/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2020, Google Inc.
 *
 * encoder_libjpeg.cpp - JPEG encoding using libjpeg native API
 */

#include "encoder_libjpeg.h"

#include <fcntl.h>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
#include <vector>

#include <libcamera/camera.h>
#include <libcamera/formats.h>
#include <libcamera/pixel_format.h>

#include "libcamera/internal/formats.h"
#include "libcamera/internal/log.h"

using namespace libcamera;

LOG_DECLARE_CATEGORY(JPEG)

namespace {

struct JPEGPixelFormatInfo {
	J_COLOR_SPACE colorSpace;
	const PixelFormatInfo &pixelFormatInfo;
	bool nvSwap;
};

const std::map<PixelFormat, JPEGPixelFormatInfo> pixelInfo{
	{ formats::R8, { JCS_GRAYSCALE, PixelFormatInfo::info(formats::R8), false } },

	{ formats::RGB888, { JCS_EXT_BGR, PixelFormatInfo::info(formats::RGB888), false } },
	{ formats::BGR888, { JCS_EXT_RGB, PixelFormatInfo::info(formats::BGR888), false } },

	{ formats::NV12, { JCS_YCbCr, PixelFormatInfo::info(formats::NV12), false } },
	{ formats::NV21, { JCS_YCbCr, PixelFormatInfo::info(formats::NV21), true } },
	{ formats::NV16, { JCS_YCbCr, PixelFormatInfo::info(formats::NV16), false } },
	{ formats::NV61, { JCS_YCbCr, PixelFormatInfo::info(formats::NV61), true } },
	{ formats::NV24, { JCS_YCbCr, PixelFormatInfo::info(formats::NV24), false } },
	{ formats::NV42, { JCS_YCbCr, PixelFormatInfo::info(formats::NV42), true } },
};

const struct JPEGPixelFormatInfo &findPixelInfo(const PixelFormat &format)
{
	static const struct JPEGPixelFormatInfo invalidPixelFormat {
		JCS_UNKNOWN, PixelFormatInfo(), false
	};

	const auto iter = pixelInfo.find(format);
	if (iter == pixelInfo.end()) {
		LOG(JPEG, Error) << "Unsupported pixel format for JPEG encoder: "
				 << format.toString();
		return invalidPixelFormat;
	}

	return iter->second;
}

} /* namespace */

EncoderLibJpeg::EncoderLibJpeg()
{
	/* \todo Expand error handling coverage with a custom handler. */
	compress_.err = jpeg_std_error(&jerr_);

	jpeg_create_compress(&compress_);
}

EncoderLibJpeg::~EncoderLibJpeg()
{
	jpeg_destroy_compress(&compress_);
}

int EncoderLibJpeg::configure(const StreamConfiguration &cfg)
{
	const struct JPEGPixelFormatInfo info = findPixelInfo(cfg.pixelFormat);
	if (info.colorSpace == JCS_UNKNOWN)
		return -ENOTSUP;

	compress_.image_width = cfg.size.width;
	compress_.image_height = cfg.size.height;
	compress_.in_color_space = info.colorSpace;

	compress_.input_components = info.colorSpace == JCS_GRAYSCALE ? 1 : 3;

	jpeg_set_defaults(&compress_);

	pixelFormatInfo_ = &info.pixelFormatInfo;

	nv_ = pixelFormatInfo_->numPlanes() == 2;
	nvSwap_ = info.nvSwap;

	return 0;
}

void EncoderLibJpeg::compressRGB(Span<const uint8_t> frame)
{
	unsigned char *src = const_cast<unsigned char *>(frame.data());
	/* \todo Stride information should come from buffer configuration. */
	unsigned int stride = pixelFormatInfo_->stride(compress_.image_width, 0);

	JSAMPROW row_pointer[1];

	while (compress_.next_scanline < compress_.image_height) {
		row_pointer[0] = &src[compress_.next_scanline * stride];
		jpeg_write_scanlines(&compress_, row_pointer, 1);
	}
}

/*
 * Compress the incoming buffer from a supported NV format.
 * This naively unpacks the semi-planar NV12 to a YUV888 format for libjpeg.
 */
void EncoderLibJpeg::compressNV(Span<const uint8_t> frame)
{
	uint8_t tmprowbuf[compress_.image_width * 3];

	/*
	 * \todo Use the raw api, and only unpack the cb/cr samples to new line
	 * buffers. If possible, see if we can set appropriate pixel strides
	 * too to save even that copy.
	 *
	 * Possible hints at:
	 * https://sourceforge.net/p/libjpeg/mailman/message/30815123/
	 */
	unsigned int y_stride = pixelFormatInfo_->stride(compress_.image_width, 0);
	unsigned int c_stride = pixelFormatInfo_->stride(compress_.image_width, 1);

	unsigned int horzSubSample = 2 * compress_.image_width / c_stride;
	unsigned int vertSubSample = pixelFormatInfo_->planes[1].verticalSubSampling;

	unsigned int c_inc = horzSubSample == 1 ? 2 : 0;
	unsigned int cb_pos = nvSwap_ ? 1 : 0;
	unsigned int cr_pos = nvSwap_ ? 0 : 1;

	const unsigned char *src = frame.data();
	const unsigned char *src_c = src + y_stride * compress_.image_h<span class="hl com">/* SPDX-License-Identifier: BSD-2-Clause */</span>
<span class="hl com">/*</span>
<span class="hl com"> * Copyright (C) 2019, Raspberry Pi (Trading) Limited</span>
<span class="hl com"> *</span>
<span class="hl com"> * ccm_status.h - CCM (colour correction matrix) control algorithm status</span>
<span class="hl com"> */</span>
<span class="hl ppc">#pragma once</span>

<span class="hl slc">// The &quot;ccm&quot; algorithm generates an appropriate colour matrix.</span>

<span class="hl ppc">#ifdef __cplusplus</span>
<span class="hl kwc">extern</span> <span class="hl str">&quot;C&quot;</span> <span class="hl opt">{</span>
<span class="hl ppc">#endif</span>

<span class="hl kwb">struct</span> CcmStatus <span class="hl opt">{</span>
	<span class="hl kwb">double</span> matrix<span class="hl opt">[</span><span class="hl num">9</span><span class="hl opt">];</span>
	<span class="hl kwb">double</span> saturation<span class="hl opt">;</span>
<span class="hl opt">};</span>

<span class="hl ppc">#ifdef __cplusplus</span>
<span class="hl opt">}</span>
<span class="hl ppc">#endif</span>
</code></pre></td></tr></table>
</div> <!-- class=content -->
<div class='footer'>generated by <a href='https://git.zx2c4.com/cgit/about/'>cgit v1.2.1</a> (<a href='https://git-scm.com/'>git 2.18.0</a>) at 2025-05-11 19:02:03 +0000</div>
</div> <!-- id=cgit -->
</body>
</html>
, quality, TRUE);

	/*
	 * The jpeg_mem_dest will reallocate if the required size is not
	 * sufficient. That means the output won't be written to the correct
	 * buffers.
	 *
	 * \todo Implement our own custom memory destination to prevent
	 * reallocation and prefer failure with correct reporting.
	 */
	jpeg_mem_dest(&compress_, &destination, &size);

	jpeg_start_compress(&compress_, TRUE);

	if (exifData.size())
		/* Store Exif data in the JPEG_APP1 data block. */
		jpeg_write_marker(&compress_, JPEG_APP0 + 1,
				  static_cast<const JOCTET *>(exifData.data()),
				  exifData.size());

	LOG(JPEG, Debug) << "JPEG Encode Starting:" << compress_.image_width
			 << "x" << compress_.image_height;

	if (nv_)
		compressNV(src);
	else
		compressRGB(src);

	jpeg_finish_compress(&compress_);

	return size;
}