Initial file commit

SourceGen/XrefSet.cs

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+/*
+ * Copyright 2018 faddenSoft
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics;
+
+namespace SourceGen {
+    /// <summary>
+    /// Tracks a set of offsets that reference a single address or label.
+    /// 
+    /// This is used internally, when refactoring labels, as well as for the "references"
+    /// UI panel and label localizer.
+    /// </summary>
+    public class XrefSet : IEnumerable<XrefSet.Xref> {
+        /// <summary>
+        /// Reference type.  This is mostly useful for display to the user.
+        /// </summary>
+        public enum XrefType {
+            Unknown = 0,
+            InstrOperand,       // generic instruction operand
+            BranchOperand,      // branch instruction
+            DataOperand         // e.g. ".dd2 <address>"
+        }
+
+        /// <summary>
+        /// Cross-reference descriptor.  Instances are immutable.
+        /// </summary>
+        public class Xref {
+            /// <summary>
+            /// Offset of start of instruction or data with the reference.
+            /// </summary>
+            public int Offset { get; private set; }
+
+            /// <summary>
+            /// True if this reference is by name.
+            /// </summary>
+            public bool IsSymbolic { get; private set; }
+
+            /// <summary>
+            /// Type of reference.
+            /// </summary>
+            public XrefType Type { get; private set; }
+
+            /// <summary>
+            /// Adjustment to symbol.  For example, "LDA label+2" adds an xref entry to
+            /// "label", with an adjustment of +2.
+            /// </summary>
+            public int Adjustment { get; private set; }
+
+            public Xref(int offset, bool isSymbolic, XrefType type, int adjustment) {
+                Offset = offset;
+                IsSymbolic = isSymbolic;
+                Type = type;
+                Adjustment = adjustment;
+            }
+
+            public override string ToString() {
+                return "Xref off=+" + Offset.ToString("x6") + " sym=" + IsSymbolic +
+                    " type=" + Type + " adj=" + Adjustment;
+            }
+        }
+
+        /// <summary>
+        /// Internal storage for xrefs.
+        /// </summary>
+        private List<Xref> mRefs = new List<Xref>();
+
+
+        /// <summary>
+        /// Constructs an empty set.
+        /// </summary>
+        public XrefSet() { }
+
+        /// <summary>
+        /// Returns the number of cross-references in the set.
+        /// </summary>
+        public int Count { get { return mRefs.Count; } }
+
+        /// <summary>
+        /// Removes all entries from the set.
+        /// </summary>
+        public void Clear() {
+            mRefs.Clear();
+        }
+
+        /// <summary>
+        /// Returns the Nth entry in the set.
+        /// </summary>
+        public Xref this[int index] {
+            get {
+                return mRefs[index];
+            }
+        }
+
+        /// <summary>
+        /// Adds an xref to the set.
+        /// </summary>
+        public void Add(Xref xref) {
+            // TODO(someday): not currently enforcing set behavior; start by adding .equals to
+            //   Xref, then check Contains before allowing Add.  (Should probably complain
+            //   loudly if item already exists, since we're not expecting that.)
+            mRefs.Add(xref);
+        }
+
+        // IEnumerable
+        public IEnumerator GetEnumerator() {
+            return ((IEnumerable)mRefs).GetEnumerator();
+        }
+
+        // IEnumerable, generic
+        IEnumerator<Xref> IEnumerable<Xref>.GetEnumerator() {
+            return ((IEnumerable<Xref>)mRefs).GetEnumerator();
+        }
+    }
+}