#include <sstream>
#include <tuple>
#include <uchar.h>
#include <libcamera/base/log.h>
#include <libcamera/base/utils.h>
using namespace libcamera;
LOG_DEFINE_CATEGORY(EXIF)
/*
* List of EXIF tags that we set directly because they are not supported
* by libexif version 0.6.21.
*/
enum class _ExifTag {
OFFSET_TIME = 0x9010,
OFFSET_TIME_ORIGINAL = 0x9011,
OFFSET_TIME_DIGITIZED = 0x9012,
};
/*
* The Exif class should be instantiated and specific properties set
* through the exposed public API.
*
* Once all desired properties have been set, the user shall call
* generate() to process the entries and generate the Exif data.
*
* Calls to generate() must check the return code to determine if any error
* occurred during the construction of the Exif data, and if successful the
* data can be obtained using the data() function.
*/
Exif::Exif()
: valid_(false), data_(nullptr), order_(EXIF_BYTE_ORDER_INTEL),
exifData_(0), size_(0)
{
/* Create an ExifMem allocator to construct entries. */
mem_ = exif_mem_new_default();
if (!mem_) {
LOG(EXIF, Error) << "Failed to allocate ExifMem Allocator";
return;
}
data_ = exif_data_new_mem(mem_);
if (!data_) {
LOG(EXIF, Error) << "Failed to allocate an ExifData structure";
return;
}
valid_ = true;
exif_data_set_option(data_, EXIF_DATA_OPTION_FOLLOW_SPECIFICATION);
exif_data_set_data_type(data_, EXIF_DATA_TYPE_COMPRESSED);
/*
* Big-Endian: EXIF_BYTE_ORDER_MOTOROLA
* Little Endian: EXIF_BYTE_ORDER_INTEL
*/
exif_data_set_byte_order(data_, order_);
setString(EXIF_IFD_EXIF, EXIF_TAG_EXIF_VERSION,
EXIF_FORMAT_UNDEFINED, "0231");
/* Create the mandatory EXIF fields with default data. */
exif_data_fix(data_);
}
Exif::~Exif()
{
if (exifData_)
free(exifData_);
if (data_) {
/*
* Reset thumbnail data to avoid getting double-freed by
* libexif. It is owned by the caller (i.e. PostProcessorJpeg).
*/
data_->data = nullptr;
data_->size = 0;
exif_data_unref(data_);
}
if (mem_)
exif_mem_unref(mem_);
}
ExifEntry *Exif::createEntry(ExifIfd ifd, ExifTag tag)
{
ExifContent *content = data_->ifd[ifd];
ExifEntry *entry = exif_content_get_entry(content, tag);
if (entry) {
exif_entry_ref(entry);
return entry;
}
entry = exif_entry_new_mem(mem_);
if (!entry) {
LOG(EXIF, Error) << "Failed to allocated new entry";
valid_ = false;
return nullptr;
}
exif_content_add_entry(content, entry);
exif_entry_initialize(entry, tag);
return entry;
}
ExifEntry *Exif::createEntry(ExifIfd ifd, ExifTag tag, ExifFormat format,
unsigned long components, unsigned int size)
{
ExifContent *content = data_->ifd[ifd];
/* Replace any existing entry with the same tag. */
ExifEntry *existing = exif_content_get_entry(content, tag);
exif_content_remove_entry(content, existing);
ExifEntry *entry = exif_entry_new_mem(mem_);
if (!entry) {
LOG(EXIF, Error) << "Failed to allocated new entry";
valid_ = false;
return nullptr;
}
void *buffer = exif_mem_alloc(mem_, size);
if (!buffer) {
LOG(EXIF, Error) << "Failed to allocate buffer for variable entry";
exif_mem_unref(mem_);
valid_ = false;
return nullptr;
}
entry->data = static_cast<unsigned char *>(buffer);
entry->components = components;
entry->format = format;
entry->size = size;
entry->tag = tag;
exif_content_add_entry(content, entry);
return entry;
}
void Exif::setByte(ExifIfd ifd, ExifTag tag, uint8_t item)
{
ExifEntry *entry = createEntry(ifd, tag, EXIF_FORMAT_BYTE, 1, 1);
if (!entry)
return;
entry->data[0] = item;
exif_entry_unref(entry);
}
void Exif::setShort(ExifIfd ifd, ExifTag tag, uint16_t item)
{
ExifEntry *entry = createEntry(ifd, tag);
if (!entry)
return;
exif_set_short(entry->data, order_, item);
exif_entry_unref(entry);
}
void Exif::setLong(ExifIfd ifd, ExifTag tag, uint32_t item)
{
ExifEntry *entry = createEntry(ifd, tag);
if (!entry)
return;
exif_set_long(entry->data, order_, item);
exif_entry_unref(entry);
}
void Exif::setRational(ExifIfd ifd, ExifTag tag, ExifRational item)
{
setRational(ifd, tag, { &item, 1 });
}
void Exif::setRational(ExifIfd ifd, ExifTag tag, Span<const ExifRational> items)
{
ExifEntry *entry = createEntry(ifd, tag, EXIF_FORMAT_RATIONAL,
items.size(),
items.size() * sizeof(ExifRational));
if (!entry)
return;
for (size_t i = 0; i < items.size(); i++)
exif_set_rational(entry->data + i * sizeof(ExifRational),
order_, items[i]);
exif_entry_unref(entry);
}
static const std::map<Exif::StringEncoding, std::array<uint8_t, 8>> stringEncodingCodes = {
{ Exif::ASCII, { 0x41, 0x53, 0x43, 0x49, 0x49, 0x00, 0x00, 0x00 } },
{ Exif::Unicode, { 0x55, 0x4e, 0x49, 0x43, 0x4f, 0x44, 0x45, 0x00 } },
};
void Exif::setString(ExifIfd ifd, ExifTag tag, ExifFormat format,
const std::string &item, StringEncoding encoding)
{
std::string ascii;
size_t length;
const char *str;
std::vector<uint8_t> buf;
if (format == EXIF_FORMAT_ASCII) {
ascii = utils::toAscii(item);
str = ascii.c_str();
/* Pad 1 extra byte to null-terminate the ASCII string. */
length = ascii.length() + 1;
} else {
std::u16string u16str;
auto encodingString = stringEncodingCodes.find(encoding);
if (encodingString != stringEncodingCodes.end()) {
buf = {
encodingString->second.begin(),
encodingString->second.end()
};
}
switch (encoding) {
case Unicode:
u16str = utf8ToUtf16(item);
buf.resize(8 + u16str.size() * 2);
for (size_t i = 0; i < u16str.size(); i++) {
if (order_ == EXIF_BYTE_ORDER_INTEL) {
buf[8 + 2 * i] = u16str[i] & 0xff;
buf[8 + 2 * i + 1] = (u16str[i] >> 8) & 0xff;
} else {
buf[8 + 2 * i] = (u16str[i] >> 8) & 0xff;
buf[8 + 2 * i + 1] = u16str[i] & 0xff;
}
}
break;
case ASCII:
case NoEncoding:
buf.insert(buf.end(), item.begin(), item.end());
break;
}
str = reinterpret_cast<const char *>(buf.data());
/*
* Strings stored in different formats (EXIF_FORMAT_UNDEFINED)
* are not null-terminated.
*/
length = buf.size();
}
ExifEntry *entry = createEntry(ifd, tag, format, length, length);
if (!entry)
return;
memcpy(entry->data, str, length);
exif_entry_unref(entry);
}
void Exif::setMake(const std::string &make)
{
setString(EXIF_IFD_0, EXIF_TAG_MAKE, EXIF_FORMAT_ASCII, make);
}
void Exif::setModel(const std::string &model)
{
setString(EXIF_IFD_0, EXIF_TAG_MODEL, EXIF_FORMAT_ASCII, model);
}
void Exif::setSize(const Size &size)
{
setLong(EXIF_IFD_EXIF, EXIF_TAG_PIXEL_Y_DIMENSION, size.height);
setLong(EXIF_IFD_EXIF, EXIF_TAG_PIXEL_X_DIMENSION, size.width);
}
void Exif::setTimestamp(time_t timestamp, std::chrono::milliseconds msec)
{
struct tm tm;
localtime_r(×tamp, &tm);
char str[20];
strftime(str, sizeof(str), "%Y:%m:%d %H:%M:%S", &tm);
std::string ts(str);
setString(EXIF_IFD_0, EXIF_TAG_DATE_TIME, EXIF_FORMAT_ASCII, ts);
setString(EXIF_IFD_EXIF, EXIF_TAG_DATE_TIME_ORIGINAL, EXIF_FORMAT_ASCII, ts);
setString(EXIF_IFD_EXIF, EXIF_TAG_DATE_TIME_DIGITIZED, EXIF_FORMAT_ASCII, ts);
/* Query and set timezone information if available. */
int r = strftime(str, sizeof(str), "%z", &tm);
if (r <= 0)
return;
std::string tz(str);
tz.insert(3, 1, ':');
setString(EXIF_IFD_EXIF,
static_cast<ExifTag>(_ExifTag::OFFSET_TIME),
EXIF_FORMAT_ASCII, tz);
setString(EXIF_IFD_EXIF,
static_cast<ExifTag>(_ExifTag::OFFSET_TIME_ORIGINAL),
EXIF_FORMAT_ASCII, tz);
setString(EXIF_IFD_EXIF,
static_cast<ExifTag>(_ExifTag::OFFSET_TIME_DIGITIZED),
EXIF_FORMAT_ASCII, tz);
std::stringstream sstr;
sstr << std::setfill('0') << std::setw(3) << msec.count();
std::string subsec = sstr.str();
setString(EXIF_IFD_EXIF, EXIF_TAG_SUB_SEC_TIME,
EXIF_FORMAT_ASCII, subsec);
setString(EXIF_IFD_EXIF, EXIF_TAG_SUB_SEC_TIME_ORIGINAL,
EXIF_FORMAT_ASCII, subsec);
setString(EXIF_IFD_EXIF, EXIF_TAG_SUB_SEC_TIME_DIGITIZED,
EXIF_FORMAT_ASCII, subsec);
}
void Exif::setGPSDateTimestamp(time_t timestamp)
{
struct tm tm;
gmtime_r(×tamp, &tm);
char str[11];
strftime(str, sizeof(str), "%Y:%m:%d", &tm);
std::string tsStr(str);
setString(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_DATE_STAMP),
EXIF_FORMAT_ASCII, tsStr);
/* Set GPS_TIME_STAMP */
ExifRational ts[] = {
{ static_cast<ExifLong>(tm.tm_hour), 1 },
{ static_cast<ExifLong>(tm.tm_min), 1 },
{ static_cast<ExifLong>(tm.tm_sec), 1 },
};
setRational(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_TIME_STAMP),
ts);
}
std::tuple<int, int, int> Exif::degreesToDMS(double decimalDegrees)
{
int degrees = std::trunc(decimalDegrees);
double minutes = std::abs((decimalDegrees - degrees) * 60);
double seconds = (minutes - std::trunc(minutes)) * 60;
return { degrees, std::trunc(minutes), std::round(seconds) };
}
void Exif::setGPSDMS(ExifIfd ifd, ExifTag tag, int deg, int min, int sec)
{
ExifRational coords[] = {
{ static_cast<ExifLong>(deg), 1 },
{ static_cast<ExifLong>(min), 1 },
{ static_cast<ExifLong>(sec), 1 },
};
setRational(ifd, tag, coords);
}
/*
* \brief Set GPS location (lat, long, alt)
* \param[in] coords Pointer to coordinates latitude, longitude, and altitude,
* first two in degrees, the third in meters
*/
void Exif::setGPSLocation(const double *coords)
{
int deg, min, sec;
std::tie<int, int, int>(deg, min, sec) = degreesToDMS(coords[0]);
setString(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_LATITUDE_REF),
EXIF_FORMAT_ASCII, deg >= 0 ? "N" : "S");
setGPSDMS(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_LATITUDE),
std::abs(deg), min, sec);
std::tie<int, int, int>(deg, min, sec) = degreesToDMS(coords[1]);
setString(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_LONGITUDE_REF),
EXIF_FORMAT_ASCII, deg >= 0 ? "E" : "W");
setGPSDMS(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_LONGITUDE),
std::abs(deg), min, sec);
setByte(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_ALTITUDE_REF),
coords[2] >= 0 ? 0 : 1);
setRational(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_ALTITUDE),
ExifRational{ static_cast<ExifLong>(std::abs(coords[2])), 1 });
}
void Exif::setGPSMethod(const std::string &method)
{
setString(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_PROCESSING_METHOD),
EXIF_FORMAT_UNDEFINED, method, NoEncoding);
}
void Exif::setOrientation(int orientation)
{
int value;
switch (orientation) {
case 0:
default:
value = 1;
break;
case 90:
value = 6;
break;
case 180:
value = 3;
break;
case 270:
value = 8;
break;
}
setShort(EXIF_IFD_0, EXIF_TAG_ORIENTATION, value);
}
/*
* The thumbnail data should remain valid until the Exif object is destroyed.
* Failing to do so, might result in no thumbnail data being set even after a
* call to Exif::setThumbnail().
*/
void Exif::setThumbnail(Span<const unsigned char> thumbnail,
Compression compression)
{
data_->data = const_cast<unsigned char *>(thumbnail.data());
data_->size = thumbnail.size();
setShort(EXIF_IFD_0, EXIF_TAG_COMPRESSION, compression);
}
void Exif::setFocalLength(float length)
{
ExifRational rational = { static_cast<ExifLong>(length * 1000), 1000 };
setRational(EXIF_IFD_EXIF, EXIF_TAG_FOCAL_LENGTH, rational);
}
void Exif::setExposureTime(uint64_t nsec)
{
ExifRational rational = { static_cast<ExifLong>(nsec), 1000000000 };
setRational(EXIF_IFD_EXIF, EXIF_TAG_EXPOSURE_TIME, rational);
}
void Exif::setAperture(float size)
{
ExifRational rational = { static_cast<ExifLong>(size * 10000), 10000 };
setRational(EXIF_IFD_EXIF, EXIF_TAG_FNUMBER, rational);
}
void Exif::setISO(uint16_t iso)
{
setShort(EXIF_IFD_EXIF, EXIF_TAG_ISO_SPEED_RATINGS, iso);
}
void Exif::setFlash(Flash flash)
{
setShort(EXIF_IFD_EXIF, EXIF_TAG_FLASH, static_cast<ExifShort>(flash));
}
void Exif::setWhiteBalance(WhiteBalance wb)
{
setShort(EXIF_IFD_EXIF, EXIF_TAG_WHITE_BALANCE, static_cast<ExifShort>(wb));
}
/**
* \brief Convert UTF-8 string to UTF-16 string
* \param[in] str String to convert
*
* \return \a str in UTF-16
*/
std::u16string Exif::utf8ToUtf16(const std::string &str)
{
mbstate_t state{};
char16_t c16;
const char *ptr = str.data();
const char *end = ptr + str.size();
std::u16string ret;
while (size_t rc = mbrtoc16(&c16, ptr, end - ptr + 1, &state)) {
if (rc == static_cast<size_t>(-2) ||
rc == static_cast<size_t>(-1))
break;
ret.push_back(c16);
if (rc > 0)
ptr += rc;
}
return ret;
}
[[nodiscard]] int Exif::generate()
{
if (exifData_) {
free(exifData_);
exifData_ = nullptr;
}
if (!valid_) {
LOG(EXIF, Error) << "Generated EXIF data is invalid";
return -1;
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