X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=libtomcrypt%2Fsrc%2Fpk%2Fasn1%2Fder%2Fshort_integer%2Fder_decode_short_integer.c;fp=libtomcrypt%2Fsrc%2Fpk%2Fasn1%2Fder%2Fshort_integer%2Fder_decode_short_integer.c;h=71debf31041fd4061f47bd4c3ae72187826b48c4;hb=66bc25938679f1d6a1d1200f329093d82a5e99b4;hp=0000000000000000000000000000000000000000;hpb=a52ee0733f420ca20224049260d6fc5cf7d8f621;p=zpackage

diff --git a/libtomcrypt/src/pk/asn1/der/short_integer/der_decode_short_integer.c b/libtomcrypt/src/pk/asn1/der/short_integer/der_decode_short_integer.c
new file mode 100644
index 0000000..71debf3
--- /dev/null
+++ b/libtomcrypt/src/pk/asn1/der/short_integer/der_decode_short_integer.c
@@ -0,0 +1,66 @@
+/* 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_decode_short_integer.c
+  ASN.1 DER, decode an integer, Tom St Denis
+*/
+
+
+#ifdef LTC_DER
+
+/**
+  Read a short integer
+  @param in       The DER encoded data
+  @param inlen    Size of data
+  @param num      [out] The integer to decode
+  @return CRYPT_OK if successful
+*/
+int der_decode_short_integer(const unsigned char *in, unsigned long inlen, unsigned long *num)
+{
+   unsigned long len, x, y;
+
+   LTC_ARGCHK(num    != NULL);
+   LTC_ARGCHK(in     != NULL);
+
+   /* check length */
+   if (inlen < 2) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* check header */
+   x = 0;
+   if ((in[x++] & 0x1F) != 0x02) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* get the packet len */
+   len = in[x++];
+
+   if (x + len > inlen) {
+      return CRYPT_INVALID_PACKET;
+   }
+
+   /* read number */
+   y = 0;
+   while (len--) {
+      y = (y<<8) | (unsigned long)in[x++];
+   }
+   *num = y;
+
+   return CRYPT_OK;
+
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */