/*

 * Copyright 2007 Red Hat, Inc.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * on the rights to use, copy, modify, merge, publish, distribute, sub

 * license, and/or sell copies of the Software, and to permit persons to whom

 * the Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER

 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 */

/* Author: Soren Sandmann <sandmann@redhat.com> */

#include "edid.h"

#include <stdlib.h>

#include <string.h>

#include <math.h>

#include <stdio.h>

#define TRUE 1

#define FALSE 0

static int

get_bit (int in, int bit)

{

    return (in & (1 << bit)) >> bit;

}

static int

get_bits (int in, int begin, int end)

{

    int mask = (1 << (end - begin + 1)) - 1;

    return (in >> begin) & mask;

}

static int

decode_header (const uchar *edid)

{

    if (memcmp (edid, "\x00\xff\xff\xff\xff\xff\xff\x00", 8) == 0)

	return TRUE;

    return FALSE;

}

static int

decode_vendor_and_product_identification (const uchar *edid, MonitorInfo *info)

{

    int is_model_year;

    /* Manufacturer Code */

    info->manufacturer_code[0]  = get_bits (edid[0x08], 2, 6);

    info->manufacturer_code[1]  = get_bits (edid[0x08], 0, 1) << 3;

    info->manufacturer_code[1] |= get_bits (edid[0x09], 5, 7);

    info->manufacturer_code[2]  = get_bits (edid[0x09], 0, 4);

    info->manufacturer_code[3]  = '\0';

    info->manufacturer_code[0] += 'A' - 1;

    info->manufacturer_code[1] += 'A' - 1;

    info->manufacturer_code[2] += 'A' - 1;

    /* Product Code */

    info->product_code = edid[0x0b] << 8 | edid[0x0a];

    /* Serial Number */

    info->serial_number =

	edid[0x0c] | edid[0x0d] << 8 | edid[0x0e] << 16 | edid[0x0f] << 24;

    /* Week and Year */

    is_model_year = FALSE;

    switch (edid[0x10])

    {

    case 0x00:

	info->production_week = -1;

	break;

    case 0xff:

	info->production_week = -1;

	is_model_year = TRUE;

	break;

    default:

	info->production_week = edid[0x10];

	break;

    }

    if (is_model_year)

    {

	info->production_year = -1;

	info->model_year = 1990 + edid[0x11];

    }

    else

    {

	info->production_year = 1990 + edid[0x11];

	info->model_year = -1;

    }

    return TRUE;

}

static int

decode_edid_version (const uchar *edid, MonitorInfo *info)

{

    info->major_version = edid[0x12];

    info->minor_version = edid[0x13];

    return TRUE;

}

static int

decode_display_parameters (const uchar *edid, MonitorInfo *info)

{

    /* Digital vs Analog */

    info->is_digital = get_bit (edid[0x14], 7);

    if (info->is_digital)

    {

	int bits;

	static const int bit_depth[8] =

	{

	    -1, 6, 8, 10, 12, 14, 16, -1

	};

	static const Interface interfaces[6] =

	{

	    UNDEFINED, DVI, HDMI_A, HDMI_B, MDDI, DISPLAY_PORT

	};

	bits = get_bits (edid[0x14], 4, 6);

	info->digital.bits_per_primary = bit_depth[bits];

	bits = get_bits (edid[0x14], 0, 3);

	if (bits <= 5)

	    info->digital.interface = interfaces[bits];

	else

	    info->digital.interface = UNDEFINED;

    }

    else

    {

	int bits = get_bits (edid[0x14], 5, 6);

	static const double levels[][3] =

	{

	    { 0.7,   0.3,    1.0 },

	    { 0.714, 0.286,  1.0 },

	    { 1.0,   0.4,    1.4 },

	    { 0.7,   0.0,    0.7 },

	};

	info->analog.video_signal_level = levels[bits][0];

	info->analog.sync_signal_level = levels[bits][1];

	info->analog.total_signal_level = levels[bits][2];

	info->analog.blank_to_black = get_bit (edid[0x14], 4);

	info->analog.separate_hv_sync = get_bit (edid[0x14], 3);

	info->analog.composite_sync_on_h = get_bit (edid[0x14], 2);

	info->analog.composite_sync_on_green = get_bit (edid[0x14], 1);

	info->analog.serration_on_vsync = get_bit (edid[0x14], 0);

    }

    /* Screen Size / Aspect Ratio */

    if (edid[0x15] == 0 && edid[0x16] == 0)

    {

	info->width_mm = -1;

	info->height_mm = -1;

	info->aspect_ratio = -1.0;

    }

    else if (edid[0x16] == 0)

    {

	info->width_mm = -1;

	info->height_mm = -1; 

	info->aspect_ratio = 100.0 / (edid[0x15] + 99);

    }

    else if (edid[0x15] == 0)

    {

	info->width_mm = -1;

	info->height_mm = -1;

	info->aspect_ratio = 100.0 / (edid[0x16] + 99);

	info->aspect_ratio = 1/info->aspect_ratio; /* portrait */

    }

    else

    {

	info->width_mm = 10 * edid[0x15];

	info->height_mm = 10 * edid[0x16];

    }

    /* Gamma */

    if (edid[0x17] == 0xFF)

	info->gamma = -1.0;

    else

	info->gamma = (edid[0x17] + 100.0) / 100.0;

    /* Features */

    info->standby = get_bit (edid[0x18], 7);

    info->suspend = get_bit (edid[0x18], 6);

    info->active_off = get_bit (edid[0x18], 5);

    if (info->is_digital)

    {

	info->digital.rgb444 = TRUE;

	if (get_bit (edid[0x18], 3))

	    info->digital.ycrcb444 = 1;

	if (get_bit (edid[0x18], 4))

	    info->digital.ycrcb422 = 1;

    }

    else

    {

	int bits = get_bits (edid[0x18], 3, 4);

	ColorType color_type[4] =

	{

	    MONOCHROME, RGB, OTHER_COLOR, UNDEFINED_COLOR

	};

	info->analog.color_type = color_type[bits];

    }

    info->srgb_is_standard = get_bit (edid[0x18], 2);

    /* In 1.3 this is called "has preferred timing" */

    info->preferred_timing_includes_native = get_bit (edid[0x18], 1);

    /* FIXME: In 1.3 this indicates whether the monitor accepts GTF */

    info->continuous_frequency = get_bit (edid[0x18], 0);

    return TRUE;

}

static double

decode_fraction (int high, int low)

{

    double result = 0.0;

    int i;

    high = (high << 2) | low;

    for (i = 0; i < 10; ++i)

	result += get_bit (high, i) * pow (2, i - 10);

    return result;

}

static int

decode_color_characteristics (const uchar *edid, MonitorInfo *info)

{

    info->red_x = decode_fraction (edid[0x1b], get_bits (edid[0x19], 6, 7));

    info->red_y = decode_fraction (edid[0x1c], get_bits (edid[0x19], 5, 4));

    info->green_x = decode_fraction (edid[0x1d], get_bits (edid[0x19], 2, 3));

    info->green_y = decode_fraction (edid[0x1e], get_bits (edid[0x19], 0, 1));

    info->blue_x = decode_fraction (edid[0x1f], get_bits (edid[0x1a], 6, 7));

    info->blue_y = decode_fraction (edid[0x20], get_bits (edid[0x1a], 4, 5));

    info->white_x = decode_fraction (edid[0x21], get_bits (edid[0x1a], 2, 3));

    info->white_y = decode_fraction (edid[0x22], get_bits (edid[0x1a], 0, 1));

    return TRUE;

}

static int

decode_established_timings (const uchar *edid, MonitorInfo *info)

{

    static const Timing established[][8] = 

    {

	{

	    { 800, 600, 60 },

	    { 800, 600, 56 },

	    { 640, 480, 75 },

	    { 640, 480, 72 },

	    { 640, 480, 67 },

	    { 640, 480, 60 },

	    { 720, 400, 88 },

	    { 720, 400, 70 }

	},

	{

	    { 1280, 1024, 75 },

	    { 1024, 768, 75 },

	    { 1024, 768, 70 },

	    { 1024, 768, 60 },

	    { 1024, 768, 87 },

	    { 832, 624, 75 },

	    { 800, 600, 75 },

	    { 800, 600, 72 }

	},

	{

	    { 0, 0, 0 },

	    { 0, 0, 0 },

	    { 0, 0, 0 },

	    { 0, 0, 0 },

	    { 0, 0, 0 },

	    { 0, 0, 0 },

	    { 0, 0, 0 },

	    { 1152, 870, 75 }

	},

    };

    int i, j, idx;

    idx = 0;

    for (i = 0; i < 3; ++i)

    {

	for (j = 0; j < 8; ++j)

	{

	    int byte = edid[0x23 + i];

	    if (get_bit (byte, j) && established[i][j].frequency != 0)

		info->established[idx++] = established[i][j];

	}

    }

    return TRUE;

}

static int

decode_standard_timings (const uchar *edid, MonitorInfo *info)

{

    int i;

    for (i = 0; i < 8; i++)

    {

	int first = edid[0x26 + 2 * i];

	int second = edid[0x27 + 2 * i];

	if (first != 0x01 && second != 0x01)

	{

	    int w = 8 * (first + 31);

	    int h;

	    switch (get_bits (second, 6, 7))

	    {

	    case 0x00: h = (w / 16) * 10; break;

	    case 0x01: h = (w / 4) * 3; break;

	    case 0x02: h = (w / 5) * 4; break;

	    case 0x03: h = (w / 16) * 9; break;

	    }

	    info->standard[i].width = w;

	    info->standard[i].height = h;

	    info->standard[i].frequency = get_bits (second, 0, 5) + 60;

	}

    }

    return TRUE;

}

static void

decode_lf_string (const uchar *s, int n_chars, char *result)

{

    int i;

    for (i = 0; i < n_chars; ++i)

    {

	if (s[i] == 0x0a)

	{

	    *result++ = '\0';

	    break;

	}

	else if (s[i] == 0x00)

	{

	    /* Convert embedded 0's to spaces */

	    *result++ = ' ';

	}

	else

	{

	    *result++ = s[i];

	}

    }

}

static void

decode_display_descriptor (const uchar *desc,

			   MonitorInfo *info)

{

    switch (desc[0x03])

    {

    case 0xFC:

	decode_lf_string (desc + 5, 13, info->dsc_product_name);

	break;

    case 0xFF:

	decode_lf_string (desc + 5, 13, info->dsc_serial_number);

	break;

    case 0xFE:

	decode_lf_string (desc + 5, 13, info->dsc_string);

	break;

    case 0xFD:

	/* Range Limits */

	break;

    case 0xFB:

	/* Color Point */

	break;

    case 0xFA:

	/* Timing Identifications */

	break;

    case 0xF9:

	/* Color Management */

	break;

    case 0xF8:

	/* Timing Codes */

	break;

    case 0xF7:

	/* Established Timings */

	break;

    case 0x10:

	break;

    }

}

static void

decode_detailed_timing (const uchar *timing,

			DetailedTiming *detailed)

{

    int bits;

    StereoType stereo[] =

    {

	NO_STEREO, NO_STEREO, FIELD_RIGHT, FIELD_LEFT,

	TWO_WAY_RIGHT_ON_EVEN, TWO_WAY_LEFT_ON_EVEN,

	FOUR_WAY_INTERLEAVED, SIDE_BY_SIDE

    };

    detailed->pixel_clock = (timing[0x00] | timing[0x01] << 8) * 10000;

    detailed->h_addr = timing[0x02] | ((timing[0x04] & 0xf0) << 4);

    detailed->h_blank = timing[0x03] | ((timing[0x04] & 0x0f) << 8);

    detailed->v_addr = timing[0x05] | ((timing[0x07] & 0xf0) << 4);

    detailed->v_blank = timing[0x06] | ((timing[0x07] & 0x0f) << 8);

    detailed->h_front_porch = timing[0x08] | get_bits (timing[0x0b], 6, 7) << 8;

    detailed->h_sync = timing[0x09] | get_bits (timing[0x0b], 4, 5) << 8;

    detailed->v_front_porch =

	get_bits (timing[0x0a], 4, 7) | get_bits (timing[0x0b], 2, 3) << 4;

    detailed->v_sync =

	get_bits (timing[0x0a], 0, 3) | get_bits (timing[0x0b], 0, 1) << 4;

    detailed->width_mm =  timing[0x0c] | get_bits (timing[0x0e], 4, 7) << 8;

    detailed->height_mm = timing[0x0d] | get_bits (timing[0x0e], 0, 3) << 8;

    detailed->right_border = timing[0x0f];

    detailed->top_border = timing[0x10];

    detailed->interlaced = get_bit (timing[0x11], 7);

    /* Stereo */

    bits = get_bits (timing[0x11], 5, 6) << 1 | get_bit (timing[0x11], 0);

    detailed->stereo = stereo[bits];

    /* Sync */

    bits = timing[0x11];

    detailed->digital_sync = get_bit (bits, 4);

    if (detailed->digital_sync)

    {

	detailed->digital.composite = !get_bit (bits, 3);

	if (detailed->digital.composite)

	{

	    detailed->digital.serrations = get_bit (bits, 2);

	    detailed->digital.negative_vsync = FALSE;

	}

	else

	{

	    detailed->digital.serrations = FALSE;

	    detailed->digital.negative_vsync = !get_bit (bits, 2);

	}

	detailed->digital.negative_hsync = !get_bit (bits, 0);

    }

    else

    {

	detailed->analog.bipolar = get_bit (bits, 3);

	detailed->analog.serrations = get_bit (bits, 2);

	detailed->analog.sync_on_green = !get_bit (bits, 1);

    }

}

static int

decode_descriptors (const uchar *edid, MonitorInfo *info)

{

    int i;

    int timing_idx;

    timing_idx = 0;

    for (i = 0; i < 4; ++i)

    {

	int index = 0x36 + i * 18;

	if (edid[index + 0] == 0x00 && edid[index + 1] == 0x00)

	{

	    decode_display_descriptor (edid + index, info);

	}

	else

	{

	    decode_detailed_timing (

		edid + index, &(info->detailed_timings[timing_idx++]));

	}

    }

    info->n_detailed_timings = timing_idx;

    return TRUE;

}

static void

decode_check_sum (const uchar *edid,

		  MonitorInfo *info)

{

    int i;

    uchar check = 0;

    for (i = 0; i < 128; ++i)

	check += edid[i];

    info->checksum = check;

}

MonitorInfo *

decode_edid (const uchar *edid)

{

    MonitorInfo *info = calloc (1, sizeof (MonitorInfo));

    decode_check_sum (edid, info);

    if (!decode_header (edid))

	return NULL;