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/* 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_length_utf8_string.c
ASN.1 DER, get length of UTF8 STRING, Tom St Denis
*/
#ifdef LTC_DER
/** Return the size in bytes of a UTF-8 character
@param c The UTF-8 character to measure
@return The size in bytes
*/
unsigned long der_utf8_charsize(const wchar_t c)
{
if (c <= 0x7F) {
return 1;
} else if (c <= 0x7FF) {
return 2;
} else if (c <= 0xFFFF) {
return 3;
} else {
return 4;
}
}
/**
Gets length of DER encoding of UTF8 STRING
@param in The characters to measure the length of
@param noctets The number of octets in the string to encode
@param outlen [out] The length of the DER encoding for the given string
@return CRYPT_OK if successful
*/
int der_length_utf8_string(const wchar_t *in, unsigned long noctets, unsigned long *outlen)
{
unsigned long x, len;
LTC_ARGCHK(in != NULL);
LTC_ARGCHK(outlen != NULL);
len = 0;
for (x = 0; x < noctets; x++) {
if (in[x] < 0 || in[x] > 0x10FFFF) {
return CRYPT_INVALID_ARG;
}
len += der_utf8_charsize(in[x]);
}
if (len < 128) {
/* 0C LL DD DD DD ... */
*outlen = 2 + len;
} else if (len < 256) {
/* 0C 81 LL DD DD DD ... */
*outlen = 3 + len;
} else if (len < 65536UL) {
/* 0C 82 LL LL DD DD DD ... */
*outlen = 4 + len;
} else if (len < 16777216UL) {
/* 0C 83 LL LL LL DD DD DD ... */
*outlen = 5 + len;
} else {
return CRYPT_INVALID_ARG;
}
return CRYPT_OK;
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/utf8/der_length_utf8_string.c,v $ */
/* $Revision: 1.5 $ */
/* $Date: 2006/12/16 17:41:21 $ */
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