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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2020, Google Inc.
*
* exif.cpp - EXIF tag creation using libexif
*/
#include "exif.h"
#include "libcamera/internal/log.h"
using namespace libcamera;
LOG_DEFINE_CATEGORY(EXIF)
/*
* 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() method.
*/
Exif::Exif()
: valid_(false), data_(nullptr), 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_, EXIF_BYTE_ORDER_INTEL);
/* Create the mandatory EXIF fields with default data. */
exif_data_fix(data_);
}
Exif::~Exif()
{
if (exifData_)
free(exifData_);
if (data_)
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::setShort(ExifIfd ifd, ExifTag tag, uint16_t item)
{
ExifEntry *entry = createEntry(ifd, tag);
if (!entry)
return;
exif_set_short(entry->data, EXIF_BYTE_ORDER_INTEL, 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, EXIF_BYTE_ORDER_INTEL, item);
exif_entry_unref(entry);
}
void Exif::setRational(ExifIfd ifd, ExifTag tag, ExifRational item)
{
ExifEntry *entry = createEntry(ifd, tag);
if (!entry)
return;
exif_set_rational(entry->data, EXIF_BYTE_ORDER_INTEL, item);
exif_entry_unref(entry);
}
void Exif::setString(ExifIfd ifd, ExifTag tag, ExifFormat format, const std::string &item)
{
/* Pad 1 extra byte for null-terminated string. */
size_t length = item.length() + 1;
ExifEntry *entry = createEntry(ifd, tag, format, length, length);
if (!entry)
return;
memcpy(entry->data, item.c_str(), length);
exif_entry_unref(entry);
}
[[nodiscard]] int Exif::generate()
{
if (exifData_) {
free(exifData_);
exifData_ = nullptr;
}
if (!valid_) {
LOG(EXIF, Error) << "Generated EXIF data is invalid";
return -1;
}
exif_data_save_data(data_, &exifData_, &size_);
LOG(EXIF, Debug) << "Created EXIF instance (" << size_ << " bytes)";
return 0;
}
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