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://libtom.org
   */
  #include "tomcrypt.h"
  
  /**
    @file der_encode_utf8_string.c
    ASN.1 DER, encode a UTF8 STRING, Tom St Denis
  */
  
  
  #ifdef LTC_DER
  
  /**
    Store an UTF8 STRING
    @param in       The array of UTF8 to store (one per wchar_t)
    @param inlen    The number of UTF8 to store
    @param out      [out] The destination for the DER encoded UTF8 STRING
    @param outlen   [in/out] The max size and resulting size of the DER UTF8 STRING
    @return CRYPT_OK if successful
  */
  int der_encode_utf8_string(const wchar_t *in,  unsigned long inlen,
                             unsigned char *out, unsigned long *outlen)
  {
     unsigned long x, y, len;
  
     LTC_ARGCHK(in     != NULL);
     LTC_ARGCHK(out    != NULL);
     LTC_ARGCHK(outlen != NULL);
  
     /* get the size */
     for (x = len = 0; x < inlen; x++) {
         if (in[x] < 0 || in[x] > 0x1FFFF) { 
            return CRYPT_INVALID_ARG;
         }
         len += der_utf8_charsize(in[x]);
     }
  
     if (len < 128) {
        y = 2 + len;
     } else if (len < 256) {
        y = 3 + len;
     } else if (len < 65536UL) {
        y = 4 + len;
     } else if (len < 16777216UL) {
        y = 5 + len;
     } else {
        return CRYPT_INVALID_ARG;
     }
  
     /* too big? */
     if (y > *outlen) {
        *outlen = len;
        return CRYPT_BUFFER_OVERFLOW;
     }
  
     /* encode the header+len */
     x = 0;
     out[x++] = 0x0C;
     if (len < 128) {
        out[x++] = (unsigned char)len;
     } else if (len < 256) {
        out[x++] = 0x81;
        out[x++] = (unsigned char)len;
     } else if (len < 65536UL) {
        out[x++] = 0x82;
        out[x++] = (unsigned char)((len>>8)&255);
        out[x++] = (unsigned char)(len&255);
     } else if (len < 16777216UL) {
        out[x++] = 0x83;
        out[x++] = (unsigned char)((len>>16)&255);
        out[x++] = (unsigned char)((len>>8)&255);
        out[x++] = (unsigned char)(len&255);
     } else {
        return CRYPT_INVALID_ARG;
     }
  
     /* store UTF8 */
     for (y = 0; y < inlen; y++) {
         switch (der_utf8_charsize(in[y])) {
            case 1: out[x++] = (unsigned char)in[y]; break;
            case 2: out[x++] = 0xC0 | ((in[y] >> 6) & 0x1F);  out[x++] = 0x80 | (in[y] & 0x3F); break;
            case 3: out[x++] = 0xE0 | ((in[y] >> 12) & 0x0F); out[x++] = 0x80 | ((in[y] >> 6) & 0x3F); out[x++] = 0x80 | (in[y] & 0x3F); break;
            case 4: out[x++] = 0xF0 | ((in[y] >> 18) & 0x07); out[x++] = 0x80 | ((in[y] >> 12) & 0x3F); out[x++] = 0x80 | ((in[y] >> 6) & 0x3F); out[x++] = 0x80 | (in[y] & 0x3F); break;
         }
     }
  
     /* retun length */
     *outlen = x;
  
     return CRYPT_OK;
  }
  
  #endif
  
  /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/utf8/der_encode_utf8_string.c,v $ */
  /* $Revision: 1.9 $ */
  /* $Date: 2006/12/28 01:27:24 $ */
  