From a739070310ebdcdde23658c8966db1ade9b510eb Mon Sep 17 00:00:00 2001
From: davu <davu@mir-robots.com>
Date: Sun, 12 Mar 2023 19:16:34 +0100
Subject: [PATCH] moving utils to dsymbol

---
 dsymbol/src/dsymbol/utils.d | 155 ++++++++++++++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100644 dsymbol/src/dsymbol/utils.d

diff --git a/dsymbol/src/dsymbol/utils.d b/dsymbol/src/dsymbol/utils.d
new file mode 100644
index 0000000..518166c
--- /dev/null
+++ b/dsymbol/src/dsymbol/utils.d
@@ -0,0 +1,155 @@
+module dsymbol.utils;
+import dparse.lexer : tok, IdType;
+
+enum TYPE_IDENT_CASES = q{
+	case tok!"int":
+	case tok!"uint":
+	case tok!"long":
+	case tok!"ulong":
+	case tok!"char":
+	case tok!"wchar":
+	case tok!"dchar":
+	case tok!"bool":
+	case tok!"byte":
+	case tok!"ubyte":
+	case tok!"short":
+	case tok!"ushort":
+	case tok!"cent":
+	case tok!"ucent":
+	case tok!"float":
+	case tok!"ifloat":
+	case tok!"cfloat":
+	case tok!"idouble":
+	case tok!"cdouble":
+	case tok!"double":
+	case tok!"real":
+	case tok!"ireal":
+	case tok!"creal":
+	case tok!"this":
+	case tok!"super":
+	case tok!"identifier":
+};
+
+enum STRING_LITERAL_CASES = q{
+	case tok!"stringLiteral":
+	case tok!"wstringLiteral":
+	case tok!"dstringLiteral":
+};
+
+enum TYPE_IDENT_AND_LITERAL_CASES = TYPE_IDENT_CASES ~ STRING_LITERAL_CASES;
+
+/**
+ * Skips blocks of parentheses until the starting block has been closed
+ */
+void skipParen(T)(T tokenSlice, ref size_t i, IdType open, IdType close)
+{
+	if (i >= tokenSlice.length || tokenSlice.length <= 0)
+		return;
+	int depth = 1;
+	while (depth != 0 && i + 1 != tokenSlice.length)
+	{
+		i++;
+		if (tokenSlice[i].type == open)
+			depth++;
+		else if (tokenSlice[i].type == close)
+			depth--;
+	}
+}
+
+
+/**
+ * Skips blocks of parentheses in reverse until the starting block has been opened
+ */
+size_t skipParenReverse(T)(T beforeTokens, size_t i, IdType open, IdType close)
+{
+	if (i == 0)
+		return 0;
+	int depth = 1;
+	while (depth != 0 && i != 0)
+	{
+		i--;
+		if (beforeTokens[i].type == open)
+			depth++;
+		else if (beforeTokens[i].type == close)
+			depth--;
+	}
+	return i;
+}
+
+
+
+size_t skipParenReverseBefore(T)(T beforeTokens, size_t i, IdType open, IdType close)
+{
+	i = skipParenReverse(beforeTokens, i, open, close);
+	if (i != 0)
+		i--;
+	return i;
+}
+
+
+/**
+ * Traverses a token slice in reverse to find the opening parentheses or square bracket
+ * that begins the block the last token is in.
+ */
+size_t goBackToOpenParen(T)(T beforeTokens)
+in
+{
+	assert (beforeTokens.length > 0);
+}
+do
+{
+	size_t i = beforeTokens.length - 1;
+	while (true) switch (beforeTokens[i].type)
+	{
+	case tok!",":
+	case tok!".":
+	case tok!"*":
+	case tok!"&":
+	case tok!"doubleLiteral":
+	case tok!"floatLiteral":
+	case tok!"idoubleLiteral":
+	case tok!"ifloatLiteral":
+	case tok!"intLiteral":
+	case tok!"longLiteral":
+	case tok!"realLiteral":
+	case tok!"irealLiteral":
+	case tok!"uintLiteral":
+	case tok!"ulongLiteral":
+	case tok!"characterLiteral":
+	mixin(TYPE_IDENT_AND_LITERAL_CASES);
+		if (i == 0)
+			return size_t.max;
+		else
+			i--;
+		break;
+	case tok!"(":
+	case tok!"[":
+		return i + 1;
+	case tok!")":
+		i = beforeTokens.skipParenReverseBefore(i, tok!")", tok!"(");
+		break;
+	case tok!"}":
+		i = beforeTokens.skipParenReverseBefore(i, tok!"}", tok!"{");
+		break;
+	case tok!"]":
+		i = beforeTokens.skipParenReverseBefore(i, tok!"]", tok!"[");
+		break;
+	default:
+		return size_t.max;
+	}
+}
+
+///Testing skipping
+unittest
+{
+	Token[] t = [
+		Token(tok!"identifier"), Token(tok!"identifier"), Token(tok!"("),
+		Token(tok!"identifier"), Token(tok!"("), Token(tok!")"), Token(tok!",")
+	];
+	size_t i = t.length - 1;
+	i = skipParenReverse(t, i, tok!")", tok!"(");
+	assert(i == 2);
+	i = t.length - 1;
+	i = skipParenReverseBefore(t, i, tok!")", tok!"(");
+	assert(i == 1);
+}