source: mainline/uspace/lib/usbhid/src/hidparser.c@ 1bab1c8

/*
 * Copyright (c) 2011 Matej Klonfar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 */

/** @addtogroup libusbhid
 * @{
 */
/** @file
 * USB HID report data parser implementation.
 */
#include <usb/hid/hidparser.h>
#include <errno.h>
#include <stdio.h>
#include <malloc.h>
#include <mem.h>
#include <usb/debug.h>
#include <assert.h>
#include <bitops.h>
#include <macros.h>


/*
 * Data translation private functions
 */
uint32_t usb_hid_report_tag_data_uint32(const uint8_t *data, size_t size);

int usb_hid_translate_data(usb_hid_report_field_t *item, const uint8_t *data);

uint32_t usb_hid_translate_data_reverse(usb_hid_report_field_t *item, 
        int32_t value);



static int usb_pow(int a, int b)
{
        switch (b) {
        case 0:
                return 1;
                break;
        case 1:
                return a;
                break;
        default:
                return a * usb_pow(a, b - 1);
                break;
        }
}


/** Returns size of report of specified report id and type in items
 *
 * @param parser Opaque report parser structure
 * @param report_id 
 * @param type
 * @return Number of items in specified report
 */
size_t usb_hid_report_size(usb_hid_report_t *report, uint8_t report_id, 
    usb_hid_report_type_t type)
{
        usb_hid_report_description_t *report_des;

        if (report == NULL) {
                return 0;
        }

        report_des = usb_hid_report_find_description(report, report_id, type);
        if (report_des == NULL) {
                return 0;
        } else {
                return report_des->item_length;
        }
}

/** Returns size of report of specified report id and type in bytes
 *
 * @param parser Opaque report parser structure
 * @param report_id 
 * @param type
 * @return Number of items in specified report
 */
size_t usb_hid_report_byte_size(usb_hid_report_t *report, uint8_t report_id, 
    usb_hid_report_type_t type)
{
        usb_hid_report_description_t *report_des;

        if (report == NULL) {
                return 0;
        }

        report_des = usb_hid_report_find_description(report, report_id, type);
        if (report_des == NULL) {
                return 0;
        } else {
                return ((report_des->bit_length + 7) / 8) ;
        }
}


/** Parse and act upon a HID report.
 *
 * @see usb_hid_parse_report_descriptor
 *
 * @param parser Opaque HID report parser structure.
 * @param data Data for the report.
 * @return Error code.
 */ 
int usb_hid_parse_report(const usb_hid_report_t *report, const uint8_t *data, 
    size_t size, uint8_t *report_id)
{
        usb_hid_report_description_t *report_des;
        usb_hid_report_type_t type = USB_HID_REPORT_TYPE_INPUT;
        
        if (report == NULL) {
                return EINVAL;
        }

        if (report->use_report_ids != 0) {
                *report_id = data[0];
        } else {
                *report_id = 0;
        }

        report_des = usb_hid_report_find_description(report, *report_id, 
            type);

        if (report_des == NULL) {
                return EINVAL;
        }

        /* read data */
        list_foreach(report_des->report_items, ritems_link,
            usb_hid_report_field_t, item) {

                if (USB_HID_ITEM_FLAG_CONSTANT(item->item_flags) == 0) {
                        
                        if (USB_HID_ITEM_FLAG_VARIABLE(item->item_flags) == 0) {
                                /* array */
                                item->value = 
                                        usb_hid_translate_data(item, data);
                                
                                item->usage = USB_HID_EXTENDED_USAGE(
                                    item->usages[item->value -
                                    item->physical_minimum]);

                                item->usage_page = 
                                    USB_HID_EXTENDED_USAGE_PAGE(
                                    item->usages[item->value -
                                    item->physical_minimum]);

                                usb_hid_report_set_last_item(
                                    item->collection_path, 
                                    USB_HID_TAG_CLASS_GLOBAL, 
                                    item->usage_page);

                                usb_hid_report_set_last_item(
                                    item->collection_path, 
                                    USB_HID_TAG_CLASS_LOCAL, item->usage);
                        } else {
                                /* variable item */
                                item->value = usb_hid_translate_data(item, 
                                    data);
                        }
                }
        }
        
        return EOK;
}


/**
 * Translate data from the report as specified in report descriptor item
 *
 * @param item Report descriptor item with definition of translation
 * @param data Data to translate
 * @return Translated data
 */
int usb_hid_translate_data(usb_hid_report_field_t *item, const uint8_t *data)
{
        /* now only short tags are allowed */
        if (item->size > 32) {
                return 0;
        }

        if ((item->physical_minimum == 0) && (item->physical_maximum == 0)) {
                item->physical_minimum = item->logical_minimum;
                item->physical_maximum = item->logical_maximum;
        }

        int resolution;
        if (item->physical_maximum == item->physical_minimum) {
            resolution = 1;
        } else {
            resolution = (item->logical_maximum - item->logical_minimum) /
                ((item->physical_maximum - item->physical_minimum) *
                (usb_pow(10, (item->unit_exponent))));
        }

        int32_t value = 0;

        /* First, skip all bytes we don't care */
        data += item->offset / 8;

        int bits = item->size;
        int taken = 0;

        /* Than we take the higher bits from the LSB */
        const unsigned bit_offset = item->offset % 8;
        const int lsb_bits = min(bits, 8);

        value |= (*data >> bit_offset) & BIT_RRANGE(uint8_t, lsb_bits);
        bits -= lsb_bits;
        taken += lsb_bits;
        data++;

        /* Then there may be bytes, which we take as a whole. */
        while (bits > 8) {
                value |= *data << taken;
                taken += 8;
                bits -= 8;
                data++;
        }

        /* And, finally, lower bits from HSB. */
        if (bits > 0) {
                value |= (*data & BIT_RRANGE(uint8_t, bits)) << taken;
        }

        if ((item->logical_minimum < 0) || (item->logical_maximum < 0)) {
                value = USB_HID_UINT32_TO_INT32(value, item->size);
        }

        return (int) (((value - item->logical_minimum) / resolution) + 
            item->physical_minimum);
}


/* OUTPUT API */

/** 
 * Allocates output report buffer for output report
 *
 * @param parser Report parsed structure
 * @param size Size of returned buffer
 * @param report_id Report id of created output report
 * @return Returns allocated output buffer for specified output
 */
uint8_t *usb_hid_report_output(usb_hid_report_t *report, size_t *size, 
    uint8_t report_id)
{
        if (report == NULL) {
                *size = 0;
                return NULL;
        }

        usb_hid_report_description_t *report_des = NULL;

        list_foreach(report->reports, reports_link,
            usb_hid_report_description_t, rdes) {
                if ((rdes->report_id == report_id) &&
                    (rdes->type == USB_HID_REPORT_TYPE_OUTPUT)) {
                        report_des = rdes;
                        break;
                }
        }

        if (report_des == NULL) {
                *size = 0;
                return NULL;
        } else {
                *size = (report_des->bit_length + (8 - 1)) / 8;
                uint8_t *ret = malloc((*size) * sizeof(uint8_t));
                memset(ret, 0, (*size) * sizeof(uint8_t));
                return ret;
        }
}


/** Frees output report buffer
 *
 * @param output Output report buffer
 * @return void
 */
void usb_hid_report_output_free(uint8_t *output)
{
        if (output != NULL) {
                free(output);
        }
}

/** Makes the output report buffer for data given in the report structure
 *
 * @param parser Opaque report parser structure
 * @param path Usage path specifing which parts of output will be set
 * @param flags Usage path structure comparison flags
 * @param buffer Output buffer
 * @param size Size of output buffer
 * @return Error code
 */
int usb_hid_report_output_translate(usb_hid_report_t *report, 
    uint8_t report_id, uint8_t *buffer, size_t size)
{
        int32_t value = 0;
        int offset;
        int length;
        int32_t tmp_value;
        
        if (report == NULL) {
                return EINVAL;
        }

        if (report->use_report_ids != 0) {
                buffer[0] = report_id;
        }

        usb_hid_report_description_t *report_des;
        report_des = usb_hid_report_find_description(report, report_id, 
            USB_HID_REPORT_TYPE_OUTPUT);
        
        if (report_des == NULL) {
                return EINVAL;
        }

        list_foreach(report_des->report_items, ritems_link,
            usb_hid_report_field_t, report_item) {
                value = usb_hid_translate_data_reverse(report_item, 
                    report_item->value);

                offset = report_des->bit_length - report_item->offset - 1;
                length = report_item->size;
                
                usb_log_debug("\ttranslated value: %x", value);

                if ((offset / 8) == ((offset + length - 1) / 8)) {
                        if (((size_t) (offset / 8) >= size) || 
                            ((size_t) (offset + length - 1) / 8) >= size) {
                                break; // TODO ErrorCode
                        }
                        size_t shift = 8 - offset % 8 - length;
                        value = value << shift;
                        value = value & (((1 << length) - 1) << shift);
                        
                        uint8_t mask = 0;
                        mask = 0xff - (((1 << length) - 1) << shift);
                        buffer[offset / 8] = (buffer[offset / 8] & mask) |
                            value;
                } else {
                        int i = 0;
                        uint8_t mask = 0;
                        for (i = (offset / 8);
                            i <= ((offset + length - 1) / 8); i++) {
                                if (i == (offset / 8)) {
                                        tmp_value = value;
                                        tmp_value = tmp_value & 
                                            ((1 << (8 - (offset % 8))) - 1);

                                        tmp_value = tmp_value << (offset % 8);
                                        
                                        mask = ~(((1 << (8 - (offset % 8))) - 1)
                                            << (offset % 8));

                                        buffer[i] = (buffer[i] & mask) | 
                                            tmp_value;
                                } else if (i == ((offset + length - 1) / 8)) {
                                        
                                        value = value >> (length - 
                                            ((offset + length) % 8));

                                        value = value & ((1 << (length - 
                                            ((offset + length) % 8))) - 1);
                                        
                                        mask = (1 << (length - 
                                            ((offset + length) % 8))) - 1;

                                        buffer[i] = (buffer[i] & mask) | value;
                                } else {
                                        buffer[i] = value & (0xff << i);
                                }
                        }
                }

                /* reset value */
                report_item->value = 0;
        }
        
        return EOK;
}


/**
 * Translate given data for putting them into the outoput report
 * @param item Report item structure
 * @param value Value to translate
 * @return ranslated value
 */
uint32_t usb_hid_translate_data_reverse(usb_hid_report_field_t *item, 
    int value)
{
        int ret = 0;
        int resolution;

        if (USB_HID_ITEM_FLAG_CONSTANT(item->item_flags)) {
                return item->logical_minimum;
        }

        if ((item->physical_minimum == 0) && (item->physical_maximum == 0)) {
                item->physical_minimum = item->logical_minimum;
                item->physical_maximum = item->logical_maximum;                 
        }
        
        /* variable item */
        if (item->physical_maximum == item->physical_minimum) {
            resolution = 1;
        } else {
            resolution = (item->logical_maximum - item->logical_minimum) /
                ((item->physical_maximum - item->physical_minimum) *
                (usb_pow(10, (item->unit_exponent))));
        }

        ret = ((value - item->physical_minimum) * resolution) + 
            item->logical_minimum;

        usb_log_debug("\tvalue(%x), resolution(%x), phymin(%x) logmin(%x), "
            "ret(%x)\n", value, resolution, item->physical_minimum, 
            item->logical_minimum, ret);
        
        if ((item->logical_minimum < 0) || (item->logical_maximum < 0)) {
                return USB_HID_INT32_TO_UINT32(ret, item->size);
        }

        return (int32_t) 0 + ret;
}


/**
 * Clones given state table
 *
 * @param item State table to clone
 * @return Pointer to the cloned item
 */
usb_hid_report_item_t *usb_hid_report_item_clone(
    const usb_hid_report_item_t *item)
{
        usb_hid_report_item_t *new_report_item;
        
        if (!(new_report_item = malloc(sizeof(usb_hid_report_item_t)))) {
                return NULL;
        }                                       
        memcpy(new_report_item,item, sizeof(usb_hid_report_item_t));
        link_initialize(&(new_report_item->link));

        return new_report_item;
}


/**
 * Function for sequence walking through the report. Returns next field in the
 * report or the first one when no field is given.
 *
 * @param report Searched report structure
 * @param field Current field. If NULL is given, the first one in the report
 * is returned. Otherwise the next one i nthe list is returned.
 * @param path Usage path specifying which fields wa are interested in. 
 * @param flags Flags defining mode of usage paths comparison
 * @param type Type of report we search.
 * @retval NULL if no field is founded
 * @retval Pointer to the founded report structure when founded
 */
usb_hid_report_field_t *usb_hid_report_get_sibling(usb_hid_report_t *report, 
    usb_hid_report_field_t *field, usb_hid_report_path_t *path, int flags, 
    usb_hid_report_type_t type)
{
        usb_hid_report_description_t *report_des = 
            usb_hid_report_find_description(report, path->report_id, type);

        link_t *field_it;
        
        if (report_des == NULL) {
                return NULL;
        }

        if (field == NULL) {
                field_it = report_des->report_items.head.next;
        } else {
                field_it = field->ritems_link.next;
        }

        while (field_it != &report_des->report_items.head) {
                field = list_get_instance(field_it, usb_hid_report_field_t, 
                    ritems_link);

                if (USB_HID_ITEM_FLAG_CONSTANT(field->item_flags) == 0) {
                        usb_hid_report_path_append_item(field->collection_path,
                            field->usage_page, field->usage);

                        if (usb_hid_report_compare_usage_path(
                            field->collection_path, path, flags) == EOK) {
                                usb_hid_report_remove_last_item(
                                    field->collection_path);
                                return field;
                        }
                        usb_hid_report_remove_last_item(field->collection_path);
                }
                field_it = field_it->next;
        }

        return NULL;
}


/**
 * Returns next report_id of report of specified type. If zero is given than
 * first report_id of specified type is returned (0 is not legal value for
 * repotr_id)
 *
 * @param report_id Current report_id, 0 if there is no current report_id
 * @param type Type of searched report
 * @param report Report structure inwhich we search
 * @retval 0 if report structure is null or there is no specified report
 * @retval report_id otherwise
 */
uint8_t usb_hid_get_next_report_id(usb_hid_report_t *report, uint8_t report_id,
    usb_hid_report_type_t type)
{
        if (report == NULL) {
                return 0;
        }

        usb_hid_report_description_t *report_des;
        link_t *report_it;
        
        if (report_id > 0) {
                report_des = usb_hid_report_find_description(report, report_id, 
                    type);
                if (report_des == NULL) {
                        return 0;
                } else {
                        report_it = report_des->reports_link.next;
                }       
        } else {
                report_it = report->reports.head.next;
        }

        while (report_it != &report->reports.head) {
                report_des = list_get_instance(report_it, 
                    usb_hid_report_description_t, reports_link);

                if (report_des->type == type) {
                        return report_des->report_id;
                }

                report_it = report_it->next;
        }

        return 0;
}


/**
 * Reset all local items in given state table
 *
 * @param report_item State table containing current state of report
 * descriptor parsing
 *
 * @return void
 */
void usb_hid_report_reset_local_items(usb_hid_report_item_t *report_item)
{
        if (report_item == NULL) {
                return;
        }
        
        report_item->usages_count = 0;
        memset(report_item->usages, 0, USB_HID_MAX_USAGES);
        
        report_item->extended_usage_page = 0;
        report_item->usage_minimum = 0;
        report_item->usage_maximum = 0;
        report_item->designator_index = 0;
        report_item->designator_minimum = 0;
        report_item->designator_maximum = 0;
        report_item->string_index = 0;
        report_item->string_minimum = 0;
        report_item->string_maximum = 0;
}

/**
 * @}
 */