Make APER encoding/decoding of constrained OCTET_STRING correct

mouse07410 · Aug 21, 2024 · 8d05d71 · 8d05d71
1 parent 1ad922d
commit 8d05d71
Showing 1 changed file with 40 additions and 26 deletions.
diff --git a/skeletons/OCTET_STRING_aper.c b/skeletons/OCTET_STRING_aper.c
@@ -61,28 +61,36 @@ OCTET_STRING_decode_aper(const asn_codec_ctx_t *opt_codec_ctx,
     switch(specs->subvariant) {
     case ASN_OSUBV_ANY:
         canonical_unit_bits = unit_bits = 8;
-        if(cval->flags & APC_CONSTRAINED)
-          unit_bits = cval->range_bits; 
-        bpc = OS__BPC_CHAR;
-        break;
-    case ASN_OSUBV_STR:
-        canonical_unit_bits = unit_bits = 8;
-        /*
-        if(cval->flags & APC_CONSTRAINED)
-          unit_bits = cval->range_bits; 
-        */
+        if(cval->flags & APC_CONSTRAINED) {
+            /* follow power of 2 rule */
+            if (cval->range_bits <= 2) {
+        		unit_bits = 2;
+            } else {
+        		if (cval->range_bits <= 4) {
+        	   		unit_bits = 4;
+        	   		/* otherwise, unit_bits = 8; */
+        		}
+	    	}
+            /* unit_bits = cval->range_bits; */
+            ASN_DEBUG("APER decoding ASN_OSUBV_STR range_bits = %d unit_bits = %d\n",
+            	cval->range_bits, unit_bits);
+        }
         bpc = OS__BPC_CHAR;
         break;
     case ASN_OSUBV_U16:
         canonical_unit_bits = unit_bits = 16;
-        if(cval->flags & APC_CONSTRAINED)
+        if(cval->flags & APC_CONSTRAINED) {
             unit_bits = cval->range_bits;
+            ASN_DEBUG("APER decoding ASN_OSUBV_U16 range_bits = %d\n", cval->range_bits);
+        }
         bpc = OS__BPC_U16;
         break;
     case ASN_OSUBV_U32:
         canonical_unit_bits = unit_bits = 32;
-        if(cval->flags & APC_CONSTRAINED)
+        if(cval->flags & APC_CONSTRAINED) {
             unit_bits = cval->range_bits;
+            ASN_DEBUG("APER decoding ASN_OSUBV_U32 range_bits = %d\n", cval->range_bits);
+        }
         bpc = OS__BPC_U32;
         break;
 /*
@@ -275,30 +283,37 @@ OCTET_STRING_encode_aper(const asn_TYPE_descriptor_t *td,
     switch(specs->subvariant) {
     case ASN_OSUBV_ANY:
         canonical_unit_bits = unit_bits = 8;
-        if(cval->flags & APC_CONSTRAINED)
-            unit_bits = 8;
-        bpc = OS__BPC_CHAR;
-        break;
-    case ASN_OSUBV_STR:
-        canonical_unit_bits = unit_bits = 8;
-/*
-        if(cval->flags & APC_CONSTRAINED)
-            unit_bits = 8;
-*/
+        if(cval->flags & APC_CONSTRAINED) {
+        	/* follow power of 2 rule */
+        	if (cval->range_bits <= 2) {
+        		unit_bits = 2;
+        	} else {
+        		if (cval->range_bits <= 4)
+        			unit_bits = 4;
+        		/* otherwise, unit_bits = 8; */
+        	}
+            /* unit_bits = cval->range_bits; */
+            ASN_DEBUG("APER encoding ASN_OSUBV_STR range_bits = %d unit_bits = %d\n", 
+            		cval->range_bits, unit_bits);
+        }
         bpc = OS__BPC_CHAR;
         sizeinunits = st->size;
         break;
     case ASN_OSUBV_U16:
         canonical_unit_bits = unit_bits = 16;
-        if(cval->flags & APC_CONSTRAINED)
+        if(cval->flags & APC_CONSTRAINED) {
             unit_bits = cval->range_bits;
+            ASN_DEBUG("APER encoding ASN_OSUBV_U16 range_bits = %d\n", cval->range_bits);
+        }
         bpc = OS__BPC_U16;
         sizeinunits = st->size / 2;
         break;
     case ASN_OSUBV_U32:
         canonical_unit_bits = unit_bits = 32;
-        if(cval->flags & APC_CONSTRAINED)
+        if(cval->flags & APC_CONSTRAINED) {
             unit_bits = cval->range_bits;
+            ASN_DEBUG("APER encoding ASN_OSUBV_U32 range_bits = %d\n", cval->range_bits);
+        }
         bpc = OS__BPC_U32;
         sizeinunits = st->size / 4;
         break;
@@ -311,8 +326,7 @@ OCTET_STRING_encode_aper(const asn_TYPE_descriptor_t *td,
         canonical_unit_bits = unit_bits = 1;
         bpc = OS__BPC_BIT;
         sizeinunits = st->size * 8 - (st->bits_unused & 0x07);
-        ASN_DEBUG("BIT STRING of %d bytes",
-                  sizeinunits);
+        ASN_DEBUG("BIT STRING of %d bytes", sizeinunits);
         break;
     }