/**
 * @file lv_sjpg.c
 *
 */

/*----------------------------------------------------------------------------------------------------------------------------------
/    Added normal JPG support [7/10/2020]
/    ----------
/    SJPEG is a custom created modified JPEG file format for small embedded platforms.
/    It will contain multiple JPEG fragments all embedded into a single file with a custom header.
/    This makes JPEG decoding easier using any JPEG library. Overall file size will be almost
/    similar to the parent jpeg file. We can generate sjpeg from any jpeg using a python script
/    provided along with this project.
/                                                                                     (by vinodstanur | 2020 )
/    SJPEG FILE STRUCTURE
/    --------------------------------------------------------------------------------------------------------------------------------
/    Bytes                       |   Value                                                                                           |
/    --------------------------------------------------------------------------------------------------------------------------------
/
/    0 - 7                       |   "_SJPG__" followed by '\0'
/
/    8 - 13                      |   "V1.00" followed by '\0'       [VERSION OF SJPG FILE for future compatibiliby]
/
/    14 - 15                     |   X_RESOLUTION (width)            [little endian]
/
/    16 - 17                     |   Y_RESOLUTION (height)           [little endian]
/
/    18 - 19                     |   TOTAL_FRAMES inside sjpeg       [little endian]
/
/    20 - 21                     |   JPEG BLOCK WIDTH (16 normally)  [little endian]
/
/    22 - [(TOTAL_FRAMES*2 )]    |   SIZE OF EACH JPEG SPLIT FRAGMENTS   (FRAME_INFO_ARRAY)
/
/   SJPEG data                   |   Each JPEG frame can be extracted from SJPEG data by parsing the FRAME_INFO_ARRAY one time.
/
/----------------------------------------------------------------------------------------------------------------------------------
/                   JPEG DECODER
/                   ------------
/   We are using TJpgDec - Tiny JPEG Decompressor library from ELM-CHAN for decoding each split-jpeg fragments.
/   The tjpgd.c and tjpgd.h is not modified and those are used as it is. So if any update comes for the tiny-jpeg,
/   just replace those files with updated files.
/---------------------------------------------------------------------------------------------------------------------------------*/

/*********************
 *      INCLUDES
 *********************/

#include "../../../lvgl.h"
#if LV_USE_SJPG

#include "tjpgd.h"
#include "lv_sjpg.h"
#include "../../../misc/lv_fs.h"

/*********************
 *      DEFINES
 *********************/
#define TJPGD_WORKBUFF_SIZE             4096    //Recommended by TJPGD libray

//NEVER EDIT THESE OFFSET VALUES
#define SJPEG_VERSION_OFFSET            8
#define SJPEG_X_RES_OFFSET              14
#define SJPEG_y_RES_OFFSET              16
#define SJPEG_TOTAL_FRAMES_OFFSET       18
#define SJPEG_BLOCK_WIDTH_OFFSET        20
#define SJPEG_FRAME_INFO_ARRAY_OFFSET   22

/**********************
 *      TYPEDEFS
 **********************/

enum io_source_type {
    SJPEG_IO_SOURCE_C_ARRAY,
    SJPEG_IO_SOURCE_DISK,
};

typedef struct {
    enum io_source_type type;
    lv_fs_file_t lv_file;
    uint8_t * img_cache_buff;
    int img_cache_x_res;
    int img_cache_y_res;
    uint8_t * raw_sjpg_data;              //Used when type==SJPEG_IO_SOURCE_C_ARRAY.
    uint32_t raw_sjpg_data_size;          //Num bytes pointed to by raw_sjpg_data.
    uint32_t raw_sjpg_data_next_read_pos; //Used for all types.
} io_source_t;

typedef struct {
    uint8_t * sjpeg_data;
    uint32_t sjpeg_data_size;
    int sjpeg_x_res;
    int sjpeg_y_res;
    int sjpeg_total_frames;
    int sjpeg_single_frame_height;
    int sjpeg_cache_frame_index;
    uint8_t ** frame_base_array;        //to save base address of each split frames upto sjpeg_total_frames.
    int * frame_base_offset;            //to save base offset for fseek
    uint8_t * frame_cache;
    uint8_t * workb;                    //JPG work buffer for jpeg library
    JDEC * tjpeg_jd;
    io_source_t io;
} SJPEG;

/**********************
 *  STATIC PROTOTYPES
 **********************/
static lv_res_t decoder_info(lv_img_decoder_t * decoder, const void * src, lv_img_header_t * header);
static lv_res_t decoder_open(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc);
static lv_res_t decoder_read_line(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc, lv_coord_t x, lv_coord_t y,
                                  lv_coord_t len, uint8_t * buf);
static void decoder_close(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc);
static size_t input_func(JDEC * jd, uint8_t * buff, size_t ndata);
static int is_jpg(const uint8_t * raw_data, size_t len);
static void lv_sjpg_cleanup(SJPEG * sjpeg);
static void lv_sjpg_free(SJPEG * sjpeg);

/**********************
 *  STATIC VARIABLES
 **********************/

/**********************
 *      MACROS
 **********************/

/**********************
 *   GLOBAL FUNCTIONS
 **********************/
void lv_split_jpeg_init(void)
{
    lv_img_decoder_t * dec = lv_img_decoder_create();
    lv_img_decoder_set_info_cb(dec, decoder_info);
    lv_img_decoder_set_open_cb(dec, decoder_open);
    lv_img_decoder_set_close_cb(dec, decoder_close);
    lv_img_decoder_set_read_line_cb(dec, decoder_read_line);
}

/**********************
 *   STATIC FUNCTIONS
 **********************/
/**
 * Get info about an SJPG / JPG image
 * @param decoder pointer to the decoder where this function belongs
 * @param src can be file name or pointer to a C array
 * @param header store the info here
 * @return LV_RES_OK: no error; LV_RES_INV: can't get the info
 */
static lv_res_t decoder_info(lv_img_decoder_t * decoder, const void * src, lv_img_header_t * header)
{
    LV_UNUSED(decoder);

    /*Check whether the type `src` is known by the decoder*/
    /* Read the SJPG/JPG header and find `width` and `height` */

    lv_img_src_t src_type = lv_img_src_get_type(src);          /*Get the source type*/

    lv_res_t ret = LV_RES_OK;

    if(src_type == LV_IMG_SRC_VARIABLE) {
        const lv_img_dsc_t * img_dsc = src;
        uint8_t * raw_sjpeg_data = (uint8_t *)img_dsc->data;
        const uint32_t raw_sjpeg_data_size = img_dsc->data_size;

        if(!strncmp((char *)raw_sjpeg_data, "_SJPG__", strlen("_SJPG__"))) {

            raw_sjpeg_data += 14; //seek to res info ... refer sjpeg format
            header->always_zero = 0;
            header->cf = LV_IMG_CF_RAW;

            header->w = *raw_sjpeg_data++;
            header->w |= *raw_sjpeg_data++ << 8;

            header->h = *raw_sjpeg_data++;
            header->h |= *raw_sjpeg_data++ << 8;

            return ret;

        }
        else if(is_jpg(raw_sjpeg_data, raw_sjpeg_data_size) == true) {
            header->always_zero = 0;
            header->cf = LV_IMG_CF_RAW;

            uint8_t * workb_temp = lv_mem_alloc(TJPGD_WORKBUFF_SIZE);
            if(!workb_temp) return LV_RES_INV;

            io_source_t io_source_temp;
            io_source_temp.type = SJPEG_IO_SOURCE_C_ARRAY;
            io_source_temp.raw_sjpg_data = raw_sjpeg_data;
            io_source_temp.raw_sjpg_data_size = raw_sjpeg_data_size;
            io_source_temp.raw_sjpg_data_next_read_pos = 0;

            JDEC jd_tmp;

            JRESULT rc = jd_prepare(&jd_tmp, input_func, workb_temp, (size_t)TJPGD_WORKBUFF_SIZE, &io_source_temp);
            if(rc == JDR_OK) {
                header->w = jd_tmp.width;
                header->h = jd_tmp.height;

            }
            else {
                ret = LV_RES_INV;
                goto end;
            }

end:
            lv_mem_free(workb_temp);

            return ret;

        }
    }
    else if(src_type == LV_IMG_SRC_FILE) {
        const char * fn = src;
        if(strcmp(lv_fs_get_ext(fn), "sjpg") == 0) {

            uint8_t buff[22];
            memset(buff, 0, sizeof(buff));

            lv_fs_file_t file;
            lv_fs_res_t res = lv_fs_open(&file, fn, LV_FS_MODE_RD);
            if(res != LV_FS_RES_OK) return 78;

            uint32_t rn;
            res = lv_fs_read(&file, buff, 8, &rn);
            if(res != LV_FS_RES_OK || rn != 8) {
                lv_fs_close(&file);
                return LV_RES_INV;
            }

            if(strcmp((char *)buff, "_SJPG__") == 0) {
                lv_fs_seek(&file, 14, LV_FS_SEEK_SET);
                res = lv_fs_read(&file, buff, 4, &rn);
                if(res != LV_FS_RES_OK || rn != 4) {
                    lv_fs_close(&file);
                    return LV_RES_INV;
                }
                header->always_zero = 0;
                header->cf = LV_IMG_CF_RAW;
                uint8_t * raw_sjpeg_data = buff;
                header->w = *raw_sjpeg_data++;
                header->w |= *raw_sjpeg_data++ << 8;
                header->h = *raw_sjpeg_data++;
                header->h |= *raw_sjpeg_data++ << 8;
                lv_fs_close(&file);
                return LV_RES_OK;

            }
        }
        else if(strcmp(lv_fs_get_ext(fn), "jpg") == 0) {
            lv_fs_file_t file;
            lv_fs_res_t res = lv_fs_open(&file, fn, LV_FS_MODE_RD);
            if(res != LV_FS_RES_OK) return 78;

            uint8_t * workb_temp = lv_mem_alloc(TJPGD_WORKBUFF_SIZE);
            if(!workb_temp) {
                lv_fs_close(&file);
                return LV_RES_INV;
            }

            io_source_t io_source_temp;
            io_source_temp.type = SJPEG_IO_SOURCE_DISK;
            io_source_temp.raw_sjpg_data_next_read_pos = 0;
            io_source_temp.img_cache_buff = NULL;
            io_source_temp.lv_file = file;
            JDEC jd_tmp;

            JRESULT rc = jd_prepare(&jd_tmp, input_func, workb_temp, (size_t)TJPGD_WORKBUFF_SIZE, &io_source_temp);
            lv_mem_free(workb_temp);
            lv_fs_close(&file);

            if(rc == JDR_OK) {
                header->always_zero = 0;
                header->cf = LV_IMG_CF_RAW;
                header->w = jd_tmp.width;
                header->h = jd_tmp.height;
                return LV_RES_OK;
            }
        }
    }
    return LV_RES_INV;
}

static int img_data_cb(JDEC * jd, void * data, JRECT * rect)
{
    io_source_t * io = jd->device;
    uint8_t * cache = io->img_cache_buff;
    const int xres = io->img_cache_x_res;
    uint8_t * buf = data;
    const int INPUT_PIXEL_SIZE = 3;
    const int row_width = rect->right - rect->left + 1; // Row width in pixels.
    const int row_size = row_width * INPUT_PIXEL_SIZE;  // Row size (bytes).

    for(int y = rect->top; y <= rect->bottom; y++) {
        int row_offset = y * xres * INPUT_PIXEL_SIZE + rect->left * INPUT_PIXEL_SIZE;
        memcpy(cache + row_offset, buf, row_size);
        buf += row_size;
    }

    return 1;
}

static size_t input_func(JDEC * jd, uint8_t * buff, size_t ndata)
{
    io_source_t * io = jd->device;

    if(!io) return 0;

    if(io->type == SJPEG_IO_SOURCE_C_ARRAY) {
        const uint32_t bytes_left = io->raw_sjpg_data_size - io->raw_sjpg_data_next_read_pos;
        const uint32_t to_read = ndata <= bytes_left ? (uint32_t)ndata : bytes_left;
        if(to_read == 0)
            return 0;
        if(buff) {
            memcpy(buff, io->raw_sjpg_data + io->raw_sjpg_data_next_read_pos, to_read);
        }
        io->raw_sjpg_data_next_read_pos += to_read;
        return to_read;
    }
    else if(io->type == SJPEG_IO_SOURCE_DISK) {

        lv_fs_file_t * lv_file_p = &(io->lv_file);

        if(buff) {
            uint32_t rn = 0;
            lv_fs_read(lv_file_p, buff, (uint32_t)ndata, &rn);
            return rn;
        }
        else {
            uint32_t pos;
            lv_fs_tell(lv_file_p, &pos);
            lv_fs_seek(lv_file_p, (uint32_t)(ndata + pos),  LV_FS_SEEK_SET);
            return ndata;
        }
    }
    return 0;
}

/**
 * Open SJPG image and return the decided image
 * @param decoder pointer to the decoder where this function belongs
 * @param dsc pointer to a descriptor which describes this decoding session
 * @return LV_RES_OK: no error; LV_RES_INV: can't get the info
 */
static lv_res_t decoder_open(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc)
{
    LV_UNUSED(decoder);
    lv_res_t lv_ret = LV_RES_OK;

    if(dsc->src_type == LV_IMG_SRC_VARIABLE) {
        uint8_t * data;
        SJPEG * sjpeg = (SJPEG *) dsc->user_data;
        const uint32_t raw_sjpeg_data_size = ((lv_img_dsc_t *)dsc->src)->data_size;
        if(sjpeg == NULL) {
            sjpeg =  lv_mem_alloc(sizeof(SJPEG));
            if(!sjpeg) return LV_RES_INV;

            memset(sjpeg, 0, sizeof(SJPEG));

            dsc->user_data = sjpeg;
            sjpeg->sjpeg_data = (uint8_t *)((lv_img_dsc_t *)(dsc->src))->data;
            sjpeg->sjpeg_data_size = ((lv_img_dsc_t *)(dsc->src))->data_size;
        }

        if(!strncmp((char *) sjpeg->sjpeg_data, "_SJPG__", strlen("_SJPG__"))) {

            data = sjpeg->sjpeg_data;
            data += 14;

            sjpeg->sjpeg_x_res = *data++;
            sjpeg->sjpeg_x_res |= *data++ << 8;

            sjpeg->sjpeg_y_res = *data++;
            sjpeg->sjpeg_y_res |= *data++ << 8;

            sjpeg->sjpeg_total_frames = *data++;
            sjpeg->sjpeg_total_frames |= *data++ << 8;

            sjpeg->sjpeg_single_frame_height = *data++;
            sjpeg->sjpeg_single_frame_height |= *data++ << 8;

            sjpeg->frame_base_array = lv_mem_alloc(sizeof(uint8_t *) * sjpeg->sjpeg_total_frames);
            if(! sjpeg->frame_base_array) {
                lv_sjpg_cleanup(sjpeg);
                sjpeg = NULL;
                return LV_RES_INV;
            }

            sjpeg->frame_base_offset = NULL;

            uint8_t * img_frame_base = data +  sjpeg->sjpeg_total_frames * 2;
            sjpeg->frame_base_array[0] = img_frame_base;

            for(int i = 1; i <  sjpeg->sjpeg_total_frames; i++) {
                int offset = *data++;
                offset |= *data++ << 8;
                sjpeg->frame_base_array[i] = sjpeg->frame_base_array[i - 1] + offset;
            }
            sjpeg->sjpeg_cache_frame_index = -1;
            sjpeg->frame_cache = (void *)lv_mem_alloc(sjpeg->sjpeg_x_res * sjpeg->sjpeg_single_frame_height * 3/*2*/);
            if(! sjpeg->frame_cache) {
                lv_sjpg_cleanup(sjpeg);
                sjpeg = NULL;
                return LV_RES_INV;
            }
            sjpeg->io.img_cache_buff = sjpeg->frame_cache;
            sjpeg->io.img_cache_x_res = sjpeg->sjpeg_x_res;
            sjpeg->workb =   lv_mem_alloc(TJPGD_WORKBUFF_SIZE);
            if(! sjpeg->workb) {
                lv_sjpg_cleanup(sjpeg);
                sjpeg = NULL;
                return LV_RES_INV;
            }

            sjpeg->tjpeg_jd =   lv_mem_alloc(sizeof(JDEC));
            if(! sjpeg->tjpeg_jd) {
                lv_sjpg_cleanup(sjpeg);
                sjpeg = NULL;
                return LV_RES_INV;
            }
            sjpeg->io.type = SJPEG_IO_SOURCE_C_ARRAY;
            sjpeg->io.lv_file.file_d = NULL;
            dsc->img_data = NULL;
            return lv_ret;
        }
        else if(is_jpg(sjpeg->sjpeg_data, raw_sjpeg_data_size) == true) {

            uint8_t * workb_temp = lv_mem_alloc(TJPGD_WORKBUFF_SIZE);
            if(! workb_temp) {
                lv_sjpg_cleanup(sjpeg);
                sjpeg = NULL;
                return LV_RES_INV;
            }
            io_source_t io_source_temp;
            io_source_temp.type = SJPEG_IO_SOURCE_C_ARRAY;
            io_source_temp.raw_sjpg_data =  sjpeg->sjpeg_data;
            io_source_temp.raw_sjpg_data_size = sjpeg->sjpeg_data_size;
            io_source_temp.raw_sjpg_data_next_read_pos = 0;

            JDEC jd_tmp;
            JRESULT rc = jd_prepare(&jd_tmp, input_func, workb_temp, (size_t)TJPGD_WORKBUFF_SIZE, &io_source_temp);
            lv_mem_free(workb_temp);

            if(rc == JDR_OK) {
                sjpeg->sjpeg_x_res = jd_tmp.width;
                sjpeg->sjpeg_y_res = jd_tmp.height;
                sjpeg->sjpeg_total_frames = 1;
                sjpeg->sjpeg_single_frame_height = jd_tmp.height;

                sjpeg->frame_base_array = lv_mem_alloc(sizeof(uint8_t *) * sjpeg->sjpeg_total_frames);
                if(! sjpeg->frame_base_array) {
                    lv_sjpg_cleanup(sjpeg);
                    sjpeg = NULL;
                    return LV_RES_INV;
                }
                sjpeg->frame_base_offset = NULL;

                uint8_t * img_frame_base = sjpeg->sjpeg_data;
                sjpeg->frame_base_array[0] = img_frame_base;

                sjpeg->sjpeg_cache_frame_index = -1;
                sjpeg->frame_cache = (void *)lv_mem_alloc(sjpeg->sjpeg_x_res * sjpeg->sjpeg_single_frame_height * 3);
                if(! sjpeg->frame_cache) {
                    lv_sjpg_cleanup(sjpeg);
                    sjpeg = NULL;
                    return LV_RES_INV;
                }

                sjpeg->io.img_cache_buff = sjpeg->frame_cache;
                sjpeg->io.img_cache_x_res = sjpeg->sjpeg_x_res;
                sjpeg->workb =   lv_mem_alloc(TJPGD_WORKBUFF_SIZE);
                if(! sjpeg->workb) {
                    lv_sjpg_cleanup(sjpeg);
                    sjpeg = NULL;
                    return LV_RES_INV;
                }

                sjpeg->tjpeg_jd =   lv_mem_alloc(sizeof(JDEC));
                if(! sjpeg->tjpeg_jd) {
                    lv_sjpg_cleanup(sjpeg);
                    sjpeg = NULL;
                    return LV_RES_INV;
                }

                sjpeg->io.type = SJPEG_IO_SOURCE_C_ARRAY;
                sjpeg->io.lv_file.file_d = NULL;
                dsc->img_data = NULL;
                return lv_ret;
            }
            else {
                lv_ret = LV_RES_INV;
                goto end;
            }

end:
            lv_mem_free(workb_temp);

            return lv_ret;
        }
    }
    else if(dsc->src_type == LV_IMG_SRC_FILE) {
        /* If all fine, then the file will be kept open */
        const char * fn = dsc->src;
        uint8_t * data;

        if(strcmp(lv_fs_get_ext(fn), "sjpg") == 0) {

            uint8_t buff[22];
            memset(buff, 0, sizeof(buff));

            lv_fs_file_t lv_file;
            lv_fs_res_t res = lv_fs_open(&lv_file, fn, LV_FS_MODE_RD);
            if(res != LV_FS_RES_OK) {
                return 78;
            }

            uint32_t rn;
            res = lv_fs_read(&lv_file, buff, 22, &rn);
            if(res != LV_FS_RES_OK || rn != 22) {
                lv_fs_close(&lv_file);
                return LV_RES_INV;
            }

            if(strcmp((char *)buff, "_SJPG__") == 0) {

                SJPEG * sjpeg = (SJPEG *) dsc->user_data;
                if(sjpeg == NULL) {
                    sjpeg = lv_mem_alloc(sizeof(SJPEG));

                    if(! sjpeg) {
                        lv_fs_close(&lv_file);
                        return LV_RES_INV;
                    }
                    memset(sjpeg, 0, sizeof(SJPEG));

                    dsc->user_data = sjpeg;
                    sjpeg->sjpeg_data = (uint8_t *)((lv_img_dsc_t *)(dsc->src))->data;
                    sjpeg->sjpeg_data_size = ((lv_img_dsc_t *)(dsc->src))->data_size;
                }
                data = buff;
                data += 14;

                sjpeg->sjpeg_x_res = *data++;
                sjpeg->sjpeg_x_res |= *data++ << 8;

                sjpeg->sjpeg_y_res = *data++;
                sjpeg->sjpeg_y_res |= *data++ << 8;

                sjpeg->sjpeg_total_frames = *data++;
                sjpeg->sjpeg_total_frames |= *data++ << 8;

                sjpeg->sjpeg_single_frame_height = *data++;
                sjpeg->sjpeg_single_frame_height |= *data++ << 8;

                sjpeg->frame_base_array = NULL;//lv_mem_alloc( sizeof(uint8_t *) * sjpeg->sjpeg_total_frames );
                sjpeg->frame_base_offset = lv_mem_alloc(sizeof(int) * sjpeg->sjpeg_total_frames);
                if(! sjpeg->frame_base_offset) {
                    lv_fs_close(&lv_file);
                    lv_sjpg_cleanup(sjpeg);
                    return LV_RES_INV;
                }
                int img_frame_start_offset = (SJPEG_FRAME_INFO_ARRAY_OFFSET + sjpeg->sjpeg_total_frames * 2);
                sjpeg->frame_base_offset[0] = img_frame_start_offset; //pointer used to save integer for now...

                for(int i = 1; i <  sjpeg->sjpeg_total_frames; i++) {
                    res = lv_fs_read(&lv_file, buff, 2, &rn);
                    if(res != LV_FS_RES_OK || rn != 2) {
                        lv_fs_close(&lv_file);
                        return LV_RES_INV;
                    }

                    data = buff;
                    int offset = *data++;
                    offset |= *data++ << 8;
                    sjpeg->frame_base_offset[i] = sjpeg->frame_base_offset[i - 1] + offset;
                }

                sjpeg->sjpeg_cache_frame_index = -1; //INVALID AT BEGINNING for a forced compare mismatch at first time.
                sjpeg->frame_cache = (void *)lv_mem_alloc(sjpeg->sjpeg_x_res * sjpeg->sjpeg_single_frame_height * 3);
                if(! sjpeg->frame_cache) {
                    lv_fs_close(&lv_file);
                    lv_sjpg_cleanup(sjpeg);
                    return LV_RES_INV;
                }
                sjpeg->io.img_cache_buff = sjpeg->frame_cache;
                sjpeg->io.img_cache_x_res = sjpeg->sjpeg_x_res;
                sjpeg->workb =   lv_mem_alloc(TJPGD_WORKBUFF_SIZE);
                if(! sjpeg->workb) {
                    lv_fs_close(&lv_file);
                    lv_sjpg_cleanup(sjpeg);
                    return LV_RES_INV;
                }

                sjpeg->tjpeg_jd =    lv_mem_alloc(sizeof(JDEC));
                if(! sjpeg->tjpeg_jd) {
                    lv_fs_close(&lv_file);
                    lv_sjpg_cleanup(sjpeg);
                    return LV_RES_INV;
                }

                sjpeg->io.type = SJPEG_IO_SOURCE_DISK;
                sjpeg->io.lv_file = lv_file;
                dsc->img_data = NULL;
                return LV_RES_OK;
            }
        }
        else if(strcmp(lv_fs_get_ext(fn), "jpg") == 0) {

            lv_fs_file_t lv_file;
            lv_fs_res_t res = lv_fs_open(&lv_file, fn, LV_FS_MODE_RD);
            if(res != LV_FS_RES_OK) {
                return LV_RES_INV;
            }

            SJPEG * sjpeg = (SJPEG *) dsc->user_data;
            if(sjpeg == NULL) {
                sjpeg = lv_mem_alloc(sizeof(SJPEG));
                if(! sjpeg) {
                    lv_fs_close(&lv_file);
                    return LV_RES_INV;
                }

                memset(sjpeg, 0, sizeof(SJPEG));
                dsc->user_data = sjpeg;
                sjpeg->sjpeg_data = (uint8_t *)((lv_img_dsc_t *)(dsc->src))->data;
                sjpeg->sjpeg_data_size = ((lv_img_dsc_t *)(dsc->src))->data_size;
            }

            uint8_t * workb_temp = lv_mem_alloc(TJPGD_WORKBUFF_SIZE);
            if(! workb_temp) {
                lv_fs_close(&lv_file);
                lv_sjpg_cleanup(sjpeg);
                return LV_RES_INV;
            }

            io_source_t io_source_temp;
            io_source_temp.type = SJPEG_IO_SOURCE_DISK;
            io_source_temp.raw_sjpg_data_next_read_pos = 0;
            io_source_temp.img_cache_buff = NULL;
            io_source_temp.lv_file = lv_file;

            JDEC jd_tmp;

            JRESULT rc = jd_prepare(&jd_tmp, input_func, workb_temp, (size_t)TJPGD_WORKBUFF_SIZE, &io_source_temp);

            lv_mem_free(workb_temp);

            if(rc == JDR_OK) {
                sjpeg->sjpeg_x_res = jd_tmp.width;
                sjpeg->sjpeg_y_res = jd_tmp.height;
                sjpeg->sjpeg_total_frames = 1;
                sjpeg->sjpeg_single_frame_height = jd_tmp.height;

                sjpeg->frame_base_array = NULL;
                sjpeg->frame_base_offset =  lv_mem_alloc(sizeof(uint8_t *) * sjpeg->sjpeg_total_frames);
                if(! sjpeg->frame_base_offset) {
                    lv_fs_close(&lv_file);
                    lv_sjpg_cleanup(sjpeg);
                    return LV_RES_INV;
                }

                int img_frame_start_offset = 0;
                sjpeg->frame_base_offset[0] = img_frame_start_offset;

                sjpeg->sjpeg_cache_frame_index = -1;
                sjpeg->frame_cache = (void *)lv_mem_alloc(sjpeg->sjpeg_x_res * sjpeg->sjpeg_single_frame_height * 3);
                if(! sjpeg->frame_cache) {
                    lv_fs_close(&lv_file);
                    lv_sjpg_cleanup(sjpeg);
                    return LV_RES_INV;
                }

                sjpeg->io.img_cache_buff = sjpeg->frame_cache;
                sjpeg->io.img_cache_x_res = sjpeg->sjpeg_x_res;
                sjpeg->workb =   lv_mem_alloc(TJPGD_WORKBUFF_SIZE);
                if(! sjpeg->workb) {
                    lv_fs_close(&lv_file);
                    lv_sjpg_cleanup(sjpeg);
                    return LV_RES_INV;
                }

                sjpeg->tjpeg_jd =   lv_mem_alloc(sizeof(JDEC));
                if(! sjpeg->tjpeg_jd) {
                    lv_fs_close(&lv_file);
                    lv_sjpg_cleanup(sjpeg);
                    return LV_RES_INV;
                }

                sjpeg->io.type = SJPEG_IO_SOURCE_DISK;
                sjpeg->io.lv_file = lv_file;
                dsc->img_data = NULL;
                return LV_RES_OK;

            }
            else {
                if(dsc->user_data) lv_mem_free(dsc->user_data);
                lv_fs_close(&lv_file);
                return  LV_RES_INV;
            }
        }
    }

    return LV_RES_INV;
}

/**
 * Decode `len` pixels starting from the given `x`, `y` coordinates and store them in `buf`.
 * Required only if the "open" function can't open the whole decoded pixel array. (dsc->img_data == NULL)
 * @param decoder pointer to the decoder the function associated with
 * @param dsc pointer to decoder descriptor
 * @param x start x coordinate
 * @param y start y coordinate
 * @param len number of pixels to decode
 * @param buf a buffer to store the decoded pixels
 * @return LV_RES_OK: ok; LV_RES_INV: failed
 */

static lv_res_t decoder_read_line(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc, lv_coord_t x, lv_coord_t y,
                                  lv_coord_t len, uint8_t * buf)
{
    LV_UNUSED(decoder);
    if(dsc->src_type == LV_IMG_SRC_VARIABLE) {
        SJPEG * sjpeg = (SJPEG *) dsc->user_data;
        JRESULT rc;

        int sjpeg_req_frame_index = y / sjpeg->sjpeg_single_frame_height;

        /*If line not from cache, refresh cache */
        if(sjpeg_req_frame_index != sjpeg->sjpeg_cache_frame_index) {
            sjpeg->io.raw_sjpg_data = sjpeg->frame_base_array[ sjpeg_req_frame_index ];
            if(sjpeg_req_frame_index == (sjpeg->sjpeg_total_frames - 1)) {
                /*This is the last frame. */
                const uint32_t frame_offset = (uint32_t)(sjpeg->io.raw_sjpg_data - sjpeg->sjpeg_data);
                sjpeg->io.raw_sjpg_data_size = sjpeg->sjpeg_data_size - frame_offset;
            }
            else {
                sjpeg->io.raw_sjpg_data_size =
                    (uint32_t)(sjpeg->frame_base_array[sjpeg_req_frame_index + 1] - sjpeg->io.raw_sjpg_data);
            }
            sjpeg->io.raw_sjpg_data_next_read_pos = 0;
            rc = jd_prepare(sjpeg->tjpeg_jd, input_func, sjpeg->workb, (size_t)TJPGD_WORKBUFF_SIZE, &(sjpeg->io));
            if(rc != JDR_OK) return LV_RES_INV;
            rc = jd_decomp(sjpeg->tjpeg_jd, img_data_cb, 0);
            if(rc != JDR_OK) return LV_RES_INV;
            sjpeg->sjpeg_cache_frame_index = sjpeg_req_frame_index;
        }

        int offset = 0;
        uint8_t * cache = (uint8_t *)sjpeg->frame_cache + x * 3 + (y % sjpeg->sjpeg_single_frame_height) * sjpeg->sjpeg_x_res *
                          3;

#if  LV_COLOR_DEPTH == 32
        for(int i = 0; i < len; i++) {
            buf[offset + 3] = 0xff;
            buf[offset + 2] = *cache++;
            buf[offset + 1] = *cache++;
            buf[offset + 0] = *cache++;
            offset += 4;
        }

#elif  LV_COLOR_DEPTH == 16

        for(int i = 0; i < len; i++) {
            uint16_t col_16bit = (*cache++ & 0xf8) << 8;
            col_16bit |= (*cache++ & 0xFC) << 3;
            col_16bit |= (*cache++ >> 3);
#if  LV_BIG_ENDIAN_SYSTEM == 1 || LV_COLOR_16_SWAP == 1
            buf[offset++] = col_16bit >> 8;
            buf[offset++] = col_16bit & 0xff;
#else
            buf[offset++] = col_16bit & 0xff;
            buf[offset++] = col_16bit >> 8;
#endif // LV_BIG_ENDIAN_SYSTEM
        }

#elif  LV_COLOR_DEPTH == 8

        for(int i = 0; i < len; i++) {
            uint8_t col_8bit = (*cache++ & 0xC0);
            col_8bit |= (*cache++ & 0xe0) >> 2;
            col_8bit |= (*cache++ & 0xe0) >> 5;
            buf[offset++] = col_8bit;
        }
#else
#error Unsupported LV_COLOR_DEPTH

#endif // LV_COLOR_DEPTH
        return LV_RES_OK;
    }
    else if(dsc->src_type == LV_IMG_SRC_FILE) {
        SJPEG * sjpeg = (SJPEG *) dsc->user_data;
        JRESULT rc;
        int sjpeg_req_frame_index = y / sjpeg->sjpeg_single_frame_height;

        lv_fs_file_t * lv_file_p = &(sjpeg->io.lv_file);
        if(!lv_file_p) goto end;

        /*If line not from cache, refresh cache */
        if(sjpeg_req_frame_index != sjpeg->sjpeg_cache_frame_index) {
            sjpeg->io.raw_sjpg_data_next_read_pos = (int)(sjpeg->frame_base_offset [ sjpeg_req_frame_index ]);
            lv_fs_seek(&(sjpeg->io.lv_file), sjpeg->io.raw_sjpg_data_next_read_pos, LV_FS_SEEK_SET);

            rc = jd_prepare(sjpeg->tjpeg_jd, input_func, sjpeg->workb, (size_t)TJPGD_WORKBUFF_SIZE, &(sjpeg->io));
            if(rc != JDR_OK) return LV_RES_INV;

            rc = jd_decomp(sjpeg->tjpeg_jd, img_data_cb, 0);
            if(rc != JDR_OK) return LV_RES_INV;

            sjpeg->sjpeg_cache_frame_index = sjpeg_req_frame_index;
        }

        int offset = 0;
        uint8_t * cache = (uint8_t *)sjpeg->frame_cache + x * 3 + (y % sjpeg->sjpeg_single_frame_height) * sjpeg->sjpeg_x_res *
                          3;

#if LV_COLOR_DEPTH == 32
        for(int i = 0; i < len; i++) {
            buf[offset + 3] = 0xff;
            buf[offset + 2] = *cache++;
            buf[offset + 1] = *cache++;
            buf[offset + 0] = *cache++;
            offset += 4;
        }
#elif  LV_COLOR_DEPTH == 16

        for(int i = 0; i < len; i++) {
            uint16_t col_8bit = (*cache++ & 0xf8) << 8;
            col_8bit |= (*cache++ & 0xFC) << 3;
            col_8bit |= (*cache++ >> 3);
#if  LV_BIG_ENDIAN_SYSTEM == 1 || LV_COLOR_16_SWAP == 1
            buf[offset++] = col_8bit >> 8;
            buf[offset++] = col_8bit & 0xff;
#else
            buf[offset++] = col_8bit & 0xff;
            buf[offset++] = col_8bit >> 8;
#endif // LV_BIG_ENDIAN_SYSTEM
        }

#elif  LV_COLOR_DEPTH == 8

        for(int i = 0; i < len; i++) {
            uint8_t col_8bit = (*cache++ & 0xC0);
            col_8bit |= (*cache++ & 0xe0) >> 2;
            col_8bit |= (*cache++ & 0xe0) >> 5;
            buf[offset++] = col_8bit;
        }

#else
#error Unsupported LV_COLOR_DEPTH

#endif // LV_COLOR_DEPTH

        return LV_RES_OK;
    }
end:
    return LV_RES_INV;
}

/**
 * Free the allocated resources
 * @param decoder pointer to the decoder where this function belongs
 * @param dsc pointer to a descriptor which describes this decoding session
 */
static void decoder_close(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc)
{
    LV_UNUSED(decoder);
    /*Free all allocated data*/
    SJPEG * sjpeg = (SJPEG *) dsc->user_data;
    if(!sjpeg) return;

    switch(dsc->src_type) {
        case LV_IMG_SRC_FILE:
            if(sjpeg->io.lv_file.file_d) {
                lv_fs_close(&(sjpeg->io.lv_file));
            }
            lv_sjpg_cleanup(sjpeg);
            break;

        case LV_IMG_SRC_VARIABLE:
            lv_sjpg_cleanup(sjpeg);
            break;

        default:
            ;
    }
}

static int is_jpg(const uint8_t * raw_data, size_t len)
{
    const uint8_t jpg_signature[] = {0xFF, 0xD8, 0xFF,  0xE0,  0x00,  0x10, 0x4A,  0x46, 0x49, 0x46};
    if(len < sizeof(jpg_signature)) return false;
    return memcmp(jpg_signature, raw_data, sizeof(jpg_signature)) == 0;
}

static void lv_sjpg_free(SJPEG * sjpeg)
{
    if(sjpeg->frame_cache) lv_mem_free(sjpeg->frame_cache);
    if(sjpeg->frame_base_array) lv_mem_free(sjpeg->frame_base_array);
    if(sjpeg->frame_base_offset) lv_mem_free(sjpeg->frame_base_offset);
    if(sjpeg->tjpeg_jd) lv_mem_free(sjpeg->tjpeg_jd);
    if(sjpeg->workb) lv_mem_free(sjpeg->workb);
}

static void lv_sjpg_cleanup(SJPEG * sjpeg)
{
    if(! sjpeg) return;

    lv_sjpg_free(sjpeg);
    lv_mem_free(sjpeg);
}

#endif /*LV_USE_SJPG*/