/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com */#include "tomcrypt.h"/**  @file der_decode_object_identifier.c  ASN.1 DER, Decode Object Identifier, Tom St Denis*/#ifdef LTC_DER/**  Decode OID data and store the array of integers in words  @param in      The OID DER encoded data  @param inlen   The length of the OID data  @param words   [out] The destination of the OID words  @param outlen  [in/out] The number of OID words  @return CRYPT_OK if successful*/int der_decode_object_identifier(const unsigned char *in,    unsigned long  inlen,                                       unsigned long *words, unsigned long *outlen){   unsigned long x, y, t, len;   LTC_ARGCHK(in     != NULL);   LTC_ARGCHK(words  != NULL);   LTC_ARGCHK(outlen != NULL);   /* header is at least 3 bytes */   if (inlen < 3) {      return CRYPT_INVALID_PACKET;   }   /* must be room for at least two words */   if (*outlen < 2) {      return CRYPT_BUFFER_OVERFLOW;   }   /* decode the packet header */   x = 0;   if ((in[x++] & 0x1F) != 0x06) {      return CRYPT_INVALID_PACKET;   }      /* get the length */   if (in[x] < 128) {      len = in[x++];    } else {       if (in[x] < 0x81 || in[x] > 0x82) {          return CRYPT_INVALID_PACKET;       }       y   = in[x++] & 0x7F;       len = 0;       while (y--) {          len = (len << 8) | (unsigned long)in[x++];       }   }   if (len < 1 || (len + x) > inlen) {      return CRYPT_INVALID_PACKET;   }   /* decode words */   y = 0;   t = 0;   while (len--) {       t = (t << 7) | (in[x] & 0x7F);       if (!(in[x++] & 0x80)) {           /* store t */           if (y >= *outlen) {              return CRYPT_BUFFER_OVERFLOW;           }      if (y == 0) {         words[0] = t / 40;         words[1] = t % 40;         y = 2;      } else {              words[y++] = t;      }           t          = 0;       }   }          *outlen = y;   return CRYPT_OK;}#endif/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/object_identifier/der_decode_object_identifier.c,v $ *//* $Revision: 1.5 $ *//* $Date: 2006/11/21 00:18:23 $ */