int wc_BerToDer(const byte* ber, word32 berSz, byte* der, word32* derSz)
{
    int ret = 0;
    word32 i, j;
#ifdef WOLFSSL_SMALL_STACK
    IndefItems* indefItems = NULL;
#else
    IndefItems indefItems[1];
#endif
    byte tag, basic;
    word32 length;
    int indef;

    if (ber == NULL || derSz == NULL)
        return BAD_FUNC_ARG;

#ifdef WOLFSSL_SMALL_STACK
    indefItems = (IndefItems *)XMALLOC(sizeof(IndefItems), NULL, DYNAMIC_TYPE_TMP_BUFFER);
    if (indefItems == NULL) {
        ret = MEMORY_E;
        goto end;
    }
#endif

    XMEMSET(indefItems, 0, sizeof(*indefItems));

    /* Calculate indefinite item lengths */
    for (i = 0; i < berSz; ) {
        word32 start = i;

        /* Get next BER item */
        ret = GetBerHeader(ber, &i, berSz, &tag, &length, &indef);
        if (ret != 0) {
            goto end;
        }

        if (indef) {
            /* Indefinite item - add to list */
            ret = IndefItems_AddItem(indefItems, i);
            if (ret != 0) {
                goto end;
            }

            if ((tag & 0xC0) == 0 &&
                tag != (ASN_SEQUENCE | ASN_CONSTRUCTED) &&
                tag != (ASN_SET      | ASN_CONSTRUCTED)) {
                /* Constructed basic type - get repeating tag */
                basic = tag & (~ASN_CONSTRUCTED);

                /* Add up lengths of each item below */
                for (; i < berSz; ) {
                    /* Get next BER_item */
                    ret = GetBerHeader(ber, &i, berSz, &tag, &length, &indef);
                    if (ret != 0) {
                        goto end;
                    }

                    /* End of content closes item */
                    if (tag == ASN_EOC) {
                        /* Must be zero length */
                        if (length != 0) {
                            ret = ASN_PARSE_E;
                            goto end;
                        }
                        break;
                    }

                    /* Must not be indefinite and tag must match parent */
                    if (indef || tag != basic) {
                        ret = ASN_PARSE_E;
                        goto end;
                    }

                    /* Add to length */
                    IndefItems_AddData(indefItems, length);
                    /* Skip data */
                    i += length;
                }

                /* Ensure we got an EOC and not end of data */
                if (tag != ASN_EOC) {
                    ret = ASN_PARSE_E;
                    goto end;
                }

                /* Set the header length to include the length field */
                IndefItems_UpdateHeaderLen(indefItems);
                /* Go to indefinte parent item */
                IndefItems_Up(indefItems);
            }
        }
        else if (tag == ASN_EOC) {
            /* End-of-content must be 0 length */
            if (length != 0) {
                ret = ASN_PARSE_E;
                goto end;
            }
            /* Check there is an item to close - missing EOC */
            if (indefItems->depth == 0) {
                ret = ASN_PARSE_E;
                goto end;
            }

            /* Finish calculation of data length for indefinite item */
            IndefItems_CalcLength(indefItems);
            /* Go to indefinte parent item */
            IndefItems_Up(indefItems);
        }
        else {
            /* Known length item to add in - make sure enough data for it */
            if (i + length > berSz) {
                ret = ASN_PARSE_E;
                goto end;
            }

            /* Include all data - can't have indefinite inside definite */
            i += length;
            /* Add entire item to current indefinite item */
            IndefItems_MoreData(indefItems, i - start);
        }
    }
    /* Check we had a EOC for each indefinite item */
    if (indefItems->depth != 0) {
        ret = ASN_PARSE_E;
        goto end;
    }

    /* Write out DER */

    j = 0;
    /* Reset index */
    indefItems->idx = 0;
    for (i = 0; i < berSz; ) {
        word32 start = i;

        /* Get item - checked above */
        (void)GetBerHeader(ber, &i, berSz, &tag, &length, &indef);
        if (indef) {
            if (der != NULL) {
                /* Check enough space for header */
                if (j + IndefItems_HeaderLen(indefItems) > *derSz) {
                    ret = BUFFER_E;
                    goto end;
                }

                if ((tag & 0xC0) == 0 &&
                    tag != (ASN_SEQUENCE | ASN_CONSTRUCTED) &&
                    tag != (ASN_SET      | ASN_CONSTRUCTED)) {
                    /* Remove constructed tag for basic types */
                    tag &= ~ASN_CONSTRUCTED;
                }
                /* Add tag and length */
                der[j] = tag;
                (void)SetLength(IndefItems_Len(indefItems), der + j + 1);
            }
            /* Add header length of indefinite item */
            j += IndefItems_HeaderLen(indefItems);

            if ((tag & 0xC0) == 0 &&
                tag != (ASN_SEQUENCE | ASN_CONSTRUCTED) &&
                tag != (ASN_SET      | ASN_CONSTRUCTED)) {
                /* For basic type - get each child item and add data */
                for (; i < berSz; ) {
                    (void)GetBerHeader(ber, &i, berSz, &tag, &length, &indef);
                    if (tag == ASN_EOC) {
                        break;
                    }
                    if (der != NULL) {
                        if (j + length > *derSz) {
                            ret = BUFFER_E;
                            goto end;
                        }
                        XMEMCPY(der + j, ber + i, length);
                    }
                    j += length;
                    i += length;
                }
            }

            /* Move to next indef item in list */
            indefItems->idx++;
        }
        else if (tag == ASN_EOC) {
            /* End-Of-Content is not written out in DER */
        }
        else {
            /* Write out definite length item as is. */
            i += length;
            if (der != NULL) {
                /* Ensure space for item */
                if (j + i - start > *derSz) {
                    ret = BUFFER_E;
                    goto end;
                }
                /* Copy item as is */
                XMEMCPY(der + j, ber + start, i - start);
            }
            j += i - start;
        }
    }

    /* Return the length of the DER encoded ASN.1 */
    *derSz = j;
    if (der == NULL) {
        ret = LENGTH_ONLY_E;
    }
end:
#ifdef WOLFSSL_SMALL_STACK
    if (indefItems != NULL) {
        XFREE(indefItems, NULL, DYNAMIC_TYPE_TMP_BUFFER);
    }
#endif
    return ret;
}
int wc_BerToDer(const byte* ber, word32 berSz, byte* der, word32* derSz)
{
    int ret = 0;
    word32 i, j;
#ifdef WOLFSSL_SMALL_STACK
    IndefItems* indefItems = NULL;
#else
    IndefItems indefItems[1];
#endif
    byte tag, basic;
    word32 length;
    int indef;

    if (ber == NULL || derSz == NULL)
        return BAD_FUNC_ARG;

#ifdef WOLFSSL_SMALL_STACK
    indefItems = (IndefItems *)XMALLOC(sizeof(IndefItems), NULL, DYNAMIC_TYPE_TMP_BUFFER);
    if (indefItems == NULL) {
        ret = MEMORY_E;
        goto end;
    }
#endif

    XMEMSET(indefItems, 0, sizeof(*indefItems));

     
    for (i = 0; i < berSz; ) {
        word32 start = i;

         
        ret = GetBerHeader(ber, &i, berSz, &tag, &length, &indef);
        if (ret != 0) {
            goto end;
        }

        if (indef) {
             
            ret = IndefItems_AddItem(indefItems, i);
            if (ret != 0) {
                goto end;
            }

            if ((tag & 0xC0) == 0 &&
                tag != (ASN_SEQUENCE | ASN_CONSTRUCTED) &&
                tag != (ASN_SET      | ASN_CONSTRUCTED)) {
                 
                basic = tag & (~ASN_CONSTRUCTED);

                 
                for (; i < berSz; ) {
                     
                    ret = GetBerHeader(ber, &i, berSz, &tag, &length, &indef);
                    if (ret != 0) {
                        goto end;
                    }

                     
                    if (tag == ASN_EOC) {
                         
                        if (length != 0) {
                            ret = ASN_PARSE_E;
                            goto end;
                        }
                        break;
                    }

                     
                    if (indef || tag != basic) {
                        ret = ASN_PARSE_E;
                        goto end;
                    }

                     
                    IndefItems_AddData(indefItems, length);
                     
                    i += length;
                }

                 
                if (tag != ASN_EOC) {
                    ret = ASN_PARSE_E;
                    goto end;
                }

                 
                IndefItems_UpdateHeaderLen(indefItems);
                 
                IndefItems_Up(indefItems);
            }
        }
        else if (tag == ASN_EOC) {
             
            if (length != 0) {
                ret = ASN_PARSE_E;
                goto end;
            }
             
            if (indefItems->depth == 0) {
                ret = ASN_PARSE_E;
                goto end;
            }

             
            IndefItems_CalcLength(indefItems);
             
            IndefItems_Up(indefItems);
        }
        else {
             
            if (i + length > berSz) {
                ret = ASN_PARSE_E;
                goto end;
            }

             
            i += length;
             
            IndefItems_MoreData(indefItems, i - start);
        }
    }
     
    if (indefItems->depth != 0) {
        ret = ASN_PARSE_E;
        goto end;
    }

     

    j = 0;
     
    indefItems->idx = 0;
    for (i = 0; i < berSz; ) {
        word32 start = i;

         
        (void)GetBerHeader(ber, &i, berSz, &tag, &length, &indef);
        if (indef) {
            if (der != NULL) {
                 
                if (j + IndefItems_HeaderLen(indefItems) > *derSz) {
                    ret = BUFFER_E;
                    goto end;
                }

                if ((tag & 0xC0) == 0 &&
                    tag != (ASN_SEQUENCE | ASN_CONSTRUCTED) &&
                    tag != (ASN_SET      | ASN_CONSTRUCTED)) {
                     
                    tag &= ~ASN_CONSTRUCTED;
                }
                 
                der[j] = tag;
                (void)SetLength(IndefItems_Len(indefItems), der + j + 1);
            }
             
            j += IndefItems_HeaderLen(indefItems);

            if ((tag & 0xC0) == 0 &&
                tag != (ASN_SEQUENCE | ASN_CONSTRUCTED) &&
                tag != (ASN_SET      | ASN_CONSTRUCTED)) {
                 
                for (; i < berSz; ) {
                    (void)GetBerHeader(ber, &i, berSz, &tag, &length, &indef);
                    if (tag == ASN_EOC) {
                        break;
                    }
                    if (der != NULL) {
                        if (j + length > *derSz) {
                            ret = BUFFER_E;
                            goto end;
                        }
                        XMEMCPY(der + j, ber + i, length);
                    }
                    j += length;
                    i += length;
                }
            }

             
            indefItems->idx++;
        }
        else if (tag == ASN_EOC) {
             
        }
        else {
             
            i += length;
            if (der != NULL) {
                 
                if (j + i - start > *derSz) {
                    ret = BUFFER_E;
                    goto end;
                }
                 
                XMEMCPY(der + j, ber + start, i - start);
            }
            j += i - start;
        }
    }

     
    *derSz = j;
    if (der == NULL) {
        ret = LENGTH_ONLY_E;
    }
end:
#ifdef WOLFSSL_SMALL_STACK
    if (indefItems != NULL) {
        XFREE(indefItems, NULL, DYNAMIC_TYPE_TMP_BUFFER);
    }
#endif
    return ret;
}