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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "node_modules/piex/src/piex.h"
#include <assert.h>
#include <emscripten.h>
#include <emscripten/bind.h>
#include <emscripten/val.h>
#include <stdint.h>
#include <string.h>
class PiexStreamReader : public piex::StreamInterface {
public:
PiexStreamReader(const char* data, size_t size) : data_(data), size_(size) {}
piex::Error GetData(const size_t offset, const size_t length, uint8_t* out) {
if (!EnsureData(offset, length))
return piex::kFail;
memcpy(out, data_ + offset, length);
return piex::kOk;
}
private:
bool EnsureData(const size_t offset, const size_t length) const {
if (offset > size_ || (size_ - offset) < length)
return false;
return true;
}
private:
const char* data_;
const size_t size_;
};
class PiexReader {
public:
static emscripten::val ReadImage(const char* data, size_t size) {
assert(data);
auto result = emscripten::val::object();
PiexStreamReader reader(data, size);
piex::PreviewImageData image;
switch (piex::GetPreviewImageData(&reader, &image)) {
case piex::kFail:
result.set("error", emscripten::val("failed to extract preview"));
break;
case piex::kUnsupported:
result.set("error", emscripten::val("unsupported preview type"));
break;
case piex::kOk:
result = GetProperties(image);
break;
default:
result.set("error", emscripten::val("unknown error"));
break;
}
return result;
}
private:
static emscripten::val GetProperties(const piex::PreviewImageData& image) {
auto result = emscripten::val::object();
result.set("details", GetDetails(image));
result.set("preview", GetPreview(image));
result.set("thumbnail", GetThumbnail(image));
return result;
}
static emscripten::val GetDetails(const piex::PreviewImageData& image) {
auto object = emscripten::val::object();
object.set("cameraMaker", emscripten::val(image.maker));
object.set("cameraModel", emscripten::val(image.model));
object.set("aperture", GetRational(image.fnumber));
object.set("focalLength", GetRational(image.focal_length));
object.set("exposureTime", GetRational(image.exposure_time));
object.set("isoSpeed", GetNonZeroValue(image.iso));
object.set("width", emscripten::val(image.full_width));
object.set("height", emscripten::val(image.full_height));
object.set("orientation", emscripten::val(image.exif_orientation));
object.set("colorSpace", emscripten::val("sRGB"));
const auto space = static_cast<uint32_t>(image.color_space);
if (space == piex::PreviewImageData::kAdobeRgb)
object.set("colorSpace", emscripten::val("AdobeRGB1998"));
object.set("date", emscripten::val(image.date_time));
return object;
}
static emscripten::val GetPreview(const piex::PreviewImageData& image) {
const auto undefined = emscripten::val::undefined();
const auto format = static_cast<uint32_t>(image.preview.format);
if (format != piex::Image::Format::kJpegCompressed)
return undefined;
if (!image.preview.offset || !image.preview.length)
return undefined;
auto object = emscripten::val::object();
object.set("colorSpace", GetColorSpace(image));
object.set("orientation", emscripten::val(image.exif_orientation));
object.set("format", emscripten::val(format));
object.set("offset", emscripten::val(image.preview.offset));
object.set("length", emscripten::val(image.preview.length));
object.set("width", emscripten::val(image.preview.width));
object.set("height", emscripten::val(image.preview.height));
return object;
}
static emscripten::val GetThumbnail(const piex::PreviewImageData& image) {
const auto undefined = emscripten::val::undefined();
const auto format = static_cast<uint32_t>(image.thumbnail.format);
if (format > piex::Image::Format::kUncompressedRgb)
return undefined;
if (!image.thumbnail.offset || !image.thumbnail.length)
return undefined;
auto object = emscripten::val::object();
object.set("colorSpace", GetColorSpace(image));
object.set("orientation", emscripten::val(image.exif_orientation));
object.set("format", emscripten::val(format));
object.set("offset", emscripten::val(image.thumbnail.offset));
object.set("length", emscripten::val(image.thumbnail.length));
object.set("width", emscripten::val(image.thumbnail.width));
object.set("height", emscripten::val(image.thumbnail.height));
return object;
}
static emscripten::val GetColorSpace(const piex::PreviewImageData& image) {
const auto space = static_cast<uint32_t>(image.color_space);
if (space == piex::PreviewImageData::kAdobeRgb)
return emscripten::val("adobeRgb");
return emscripten::val("sRgb");
}
static emscripten::val GetNonZeroValue(const uint32_t value) {
return value > 0 ? emscripten::val(value) : emscripten::val::undefined();
}
static float GetRational(const piex::PreviewImageData::Rational& number) {
if (number.denominator != 0)
return float(number.numerator) / number.denominator;
return 0.0f;
}
};
emscripten::val image(int data, size_t size) {
return PiexReader::ReadImage(reinterpret_cast<char*>(data), size);
}
EMSCRIPTEN_BINDINGS(PiexWasmModule) {
emscripten::function("image", &image);
}
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