/*      $NetBSD: parse.c,v 1.11 2000/09/24 02:19:54 augustss Exp $      */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1999, 2001 Lennart Augustsson <augustss@netbsd.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>

#include <dev/usb/usb.h>
#include <dev/usb/usbhid.h>

#include "usbhid.h"
#include "usbvar.h"

#define MAXUSAGE 100
#define MAXPUSH 4
#define MAXID 64
#define ITEMTYPES 3

struct hid_pos_data {
        int32_t rid;
        uint32_t pos[ITEMTYPES];
};

struct hid_data {
        const uint8_t *start;
        const uint8_t *end;
        const uint8_t *p;
        struct hid_item cur[MAXPUSH];
        struct hid_pos_data last_pos[MAXID];
        uint32_t pos[ITEMTYPES];
        int32_t usages_min[MAXUSAGE];
        int32_t usages_max[MAXUSAGE];
        int32_t usage_last;     /* last seen usage */
        uint32_t loc_size;      /* last seen size */
        uint32_t loc_count;     /* last seen count */
        uint8_t kindset;        /* we have 5 kinds so 8 bits are enough */
        uint8_t pushlevel;      /* current pushlevel */
        uint8_t ncount;         /* end usage item count */
        uint8_t icount;         /* current usage item count */
        uint8_t nusage;         /* end "usages_min/max" index */
        uint8_t iusage;         /* current "usages_min/max" index */
        uint8_t ousage;         /* current "usages_min/max" offset */
        uint8_t susage;         /* usage set flags */
        int32_t reportid;       /* requested report ID */
};

/*------------------------------------------------------------------------*
 *      hid_clear_local
 *------------------------------------------------------------------------*/
static void
hid_clear_local(hid_item_t *c)
{

        c->usage = 0;
        c->usage_minimum = 0;
        c->usage_maximum = 0;
        c->designator_index = 0;
        c->designator_minimum = 0;
        c->designator_maximum = 0;
        c->string_index = 0;
        c->string_minimum = 0;
        c->string_maximum = 0;
        c->set_delimiter = 0;
}

static void
hid_switch_rid(struct hid_data *s, struct hid_item *c, int32_t next_rID)
{
        uint8_t i, j;

        /* check for same report ID - optimise */

        if (c->report_ID == next_rID)
                return;

        /* save current position for current rID */

        if (c->report_ID == 0) {
                i = 0;
        } else {
                for (i = 1; i != MAXID; i++) {
                        if (s->last_pos[i].rid == c->report_ID)
                                break;
                        if (s->last_pos[i].rid == 0)
                                break;
                }
        }
        if (i != MAXID) {
                s->last_pos[i].rid = c->report_ID;
                for (j = 0; j < ITEMTYPES; j++)
                        s->last_pos[i].pos[j] = s->pos[j];
        }

        /* store next report ID */

        c->report_ID = next_rID;

        /* lookup last position for next rID */

        if (next_rID == 0) {
                i = 0;
        } else {
                for (i = 1; i != MAXID; i++) {
                        if (s->last_pos[i].rid == next_rID)
                                break;
                        if (s->last_pos[i].rid == 0)
                                break;
                }
        }
        if (i != MAXID) {
                s->last_pos[i].rid = next_rID;
                for (j = 0; j < ITEMTYPES; j++)
                        s->pos[j] = s->last_pos[i].pos[j];
        } else {
                for (j = 0; j < ITEMTYPES; j++)
                        s->pos[j] = 0;  /* Out of RID entries. */
        }
}

/*------------------------------------------------------------------------*
 *      hid_start_parse
 *------------------------------------------------------------------------*/
hid_data_t
hid_start_parse(report_desc_t d, int kindset, int id)
{
        struct hid_data *s;

        s = malloc(sizeof *s);
        memset(s, 0, sizeof *s);
        s->start = s->p = d->data;
        s->end = d->data + d->size;
        s->kindset = kindset;
        s->reportid = id;
        return (s);
}

/*------------------------------------------------------------------------*
 *      hid_end_parse
 *------------------------------------------------------------------------*/
void
hid_end_parse(hid_data_t s)
{

        if (s == NULL)
                return;

        free(s);
}

/*------------------------------------------------------------------------*
 *      get byte from HID descriptor
 *------------------------------------------------------------------------*/
static uint8_t
hid_get_byte(struct hid_data *s, const uint16_t wSize)
{
        const uint8_t *ptr;
        uint8_t retval;

        ptr = s->p;

        /* check if end is reached */
        if (ptr == s->end)
                return (0);

        /* read out a byte */
        retval = *ptr;

        /* check if data pointer can be advanced by "wSize" bytes */
        if ((s->end - ptr) < wSize)
                ptr = s->end;
        else
                ptr += wSize;

        /* update pointer */
        s->p = ptr;

        return (retval);
}

/*------------------------------------------------------------------------*
 *      hid_get_item
 *------------------------------------------------------------------------*/
static int
hid_get_item_raw(hid_data_t s, hid_item_t *h)
{
        hid_item_t *c;
        unsigned int bTag, bType, bSize;
        int32_t mask;
        int32_t dval;

        if (s == NULL)
                return (0);

        c = &s->cur[s->pushlevel];

 top:
        /* check if there is an array of items */
        if (s->icount < s->ncount) {
                /* get current usage */
                if (s->iusage < s->nusage) {
                        dval = s->usages_min[s->iusage] + s->ousage;
                        c->usage = dval;
                        s->usage_last = dval;
                        if (dval == s->usages_max[s->iusage]) {
                                s->iusage ++;
                                s->ousage = 0;
                        } else {
                                s->ousage ++;
                        }
                } else {
                        /* Using last usage */
                        dval = s->usage_last;
                }
                s->icount ++;
                /* 
                 * Only copy HID item, increment position and return
                 * if correct kindset!
                 */
                if (s->kindset & (1 << c->kind)) {
                        *h = *c;
                        h->pos = s->pos[c->kind];
                        s->pos[c->kind] += c->report_size * c->report_count;
                        return (1);
                }
        }

        /* reset state variables */
        s->icount = 0;
        s->ncount = 0;
        s->iusage = 0;
        s->nusage = 0;
        s->susage = 0;
        s->ousage = 0;
        hid_clear_local(c);

        /* get next item */
        while (s->p != s->end) {

                bSize = hid_get_byte(s, 1);
                if (bSize == 0xfe) {
                        /* long item */
                        bSize = hid_get_byte(s, 1);
                        bSize |= hid_get_byte(s, 1) << 8;
                        bTag = hid_get_byte(s, 1);
                        bType = 0xff;   /* XXX what should it be */
                } else {
                        /* short item */
                        bTag = bSize >> 4;
                        bType = (bSize >> 2) & 3;
                        bSize &= 3;
                        if (bSize == 3)
                                bSize = 4;
                }

                switch(bSize) {
                case 0:
                        dval = 0;
                        mask = 0;
                        break;
                case 1:
                        dval = (int8_t)hid_get_byte(s, 1);
                        mask = 0xFF;
                        break;
                case 2:
                        dval = hid_get_byte(s, 1);
                        dval |= hid_get_byte(s, 1) << 8;
                        dval = (int16_t)dval;
                        mask = 0xFFFF;
                        break;
                case 4:
                        dval = hid_get_byte(s, 1);
                        dval |= hid_get_byte(s, 1) << 8;
                        dval |= hid_get_byte(s, 1) << 16;
                        dval |= hid_get_byte(s, 1) << 24;
                        mask = 0xFFFFFFFF;
                        break;
                default:
                        dval = hid_get_byte(s, bSize);
                        continue;
                }

                switch (bType) {
                case 0:         /* Main */
                        switch (bTag) {
                        case 8: /* Input */
                                c->kind = hid_input;
                                c->flags = dval;
                ret:
                                c->report_count = s->loc_count;
                                c->report_size = s->loc_size;

                                if (c->flags & HIO_VARIABLE) {
                                        /* range check usage count */
                                        if (c->report_count > 255) {
                                                s->ncount = 255;
                                        } else
                                                s->ncount = c->report_count;

                                        /* 
                                         * The "top" loop will return
                                         * one and one item:
                                         */
                                        c->report_count = 1;
                                        c->usage_minimum = 0;
                                        c->usage_maximum = 0;
                                } else {
                                        s->ncount = 1;
                                }
                                goto top;

                        case 9: /* Output */
                                c->kind = hid_output;
                                c->flags = dval;
                                goto ret;
                        case 10:        /* Collection */
                                c->kind = hid_collection;
                                c->collection = dval;
                                c->collevel++;
                                c->usage = s->usage_last;
                                *h = *c;
                                return (1);
                        case 11:        /* Feature */
                                c->kind = hid_feature;
                                c->flags = dval;
                                goto ret;
                        case 12:        /* End collection */
                                c->kind = hid_endcollection;
                                if (c->collevel == 0) {
                                        /* Invalid end collection. */
                                        return (0);
                                }
                                c->collevel--;
                                *h = *c;
                                return (1);
                        default:
                                break;
                        }
                        break;

                case 1:         /* Global */
                        switch (bTag) {
                        case 0:
                                c->_usage_page = dval << 16;
                                break;
                        case 1:
                                c->logical_minimum = dval;
                                break;
                        case 2:
                                c->logical_maximum = dval;
                                break;
                        case 3:
                                c->physical_minimum = dval;
                                break;
                        case 4:
                                c->physical_maximum = dval;
                                break;
                        case 5:
                                c->unit_exponent = dval;
                                break;
                        case 6:
                                c->unit = dval;
                                break;
                        case 7:
                                /* mask because value is unsigned */
                                s->loc_size = dval & mask;
                                break;
                        case 8:
                                hid_switch_rid(s, c, dval & mask);
                                break;
                        case 9:
                                /* mask because value is unsigned */
                                s->loc_count = dval & mask;
                                break;
                        case 10:        /* Push */
                                /* stop parsing, if invalid push level */
                                if ((s->pushlevel + 1) >= MAXPUSH)
                                        return (0);
                                s->pushlevel ++;
                                s->cur[s->pushlevel] = *c;
                                /* store size and count */
                                c->report_size = s->loc_size;
                                c->report_count = s->loc_count;
                                /* update current item pointer */
                                c = &s->cur[s->pushlevel];
                                break;
                        case 11:        /* Pop */
                                /* stop parsing, if invalid push level */
                                if (s->pushlevel == 0)
                                        return (0);
                                s->pushlevel --;
                                c = &s->cur[s->pushlevel];
                                /* restore size and count */
                                s->loc_size = c->report_size;
                                s->loc_count = c->report_count;
                                c->report_size = 0;
                                c->report_count = 0;
                                break;
                        default:
                                break;
                        }
                        break;
                case 2:         /* Local */
                        switch (bTag) {
                        case 0:
                                if (bSize != 4)
                                        dval = (dval & mask) | c->_usage_page;

                                /* set last usage, in case of a collection */
                                s->usage_last = dval;

                                if (s->nusage < MAXUSAGE) {
                                        s->usages_min[s->nusage] = dval;
                                        s->usages_max[s->nusage] = dval;
                                        s->nusage ++;
                                }
                                /* else XXX */

                                /* clear any pending usage sets */
                                s->susage = 0;
                                break;
                        case 1:
                                s->susage |= 1;

                                if (bSize != 4)
                                        dval = (dval & mask) | c->_usage_page;
                                c->usage_minimum = dval;

                                goto check_set;
                        case 2:
                                s->susage |= 2;

                                if (bSize != 4)
                                        dval = (dval & mask) | c->_usage_page;
                                c->usage_maximum = dval;

                        check_set:
                                if (s->susage != 3)
                                        break;

                                /* sanity check */
                                if ((s->nusage < MAXUSAGE) &&
                                    (c->usage_minimum <= c->usage_maximum)) {
                                        /* add usage range */
                                        s->usages_min[s->nusage] = 
                                            c->usage_minimum;
                                        s->usages_max[s->nusage] = 
                                            c->usage_maximum;
                                        s->nusage ++;
                                }
                                /* else XXX */

                                s->susage = 0;
                                break;
                        case 3:
                                c->designator_index = dval;
                                break;
                        case 4:
                                c->designator_minimum = dval;
                                break;
                        case 5:
                                c->designator_maximum = dval;
                                break;
                        case 7:
                                c->string_index = dval;
                                break;
                        case 8:
                                c->string_minimum = dval;
                                break;
                        case 9:
                                c->string_maximum = dval;
                                break;
                        case 10:
                                c->set_delimiter = dval;
                                break;
                        default:
                                break;
                        }
                        break;
                default:
                        break;
                }
        }
        return (0);
}

int
hid_get_item(hid_data_t s, hid_item_t *h)
{
        int r;

        for (;;) {
                r = hid_get_item_raw(s, h);
                if (r <= 0 || s->reportid == -1 || h->report_ID == s->reportid)
                        break;
        }
        return (r);
}

int
hid_report_size(report_desc_t r, enum hid_kind k, int id)
{
        struct hid_data *d;
        struct hid_item h;
        uint32_t temp;
        uint32_t hpos;
        uint32_t lpos;
        int report_id = 0;

        hpos = 0;
        lpos = 0xFFFFFFFF;

        memset(&h, 0, sizeof h);
        for (d = hid_start_parse(r, 1 << k, id); hid_get_item(d, &h); ) {
                if (h.kind == k) {
                        /* compute minimum */
                        if (lpos > h.pos)
                                lpos = h.pos;
                        /* compute end position */
                        temp = h.pos + (h.report_size * h.report_count);
                        /* compute maximum */
                        if (hpos < temp)
                                hpos = temp;
                        if (h.report_ID != 0)
                                report_id = 1;
                }
        }
        hid_end_parse(d);

        /* safety check - can happen in case of currupt descriptors */
        if (lpos > hpos)
                temp = 0;
        else
                temp = hpos - lpos;

        /* return length in bytes rounded up */
        return ((temp + 7) / 8 + report_id);
}

int
hid_locate(report_desc_t desc, unsigned int u, enum hid_kind k,
           hid_item_t *h, int id)
{
        struct hid_data *d;

        for (d = hid_start_parse(desc, 1 << k, id); hid_get_item(d, h); ) {
                if (h->kind == k && !(h->flags & HIO_CONST) && h->usage == u) {
                        hid_end_parse(d);
                        return (1);
                }
        }
        hid_end_parse(d);
        h->report_size = 0;
        return (0);
}