adding msb, lsb and spec constants

src/WordIterator.zig

@@ -10,12 +10,14 @@ const Self = @This();
 buffer: []const SpvWord,
 index: usize,
 did_jump: bool,
+next_force_skip: ?usize,
 
 pub fn init(buffer: []const SpvWord) Self {
     return .{
         .buffer = buffer,
         .index = 0,
         .did_jump = false,
+        .next_force_skip = null,
     };
 }
 
@@ -25,15 +27,37 @@ pub inline fn nextOrNull(self: *Self) ?SpvWord {
     return word;
 }
 
+/// self.index + index will be automatically skipped
+pub inline fn forceSkipIndex(self: *Self, index: SpvWord) void {
+    self.next_force_skip = self.index + index;
+}
+
 pub inline fn nextAsOrNull(self: *Self, comptime E: type) ?E {
+    if (self.next_force_skip) |skip_index| {
+        if (self.index == skip_index) {
+            _ = self.skip();
+            self.next_force_skip = null;
+        }
+    }
     return if (self.nextOrNull()) |word| std.enums.fromInt(E, word) else null;
 }
 
 pub inline fn next(self: *Self) RuntimeError!SpvWord {
+    if (self.next_force_skip) |skip_index| {
+        if (self.index == skip_index) {
+            _ = self.skip();
+            self.next_force_skip = null;
+        }
+    }
     return self.nextOrNull() orelse return RuntimeError.InvalidSpirV;
 }
 
 pub inline fn nextAs(self: *Self, comptime E: type) RuntimeError!E {
+    if (self.next_force_skip) |skip_index| {
+        if (self.index == skip_index) {
+            _ = self.skip();
+        }
+    }
     return self.nextAsOrNull(E) orelse return RuntimeError.InvalidSpirV;
 }
 
@@ -72,3 +96,10 @@ pub inline fn jumpToSourceLocation(self: *Self, source_location: usize) bool {
     self.did_jump = true;
     return true;
 }
+
+/// Like jumpToSourceLocation without toggling self.did_jump
+pub inline fn goToSourceLocation(self: *Self, source_location: usize) bool {
+    if (source_location > self.buffer.len) return false;
+    self.index = source_location;
+    return true;
+}