/* $FreeBSD: head/tools/tools/bus_autoconf/bus_sections.c 223534 2011-06-25 13:44:05Z hselasky $ */

/*-
 * Copyright (c) 2011 Hans Petter Selasky. 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 <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <sysexits.h>
#include <err.h>
#include <string.h>

#include <sys/queue.h>

#include "bus_sections.h"

#define MAX_STRING      64

struct format_info;
typedef TAILQ_HEAD(,format_info) format_info_head_t;
typedef TAILQ_ENTRY(format_info) format_info_entry_t;

static format_info_head_t format_head = TAILQ_HEAD_INITIALIZER(format_head);

struct format_info {
        format_info_entry_t entry;
        format_info_head_t fields;
        char    name[MAX_STRING];
        uint16_t bit_offset;
        uint16_t bit_size;
};

static struct format_info *
format_info_new(char *pstr, uint16_t bo, uint16_t bs)
{
        struct format_info *pfi;

        pfi = malloc(sizeof(*pfi));
        if (pfi == NULL)
                errx(EX_SOFTWARE, "Out of memory.");

        memset(pfi, 0, sizeof(*pfi));

        TAILQ_INIT(&pfi->fields);

        strlcpy(pfi->name, pstr, sizeof(pfi->name));
        pfi->bit_offset = bo;
        pfi->bit_size = bs;
        return (pfi);
}

static const struct format_info *
format_get_section(const char *section)
{
        const struct format_info *psub;
        static const struct format_info *psub_last;
        static const char *psub_cache;

        if (psub_cache && strcmp(psub_cache, section) == 0)
                return (psub_last);

        TAILQ_FOREACH(psub, &format_head, entry) {
                if (strcmp(section, psub->name) == 0) {
                        psub_cache = section;
                        psub_last = psub;
                        return (psub);
                }
        }
        warnx("Section '%s' not found", section);
        psub_cache = section;
        psub_last = psub;
        return (NULL);
}

uint16_t
format_get_section_size(const char *section)
{
        const struct format_info *pfi;

        pfi = format_get_section(section);
        if (pfi == NULL)
                return (0);

        return ((pfi->bit_offset + 7) / 8);
}


uint8_t
format_get_field(const char *section, const char *field,
    const uint8_t *ptr, uint16_t size)
{
        const struct format_info *pfi;
        const struct format_info *psub;
        uint16_t rem;
        uint16_t off;
        uint16_t sz;

        pfi = format_get_section(section);
        if (pfi == NULL)
                return (0);

        /* skip until we find the fields */
        while (pfi && TAILQ_FIRST(&pfi->fields) == NULL)
                pfi = TAILQ_NEXT(pfi, entry);

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

        TAILQ_FOREACH(psub, &pfi->fields, entry) {
                if (strcmp(field, psub->name) == 0) {

                        /* range check */
                        if (((psub->bit_offset + psub->bit_size) / 8) > size)
                                return (0);

                        /* compute byte offset */
                        rem = psub->bit_offset & 7;
                        off = psub->bit_offset / 8;
                        sz = psub->bit_size;

                        /* extract bit-field */
                        return ((ptr[off] >> rem) & ((1 << sz) - 1));
                }
        }
        warnx("Field '%s' not found in '%s'", field, pfi->name);
        return (0);
}

void
format_parse_entries(const uint8_t *ptr, uint32_t len)
{
        static const char *command_list = "012345678:";
        const char *cmd;
        struct format_info *pfi;
        struct format_info *pfi_last = NULL;
        char linebuf[3][MAX_STRING];
        uint32_t off = 0;
        uint16_t bit_offset = 0;
        uint8_t state = 0;
        uint8_t cmd_index;
        int c;

        /*
         * The format we are parsing:
         * <string>{string,string}<next_string>{...}
         */
        while (len--) {
                c = *(ptr++);

                /* skip some characters */
                if (c == 0 || c == '\n' || c == '\r' || c == ' ' || c == '\t')
                        continue;

                /* accumulate non-field delimiters */
                if (strchr("{,}", c) == NULL) {
                        if (off < (MAX_STRING - 1)) {
                                linebuf[state][off] = c;
                                off++;
                        }
                        continue;
                }
                /* parse keyword */
                linebuf[state][off] = 0;
                off = 0;
                state++;
                if (state == 3) {
                        /* check for command in command list */
                        cmd = strchr(command_list, linebuf[2][0]);
                        if (cmd != NULL)
                                cmd_index = cmd - command_list;
                        else
                                cmd_index = 255;

                        /*
                         * Check for new field, format is:
                         *
                         * <field_name>{bit_offset_xor, bit_size}
                         */
                        if (cmd_index < 9 && pfi_last != NULL) {
                                pfi = format_info_new(linebuf[0], bit_offset ^
                                    atoi(linebuf[1]), cmd_index);
                                TAILQ_INSERT_TAIL(&pfi_last->fields, pfi, entry);
                                bit_offset += cmd_index;
                        }
                        /*
                         * Check for new section, format is:
                         *
                         * <section_name>{section_bit_size, :}
                         */
                        if (cmd_index == 9) {
                                pfi_last = format_info_new(linebuf[0],
                                    atoi(linebuf[1]), cmd_index);
                                TAILQ_INSERT_TAIL(&format_head, pfi_last, entry);
                                bit_offset = 0;
                        }
                        state = 0;
                        continue;
                }
        }
}