/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <string.h>
#include "secitem.h"
#include "secport.h"
#include "secerr.h"

/* if to->data is not NULL, and to->len is large enough to hold the result,
 * then the resultant OID will be copyed into to->data, and to->len will be
 * changed to show the actual OID length.
 * Otherwise, memory for the OID will be allocated (from the caller's
 * PLArenaPool, if pool is non-NULL) and to->data will receive the address
 * of the allocated data, and to->len will receive the OID length.
 * The original value of to->data is not freed when a new buffer is allocated.
 *
 * The input string may begin with "OID." and this still be ignored.
 * The length of the input string is given in len.  If len == 0, then
 * len will be computed as strlen(from), meaning it must be NUL terminated.
 * It is an error if from == NULL, or if *from == '\0'.
 */

SECStatus
SEC_StringToOID(PLArenaPool *pool, SECItem *to, const char *from, PRUint32 len)
{
    PRUint32 decimal_numbers = 0;
    PRUint32 result_bytes = 0;
    SECStatus rv;
    PRUint8 result[1024];

    static const PRUint32 max_decimal = (0xffffffff / 10);
    static const char OIDstring[] = { "OID." };

    if (!from || !to) {
        PORT_SetError(SEC_ERROR_INVALID_ARGS);
        return SECFailure;
    }
    if (!len) {
        len = PL_strlen(from);
    }
    if (len >= 4 && !PL_strncasecmp(from, OIDstring, 4)) {
        from += 4; /* skip leading "OID." if present */
        len -= 4;
    }
    if (!len) {
    bad_data:
        PORT_SetError(SEC_ERROR_BAD_DATA);
        return SECFailure;
    }
    do {
        PRUint32 decimal = 0;
        while (len > 0 && isdigit(*from)) {
            PRUint32 addend = (*from++ - '0');
            --len;
            if (decimal > max_decimal) /* overflow */
                goto bad_data;
            decimal = (decimal * 10) + addend;
            if (decimal < addend) /* overflow */
                goto bad_data;
        }
        if (len != 0 && *from != '.') {
            goto bad_data;
        }
        if (decimal_numbers == 0) {
            if (decimal > 2)
                goto bad_data;
            result[0] = decimal * 40;
            result_bytes = 1;
        } else if (decimal_numbers == 1) {
            if (decimal > 40)
                goto bad_data;
            result[0] += decimal;
        } else {
            /* encode the decimal number,  */
            PRUint8 *rp;
            PRUint32 num_bytes = 0;
            PRUint32 tmp = decimal;
            while (tmp) {
                num_bytes++;
                tmp >>= 7;
            }
            if (!num_bytes)
                ++num_bytes; /* use one byte for a zero value */
            if (num_bytes + result_bytes > sizeof result)
                goto bad_data;
            tmp = num_bytes;
            rp = result + result_bytes - 1;
            rp[tmp] = (PRUint8)(decimal & 0x7f);
            decimal >>= 7;
            while (--tmp > 0) {
                rp[tmp] = (PRUint8)(decimal | 0x80);
                decimal >>= 7;
            }
            result_bytes += num_bytes;
        }
        ++decimal_numbers;
        if (len > 0) { /* skip trailing '.' */
            ++from;
            --len;
        }
    } while (len > 0);
    /* now result contains result_bytes of data */
    if (to->data && to->len >= result_bytes) {
        PORT_Memcpy(to->data, result, to->len = result_bytes);
        rv = SECSuccess;
    } else {
        SECItem result_item = { siBuffer, NULL, 0 };
        result_item.data = result;
        result_item.len = result_bytes;
        rv = SECITEM_CopyItem(pool, to, &result_item);
    }
    return rv;
}