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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
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2 * |
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3 * LibTomCrypt is a library that provides various cryptographic |
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4 * algorithms in a highly modular and flexible manner. |
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5 * |
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6 * The library is free for all purposes without any express |
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7 * guarantee it works. |
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8 * |
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9 * Tom St Denis, [email protected], http://libtomcrypt.com |
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10 */ |
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11 #include "tomcrypt.h" |
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12 |
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13 /** |
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14 @file der_length_utf8_string.c |
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15 ASN.1 DER, get length of UTF8 STRING, Tom St Denis |
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16 */ |
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17 |
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18 #ifdef LTC_DER |
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19 |
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20 /** Return the size in bytes of a UTF-8 character |
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21 @param c The UTF-8 character to measure |
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22 @return The size in bytes |
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23 */ |
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24 unsigned long der_utf8_charsize(const wchar_t c) |
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25 { |
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26 if (c <= 0x7F) { |
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27 return 1; |
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28 } else if (c <= 0x7FF) { |
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29 return 2; |
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30 } else if (c <= 0xFFFF) { |
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31 return 3; |
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32 } else { |
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33 return 4; |
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34 } |
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35 } |
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36 |
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37 /** |
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38 Gets length of DER encoding of UTF8 STRING |
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39 @param in The characters to measure the length of |
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40 @param noctets The number of octets in the string to encode |
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41 @param outlen [out] The length of the DER encoding for the given string |
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42 @return CRYPT_OK if successful |
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43 */ |
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44 int der_length_utf8_string(const wchar_t *in, unsigned long noctets, unsigned long *outlen) |
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45 { |
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46 unsigned long x, len; |
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47 |
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48 LTC_ARGCHK(in != NULL); |
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49 LTC_ARGCHK(outlen != NULL); |
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50 |
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51 len = 0; |
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52 for (x = 0; x < noctets; x++) { |
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53 if (in[x] < 0 || in[x] > 0x10FFFF) { |
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54 return CRYPT_INVALID_ARG; |
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55 } |
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56 len += der_utf8_charsize(in[x]); |
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57 } |
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58 |
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59 if (len < 128) { |
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60 /* 0C LL DD DD DD ... */ |
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61 *outlen = 2 + len; |
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62 } else if (len < 256) { |
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63 /* 0C 81 LL DD DD DD ... */ |
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64 *outlen = 3 + len; |
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65 } else if (len < 65536UL) { |
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66 /* 0C 82 LL LL DD DD DD ... */ |
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67 *outlen = 4 + len; |
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68 } else if (len < 16777216UL) { |
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69 /* 0C 83 LL LL LL DD DD DD ... */ |
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70 *outlen = 5 + len; |
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71 } else { |
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72 return CRYPT_INVALID_ARG; |
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73 } |
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74 |
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75 return CRYPT_OK; |
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76 } |
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77 |
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78 #endif |
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79 |
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80 |
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81 /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/utf8/der_length_utf8_string.c,v $ */ |
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82 /* $Revision: 1.5 $ */ |
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83 /* $Date: 2006/12/16 17:41:21 $ */ |
