/*
 * Copyright (c) 1997 - 2001 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * 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.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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 <config.h>

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include "roken.h"
#include "parse_units.h"

/*
 * Parse string in `s' according to `units' and return value.
 * def_unit defines the default unit.
 */

static int
parse_something (const char *s, const struct units *units,
                 const char *def_unit,
                 int (*func)(int res, int val, unsigned mult),
                 int init,
                 int accept_no_val_p)
{
    const char *p;
    int res = init;
    unsigned def_mult = 1;

    if (def_unit != NULL) {
        const struct units *u;

        for (u = units; u->name; ++u) {
            if (strcasecmp (u->name, def_unit) == 0) {
                def_mult = u->mult;
                break;
            }
        }
        if (u->name == NULL)
            return -1;
    }

    p = s;
    while (*p) {
        int val;
        char *next;
        const struct units *u, *partial_unit;
        size_t u_len;
        unsigned partial;
        int no_val_p = 0;

        while(isspace((unsigned char)*p) || *p == ',')
            ++p;

        val = strtol(p, &next, 0);
        if (p == next) {
            val = 0;
            if(!accept_no_val_p)
                return -1;
            no_val_p = 1;
        }
        p = next;
        while (isspace((unsigned char)*p))
            ++p;
        if (*p == '\0') {
            res = (*func)(res, val, def_mult);
            if (res < 0)
                return res;
            break;
        } else if (*p == '+') {
            ++p;
            val = 1;
        } else if (*p == '-') {
            ++p;
            val = -1;
        }
        if (no_val_p && val == 0)
            val = 1;
        u_len = strcspn (p, ", \t");
        partial = 0;
        partial_unit = NULL;
        if (u_len > 1 && p[u_len - 1] == 's')
            --u_len;
        for (u = units; u->name; ++u) {
            if (strncasecmp (p, u->name, u_len) == 0) {
                if (u_len == strlen (u->name)) {
                    p += u_len;
                    res = (*func)(res, val, u->mult);
                    if (res < 0)
                        return res;
                    break;
                } else {
                    ++partial;
                    partial_unit = u;
                }
            }
        }
        if (u->name == NULL) {
            if (partial == 1) {
                p += u_len;
                res = (*func)(res, val, partial_unit->mult);
                if (res < 0)
                    return res;
            } else {
                return -1;
            }
        }
        if (*p == 's')
            ++p;
    }
    return res;
}

/*
 * The string consists of a sequence of `n unit'
 */

static int
acc_units(int res, int val, unsigned mult)
{
    return res + val * mult;
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
parse_units (const char *s, const struct units *units,
             const char *def_unit)
{
    return parse_something (s, units, def_unit, acc_units, 0, 0);
}

/*
 * The string consists of a sequence of `[+-]flag'.  `orig' consists
 * the original set of flags, those are then modified and returned as
 * the function value.
 */

static int
acc_flags(int res, int val, unsigned mult)
{
    if(val == 1)
        return res | mult;
    else if(val == -1)
        return res & ~mult;
    else if (val == 0)
        return mult;
    else
        return -1;
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
parse_flags (const char *s, const struct units *units,
             int orig)
{
    return parse_something (s, units, NULL, acc_flags, orig, 1);
}

/*
 * Return a string representation according to `units' of `num' in `s'
 * with maximum length `len'.  The actual length is the function value.
 */

static int
unparse_something (int num, const struct units *units, char *s, size_t len,
                   int (*print) (char *, size_t, int, const char *, int),
                   int (*update) (int, unsigned),
                   const char *zero_string)
{
    const struct units *u;
    int ret = 0, tmp;

    if (num == 0)
        return snprintf (s, len, "%s", zero_string);

    for (u = units; num > 0 && u->name; ++u) {
        int divisor;

        divisor = num / u->mult;
        if (divisor) {
            num = (*update) (num, u->mult);
            tmp = (*print) (s, len, divisor, u->name, num);
            if (tmp < 0)
                return tmp;
            if (tmp > (int) len) {
                len = 0;
                s = NULL;
            } else {
                len -= tmp;
                s += tmp;
            }
            ret += tmp;
        }
    }
    return ret;
}

static int
print_unit (char *s, size_t len, int divisor, const char *name, int rem)
{
    return snprintf (s, len, "%u %s%s%s",
                     divisor, name,
                     divisor == 1 ? "" : "s",
                     rem > 0 ? " " : "");
}

static int
update_unit (int in, unsigned mult)
{
    return in % mult;
}

static int
update_unit_approx (int in, unsigned mult)
{
    if (in / mult > 0)
        return 0;
    else
        return update_unit (in, mult);
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
unparse_units (int num, const struct units *units, char *s, size_t len)
{
    return unparse_something (num, units, s, len,
                              print_unit,
                              update_unit,
                              "0");
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
unparse_units_approx (int num, const struct units *units, char *s, size_t len)
{
    return unparse_something (num, units, s, len,
                              print_unit,
                              update_unit_approx,
                              "0");
}

ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
print_units_table (const struct units *units, FILE *f)
{
    const struct units *u, *u2;
    size_t max_sz = 0;

    for (u = units; u->name; ++u) {
        max_sz = max(max_sz, strlen(u->name));
    }

    for (u = units; u->name;) {
        char buf[1024];
        const struct units *next;

        for (next = u + 1; next->name && next->mult == u->mult; ++next)
            ;

        if (next->name) {
            for (u2 = next;
                 u2->name && u->mult % u2->mult != 0;
                 ++u2)
                ;
            if (u2->name == NULL)
                --u2;
            unparse_units (u->mult, u2, buf, sizeof(buf));
            fprintf (f, "1 %*s = %s\n", (int)max_sz, u->name, buf);
        } else {
            fprintf (f, "1 %s\n", u->name);
        }
        u = next;
    }
}

static int
print_flag (char *s, size_t len, int divisor, const char *name, int rem)
{
    return snprintf (s, len, "%s%s", name, rem > 0 ? ", " : "");
}

static int
update_flag (int in, unsigned mult)
{
    return in - mult;
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
unparse_flags (int num, const struct units *units, char *s, size_t len)
{
    return unparse_something (num, units, s, len,
                              print_flag,
                              update_flag,
                              "");
}

ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
print_flags_table (const struct units *units, FILE *f)
{
    const struct units *u;

    for(u = units; u->name; ++u)
        fprintf(f, "%s%s", u->name, (u+1)->name ? ", " : "\n");
}