Dedupe Index & Branch

src/Class/Code/Instruction.zig

@@ -1,6 +1,7 @@
 const std = @import("std");
 
 const Class = @import("../../Class.zig");
+const ConstantPool = Class.ConstantPool;
 const ParseError = Class.ParseError;
 
 const Op = enum(u8) {
@@ -208,47 +209,29 @@ const Op = enum(u8) {
     wide = 0xc4,
 };
 
-const IndexU8 = struct {
+fn Index(comptime T: type) type {
-    index: u8,
+    const bits = @typeInfo(T).int.bits;
+    if (bits % 8 != 0) {
+        @compileError("Bits should be multiple of 8");
+    }
+    const bytes = bits / 8;
+
+    return struct {
+        index: T,
 
         const Self = @This();
 
         pub fn parse(input: *std.Io.Reader, byte_index: *usize) ParseError!Self {
-        defer byte_index.* += 1;
+            defer byte_index.* += bytes;
+
+            const index = try if (bytes == 1) input.takeByte() else input.takeInt(T, .big);
 
             return .{
-            .index = try input.takeByte(),
+                .index = index,
             };
         }
-};
-
-const IndexU16 = struct {
-    index: u16,
-
-    const Self = @This();
-
-    pub fn parse(input: *std.Io.Reader, byte_index: *usize) ParseError!Self {
-        defer byte_index.* += 2;
-
-        return .{
-            .index = try input.takeInt(u16, .big),
     };
-    }
+}
-};
-
-const IndexU32 = struct {
-    index: u32,
-
-    const Self = @This();
-
-    pub fn parse(input: *std.Io.Reader, byte_index: *usize) ParseError!Self {
-        defer byte_index.* += 4;
-
-        return .{
-            .index = try input.takeInt(u32, .big),
-        };
-    }
-};
 
 const Byte = struct {
     byte: u8,
@@ -264,33 +247,27 @@ const Byte = struct {
     }
 };
 
-const BranchU16 = struct {
+fn Branch(comptime T: type) type {
-    branch: u16,
+    const bits = @typeInfo(T).int.bits;
+    if (bits % 8 != 0) {
+        @compileError("Bits should be multiple of 8");
+    }
+    const bytes = bits / 8;
+
+    return struct {
+        branch: T,
 
         const Self = @This();
 
         pub fn parse(input: *std.Io.Reader, byte_index: *usize) ParseError!Self {
-        defer byte_index.* += 2;
+            defer byte_index.* += bytes;
 
             return .{
                 .branch = try input.takeInt(u16, .big),
             };
         }
-};
-
-const BranchU32 = struct {
-    branch: u32,
-
-    const Self = @This();
-
-    pub fn parse(input: *std.Io.Reader, byte_index: *usize) ParseError!Self {
-        defer byte_index.* += 4;
-
-        return .{
-            .branch = try input.takeInt(u32, .big),
     };
-    }
+}
-};
 
 const IInc = struct {
     index: u8,
@@ -537,15 +514,15 @@ pub const Instruction = union(Op) {
     aaload,
     aastore,
     aconst_null,
-    aload: IndexU8,
+    aload: Index(u8),
     aload_0,
     aload_1,
     aload_2,
     aload_3,
-    anewarray: IndexU16,
+    anewarray: Index(u16),
     areturn,
     arraylength,
-    astore: IndexU8,
+    astore: Index(u8),
     astore_0,
     astore_1,
     astore_2,
@@ -556,7 +533,7 @@ pub const Instruction = union(Op) {
     bipush: Byte,
     caload,
     castore,
-    checkcast: IndexU16,
+    checkcast: Index(u16),
     d2f,
     d2i,
     d2l,
@@ -568,7 +545,7 @@ pub const Instruction = union(Op) {
     dconst_0,
     dconst_1,
     ddiv,
-    dload: IndexU8,
+    dload: Index(u8),
     dload_0,
     dload_1,
     dload_2,
@@ -577,7 +554,7 @@ pub const Instruction = union(Op) {
     dneg,
     drem,
     dreturn,
-    dstore: IndexU8,
+    dstore: Index(u8),
     dstore_0,
     dstore_1,
     dstore_2,
@@ -601,7 +578,7 @@ pub const Instruction = union(Op) {
     fconst_1,
     fconst_2,
     fdiv,
-    fload: IndexU8,
+    fload: Index(u8),
     fload_0,
     fload_1,
     fload_2,
@@ -610,16 +587,16 @@ pub const Instruction = union(Op) {
     fneg,
     frem,
     freturn,
-    fstore: IndexU8,
+    fstore: Index(u8),
     fstore_0,
     fstore_1,
     fstore_2,
     fstore_3,
     fsub,
-    getfield: IndexU16,
+    getfield: Index(u16),
-    getstatic: IndexU16,
+    getstatic: Index(u16),
-    goto: IndexU16,
+    goto: Index(u16),
-    goto_w: IndexU32,
+    goto_w: Index(u32),
     i2b,
     i2c,
     i2d,
@@ -638,42 +615,42 @@ pub const Instruction = union(Op) {
     iconst_4,
     iconst_5,
     idiv,
-    if_acmpeq: BranchU16,
+    if_acmpeq: Branch(u16),
-    if_acmpne: BranchU16,
+    if_acmpne: Branch(u16),
-    if_icmpeq: BranchU16,
+    if_icmpeq: Branch(u16),
-    if_icmpne: BranchU16,
+    if_icmpne: Branch(u16),
-    if_icmplt: BranchU16,
+    if_icmplt: Branch(u16),
-    if_icmpge: BranchU16,
+    if_icmpge: Branch(u16),
-    if_icmpgt: BranchU16,
+    if_icmpgt: Branch(u16),
-    if_icmple: BranchU16,
+    if_icmple: Branch(u16),
-    ifeq: BranchU16,
+    ifeq: Branch(u16),
-    ifne: BranchU16,
+    ifne: Branch(u16),
-    iflt: BranchU16,
+    iflt: Branch(u16),
-    ifge: BranchU16,
+    ifge: Branch(u16),
-    ifgt: BranchU16,
+    ifgt: Branch(u16),
-    ifle: BranchU16,
+    ifle: Branch(u16),
-    ifnonnull: BranchU16,
+    ifnonnull: Branch(u16),
-    ifnull: BranchU16,
+    ifnull: Branch(u16),
     iinc: IInc,
-    iload: IndexU8,
+    iload: Index(u8),
     iload_0,
     iload_1,
     iload_2,
     iload_3,
     imul,
     ineg,
-    instanceof: IndexU16,
+    instanceof: Index(u16),
     invokedynamic: InvokeDynamic,
     invokeinterface: InvokeInterface,
-    invokespecial: IndexU16,
+    invokespecial: Index(u16),
-    invokestatic: IndexU16,
+    invokestatic: Index(u16),
-    invokevirtual: IndexU16,
+    invokevirtual: Index(u16),
     ior,
     irem,
     ireturn,
     ishl,
     ishr,
-    istore: IndexU8,
+    istore: Index(u8),
     istore_0,
     istore_1,
     istore_2,
@@ -681,8 +658,8 @@ pub const Instruction = union(Op) {
     isub,
     iushr,
     ixor,
-    jsr: BranchU16,
+    jsr: Branch(u16),
-    jsr_w: BranchU32,
+    jsr_w: Branch(u32),
     l2d,
     l2f,
     l2i,
@@ -693,11 +670,11 @@ pub const Instruction = union(Op) {
     lcmp,
     lconst_0,
     lconst_1,
-    ldc: IndexU8,
+    ldc: Index(u8),
-    ldc_w: IndexU16,
+    ldc_w: Index(u16),
-    ldc2_w: IndexU16,
+    ldc2_w: Index(u16),
     ldiv,
-    lload: IndexU8,
+    lload: Index(u8),
     lload_0,
     lload_1,
     lload_2,
@@ -710,7 +687,7 @@ pub const Instruction = union(Op) {
     lreturn,
     lshl,
     lshr,
-    lstore: IndexU8,
+    lstore: Index(u8),
     lstore_0,
     lstore_1,
     lstore_2,
@@ -721,14 +698,14 @@ pub const Instruction = union(Op) {
     monitorenter,
     monitorexit,
     multianewarray: MultiANewArray,
-    new: IndexU16,
+    new: Index(u16),
     newarray: NewArray,
     nop,
     pop,
     pop2,
-    putfield: IndexU16,
+    putfield: Index(u16),
-    putstatic: IndexU16,
+    putstatic: Index(u16),
-    ret: IndexU8,
+    ret: Index(u8),
     @"return",
     saload,
     sastore,