Coverity-396111: Fix possibly unitialized binop variable in bytecode module

Fix possibly unitialized binop variable in bytecode module for STORE
and COPY instructions in bytecode module.

Refactored slightly to include additional opcode login in the switch statement.

libclamav/bytecode.c

@@ -1258,6 +1258,10 @@ static cl_error_t parseBB(struct cli_bc *bc, unsigned func, unsigned bb, unsigne
     BB->insts    = &bcfunc->allinsts[bcfunc->insn_idx];
     while (!last) {
         unsigned numOp;
+
+        // Initialize instruction to zero
+        memset(&inst, 0, sizeof(inst));
+
         if (buffer[offset] == 'T') {
             last = 1;
             offset++;
@@ -1355,6 +1359,33 @@ static cl_error_t parseBB(struct cli_bc *bc, unsigned func, unsigned bb, unsigne
                         inst.u.ops.ops[i] = readOperand(bcfunc, buffer, &offset, len, &ok);
                 }
                 break;
+            case OP_BC_STORE:
+                numOp = operand_counts[inst.opcode];
+                if (2 != numOp) {
+                    // invalid number of operands
+                    cli_errmsg("Invalid number of operands (%u) for OP_BC_STORE opcode\n", numOp);
+                    return CL_EMALFDB;
+                }
+                inst.u.binop[0] = readOperand(bcfunc, buffer, &offset, len, &ok);
+                inst.u.binop[1] = readOperand(bcfunc, buffer, &offset, len, &ok);
+
+                int16_t t = get_optype(bcfunc, inst.u.binop[0]);
+                if (t) {
+                    inst.type = t;
+                }
+                break;
+            case OP_BC_COPY:
+                numOp = operand_counts[inst.opcode];
+                if (2 != numOp) {
+                    // invalid number of operands
+                    cli_errmsg("Invalid number of operands (%u) for OP_BC_COPY opcode\n", numOp);
+                    return CL_EMALFDB;
+                }
+                inst.u.binop[0] = readOperand(bcfunc, buffer, &offset, len, &ok);
+                inst.u.binop[1] = readOperand(bcfunc, buffer, &offset, len, &ok);
+
+                inst.type = get_optype(bcfunc, inst.u.binop[1]);
+                break;
             case OP_BC_ICMP_EQ:
             case OP_BC_ICMP_NE:
             case OP_BC_ICMP_UGT:
@@ -1391,22 +1422,18 @@ static cl_error_t parseBB(struct cli_bc *bc, unsigned func, unsigned bb, unsigne
                         break;
                 }
         }
-        if (inst.opcode == OP_BC_STORE) {
-            int16_t t = get_optype(bcfunc, inst.u.binop[0]);
-            if (t)
-                inst.type = t;
-        }
-        if (inst.opcode == OP_BC_COPY)
-            inst.type = get_optype(bcfunc, inst.u.binop[1]);
+
         if (!ok) {
             cli_errmsg("Invalid instructions or operands\n");
             return CL_EMALFDB;
         }
+
         if (bcfunc->insn_idx + BB->numInsts >= bcfunc->numInsts) {
             cli_errmsg("More instructions than declared in total: %u > %u!\n",
                        bcfunc->insn_idx + BB->numInsts, bcfunc->numInsts);
             return CL_EMALFDB;
         }
+
         inst.interp_op = inst.opcode * 5;
         if (inst.type > 1) {
             if (inst.type <= 8)