Initial commit of files

src/libasn1/oer_get_ext.c

@@ -0,0 +1,143 @@
+/*****************************************************************************
+ * Copyright (C) 2004-2021
+ * ProbeStar Technical Systems, LLC
+ * All Rights Reserved.  Proprietary and Confidential.
+ *============================================================================
+*****************************************************************************/
+
+/*****************************************************************************
+ * includes
+*****************************************************************************/
+
+#include "embtypes.h"
+#include "asn1oer.h"
+
+/*****************************************************************************
+ * defines
+*****************************************************************************/
+
+/*****************************************************************************
+ * macros
+*****************************************************************************/
+
+#define min(A,B)        ((A)<(B)?(A):(B))
+#define max(A,B)        ((A)>(B)?(A):(B))
+
+/*****************************************************************************
+ * structs & typedefs
+*****************************************************************************/
+
+/*****************************************************************************
+ * global constants
+*****************************************************************************/
+
+/*****************************************************************************
+ * global variables
+*****************************************************************************/
+
+/*****************************************************************************
+ * static constants
+*****************************************************************************/
+
+/*****************************************************************************
+ * static variables
+*****************************************************************************/
+
+/*****************************************************************************
+ * static prototypes
+*****************************************************************************/
+
+/*****************************************************************************
+ * C functions
+*****************************************************************************/
+
+// grab extension bits, check for extension defined by ellipses
+uint oer_get_extension(OER_Stream *oer, OER_Extension *ext, uint noptions, uint ellipses)
+{
+  if (!oer || !ext)
+    return 0;
+
+  ellipses &= 1;
+  if ((noptions+ellipses)==0) {
+    oer->error = 1;
+    return 0;
+  }
+
+  uint64_t value = oer_get_value(oer, ellipses+noptions);
+ 
+  uint nbits = ellipses + noptions;
+  uint shift = (64 - nbits) % 8;
+  if (_asn1_debug_on_ == 2)
+    printf("\tEXT_VALUE = %lx (%ld) >> %d\n", value, value, shift);
+  value >>= shift;
+
+  // mask
+  uint64_t mask = (0xffffffffffffffffULL >> (64 - nbits));
+  ext->value = value & mask;
+  
+  if (ellipses) {
+    ext->ellipses = (ext->value >> noptions) & 1;
+
+    ext->length = oer_get_length(oer, NULL);
+    
+    if (_asn1_debug_on_)
+      printf("\tEXT_LEN = %d\n", ext->length);
+    // otherwise no ...
+  }  
+  else {
+    ext->length = 0;
+  }
+
+  if (noptions) {
+    ext->options = noptions;
+  }
+
+  return ellipses + noptions;
+}
+
+uint oer_get_ext_length(OER_Stream *oer, OER_Extension *ext)
+{
+  if (!ext->ellipses)
+    return 0;
+
+  uint len;  
+  ext->length = oer_get_length(oer, &len);
+  
+  return ext->length;
+}
+
+// if ellipses extension available
+uint oer_get_ext_ellipses(OER_Extension *ext)
+{
+  if (ext)
+    return ext->ellipses;
+  return 0;
+}
+
+// from the front (high->low bits)
+uint oer_get_ext_optional(OER_Extension *ext, uint bit)
+{
+  if (!ext || (bit>=ext->options))
+    return 0;
+  
+  return (ext->value & 1<<(ext->options-bit));
+}
+
+uint oer_get_ext_skip(OER_Stream *oer, OER_Extension *ext)
+{
+  if (!oer && !ext && !ext->length)
+    return 0;
+  
+  int bits = ext->length;
+  
+  // copy in
+  int sbit = oer->bit;        // bit order in stream (not byte)
+  int ebit = (sbit+bits) % 8; // after last bit
+
+  // copy out
+  oer->ptr += (sbit + bits) / 8;
+  oer->bit = ebit;
+  oer->consumed += bits;
+  
+  return bits;
+}