/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2019 Joyent, Inc.
 */

#include <string.h>
#include <sys/types.h>
#include <sys/debug.h>
#include "strview.h"

void
sv_init_sv(strview_t *sv, const strview_t *src)
{
        *sv = *src;
}

void
sv_init_sv_range(strview_t *sv, const strview_t *src, size_t len)
{
        VERIFY3U(sv_remaining(src), >=, len);

        sv->sv_first = src->sv_first;
        sv->sv_last = src->sv_first + len;
        sv->sv_rem = len;
}

void
sv_init_str(strview_t *sv, const char *first, const char *last)
{
        if (last == NULL)
                last = first + strlen(first);

        VERIFY3P(first, <=, last);
        sv->sv_first = first;
        sv->sv_last = last;
        sv->sv_rem = (size_t)(uintptr_t)(sv->sv_last - sv->sv_first);
}

size_t
sv_remaining(const strview_t *sv)
{
        return (sv->sv_rem);
}

boolean_t
sv_consume_if_c(strview_t *sv, char c)
{
        if (sv->sv_rem < 1 || *sv->sv_first != c)
                return (B_FALSE);

        sv->sv_first++;
        sv->sv_rem--;
        return (B_TRUE);
}

boolean_t
sv_consume_if(strview_t *sv, const char *str)
{
        size_t slen = strlen(str);

        if (sv->sv_rem < slen)
                return (B_FALSE);
        if (strncmp(sv->sv_first, str, slen) != 0)
                return (B_FALSE);

        sv->sv_first += slen;
        sv->sv_rem -= slen;
        return (B_TRUE);
}

char
sv_peek(const strview_t *sv, ssize_t n)
{
        const char *p;

        p = (n >= 0) ? sv->sv_first + n : sv->sv_last + n;
        return ((p >= sv->sv_first && p < sv->sv_last) ? *p : '\0');
}

char
sv_consume_c(strview_t *sv)
{
        char c = '\0';

        if (sv->sv_first < sv->sv_last) {
                c = *sv->sv_first++;
                sv->sv_rem--;
        }
        return (c);
}

void
sv_consume_n(strview_t *sv, size_t n)
{
        VERIFY3U(sv->sv_rem, >=, n);
        sv->sv_first += n;
        sv->sv_rem -= n;
}