text: /* 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_encode_octet_string.c
    ASN.1 DER, encode a OCTET STRING, Tom St Denis
  */
  
  
  #ifdef LTC_DER
  
  /**
    Store an OCTET STRING
    @param in       The array of OCTETS to store (one per char)
    @param inlen    The number of OCTETS to store
    @param out      [out] The destination for the DER encoded OCTET STRING
    @param outlen   [in/out] The max size and resulting size of the DER OCTET STRING
    @return CRYPT_OK if successful
  */
  int der_encode_octet_string(const unsigned char *in, unsigned long inlen,
                                    unsigned char *out, unsigned long *outlen)
  {
     unsigned long x, y, len;
     int           err;
  
     LTC_ARGCHK(in     != NULL);
     LTC_ARGCHK(out    != NULL);
     LTC_ARGCHK(outlen != NULL);
  
     /* get the size */
     if ((err = der_length_octet_string(inlen, &len)) != CRYPT_OK) {
        return err; 
     }
  
     /* too big? */
     if (len > *outlen) {
        *outlen = len;
        return CRYPT_BUFFER_OVERFLOW;
     }
  
     /* encode the header+len */
     x = 0;
     out[x++] = 0x04;
     if (inlen < 128) {
        out[x++] = (unsigned char)inlen;
     } else if (inlen < 256) {
        out[x++] = 0x81;
        out[x++] = (unsigned char)inlen;
     } else if (inlen < 65536UL) {
        out[x++] = 0x82;
        out[x++] = (unsigned char)((inlen>>8)&255);
        out[x++] = (unsigned char)(inlen&255);
     } else if (inlen < 16777216UL) {
        out[x++] = 0x83;
        out[x++] = (unsigned char)((inlen>>16)&255);
        out[x++] = (unsigned char)((inlen>>8)&255);
        out[x++] = (unsigned char)(inlen&255);
     } else {
        return CRYPT_INVALID_ARG;
     }
  
     /* store octets */
     for (y = 0; y < inlen; y++) {
         out[x++] = in[y];
     }
  
     /* retun length */
     *outlen = x;
  
     return CRYPT_OK;
  }
  
  #endif
  
  /* $Source$ */
  /* $Revision: 24838 $ */
  /* $Date: 2007-01-23 23:16:57 -0600 (Tue, 23 Jan 2007) $ */
  