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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.
*/
#include "tomcrypt.h"
/**
@file der_encode_asn1_length.c
ASN.1 DER, encode the ASN.1 length field, Steffen Jaeckel
*/
#ifdef LTC_DER
/**
Encode the ASN.1 length field
@param len The length to encode
@param out Where to write the length field to
@param outlen [in/out] The size of out available/written
@return CRYPT_OK if successful
*/
int der_encode_asn1_length(unsigned long len, unsigned char *out, unsigned long *outlen)
{
unsigned long x, y;
LTC_ARGCHK(outlen != NULL);
x = len;
y = 0;
while(x != 0) {
y++;
x >>= 8;
}
if (y == 0) {
return CRYPT_PK_ASN1_ERROR;
}
if (out == NULL) {
if (len < 128) {
x = y;
} else {
x = y + 1;
}
} else {
if (*outlen < y) {
return CRYPT_BUFFER_OVERFLOW;
}
x = 0;
if (len < 128) {
out[x++] = (unsigned char)len;
} else if (len <= 0xffUL) {
out[x++] = 0x81;
out[x++] = (unsigned char)len;
} else if (len <= 0xffffUL) {
out[x++] = 0x82;
out[x++] = (unsigned char)((len>>8UL)&255);
out[x++] = (unsigned char)(len&255);
} else if (len <= 0xffffffUL) {
out[x++] = 0x83;
out[x++] = (unsigned char)((len>>16UL)&255);
out[x++] = (unsigned char)((len>>8UL)&255);
out[x++] = (unsigned char)(len&255);
#if ULONG_MAX != ULLONG_MAX
} else {
out[x++] = 0x84;
out[x++] = (unsigned char)((len>>24UL)&255);
out[x++] = (unsigned char)((len>>16UL)&255);
out[x++] = (unsigned char)((len>>8UL)&255);
out[x++] = (unsigned char)(len&255);
}
#else
} else if (len <= 0xffffffffUL) {
out[x++] = 0x84;
out[x++] = (unsigned char)((len>>24UL)&255);
out[x++] = (unsigned char)((len>>16UL)&255);
out[x++] = (unsigned char)((len>>8UL)&255);
out[x++] = (unsigned char)(len&255);
} else if (len <= 0xffffffffffULL) {
out[x++] = 0x85;
out[x++] = (unsigned char)((len>>32ULL)&255);
out[x++] = (unsigned char)((len>>24ULL)&255);
out[x++] = (unsigned char)((len>>16ULL)&255);
out[x++] = (unsigned char)((len>>8ULL)&255);
out[x++] = (unsigned char)(len&255);
} else if (len <= 0xffffffffffffULL) {
out[x++] = 0x86;
out[x++] = (unsigned char)((len>>40ULL)&255);
out[x++] = (unsigned char)((len>>32ULL)&255);
out[x++] = (unsigned char)((len>>24ULL)&255);
out[x++] = (unsigned char)((len>>16ULL)&255);
out[x++] = (unsigned char)((len>>8ULL)&255);
out[x++] = (unsigned char)(len&255);
} else if (len <= 0xffffffffffffffULL) {
out[x++] = 0x87;
out[x++] = (unsigned char)((len>>48ULL)&255);
out[x++] = (unsigned char)((len>>40ULL)&255);
out[x++] = (unsigned char)((len>>32ULL)&255);
out[x++] = (unsigned char)((len>>24ULL)&255);
out[x++] = (unsigned char)((len>>16ULL)&255);
out[x++] = (unsigned char)((len>>8ULL)&255);
out[x++] = (unsigned char)(len&255);
} else {
out[x++] = 0x88;
out[x++] = (unsigned char)((len>>56ULL)&255);
out[x++] = (unsigned char)((len>>48ULL)&255);
out[x++] = (unsigned char)((len>>40ULL)&255);
out[x++] = (unsigned char)((len>>32ULL)&255);
out[x++] = (unsigned char)((len>>24ULL)&255);
out[x++] = (unsigned char)((len>>16ULL)&255);
out[x++] = (unsigned char)((len>>8ULL)&255);
out[x++] = (unsigned char)(len&255);
}
#endif
}
*outlen = x;
return CRYPT_OK;
}
#endif
/* ref: $Format:%D$ */
/* git commit: $Format:%H$ */
/* commit time: $Format:%ai$ */
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