// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Convert a logo in ASCII PNM format to C source suitable for inclusion in
 *  the Linux kernel
 *
 *  (C) Copyright 2001-2003 by Geert Uytterhoeven <geert@linux-m68k.org>
 */

#include <ctype.h>
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>


static const char *programname;
static const char *filename;
static const char *logoname = "linux_logo";
static const char *outputname;
static FILE *out;


#define LINUX_LOGO_MONO         1       /* monochrome black/white */
#define LINUX_LOGO_VGA16        2       /* 16 colors VGA text palette */
#define LINUX_LOGO_CLUT224      3       /* 224 colors */
#define LINUX_LOGO_GRAY256      4       /* 256 levels grayscale */

static const char *logo_types[LINUX_LOGO_GRAY256+1] = {
        [LINUX_LOGO_MONO] = "LINUX_LOGO_MONO",
        [LINUX_LOGO_VGA16] = "LINUX_LOGO_VGA16",
        [LINUX_LOGO_CLUT224] = "LINUX_LOGO_CLUT224",
        [LINUX_LOGO_GRAY256] = "LINUX_LOGO_GRAY256"
};

#define MAX_LINUX_LOGO_COLORS   224

struct color {
        unsigned char red;
        unsigned char green;
        unsigned char blue;
};

static const struct color clut_vga16[16] = {
        { 0x00, 0x00, 0x00 },
        { 0x00, 0x00, 0xaa },
        { 0x00, 0xaa, 0x00 },
        { 0x00, 0xaa, 0xaa },
        { 0xaa, 0x00, 0x00 },
        { 0xaa, 0x00, 0xaa },
        { 0xaa, 0x55, 0x00 },
        { 0xaa, 0xaa, 0xaa },
        { 0x55, 0x55, 0x55 },
        { 0x55, 0x55, 0xff },
        { 0x55, 0xff, 0x55 },
        { 0x55, 0xff, 0xff },
        { 0xff, 0x55, 0x55 },
        { 0xff, 0x55, 0xff },
        { 0xff, 0xff, 0x55 },
        { 0xff, 0xff, 0xff },
};


static int logo_type = LINUX_LOGO_CLUT224;
static unsigned int logo_width;
static unsigned int logo_height;
static struct color **logo_data;
static struct color logo_clut[MAX_LINUX_LOGO_COLORS];
static unsigned int logo_clutsize;
static int is_plain_pbm = 0;

static void die(const char *fmt, ...)
__attribute__((noreturn)) __attribute((format (printf, 1, 2)));
static void usage(void) __attribute((noreturn));


static unsigned int get_number(FILE *fp)
{
        int c, val;

        /* Skip leading whitespace */
        do {
                c = fgetc(fp);
                if (c == EOF)
                        die("%s: end of file\n", filename);
                if (c == '#') {
                        /* Ignore comments 'till end of line */
                        do {
                                c = fgetc(fp);
                                if (c == EOF)
                                        die("%s: end of file\n", filename);
                        } while (c != '\n');
                }
        } while (isspace(c));

        /* Parse decimal number */
        val = 0;
        while (isdigit(c)) {
                val = 10*val+c-'0';
                /* some PBM are 'broken'; GiMP for example exports a PBM without space
                 * between the digits. This is Ok cause we know a PBM can only have a '1'
                 * or a '0' for the digit.
                 */
                if (is_plain_pbm)
                        break;
                c = fgetc(fp);
                if (c == EOF)
                        die("%s: end of file\n", filename);
        }
        return val;
}

static unsigned int get_number255(FILE *fp, unsigned int maxval)
{
        unsigned int val = get_number(fp);

        return (255*val+maxval/2)/maxval;
}

static void read_image(void)
{
        FILE *fp;
        unsigned int i, j;
        int magic;
        unsigned int maxval;

        /* open image file */
        fp = fopen(filename, "r");
        if (!fp)
                die("Cannot open file %s: %s\n", filename, strerror(errno));

        /* check file type and read file header */
        magic = fgetc(fp);
        if (magic != 'P')
                die("%s is not a PNM file\n", filename);
        magic = fgetc(fp);
        switch (magic) {
        case '1':
        case '2':
        case '3':
                /* Plain PBM/PGM/PPM */
                break;

        case '4':
        case '5':
        case '6':
                /* Binary PBM/PGM/PPM */
                die("%s: Binary PNM is not supported\n"
                "Use pnmnoraw(1) to convert it to ASCII PNM\n", filename);

        default:
                die("%s is not a PNM file\n", filename);
        }
        logo_width = get_number(fp);
        logo_height = get_number(fp);

        /* allocate image data */
        logo_data = (struct color **)malloc(logo_height*sizeof(struct color *));
        if (!logo_data)
                die("%s\n", strerror(errno));
        for (i = 0; i < logo_height; i++) {
                logo_data[i] = malloc(logo_width*sizeof(struct color));
        if (!logo_data[i])
                die("%s\n", strerror(errno));
        }

        /* read image data */
        switch (magic) {
        case '1':
                /* Plain PBM */
                is_plain_pbm = 1;
                for (i = 0; i < logo_height; i++)
                        for (j = 0; j < logo_width; j++)
                                logo_data[i][j].red = logo_data[i][j].green =
                                        logo_data[i][j].blue = 255*(1-get_number(fp));
                break;

        case '2':
                /* Plain PGM */
                maxval = get_number(fp);
                for (i = 0; i < logo_height; i++)
                        for (j = 0; j < logo_width; j++)
                                logo_data[i][j].red = logo_data[i][j].green =
                                        logo_data[i][j].blue = get_number255(fp, maxval);
                break;

        case '3':
                /* Plain PPM */
                maxval = get_number(fp);
                for (i = 0; i < logo_height; i++)
                        for (j = 0; j < logo_width; j++) {
                                logo_data[i][j].red = get_number255(fp, maxval);
                                logo_data[i][j].green = get_number255(fp, maxval);
                                logo_data[i][j].blue = get_number255(fp, maxval);
                        }
                break;
        }

        /* close file */
        fclose(fp);
}

static inline int is_black(struct color c)
{
        return c.red == 0 && c.green == 0 && c.blue == 0;
}

static inline int is_white(struct color c)
{
        return c.red == 255 && c.green == 255 && c.blue == 255;
}

static inline int is_gray(struct color c)
{
        return c.red == c.green && c.red == c.blue;
}

static inline int is_equal(struct color c1, struct color c2)
{
        return c1.red == c2.red && c1.green == c2.green && c1.blue == c2.blue;
}

static void write_header(void)
{
        /* open logo file */
        if (outputname) {
                out = fopen(outputname, "w");
                if (!out)
                        die("Cannot create file %s: %s\n", outputname, strerror(errno));
        } else {
                out = stdout;
        }

        fputs("/*\n", out);
        fputs(" *  DO NOT EDIT THIS FILE!\n", out);
        fputs(" *\n", out);
        fprintf(out, " *  Linux logo %s\n", logoname);
        fputs(" */\n\n", out);
        fputs("#include <linux/linux_logo.h>\n\n", out);
        fprintf(out, "static const unsigned char %s_data[] __initconst = {\n",
                logoname);
}

static void write_footer(void)
{
        fputs("\n};\n\n", out);
        fprintf(out, "const struct linux_logo %s __initconst = {\n", logoname);
        fprintf(out, "\t.type\t\t= %s,\n", logo_types[logo_type]);
        fprintf(out, "\t.width\t\t= %u,\n", logo_width);
        fprintf(out, "\t.height\t\t= %u,\n", logo_height);
        if (logo_type == LINUX_LOGO_CLUT224) {
                fprintf(out, "\t.clutsize\t= %u,\n", logo_clutsize);
                fprintf(out, "\t.clut\t\t= %s_clut,\n", logoname);
        }
        fprintf(out, "\t.data\t\t= %s_data\n", logoname);
        fputs("};\n\n", out);

        /* close logo file */
        if (outputname)
                fclose(out);
}

static int write_hex_cnt;

static void write_hex(unsigned char byte)
{
        if (write_hex_cnt % 12)
                fprintf(out, ", 0x%02x", byte);
        else if (write_hex_cnt)
                fprintf(out, ",\n\t0x%02x", byte);
        else
                fprintf(out, "\t0x%02x", byte);
        write_hex_cnt++;
}

static void write_logo_mono(void)
{
        unsigned int i, j;
        unsigned char val, bit;

        /* validate image */
        for (i = 0; i < logo_height; i++)
                for (j = 0; j < logo_width; j++)
                        if (!is_black(logo_data[i][j]) && !is_white(logo_data[i][j]))
                                die("Image must be monochrome\n");

        /* write file header */
        write_header();

        /* write logo data */
        for (i = 0; i < logo_height; i++) {
                for (j = 0; j < logo_width;) {
                        for (val = 0, bit = 0x80; bit && j < logo_width; j++, bit >>= 1)
                                if (logo_data[i][j].red)
                                        val |= bit;
                        write_hex(val);
                }
        }

        /* write logo structure and file footer */
        write_footer();
}

static void write_logo_vga16(void)
{
        unsigned int i, j, k;
        unsigned char val;

        /* validate image */
        for (i = 0; i < logo_height; i++)
                for (j = 0; j < logo_width; j++) {
                        for (k = 0; k < 16; k++)
                                if (is_equal(logo_data[i][j], clut_vga16[k]))
                                        break;
                        if (k == 16)
                                die("Image must use the 16 console colors only\n"
                                    "Use ppmquant(1) -map clut_vga16.ppm to reduce the number "
                                    "of colors\n");
                }

        /* write file header */
        write_header();

        /* write logo data */
        for (i = 0; i < logo_height; i++)
                for (j = 0; j < logo_width; j++) {
                        for (k = 0; k < 16; k++)
                                if (is_equal(logo_data[i][j], clut_vga16[k]))
                                        break;
                        val = k<<4;
                        if (++j < logo_width) {
                                for (k = 0; k < 16; k++)
                                        if (is_equal(logo_data[i][j], clut_vga16[k]))
                                                break;
                                val |= k;
                        }
                        write_hex(val);
                }

        /* write logo structure and file footer */
        write_footer();
}

static void write_logo_clut224(void)
{
        unsigned int i, j, k;

        /* validate image */
        for (i = 0; i < logo_height; i++)
                for (j = 0; j < logo_width; j++) {
                        for (k = 0; k < logo_clutsize; k++)
                                if (is_equal(logo_data[i][j], logo_clut[k]))
                                        break;
                        if (k == logo_clutsize) {
                                if (logo_clutsize == MAX_LINUX_LOGO_COLORS)
                                        die("Image has more than %d colors\n"
                                            "Use ppmquant(1) to reduce the number of colors\n",
                                            MAX_LINUX_LOGO_COLORS);
                                logo_clut[logo_clutsize++] = logo_data[i][j];
                        }
                }

        /* write file header */
        write_header();

        /* write logo data */
        for (i = 0; i < logo_height; i++)
                for (j = 0; j < logo_width; j++) {
                        for (k = 0; k < logo_clutsize; k++)
                                if (is_equal(logo_data[i][j], logo_clut[k]))
                                        break;
                        write_hex(k+32);
                }
        fputs("\n};\n\n", out);

        /* write logo clut */
        fprintf(out, "static const unsigned char %s_clut[] __initconst = {\n",
                logoname);
        write_hex_cnt = 0;
        for (i = 0; i < logo_clutsize; i++) {
                write_hex(logo_clut[i].red);
                write_hex(logo_clut[i].green);
                write_hex(logo_clut[i].blue);
        }

        /* write logo structure and file footer */
        write_footer();
}

static void write_logo_gray256(void)
{
        unsigned int i, j;

        /* validate image */
        for (i = 0; i < logo_height; i++)
                for (j = 0; j < logo_width; j++)
                        if (!is_gray(logo_data[i][j]))
                                die("Image must be grayscale\n");

        /* write file header */
        write_header();

        /* write logo data */
        for (i = 0; i < logo_height; i++)
                for (j = 0; j < logo_width; j++)
                        write_hex(logo_data[i][j].red);

        /* write logo structure and file footer */
        write_footer();
}

static void die(const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        vfprintf(stderr, fmt, ap);
        va_end(ap);

        exit(1);
}

static void usage(void)
{
        die("\n"
        "Usage: %s [options] <filename>\n"
        "\n"
        "Valid options:\n"
        "       -h                : display this usage information\n"
        "       -n <name>   : specify logo name (default: linux_logo)\n"
        "       -o <output> : output to file <output> instead of stdout\n"
        "       -t <type>   : specify logo type, one of\n"
        "                                         mono  : monochrome black/white\n"
        "                                         vga16   : 16 colors VGA text palette\n"
        "                                         clut224 : 224 colors (default)\n"
        "                                         gray256 : 256 levels grayscale\n"
        "\n", programname);
}

int main(int argc, char *argv[])
{
        int opt;

        programname = argv[0];

        opterr = 0;
        while (1) {
                opt = getopt(argc, argv, "hn:o:t:");
                if (opt == -1)
                        break;

                switch (opt) {
                case 'h':
                        usage();
                        break;

                case 'n':
                        logoname = optarg;
                        break;

                case 'o':
                        outputname = optarg;
                        break;

                case 't':
                        if (!strcmp(optarg, "mono"))
                                logo_type = LINUX_LOGO_MONO;
                        else if (!strcmp(optarg, "vga16"))
                                logo_type = LINUX_LOGO_VGA16;
                        else if (!strcmp(optarg, "clut224"))
                                logo_type = LINUX_LOGO_CLUT224;
                        else if (!strcmp(optarg, "gray256"))
                                logo_type = LINUX_LOGO_GRAY256;
                        else
                                usage();
                        break;

                default:
                        usage();
                        break;
                }
        }
        if (optind != argc-1)
                usage();

        filename = argv[optind];

        read_image();
        switch (logo_type) {
        case LINUX_LOGO_MONO:
                write_logo_mono();
                break;

        case LINUX_LOGO_VGA16:
                write_logo_vga16();
                break;

        case LINUX_LOGO_CLUT224:
                write_logo_clut224();
                break;

        case LINUX_LOGO_GRAY256:
                write_logo_gray256();
                break;
        }
        exit(0);
}