src/ipa/rkisp1/ipa_context.h


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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2021-2022, Ideas On Board
 *
 * RkISP1 IPA Context
 *
 */

#pragma once

#include <memory>

#include <linux/rkisp1-config.h>

#include <libcamera/base/utils.h>

#include <libcamera/control_ids.h>
#include <libcamera/controls.h>
#include <libcamera/geometry.h>
#include <libcamera/ipa/core_ipa_interface.h>

#include <libipa/camera_sensor_helper.h>
#include <libipa/fc_queue.h>
#include <libipa/matrix.h>

namespace libcamera {

namespace ipa::rkisp1 {

struct IPAHwSettings {
	unsigned int numAeCells;
	unsigned int numHistogramBins;
	unsigned int numHistogramWeights;
	unsigned int numGammaOutSamples;
	bool compand;
};

struct IPASessionConfiguration {
	struct {
		struct rkisp1_cif_isp_window measureWindow;
	} agc;

	struct {
		struct rkisp1_cif_isp_window measureWindow;
		bool enabled;
	} awb;

	struct {
		bool enabled;
	} lsc;

	struct {
		utils::Duration minShutterSpeed;
		utils::Duration maxShutterSpeed;
		double minAnalogueGain;
		double maxAnalogueGain;

		int32_t defVBlank;
		utils::Duration lineDuration;
		Size size;
	} sensor;

	bool raw;
	uint32_t paramFormat;
};

struct IPAActiveState {
	struct {
		struct {
			uint32_t exposure;
			double gain;
		} manual;
		struct {
			uint32_t exposure;
			double gain;
		} automatic;

		bool autoEnabled;
		controls::AeConstraintModeEnum constraintMode;
		controls::AeExposureModeEnum exposureMode;
		controls::AeMeteringModeEnum meteringMode;
		utils::Duration maxFrameDuration;
	} agc;

	struct {
		struct {
			struct {
				double red;
				double green;
				double blue;
			} manual;
			struct {
				double red;
				double green;
				double blue;
			} automatic;
		} gains;

		unsigned int temperatureK;
		bool autoEnabled;
	} awb;

	struct {
		Matrix<float, 3, 3> ccm;
	} ccm;

	struct {
		int8_t brightness;
		uint8_t contrast;
		uint8_t saturation;
	} cproc;

	struct {
		bool denoise;
	} dpf;

	struct {
		uint8_t denoise;
		uint8_t sharpness;
	} filter;

	struct {
		double gamma;
	} goc;
};

struct IPAFrameContext : public FrameContext {
	struct {
		uint32_t exposure;
		double gain;
		bool autoEnabled;
		controls::AeConstraintModeEnum constraintMode;
		controls::AeExposureModeEnum exposureMode;
		controls::AeMeteringModeEnum meteringMode;
		utils::Duration maxFrameDuration;
		bool updateMetering;
	} agc;

	struct {
		struct {
			double red;
			double green;
			double blue;
		} gains;

		bool autoEnabled;
	} awb;

	struct {
		int8_t brightness;
		uint8_t contrast;
		uint8_t saturation;
		bool update;
	} cproc;

	struct {
		bool denoise;
		bool update;
	} dpf;

	struct {
		uint8_t denoise;
		uint8_t sharpness;
		bool update;
	} filter;

	struct {
		double gamma;
		bool update;
	} goc;

	struct {
		uint32_t exposure;
		double gain;
	} sensor;

	struct {
		Matrix<float, 3, 3> ccm;
	} ccm;
};

struct IPAContext {
	const IPAHwSettings *hw;
	IPACameraSensorInfo sensorInfo;
	IPASessionConfiguration configuration;
	IPAActiveState activeState;

	FCQueue<IPAFrameContext> frameContexts;

	ControlInfoMap::Map ctrlMap;

	/* Interface to the Camera Helper */
	std::unique_ptr<CameraSensorHelper> camHelper;
};

} /* namespace ipa::rkisp1 */

} /* namespace libcamera*/
/* SPDX-License-Identifier: Apache-2.0 */
/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "camera_metadata"

/*
 * Replace ALOGE() with a fprintf to stderr so that we don't need to
 * re-implement Android's logging system.  The log/log.h header file is no
 * longer necessary once we removed dependency on ALOGE().
 */
#define ALOGE(...) fprintf(stderr, LOG_TAG __VA_ARGS__)

#include <system/camera_metadata.h>
#include <camera_metadata_hidden.h>

#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <stddef.h>  // for offsetof
#include <stdio.h>
#include <stdlib.h>

#define OK              0
#define ERROR           1
#define NOT_FOUND       (-ENOENT)
#define SN_EVENT_LOG_ID 0x534e4554

#define ALIGN_TO(val, alignment) \
    (((uintptr_t)(val) + ((alignment) - 1)) & ~((alignment) - 1))

/**
 * A single metadata entry, storing an array of values of a given type. If the
 * array is no larger than 4 bytes in size, it is stored in the data.value[]
 * array; otherwise, it can found in the parent's data array at index
 * data.offset.
 */
#define ENTRY_ALIGNMENT ((size_t) 4)
typedef struct camera_metadata_buffer_entry {
    uint32_t tag;
    uint32_t count;
    union {
        uint32_t offset;
        uint8_t  value[4];
    } data;
    uint8_t  type;
    uint8_t  reserved[3];
} camera_metadata_buffer_entry_t;

typedef uint32_t metadata_uptrdiff_t;
typedef uint32_t metadata_size_t;

/**
 * A packet of metadata. This is a list of entries, each of which may point to
 * its values stored at an offset in data.
 *
 * It is assumed by the utility functions that the memory layout of the packet
 * is as follows:
 *
 *   |-----------------------------------------------|
 *   | camera_metadata_t                             |
 *   |                                               |
 *   |-----------------------------------------------|
 *   | reserved for future expansion                 |
 *   |-----------------------------------------------|
 *   | camera_metadata_buffer_entry_t #0             |
 *   |-----------------------------------------------|
 *   | ....                                          |
 *   |-----------------------------------------------|
 *   | camera_metadata_buffer_entry_t #entry_count-1 |
 *   |-----------------------------------------------|
 *   | free space for                                |
 *   | (entry_capacity-entry_count) entries          |
 *   |-----------------------------------------------|
 *   | start of camera_metadata.data                 |
 *   |                                               |
 *   |-----------------------------------------------|
 *   | free space for                                |
 *   | (data_capacity-data_count) bytes              |
 *   |-----------------------------------------------|
 *
 * With the total length of the whole packet being camera_metadata.size bytes.
 *
 * In short, the entries and data are contiguous in memory after the metadata
 * header.
 */
#define METADATA_ALIGNMENT ((size_t) 4)
struct camera_metadata {
    metadata_size_t          size;
    uint32_t                 version;
    uint32_t                 flags;
    metadata_size_t          entry_count;
    metadata_size_t          entry_capacity;
    metadata_uptrdiff_t      entries_start; // Offset from camera_metadata
    metadata_size_t          data_count;
    metadata_size_t          data_capacity;
    metadata_uptrdiff_t      data_start; // Offset from camera_metadata
    uint32_t                 padding;    // padding to 8 bytes boundary
    metadata_vendor_id_t     vendor_id;
};

/**
 * A datum of metadata. This corresponds to camera_metadata_entry_t::data
 * with the difference that each element is not a pointer. We need to have a
 * non-pointer type description in order to figure out the largest alignment
 * requirement for data (DATA_ALIGNMENT).
 */
#define DATA_ALIGNMENT ((size_t) 8)
typedef union camera_metadata_data {
    uint8_t u8;
    int32_t i32;
    float   f;
    int64_t i64;
    double  d;
    camera_metadata_rational_t r;
} camera_metadata_data_t;

_Static_assert(sizeof(metadata_size_t) == 4,
         "Size of metadata_size_t must be 4");
_Static_assert(sizeof(metadata_uptrdiff_t) == 4,
         "Size of metadata_uptrdiff_t must be 4");
_Static_assert(sizeof(metadata_vendor_id_t) == 8,
         "Size of metadata_vendor_id_t must be 8");
_Static_assert(sizeof(camera_metadata_data_t) == 8,
         "Size of camera_metadata_data_t must be 8");

_Static_assert(offsetof(camera_metadata_buffer_entry_t, tag) == 0,
         "Offset of tag must be 0");
_Static_assert(offsetof(camera_metadata_buffer_entry_t, count) == 4,
         "Offset of count must be 4");
_Static_assert(offsetof(camera_metadata_buffer_entry_t, data) == 8,
         "Offset of data must be 8");
_Static_assert(offsetof(camera_metadata_buffer_entry_t, type) == 12,
         "Offset of type must be 12");
_Static_assert(sizeof(camera_metadata_buffer_entry_t) == 16,
         "Size of camera_metadata_buffer_entry_t must be 16");

_Static_assert(offsetof(camera_metadata_t, size) == 0,
         "Offset of size must be 0");
_Static_assert(offsetof(camera_metadata_t, version) == 4,
         "Offset of version must be 4");
_Static_assert(offsetof(camera_metadata_t, flags) == 8,
         "Offset of flags must be 8");
_Static_assert(offsetof(camera_metadata_t, entry_count) == 12,
         "Offset of entry_count must be 12");
_Static_assert(offsetof(camera_metadata_t, entry_capacity) == 16,
         "Offset of entry_capacity must be 16");
_Static_assert(offsetof(camera_metadata_t, entries_start) == 20,
         "Offset of entries_start must be 20");
_Static_assert(offsetof(camera_metadata_t, data_count) == 24,
         "Offset of data_count must be 24");
_Static_assert(offsetof(camera_metadata_t, data_capacity) == 28,
         "Offset of data_capacity must be 28");
_Static_assert(offsetof(camera_metadata_t, data_start) == 32,
         "Offset of data_start must be 32");
_Static_assert(offsetof(camera_metadata_t, vendor_id) == 40,
         "Offset of vendor_id must be 40");
_Static_assert(sizeof(camera_metadata_t) == 48,
         "Size of camera_metadata_t must be 48");

/**
 * The preferred alignment of a packet of camera metadata. In general,
 * this is the lowest common multiple of the constituents of a metadata
 * package, i.e, of DATA_ALIGNMENT and ENTRY_ALIGNMENT.
 */
#define MAX_ALIGNMENT(A, B) (((A) > (B)) ? (A) : (B))
#define METADATA_PACKET_ALIGNMENT \
    MAX_ALIGNMENT(MAX_ALIGNMENT(DATA_ALIGNMENT, METADATA_ALIGNMENT), ENTRY_ALIGNMENT)

/** Versioning information */
#define CURRENT_METADATA_VERSION 1

/** Flag definitions */
#define FLAG_SORTED 0x00000001

/** Tag information */

typedef struct tag_info {
    const char *tag_name;
    uint8_t     tag_type;
} tag_info_t;

#include "camera_metadata_tag_info.c"

const size_t camera_metadata_type_size[NUM_TYPES] = {
    [TYPE_BYTE]     = sizeof(uint8_t),
    [TYPE_INT32]    = sizeof(int32_t),
    [TYPE_FLOAT]    = sizeof(float),
    [TYPE_INT64]    = sizeof(int64_t),
    [TYPE_DOUBLE]   = sizeof(double),
    [TYPE_RATIONAL] = sizeof(camera_metadata_rational_t)
};

const char *camera_metadata_type_names[NUM_TYPES] = {
    [TYPE_BYTE]     = "byte",
    [TYPE_INT32]    = "int32",
    [TYPE_FLOAT]    = "float",
    [TYPE_INT64]    = "int64",
    [TYPE_DOUBLE]   = "double",
    [TYPE_RATIONAL] = "rational"
};

static camera_metadata_buffer_entry_t *get_entries(
        const camera_metadata_t *metadata) {
    return (camera_metadata_buffer_entry_t*)
            ((uint8_t*)metadata + metadata->entries_start);
}

static uint8_t *get_data(const camera_metadata_t *metadata) {
    return (uint8_t*)metadata + metadata->data_start;
}

size_t get_camera_metadata_alignment() {
    return METADATA_PACKET_ALIGNMENT;
}

camera_metadata_t *allocate_copy_camera_metadata_checked(
        const camera_metadata_t *src,
        size_t src_size) {

    if (src == NULL) {
        return NULL;
    }

    if (src_size < sizeof(camera_metadata_t)) {
        ALOGE("%s: Source size too small!", __FUNCTION__);
        // android_errorWriteLog(0x534e4554, "67782345");
        return NULL;
    }

    void *buffer = malloc(src_size);
    memcpy(buffer, src, src_size);

    camera_metadata_t *metadata = (camera_metadata_t*) buffer;
    if (validate_camera_metadata_structure(metadata, &src_size) != OK) {
        free(buffer);
        return NULL;
    }

    return metadata;
}

camera_metadata_t *allocate_camera_metadata(size_t entry_capacity,
                                            size_t data_capacity) {

    size_t memory_needed = calculate_camera_metadata_size(entry_capacity,
                                                          data_capacity);
    void *buffer = malloc(memory_needed);
    camera_metadata_t *metadata = place_camera_metadata(
        buffer, memory_needed, entry_capacity, data_capacity);
    if (!metadata) {
        /* This should not happen when memory_needed is the same
         * calculated in this function and in place_camera_metadata.
         */
        free(buffer);
    }
    return metadata;
}

camera_metadata_t *place_camera_metadata(void *dst,
                                         size_t dst_size,
                                         size_t entry_capacity,
                                         size_t data_capacity) {
    if (dst == NULL) return NULL;

    size_t memory_needed = calculate_camera_metadata_size(entry_capacity,
                                                          data_capacity);
    if (memory_needed > dst_size) return NULL;

    camera_metadata_t *metadata = (camera_metadata_t*)dst;
    metadata->version = CURRENT_METADATA_VERSION;
    metadata->flags = 0;
    metadata->entry_count = 0;
    metadata->entry_capacity = entry_capacity;
    metadata->entries_start =
            ALIGN_TO(sizeof(camera_metadata_t), ENTRY_ALIGNMENT);
    metadata->data_count = 0;
    metadata->data_capacity = data_capacity;
    metadata->size = memory_needed;
    size_t data_unaligned = (uint8_t*)(get_entries(metadata) +
            metadata->entry_capacity) - (uint8_t*)metadata;
    metadata->data_start = ALIGN_TO(data_unaligned, DATA_ALIGNMENT);
    metadata->vendor_id = CAMERA_METADATA_INVALID_VENDOR_ID;

    assert(validate_camera_metadata_structure(metadata, NULL) == OK);
    return metadata;
}
void free_camera_metadata(camera_metadata_t *metadata) {
    free(metadata);
}

size_t calculate_camera_metadata_size(size_t entry_count,
                                      size_t data_count) {
    size_t memory_needed = sizeof(camera_metadata_t);
    // Start entry list at aligned boundary
    memory_needed = ALIGN_TO(memory_needed, ENTRY_ALIGNMENT);
    memory_needed += sizeof(camera_metadata_buffer_entry_t[entry_count]);
    // Start buffer list at aligned boundary
    memory_needed = ALIGN_TO(memory_needed, DATA_ALIGNMENT);
    memory_needed += sizeof(uint8_t[data_count]);
    // Make sure camera metadata can be stacked in continuous memory
    memory_needed = ALIGN_TO(memory_needed, METADATA_PACKET_ALIGNMENT);
    return memory_needed;
}

size_t get_camera_metadata_size(const camera_metadata_t *metadata) {
    if (metadata == NULL) return ERROR;

    return metadata->size;
}

size_t get_camera_metadata_compact_size(const camera_metadata_t *metadata) {
    if (metadata == NULL) return ERROR;

    return calculate_camera_metadata_size(metadata->entry_count,
                                          metadata->data_count);
}

size_t get_camera_metadata_entry_count(const camera_metadata_t *metadata) {
    return metadata->entry_count;
}

size_t get_camera_metadata_entry_capacity(const camera_metadata_t *metadata) {
    return metadata->entry_capacity;
}

size_t get_camera_metadata_data_count(const camera_metadata_t *metadata) {
    return metadata->data_count;
}

size_t get_camera_metadata_data_capacity(const camera_metadata_t *metadata) {
    return metadata->data_capacity;
}

camera_metadata_t* copy_camera_metadata(void *dst, size_t dst_size,
        const camera_metadata_t *src) {
    size_t memory_needed = get_camera_metadata_compact_size(src);

    if (dst == NULL) return NULL;
    if (dst_size < memory_needed) return NULL;

    camera_metadata_t *metadata =
        place_camera_metadata(dst, dst_size, src->entry_count, src->data_count);

    metadata->flags = src->flags;
    metadata->entry_count = src->entry_count;
    metadata->data_count = src->data_count;
    metadata->vendor_id = src->vendor_id;

    memcpy(get_entries(metadata), get_entries(src),
            sizeof(camera_metadata_buffer_entry_t[metadata->entry_count]));
    memcpy(get_data(metadata), get_data(src),
            sizeof(uint8_t[metadata->data_count]));

    assert(validate_camera_metadata_structure(metadata, NULL) == OK);
    return metadata;
}

// This method should be used when the camera metadata cannot be trusted. For example, when it's
// read from Parcel.
static int validate_and_calculate_camera_metadata_entry_data_size(size_t *data_size, uint8_t type,
        size_t data_count) {
    if (type >= NUM_TYPES) return ERROR;

    // Check for overflow
    if (data_count != 0 &&
            camera_metadata_type_size[type] > (SIZE_MAX - DATA_ALIGNMENT + 1) / data_count) {
        // android_errorWriteLog(SN_EVENT_LOG_ID, "30741779");
        return ERROR;
    }

    size_t data_bytes = data_count * camera_metadata_type_size[type];

    if (data_size) {
        *data_size = data_bytes <= 4 ? 0 : ALIGN_TO(data_bytes, DATA_ALIGNMENT);
    }

    return OK;
}

size_t calculate_camera_metadata_entry_data_size(uint8_t type,
        size_t data_count) {
    if (type >= NUM_TYPES) return 0;

    size_t data_bytes = data_count *
            camera_metadata_type_size[type];

    return data_bytes <= 4 ? 0 : ALIGN_TO(data_bytes, DATA_ALIGNMENT);
}

int validate_camera_metadata_structure(const camera_metadata_t *metadata,
                                       const size_t *expected_size) {

    if (metadata == NULL) {
        ALOGE("%s: metadata is null!", __FUNCTION__);
        return CAMERA_METADATA_VALIDATION_ERROR;
    }

    uintptr_t aligned_ptr = ALIGN_TO(metadata, METADATA_PACKET_ALIGNMENT);
    const uintptr_t alignmentOffset = aligned_ptr - (uintptr_t) metadata;

    // Check that the metadata pointer is well-aligned first.
    {
        static const struct {
            const char *name;
            size_t alignment;
        } alignments[] = {
            {
                .name = "camera_metadata",
                .alignment = METADATA_ALIGNMENT
            },
            {
                .name = "camera_metadata_buffer_entry",
                .alignment = ENTRY_ALIGNMENT
            },
            {
                .name = "camera_metadata_data",
                .alignment = DATA_ALIGNMENT
            },
        };

        for (size_t i = 0; i < sizeof(alignments)/sizeof(alignments[0]); ++i) {
            uintptr_t aligned_ptr = ALIGN_TO((uintptr_t) metadata + alignmentOffset,
                    alignments[i].alignment);

            if ((uintptr_t)metadata + alignmentOffset != aligned_ptr) {
                ALOGE("%s: Metadata pointer is not aligned (actual %p, "
                      "expected %p, offset %" PRIuPTR ") to type %s",
                      __FUNCTION__, metadata,
                      (void*)aligned_ptr, alignmentOffset, alignments[i].name);
                return CAMERA_METADATA_VALIDATION_ERROR;
            }
        }
    }

    /**
     * Check that the metadata contents are correct
     */

    if (expected_size != NULL && metadata->size > *expected_size) {
        ALOGE("%s: Metadata size (%" PRIu32 ") should be <= expected size (%zu)",
              __FUNCTION__, metadata->size, *expected_size);
        return CAMERA_METADATA_VALIDATION_ERROR;
    }

    if (metadata->entry_count > metadata->entry_capacity) {
        ALOGE("%s: Entry count (%" PRIu32 ") should be <= entry capacity "
              "(%" PRIu32 ")",
              __FUNCTION__, metadata->entry_count, metadata->entry_capacity);
        return CAMERA_METADATA_VALIDATION_ERROR;
    }

    if (metadata->data_count > metadata->data_capacity) {
        ALOGE("%s: Data count (%" PRIu32 ") should be <= data capacity "
              "(%" PRIu32 ")",
              __FUNCTION__, metadata->data_count, metadata->data_capacity);
        // android_errorWriteLog(SN_EVENT_LOG_ID, "30591838");
        return CAMERA_METADATA_VALIDATION_ERROR;
    }

    const metadata_uptrdiff_t entries_end =
        metadata->entries_start + metadata->entry_capacity;
    if (entries_end < metadata->entries_start || // overflow check
        entries_end > metadata->data_start) {

        ALOGE("%s: Entry start + capacity (%" PRIu32 ") should be <= data start "
              "(%" PRIu32 ")",
               __FUNCTION__,
              (metadata->entries_start + metadata->entry_capacity),
              metadata->data_start);
        return CAMERA_METADATA_VALIDATION_ERROR;
    }

    const metadata_uptrdiff_t data_end =
        metadata->data_start + metadata->data_capacity;
    if (data_end < metadata->data_start || // overflow check
        data_end > metadata->size) {

        ALOGE("%s: Data start + capacity (%" PRIu32 ") should be <= total size "
              "(%" PRIu32 ")",
               __FUNCTION__,
              (metadata->data_start + metadata->data_capacity),
              metadata->size);
        return CAMERA_METADATA_VALIDATION_ERROR;
    }

    // Validate each entry
    const metadata_size_t entry_count = metadata->entry_count;
    camera_metadata_buffer_entry_t *entries = get_entries(metadata);

    for (size_t i = 0; i < entry_count; ++i) {

        if ((uintptr_t)&entries[i] + alignmentOffset !=
                ALIGN_TO((uintptr_t)&entries[i] + alignmentOffset, ENTRY_ALIGNMENT)) {
            ALOGE("%s: Entry index %zu had bad alignment (address %p),"
                  " expected alignment %zu",
                  __FUNCTION__, i, &entries[i], ENTRY_ALIGNMENT);
            return CAMERA_METADATA_VALIDATION_ERROR;
        }

        camera_metadata_buffer_entry_t entry = entries[i];

        if (entry.type >= NUM_TYPES) {
            ALOGE("%s: Entry index %zu had a bad type %d",
                  __FUNCTION__, i, entry.type);
            return CAMERA_METADATA_VALIDATION_ERROR;
        }

        // TODO: fix vendor_tag_ops across processes so we don't need to special
        //       case vendor-specific tags
        uint32_t tag_section = entry.tag >> 16;
        int tag_type = get_local_camera_metadata_tag_type(entry.tag, metadata);
        if (tag_type != (int)entry.type && tag_section < VENDOR_SECTION) {
            ALOGE("%s: Entry index %zu had tag type %d, but the type was %d",
                  __FUNCTION__, i, tag_type, entry.type);
            return CAMERA_METADATA_VALIDATION_ERROR;
        }

        size_t data_size;
        if (validate_and_calculate_camera_metadata_entry_data_size(&data_size, entry.type,
                entry.count) != OK) {
            ALOGE("%s: Entry data size is invalid. type: %u count: %u", __FUNCTION__, entry.type,
                    entry.count);
            return CAMERA_METADATA_VALIDATION_ERROR;
        }

        if (data_size != 0) {
            camera_metadata_data_t *data =
                    (camera_metadata_data_t*) (get_data(metadata) +
                                               entry.data.offset);

            if ((uintptr_t)data + alignmentOffset !=
                        ALIGN_TO((uintptr_t)data + alignmentOffset, DATA_ALIGNMENT)) {
                ALOGE("%s: Entry index %zu had bad data alignment (address %p),"
                      " expected align %zu, (tag name %s, data size %zu)",
                      __FUNCTION__, i, data, DATA_ALIGNMENT,
                      get_local_camera_metadata_tag_name(entry.tag, metadata) ?
                              : "unknown", data_size);
                return CAMERA_METADATA_VALIDATION_ERROR;
            }

            size_t data_entry_end = entry.data.offset + data_size;
            if (data_entry_end < entry.data.offset || // overflow check
                data_entry_end > metadata->data_capacity) {

                ALOGE("%s: Entry index %zu data ends (%zu) beyond the capacity "
                      "%" PRIu32, __FUNCTION__, i, data_entry_end,
                      metadata->data_capacity);
                return CAMERA_METADATA_VALIDATION_ERROR;
            }

        } else if (entry.count == 0) {
            if (entry.data.offset != 0) {
                ALOGE("%s: Entry index %zu had 0 items, but offset was non-0 "
                     "(%" PRIu32 "), tag name: %s", __FUNCTION__, i, entry.data.offset,
                        get_local_camera_metadata_tag_name(entry.tag, metadata) ? : "unknown");
                return CAMERA_METADATA_VALIDATION_ERROR;
            }
        } // else data stored inline, so we look at value which can be anything.
    }

    if (alignmentOffset == 0) {
        return OK;
    }
    return CAMERA_METADATA_VALIDATION_SHIFTED;
}

int append_camera_metadata(camera_metadata_t *dst,
        const camera_metadata_t *src) {
    if (dst == NULL || src == NULL ) return ERROR;