Remove unnecessary use of ASN1_const_CTX

Reviewed-by: NRich Salz <rsalz@openssl.org>

crypto/asn1/a_d2i_fp.c

@@ -146,12 +146,15 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
     BUF_MEM *b;
     unsigned char *p;
     int i;
-    ASN1_const_CTX c;
     size_t want = HEADER_SIZE;
     int eos = 0;
     size_t off = 0;
     size_t len = 0;
 
+    const unsigned char *q;
+    long slen;
+    int inf, tag, xclass;
+
     b = BUF_MEM_new();
     if (b == NULL) {
         ASN1err(ASN1_F_ASN1_D2I_READ_BIO, ERR_R_MALLOC_FAILURE);
@@ -183,10 +186,9 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
         /* else data already loaded */
 
         p = (unsigned char *)&(b->data[off]);
-        c.p = p;
-        c.inf = ASN1_get_object(&(c.p), &(c.slen), &(c.tag), &(c.xclass),
-                                len - off);
-        if (c.inf & 0x80) {
+        q = p;
+        inf = ASN1_get_object(&q, &slen, &tag, &xclass, len - off);
+        if (inf & 0x80) {
             unsigned long e;
 
             e = ERR_GET_REASON(ERR_peek_error());
@@ -195,10 +197,10 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
             else
                 ERR_clear_error(); /* clear error */
         }
-        i = c.p - p;            /* header length */
+        i = q - p;            /* header length */
         off += i;               /* end of data */
 
-        if (c.inf & 1) {
+        if (inf & 1) {
             /* no data body so go round again */
             eos++;
             if (eos < 0) {
@@ -206,7 +208,7 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
                 goto err;
             }
             want = HEADER_SIZE;
-        } else if (eos && (c.slen == 0) && (c.tag == V_ASN1_EOC)) {
+        } else if (eos && (slen == 0) && (tag == V_ASN1_EOC)) {
             /* eos value, so go back and read another header */
             eos--;
             if (eos <= 0)
@@ -214,8 +216,8 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
             else
                 want = HEADER_SIZE;
         } else {
-            /* suck in c.slen bytes of data */
-            want = c.slen;
+            /* suck in slen bytes of data */
+            want = slen;
             if (want > (len - off)) {
                 want -= (len - off);
                 if (want > INT_MAX /* BIO_read takes an int length */  ||
@@ -242,11 +244,11 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
                     want -= i;
                 }
             }
-            if (off + c.slen < off) {
+            if (off + slen < off) {
                 ASN1err(ASN1_F_ASN1_D2I_READ_BIO, ASN1_R_TOO_LONG);
                 goto err;
             }
-            off += c.slen;
+            off += slen;
             if (eos <= 0) {
                 break;
             } else