Add asn1 nif for ber decode and per encode

1 files changed, 1047 insertions, 0 deletions

diff --git a/lib/asn1/c_src/asn1_erl_nif.c b/lib/asn1/c_src/asn1_erl_nif.c
new file mode 100644
index 0000000000..cf3041c45c
--- /dev/null
+++ b/lib/asn1/c_src/asn1_erl_nif.c
@@ -0,0 +1,1047 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2002-2011. All Rights Reserved.
+ *
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * %CopyrightEnd%
+ *
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "erl_nif.h"
+
+/* #define ASN1_DEBUG 1 */
+
+#define ASN1_OK 0
+#define ASN1_ERROR -1
+#define ASN1_COMPL_ERROR 1
+#define ASN1_MEMORY_ERROR 0
+#define ASN1_DECODE_ERROR 2
+#define ASN1_TAG_ERROR -3
+#define ASN1_LEN_ERROR -4
+#define ASN1_INDEF_LEN_ERROR -5
+#define ASN1_VALUE_ERROR -6
+
+#define ASN1_CLASS 0xc0
+#define ASN1_FORM 0x20
+#define ASN1_CLASSFORM (ASN1_CLASS | ASN1_FORM)
+#define ASN1_TAG 0x1f
+#define ASN1_LONG_TAG 0x7f
+
+#define ASN1_INDEFINITE_LENGTH 0x80
+#define ASN1_SHORT_DEFINITE_LENGTH 0
+
+#define ASN1_PRIMITIVE 0
+#define ASN1_CONSTRUCTED 0x20
+
+#define ASN1_COMPLETE 1
+#define ASN1_BER_TLV_DECODE 2
+#define ASN1_BER_TLV_PARTIAL_DECODE 3
+
+#define ASN1_NOVALUE 0
+
+#define ASN1_SKIPPED 0
+#define ASN1_OPTIONAL 1
+#define ASN1_CHOOSEN 2
+
+#define CEIL(X,Y) ((X-1) / Y + 1)
+
+#define INVMASK(X,M) (X & (M ^ 0xff))
+#define MASK(X,M) (X & M)
+
+int complete(ErlNifBinary *, unsigned char *, int );
+
+int insert_octets(int, unsigned char **, unsigned char **, int *);
+
+int insert_octets_except_unused(int, unsigned char **, unsigned char **, int *,
+	int);
+
+int insert_octets_as_bits_exact_len(int, int, unsigned char **,
+	unsigned char **, int *);
+
+int insert_octets_as_bits(int, unsigned char **, unsigned char **, int *);
+
+int pad_bits(int, unsigned char **, int *);
+
+int insert_least_sign_bits(int, unsigned char, unsigned char **, int *);
+
+int insert_most_sign_bits(int, unsigned char, unsigned char **, int *);
+
+int insert_bits_as_bits(int, int, unsigned char **, unsigned char **, int *);
+
+int insert_octets_unaligned(int, unsigned char **, unsigned char **, int);
+
+int realloc_memory(ErlNifBinary *, int, unsigned char **);
+
+int decode_begin(ErlNifEnv *, ERL_NIF_TERM *, unsigned char *, int,
+	unsigned int *);
+
+int decode(ErlNifEnv *, ERL_NIF_TERM *, unsigned char *, int *, int);
+
+int decode_tag(ErlNifEnv *, ERL_NIF_TERM *, unsigned char *, int, int *);
+
+int decode_value(ErlNifEnv*, ERL_NIF_TERM *, unsigned char *, int *, int, int);
+
+/*
+ *
+ * This section defines functionality for the complete encode of a
+ * PER encoded message
+ *
+ */
+
+int complete(ErlNifBinary *out_binary, unsigned char *in_buf, int in_buf_len) {
+    int counter = in_buf_len;
+    /* counter keeps track of number of bytes left in the
+     input buffer */
+
+    int buf_space = in_buf_len;
+    /* This is the amount of allocated space left of the out_binary. It
+     is possible when padding is applied that more space is needed than
+     was originally allocated. */
+
+    int buf_size = in_buf_len;
+    /* Size of the buffer. May become reallocated and thus other than
+     in_buf_len */
+
+    unsigned char *in_ptr, *ptr;
+    /* in_ptr points at the next byte in in_buf to be moved to
+     complete_buf.
+     ptr points into the new completed buffer, complete_buf, at the
+     position of the next byte that will be set */
+    int unused = 8;
+    /* unused = [1,...,8] indicates how many of the rigthmost bits of
+     the byte that ptr points at that are unassigned */
+
+    int no_bits, no_bytes, in_unused, desired_len, ret, saved_mem, needed,
+	    pad_bits;
+
+    unsigned char val;
+
+    in_ptr = in_buf;
+    ptr = out_binary->data;
+    *ptr = 0x00;
+    while (counter > 0) {
+	counter--;
+	switch (*in_ptr) {
+	case 0:
+	    /* just one zero-bit should be added to the buffer */
+	    if (unused == 1) {
+		unused = 8;
+		*++ptr = 0x00;
+		buf_space--;
+	    } else
+		unused--;
+	    break;
+
+	case 1:
+	    /* one one-bit should be added to the buffer */
+	    if (unused == 1) {
+		*ptr = *ptr | 1;
+		unused = 8;
+		*++ptr = 0x00;
+		buf_space--;
+	    } else {
+		*ptr = *ptr | (1 << (unused - 1));
+		unused--;
+	    }
+	    break;
+
+	case 2:
+	    /* align buffer to end of byte */
+	    if (unused != 8) {
+		*++ptr = 0x00;
+		buf_space--;
+		unused = 8;
+	    }
+	    break;
+
+	case 10:
+	    /* next byte in in_buf tells how many bits in the second next
+	     byte that will be used */
+	    /* The leftmost unused bits in the value byte are supposed to be
+	     zero bits */
+	    no_bits = (int) *(++in_ptr);
+	    val = *(++in_ptr);
+	    counter -= 2;
+	    if ((ret = insert_least_sign_bits(no_bits, val, &ptr, &unused))
+		    == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 20:
+	    /* in this case the next value in_ptr points at holds the number
+	     of following bytes that holds the value that will be inserted
+	     in the completed buffer */
+	    no_bytes = (int) *(++in_ptr);
+	    counter -= (no_bytes + 1);
+	    if ((counter < 0)
+		    || (ret = insert_octets(no_bytes, &in_ptr, &ptr, &unused))
+			    == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 21:
+	    /* in this case the next two bytes in_ptr points at holds the number
+	     of following bytes that holds the value that will be inserted
+	     in the completed buffer */
+	    no_bytes = (int) *(++in_ptr);
+	    no_bytes = no_bytes << 8;
+	    no_bytes = no_bytes | (int) *(++in_ptr);
+	    counter -= (2 + no_bytes);
+	    if ((counter < 0)
+		    || (ret = insert_octets(no_bytes, &in_ptr, &ptr, &unused))
+			    == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 30:
+	    /* If we call the following bytes, in the buffer in_ptr points at,
+	     By1,By2,Rest then Rest is the value that will be transfered to
+	     the completed buffer. By1 tells how many of the rightmost bits in
+	     Rest that should not be used. By2 is the length of Rest in bytes.*/
+	    in_unused = (int) *(++in_ptr);
+	    no_bytes = (int) *(++in_ptr);
+	    counter -= (2 + no_bytes);
+	    ret = -4711;
+	    if ((counter < 0)
+		    || (ret = insert_octets_except_unused(no_bytes, &in_ptr,
+			    &ptr, &unused, in_unused)) == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 31:
+	    /* If we call the following bytes, in the buffer in_ptr points at,
+	     By1,By2,By3,Rest then Rest is the value that will be transfered to
+	     the completed buffer. By1 tells how many of the rightmost bits in
+	     Rest that should not be used. By2 and By3 is the length of
+	     Rest in bytes.*/
+	    in_unused = (int) *(++in_ptr);
+	    no_bytes = (int) *(++in_ptr);
+	    no_bytes = no_bytes << 8;
+	    no_bytes = no_bytes | (int) *(++in_ptr);
+	    counter -= (3 + no_bytes);
+	    if ((counter < 0)
+		    || (ret = insert_octets_except_unused(no_bytes, &in_ptr,
+			    &ptr, &unused, in_unused)) == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 40:
+	    /* This case implies that next byte,By1,(..,By1,By2,Bin,...)
+	     is the desired length of the completed value, maybe needs
+	     padding zero bits or removal of trailing zero bits from Bin.
+	     By2 is the length of Bin and Bin is the value that will be
+	     put into the completed buffer. Each byte in Bin has the value
+	     1 or 0.*/
+	    desired_len = (int) *(++in_ptr);
+	    no_bytes = (int) *(++in_ptr);
+
+	    /* This is the algorithm for need of memory reallocation:
+	     Only when padding (cases 40 - 43,45 - 47) more memory may be
+	     used than allocated. Therefore one has to keep track of how
+	     much of the allocated memory that has been saved, i.e. the
+	     difference between the number of parsed bytes of the input buffer
+	     and the number of used bytes of the output buffer.
+	     If saved memory is less than needed for the padding then we
+	     need more memory. */
+	    saved_mem = buf_space - counter;
+	    pad_bits = desired_len - no_bytes - unused;
+	    needed = (pad_bits > 0) ? CEIL(pad_bits,8) : 0;
+	    if (saved_mem < needed) {
+		/* Have to allocate more memory */
+		buf_size += needed;
+		buf_space += needed;
+		if (realloc_memory(out_binary, buf_size, &ptr)
+			== ASN1_ERROR
+			)
+		    return ASN1_ERROR;
+	    }
+
+	    counter -= (2 + no_bytes);
+	    if ((counter < 0)
+		    || (ret = insert_octets_as_bits_exact_len(desired_len,
+			    no_bytes, &in_ptr, &ptr, &unused)) == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 41:
+	    /* Same as case 40 apart from By2, the length of Bin, which is in
+	     two bytes*/
+	    desired_len = (int) *(++in_ptr);
+	    no_bytes = (int) *(++in_ptr);
+	    no_bytes = no_bytes << 8;
+	    no_bytes = no_bytes | (int) *(++in_ptr);
+
+	    saved_mem = buf_space - counter;
+	    needed = CEIL((desired_len-unused),8) - no_bytes;
+	    if (saved_mem < needed) {
+		/* Have to allocate more memory */
+		buf_size += needed;
+		buf_space += needed;
+		if (realloc_memory(out_binary, buf_size, &ptr)
+			== ASN1_ERROR
+			)
+		    return ASN1_ERROR;
+	    }
+
+	    counter -= (3 + no_bytes);
+	    if ((counter < 0)
+		    || (ret = insert_octets_as_bits_exact_len(desired_len,
+			    no_bytes, &in_ptr, &ptr, &unused)) == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 42:
+	    /* Same as case 40 apart from By1, the desired length, which is in
+	     two bytes*/
+	    desired_len = (int) *(++in_ptr);
+	    desired_len = desired_len << 8;
+	    desired_len = desired_len | (int) *(++in_ptr);
+	    no_bytes = (int) *(++in_ptr);
+
+	    saved_mem = buf_space - counter;
+	    needed = CEIL((desired_len-unused),8) - no_bytes;
+	    if (saved_mem < needed) {
+		/* Have to allocate more memory */
+		buf_size += needed;
+		buf_space += needed;
+		if (realloc_memory(out_binary, buf_size, &ptr)
+			== ASN1_ERROR
+			)
+		    return ASN1_ERROR;
+	    }
+
+	    counter -= (3 + no_bytes);
+	    if ((counter < 0)
+		    || (ret = insert_octets_as_bits_exact_len(desired_len,
+			    no_bytes, &in_ptr, &ptr, &unused)) == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 43:
+	    /* Same as case 40 apart from By1 and By2, the desired length and
+	     the length of Bin, which are in two bytes each. */
+	    desired_len = (int) *(++in_ptr);
+	    desired_len = desired_len << 8;
+	    desired_len = desired_len | (int) *(++in_ptr);
+	    no_bytes = (int) *(++in_ptr);
+	    no_bytes = no_bytes << 8;
+	    no_bytes = no_bytes | (int) *(++in_ptr);
+
+	    saved_mem = buf_space - counter;
+	    needed = CEIL((desired_len-unused),8) - no_bytes;
+	    if (saved_mem < needed) {
+		/* Have to allocate more memory */
+		buf_size += needed;
+		buf_space += needed;
+		if (realloc_memory(out_binary, buf_size, &ptr)
+			== ASN1_ERROR
+			)
+		    return ASN1_ERROR;
+	    }
+
+	    counter -= (4 + no_bytes);
+	    if ((counter < 0)
+		    || (ret = insert_octets_as_bits_exact_len(desired_len,
+			    no_bytes, &in_ptr, &ptr, &unused)) == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 45:
+	    /* This case assumes that the following bytes in the incoming buffer
+	     (called By1,By2,Bin) is By1, which is the number of bits (n) that
+	     will be inserted in the completed buffer. By2 is the number of
+	     bytes in Bin. Each bit in the buffer Bin should be inserted from
+	     the leftmost until the nth.*/
+	    desired_len = (int) *(++in_ptr);
+	    no_bytes = (int) *(++in_ptr);
+
+	    saved_mem = buf_space - counter;
+	    needed = CEIL((desired_len-unused),8) - no_bytes;
+	    if (saved_mem < needed) {
+		/* Have to allocate more memory */
+		buf_size += needed;
+		buf_space += needed;
+		if (realloc_memory(out_binary, buf_size, &ptr)
+			== ASN1_ERROR
+			)
+		    return ASN1_ERROR;
+	    }
+
+	    counter -= (2 + no_bytes);
+
+	    if ((counter < 0)
+		    || (ret = insert_bits_as_bits(desired_len, no_bytes,
+			    &in_ptr, &ptr, &unused)) == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 46:
+	    /* Same as case 45 apart from By1, the desired length, which is
+	     in two bytes. */
+	    desired_len = (int) *(++in_ptr);
+	    desired_len = desired_len << 8;
+	    desired_len = desired_len | (int) *(++in_ptr);
+	    no_bytes = (int) *(++in_ptr);
+
+	    saved_mem = buf_space - counter;
+	    needed = CEIL((desired_len-unused),8) - no_bytes;
+	    if (saved_mem < needed) {
+		/* Have to allocate more memory */
+		buf_size += needed;
+		buf_space += needed;
+		if (realloc_memory(out_binary, buf_size, &ptr)
+			== ASN1_ERROR
+			)
+		    return ASN1_ERROR;
+	    }
+
+	    counter -= (3 + no_bytes);
+	    if ((counter < 0)
+		    || (ret = insert_bits_as_bits(desired_len, no_bytes,
+			    &in_ptr, &ptr, &unused)) == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	case 47:
+	    /* Same as case 45 apart from By1 and By2, the desired length
+	     and the length of Bin, which are in two bytes each. */
+	    desired_len = (int) *(++in_ptr);
+	    desired_len = desired_len << 8;
+	    desired_len = desired_len | (int) *(++in_ptr);
+	    no_bytes = (int) *(++in_ptr);
+	    no_bytes = no_bytes << 8;
+	    no_bytes = no_bytes | (int) *(++in_ptr);
+
+	    saved_mem = buf_space - counter;
+	    needed = CEIL((desired_len-unused),8) - no_bytes;
+	    if (saved_mem < needed) {
+		/* Have to allocate more memory */
+		buf_size += needed;
+		buf_space += needed;
+		if (realloc_memory(out_binary, buf_size, &ptr)
+			== ASN1_ERROR
+			)
+		    return ASN1_ERROR;
+	    }
+
+	    counter -= (4 + no_bytes);
+	    if ((counter < 0)
+		    || (ret = insert_bits_as_bits(desired_len, no_bytes,
+			    &in_ptr, &ptr, &unused)) == ASN1_ERROR
+		    )
+		return ASN1_ERROR;
+	    buf_space -= ret;
+	    break;
+
+	default:
+	    return ASN1_ERROR;
+	}
+	in_ptr++;
+    }
+    /* The returned buffer must be at least one byte and
+     it must be octet aligned */
+    if ((unused == 8) && (ptr != out_binary->data))
+	return (ptr - out_binary->data);
+    else {
+	ptr++; /* octet align buffer */
+	return (ptr - out_binary->data);
+    }
+}
+
+int realloc_memory(ErlNifBinary *binary, int amount, unsigned char **ptr) {
+
+    int i = *ptr - binary->data;
+
+    if (!enif_realloc_binary(binary, amount)) {
+	/*error handling due to memory allocation failure */
+	return ASN1_ERROR;
+    } else {
+	*ptr = binary->data + i;
+    }
+    return ASN1_OK;
+}
+
+int insert_most_sign_bits(int no_bits, unsigned char val,
+	unsigned char **output_ptr, int *unused) {
+    unsigned char *ptr = *output_ptr;
+
+    if (no_bits < *unused) {
+	*ptr = *ptr | (val >> (8 - *unused));
+	*unused -= no_bits;
+    } else if (no_bits == *unused) {
+	*ptr = *ptr | (val >> (8 - *unused));
+	*unused = 8;
+	*++ptr = 0x00;
+    } else {
+	*ptr = *ptr | (val >> (8 - *unused));
+	*++ptr = 0x00;
+	*ptr = *ptr | (val << *unused);
+	*unused = 8 - (no_bits - *unused);
+    }
+    *output_ptr = ptr;
+    return ASN1_OK;
+}
+
+int insert_least_sign_bits(int no_bits, unsigned char val,
+	unsigned char **output_ptr, int *unused) {
+    unsigned char *ptr = *output_ptr;
+    int ret = 0;
+
+    if (no_bits < *unused) {
+	*ptr = *ptr | (val << (*unused - no_bits));
+	*unused -= no_bits;
+    } else if (no_bits == *unused) {
+	*ptr = *ptr | val;
+	*unused = 8;
+	*++ptr = 0x00;
+	ret++;
+    } else {
+	/* first in the begun byte in the completed buffer insert
+	 so many bits that fit, then insert the rest in next byte.*/
+	*ptr = *ptr | (val >> (no_bits - *unused));
+	*++ptr = 0x00;
+	ret++;
+	*ptr = *ptr | (val << (8 - (no_bits - *unused)));
+	*unused = 8 - (no_bits - *unused);
+    }
+    *output_ptr = ptr;
+    return ret;
+}
+
+/* pad_bits adds no_bits bits in the buffer that output_ptr
+ points at.
+ */
+int pad_bits(int no_bits, unsigned char **output_ptr, int *unused) {
+    unsigned char *ptr = *output_ptr;
+    int ret = 0;
+
+    while (no_bits > 0) {
+	if (*unused == 1) {
+	    *unused = 8;
+	    *++ptr = 0x00;
+	    ret++;
+	} else
+	    (*unused)--;
+	no_bits--;
+    }
+    *output_ptr = ptr;
+    return ret;
+}
+
+/* insert_bits_as_bits removes no_bytes bytes from the buffer that in_ptr
+ points at and takes the desired_no leftmost bits from those removed
+ bytes and inserts them in the buffer(output buffer) that ptr points at.
+ The unused parameter tells how many bits that are not set in the
+ actual byte in the output buffer. If desired_no is more bits than the
+ input buffer has in no_bytes bytes, then zero bits is padded.*/
+int insert_bits_as_bits(int desired_no, int no_bytes, unsigned char **input_ptr,
+	unsigned char **output_ptr, int *unused) {
+    unsigned char *in_ptr = *input_ptr;
+    unsigned char val;
+    int no_bits, ret, ret2;
+
+    if (desired_no == (no_bytes * 8)) {
+	if (insert_octets_unaligned(no_bytes, &in_ptr, output_ptr, *unused)
+		== ASN1_ERROR
+		)
+	    return ASN1_ERROR;
+	ret = no_bytes;
+    } else if (desired_no < (no_bytes * 8)) {
+	/*     printf("insert_bits_as_bits 1\n\r"); */
+	if (insert_octets_unaligned(desired_no / 8, &in_ptr, output_ptr,
+		*unused) == ASN1_ERROR
+	)
+	    return ASN1_ERROR;
+	/*     printf("insert_bits_as_bits 2\n\r"); */
+	val = *++in_ptr;
+	/*     printf("val = %d\n\r",(int)val); */
+	no_bits = desired_no % 8;
+	/*     printf("no_bits = %d\n\r",no_bits); */
+	insert_most_sign_bits(no_bits, val, output_ptr, unused);
+	ret = CEIL(desired_no,8);
+    } else {
+	if (insert_octets_unaligned(no_bytes, &in_ptr, output_ptr, *unused)
+		== ASN1_ERROR
+		)
+	    return ASN1_ERROR;
+	ret2 = pad_bits(desired_no - (no_bytes * 8), output_ptr, unused);
+	/*     printf("ret2 = %d\n\r",ret2); */
+	ret = CEIL(desired_no,8);
+	/*     printf("ret = %d\n\r",ret); */
+    }
+    /*   printf("*unused = %d\n\r",*unused); */
+    *input_ptr = in_ptr;
+    return ret;
+}
+
+/* insert_octets_as_bits_exact_len */
+int insert_octets_as_bits_exact_len(int desired_len, int in_buff_len,
+	unsigned char **in_ptr, unsigned char **ptr, int *unused) {
+    int ret = 0;
+    int ret2 = 0;
+
+    if (desired_len == in_buff_len) {
+	if ((ret = insert_octets_as_bits(in_buff_len, in_ptr, ptr, unused))
+		== ASN1_ERROR
+		)
+	    return ASN1_ERROR;
+    } else if (desired_len > in_buff_len) {
+	if ((ret = insert_octets_as_bits(in_buff_len, in_ptr, ptr, unused))
+		== ASN1_ERROR
+		)
+	    return ASN1_ERROR;
+	/* now pad with zero bits */
+	/*     printf("~npad_bits: called with %d bits padding~n~n~r",desired_len - in_buff_len); */
+	if ((ret2 = pad_bits(desired_len - in_buff_len, ptr, unused))
+		== ASN1_ERROR
+		)
+	    return ASN1_ERROR;
+    } else {/* desired_len < no_bits */
+	if ((ret = insert_octets_as_bits(desired_len, in_ptr, ptr, unused))
+		== ASN1_ERROR
+		)
+	    return ASN1_ERROR;
+	/* now remove no_bits - desired_len bytes from in buffer */
+	*in_ptr += (in_buff_len - desired_len);
+    }
+    return (ret + ret2);
+}
+
+/* insert_octets_as_bits takes no_bytes bytes from the buffer that input_ptr
+ points at and inserts the least significant bit of it in the buffer that
+ output_ptr points at. Each byte in the input buffer must be 1 or 0
+ otherwise the function returns ASN1_ERROR. The output buffer is concatenated
+ without alignment.
+ */
+int insert_octets_as_bits(int no_bytes, unsigned char **input_ptr,
+	unsigned char **output_ptr, int *unused) {
+    unsigned char *in_ptr = *input_ptr;
+    unsigned char *ptr = *output_ptr;
+    int used_bits = 8 - *unused;
+
+    while (no_bytes > 0) {
+	switch (*++in_ptr) {
+	case 0:
+	    if (*unused == 1) {
+		*unused = 8;
+		*++ptr = 0x00;
+	    } else
+		(*unused)--;
+	    break;
+	case 1:
+	    if (*unused == 1) {
+		*ptr = *ptr | 1;
+		*unused = 8;
+		*++ptr = 0x00;
+	    } else {
+		*ptr = *ptr | (1 << (*unused - 1));
+		(*unused)--;
+	    }
+	    break;
+	default:
+	    return ASN1_ERROR;
+	}
+	no_bytes--;
+    }
+    *input_ptr = in_ptr;
+    *output_ptr = ptr;
+    return ((used_bits + no_bytes) / 8); /*return number of new bytes
+     in completed buffer */
+}
+
+/* insert_octets inserts bytes from the input buffer, *input_ptr,
+ into the output buffer, *output_ptr. Before the first byte is
+ inserted the input buffer is aligned.
+ */
+int insert_octets(int no_bytes, unsigned char **input_ptr,
+	unsigned char **output_ptr, int *unused) {
+    unsigned char *in_ptr = *input_ptr;
+    unsigned char *ptr = *output_ptr;
+    int ret = 0;
+
+    if (*unused != 8) {/* must align before octets are added */
+	*++ptr = 0x00;
+	ret++;
+	*unused = 8;
+    }
+    while (no_bytes > 0) {
+	*ptr = *(++in_ptr);
+	*++ptr = 0x00;
+	/*      *unused = *unused - 1; */
+	no_bytes--;
+    }
+    *input_ptr = in_ptr;
+    *output_ptr = ptr;
+    return (ret + no_bytes);
+}
+
+/* insert_octets_unaligned inserts bytes from the input buffer, *input_ptr,
+ into the output buffer, *output_ptr.No alignment is done.
+ */
+int insert_octets_unaligned(int no_bytes, unsigned char **input_ptr,
+	unsigned char **output_ptr, int unused) {
+    unsigned char *in_ptr = *input_ptr;
+    unsigned char *ptr = *output_ptr;
+    int n = no_bytes;
+    unsigned char val;
+
+    while (n > 0) {
+	if (unused == 8) {
+	    *ptr = *++in_ptr;
+	    *++ptr = 0x00;
+	} else {
+	    val = *++in_ptr;
+	    *ptr = *ptr | val >> (8 - unused);
+	    *++ptr = 0x00;
+	    *ptr = val << unused;
+	}
+	n--;
+    }
+    *input_ptr = in_ptr;
+    *output_ptr = ptr;
+    return no_bytes;
+}
+
+int insert_octets_except_unused(int no_bytes, unsigned char **input_ptr,
+	unsigned char **output_ptr, int *unused, int in_unused) {
+    unsigned char *in_ptr = *input_ptr;
+    unsigned char *ptr = *output_ptr;
+    int val, no_bits;
+    int ret = 0;
+
+    if (in_unused == 0) {
+	if ((ret = insert_octets_unaligned(no_bytes, &in_ptr, &ptr, *unused))
+		== ASN1_ERROR
+		)
+	    return ASN1_ERROR;
+    } else {
+	if ((ret = insert_octets_unaligned(no_bytes - 1, &in_ptr, &ptr, *unused))
+		!= ASN1_ERROR) {
+	    val = (int) *(++in_ptr);
+	    no_bits = 8 - in_unused;
+	    /* no_bits is always less than *unused since the buffer is
+	     octet aligned after insert:octets call, so the following
+	     if clasuse is obsolete I think */
+	    if (no_bits < *unused) {
+		*ptr = *ptr | (val >> (8 - *unused));
+		*unused = *unused - no_bits;
+	    } else if (no_bits == *unused) {
+		*ptr = *ptr | (val >> (8 - *unused));
+		*++ptr = 0x00;
+		ret++;
+		*unused = 8;
+	    } else {
+		*ptr = *ptr | (val >> (8 - *unused));
+		*++ptr = 0x00;
+		ret++;
+		*ptr = *ptr | (val << *unused);
+		*unused = 8 - (no_bits - *unused);
+	    }
+	} else
+	    return ASN1_ERROR;
+    }
+    *input_ptr = in_ptr;
+    *output_ptr = ptr;
+    return ret;
+}
+
+/*
+ *
+ * This section defines functionality for the partial decode of a
+ * BER encoded message
+ *
+ */
+
+/*
+ * int decode(ErlNifEnv* env, ERL_NIF_TERM *term, unsigned char *in_buf,
+	int in_buf_len, unsigned int *err_pos)
+ * term is a pointer to the term which is to be returned to erlang
+ * in_buf is a pointer into the buffer of incoming bytes.
+ * in_buf_len is the length of the incoming buffer.
+ * The function reads the bytes in the incoming buffer and structures
+ * it in a nested way as Erlang terms. The buffer contains data in the
+ * order tag - length - value. Tag, length and value has the following
+ * format:
+ * A tag is normally one byte but may be of any length, if the tag number
+ * is greater than 30. +----------+
+ *		       |CL|C|NNNNN|
+ * 		       +----------+
+ * If NNNNN is 31 then will the 7 l.s.b of each of the following tag number
+ * bytes contain the tag number. Each tag number byte that is not the last one
+ * has the m.s.b. set to 1.
+ * The length can be short definite length (sdl), long definite length (ldl)
+ * or indefinite length (il).
+ * sdl: +---------+ the L bits is the length
+ *	|0|LLLLLLL|
+ *	+---------+
+ * ldl:	+---------+ +---------+ +---------+     +-----------+
+ *	|1|lllllll| |first len| |	  |     |the Nth len|
+ *	+---------+ +---------+ +---------+ ... +-----------+
+ *    	The first byte tells how many len octets will follow, max 127
+ * il:  +---------+ +----------------------+ +--------+ +--------+
+ *	|1|0000000| |content octets (Value)| |00000000| |00000000|
+ *	+---------+ +----------------------+ +--------+ +--------+
+ *	The value octets are preceded by one octet and followed by two
+ *	exactly as above. The value must be some tag-length-value encoding.
+ *
+ * The function returns a value in Erlang nif term format:
+ * {{TagNo,Value},Rest}
+ * TagNo is an integer ((CL bsl 16) + tag number) which limits the tag number
+ * to 65535.
+ * Value is a binary if the C bit in tag was unset, otherwise (if tag was
+ * constructed) Value is a list, List.
+ * List is like: [{TagNo,Value},{TagNo,Value},...]
+ * Rest is a binary, i.e. the undecoded part of the buffer. Most often Rest
+ * is the empty binary.
+ * If some error occured during the decoding of the in_buf an error is returned.
+ */
+int decode_begin(ErlNifEnv* env, ERL_NIF_TERM *term, unsigned char *in_buf,
+	int in_buf_len, unsigned int *err_pos) {
+    int maybe_ret;
+    int ib_index = 0;
+    unsigned char *rest_data;
+    ERL_NIF_TERM decoded_term, rest;
+
+    if ((maybe_ret = decode(env, &decoded_term, in_buf, &ib_index, in_buf_len))
+	    <= ASN1_ERROR)
+	    {
+	*err_pos = ib_index;
+	return maybe_ret;
+    };
+
+    // The remaining binary after one ASN1 segment has been decoded
+    if ((rest_data = enif_make_new_binary(env, in_buf_len - ib_index, &rest))
+	    == NULL) {
+	*term = enif_make_atom(env, "could_not_alloc_binary");
+	return ASN1_ERROR;
+    }
+
+    *term = enif_make_tuple2(env, decoded_term, rest);
+    return ASN1_OK;
+}
+
+int decode(ErlNifEnv* env, ERL_NIF_TERM *term, unsigned char *in_buf,
+	int *ib_index, int in_buf_len) {
+    int maybe_ret;
+    int form;
+    ERL_NIF_TERM tag, value;
+
+    /*buffer must hold at least two bytes*/
+    if ((*ib_index + 2) > in_buf_len)
+	return ASN1_VALUE_ERROR;
+    /* "{{TagNo," */
+    if ((form = decode_tag(env, &tag, in_buf, in_buf_len, ib_index))
+	    <= ASN1_ERROR
+	    )
+	return form; /* 5 bytes */
+    if (*ib_index >= in_buf_len) {
+	return ASN1_TAG_ERROR;
+    }
+    /* buffer must hold at least one byte (0 as length and nothing as
+     value) */
+    /* "{{TagNo,Value}," */
+    if ((maybe_ret = decode_value(env, &value, in_buf, ib_index, form,
+	    in_buf_len)) <= ASN1_ERROR
+    )
+	return maybe_ret; /* at least 5 bytes */
+    *term = enif_make_tuple2(env, tag, value);
+    return ASN1_OK;
+}
+
+/*
+ * decode_tag decodes the BER encoded tag in in_buf and creates an
+ * nif term tag
+ */
+int decode_tag(ErlNifEnv* env, ERL_NIF_TERM *tag, unsigned char *in_buf,
+	int in_buf_len, int *ib_index) {
+    int tag_no, tmp_tag, form;
+
+    /* first get the class of tag and bit shift left 16*/
+    tag_no = ((MASK(in_buf[*ib_index],ASN1_CLASS)) << 10);
+
+    form = (MASK(in_buf[*ib_index],ASN1_FORM));
+
+    /* then get the tag number */
+    if ((tmp_tag = (int) INVMASK(in_buf[*ib_index],ASN1_CLASSFORM)) < 31) {
+	*tag = enif_make_ulong(env, tag_no + tmp_tag);
+	(*ib_index)++;
+    } else {
+	int n = 0; /* n is used to check that the 64K limit is not
+	 exceeded*/
+
+	/* should check that at least three bytes are left in
+	 in-buffer,at least two tag byte and at least one length byte */
+	if ((*ib_index + 3) > in_buf_len)
+	    return ASN1_VALUE_ERROR;
+	(*ib_index)++;
+	/* The tag is in the following bytes in in_buf as
+	 1ttttttt 1ttttttt ... 0ttttttt, where the t-bits
+	 is the tag number*/
+	/* In practice is the tag size limited to 64K, i.e. 16 bits. If
+	 the tag is greater then 64K return an error */
+	while (((tmp_tag = (int) in_buf[*ib_index]) >= 128) && n < 2) {
+	    /* m.s.b. = 1 */
+	    tag_no = tag_no + (MASK(tmp_tag,ASN1_LONG_TAG) << 7);
+	    (*ib_index)++;
+	    n++;
+	};
+	if ((n == 2) && in_buf[*ib_index] > 3)
+	    return ASN1_TAG_ERROR; /* tag number > 64K */
+	tag_no = tag_no + in_buf[*ib_index];
+	(*ib_index)++;
+	*tag = enif_make_ulong(env, tag_no);
+    }
+    return form;
+}
+
+/*
+ * decode_value decodes the BER encoded length and value fields in the
+ * in_buf and puts the value part in the decode_buf as an Erlang
+ * nif term into value
+ */
+int decode_value(ErlNifEnv* env, ERL_NIF_TERM *value, unsigned char *in_buf,
+	int *ib_index, int form, int in_buf_len) {
+    int maybe_ret;
+    unsigned int len = 0;
+    unsigned int lenoflen = 0;
+    int indef = 0;
+    unsigned char *tmp_out_buff;
+    ERL_NIF_TERM term = 0, curr_head = 0;
+
+    if (((in_buf[*ib_index]) & 0x80) == ASN1_SHORT_DEFINITE_LENGTH) {
+	len = in_buf[*ib_index];
+    } else if (in_buf[*ib_index] == ASN1_INDEFINITE_LENGTH
+    )
+	indef = 1;
+    else /* long definite length */{
+	lenoflen = (in_buf[*ib_index] & 0x7f); /*length of length */
+	if (lenoflen > (in_buf_len - (*ib_index + 1)))
+	    return ASN1_LEN_ERROR;
+	len = 0;
+	while (lenoflen--) {
+	    (*ib_index)++;
+	    if (!(len < (1 << (sizeof(len) - 1) * 8)))
+		return ASN1_LEN_ERROR; /* length does not fit in 32 bits */
+	    len = (len << 8) + in_buf[*ib_index];
+	}
+    }
+    if (len > (in_buf_len - (*ib_index + 1)))
+	return ASN1_VALUE_ERROR;
+    (*ib_index)++;
+    if (indef == 1) { /* in this case it is desireably to check that indefinite length
+     end bytes exist in inbuffer */
+	curr_head = enif_make_list(env, 0); // Might want to change this list to a binary
+	while (!(in_buf[*ib_index] == 0 && in_buf[*ib_index + 1] == 0)) {
+	    if (*ib_index >= in_buf_len)
+		return ASN1_INDEF_LEN_ERROR;
+
+	    if ((maybe_ret = decode(env, &term, in_buf, ib_index, in_buf_len))
+		    <= ASN1_ERROR
+		    )
+		return maybe_ret;
+	    curr_head = enif_make_list_cell(env, term, curr_head);
+	}
+	enif_make_reverse_list(env, curr_head, value);
+	(*ib_index) += 2; /* skip the indefinite length end bytes */
+    } else if (form == ASN1_CONSTRUCTED)
+    {
+	int end_index = *ib_index + len;
+	if (end_index > in_buf_len)
+	    return ASN1_LEN_ERROR;
+	curr_head = enif_make_list(env, 0); // might want to change this list to a binary
+	while (*ib_index < end_index) {
+
+	    if ((maybe_ret = decode(env, &term, in_buf, ib_index, in_buf_len))
+		    <= ASN1_ERROR
+		    )
+		return maybe_ret;
+	    curr_head = enif_make_list_cell(env, term, curr_head);
+	}
+	enif_make_reverse_list(env, curr_head, value);
+    } else {
+	if ((*ib_index + len) > in_buf_len)
+	    return ASN1_LEN_ERROR;
+	tmp_out_buff = enif_make_new_binary(env, len, value);
+	memcpy(tmp_out_buff, in_buf + *ib_index, len);
+	*ib_index = *ib_index + len;
+    }
+    return ASN1_OK;
+}
+
+static ERL_NIF_TERM encode_per_complete(ErlNifEnv* env, int argc,
+	const ERL_NIF_TERM argv[]) {
+    ErlNifBinary in_binary;
+    ErlNifBinary out_binary;
+    int complete_len;
+    if (!enif_inspect_iolist_as_binary(env, argv[0], &in_binary))
+	return enif_make_atom(env, "badarg");
+
+    if (!enif_alloc_binary(in_binary.size, &out_binary))
+	return enif_make_atom(env, "alloc_binary_failed");
+
+    if ((complete_len = complete(&out_binary, in_binary.data, in_binary.size))
+	    <= ASN1_ERROR) {
+	enif_release_binary(&out_binary);
+    }
+    if (complete_len < out_binary.size)
+	enif_realloc_binary(&out_binary, complete_len);
+
+    return enif_make_binary(env, &out_binary);
+}
+
+static ERL_NIF_TERM decode_ber_tlv(ErlNifEnv* env, int argc,
+	const ERL_NIF_TERM argv[]) {
+    ErlNifBinary in_binary;
+    ERL_NIF_TERM return_term;
+    unsigned int err_pos = 0, return_code;
+
+    if (!enif_inspect_iolist_as_binary(env, argv[0], &in_binary))
+	return enif_make_atom(env, "badarg");
+
+    if ((return_code = decode_begin(env, &return_term, in_binary.data,
+	    in_binary.size, &err_pos)) != ASN1_OK
+    )
+	return enif_make_tuple2(env, enif_make_atom(env,"error"), enif_make_tuple3(env,
+			enif_make_atom(env,""),enif_make_int(env, return_code),enif_make_int(env, err_pos)));
+    return return_term;
+}
+
+static ErlNifFunc nif_funcs[] = { { "encode_per_complete", 1,
+	encode_per_complete }, { "decode_ber_tlv", 1, decode_ber_tlv } };
+
+ERL_NIF_INIT(asn1rt_nif, nif_funcs, NULL, NULL, NULL, NULL)