/* 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 "blapit.h"

#include "secport.h"

#include "secerr.h"

/*

 * Prepare a buffer for any padded CBC encryption algorithm, growing to the

 * appropriate boundary and filling with the appropriate padding.

 * blockSize must be a power of 2.

 *

 * NOTE: If arena is non-NULL, we re-allocate from there, otherwise

 * we assume (and use) XP memory (re)allocation.

 */

unsigned char *

CBC_PadBuffer(PLArenaPool *arena, unsigned char *inbuf, unsigned int inlen,

              unsigned int *outlen, int blockSize)

{

    unsigned char *outbuf;

    unsigned int des_len;

    unsigned int i;

    unsigned char des_pad_len;

    /*

     * We need from 1 to blockSize bytes -- we *always* grow.

     * The extra bytes contain the value of the length of the padding:

     * if we have 2 bytes of padding, then the padding is "0x02, 0x02".

     */

    des_len = (inlen + blockSize) & ~(blockSize - 1);

    if (arena != NULL) {

        outbuf = (unsigned char *)PORT_ArenaGrow(arena, inbuf, inlen, des_len);

    } else {

        outbuf = (unsigned char *)PORT_Realloc(inbuf, des_len);

    }

    if (outbuf == NULL) {

        PORT_SetError(SEC_ERROR_NO_MEMORY);

        return NULL;

    }

    des_pad_len = des_len - inlen;

    for (i = inlen; i < des_len; i++)

        outbuf[i] = des_pad_len;

    *outlen = des_len;

    return outbuf;

}