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venv/lib/python3.11/site-packages/pycparser/c_generator.py

@@ -0,0 +1,502 @@
+#------------------------------------------------------------------------------
+# pycparser: c_generator.py
+#
+# C code generator from pycparser AST nodes.
+#
+# Eli Bendersky [https://eli.thegreenplace.net/]
+# License: BSD
+#------------------------------------------------------------------------------
+from . import c_ast
+
+
+class CGenerator(object):
+    """ Uses the same visitor pattern as c_ast.NodeVisitor, but modified to
+        return a value from each visit method, using string accumulation in
+        generic_visit.
+    """
+    def __init__(self, reduce_parentheses=False):
+        """ Constructs C-code generator
+
+            reduce_parentheses:
+                if True, eliminates needless parentheses on binary operators
+        """
+        # Statements start with indentation of self.indent_level spaces, using
+        # the _make_indent method.
+        self.indent_level = 0
+        self.reduce_parentheses = reduce_parentheses
+
+    def _make_indent(self):
+        return ' ' * self.indent_level
+
+    def visit(self, node):
+        method = 'visit_' + node.__class__.__name__
+        return getattr(self, method, self.generic_visit)(node)
+
+    def generic_visit(self, node):
+        if node is None:
+            return ''
+        else:
+            return ''.join(self.visit(c) for c_name, c in node.children())
+
+    def visit_Constant(self, n):
+        return n.value
+
+    def visit_ID(self, n):
+        return n.name
+
+    def visit_Pragma(self, n):
+        ret = '#pragma'
+        if n.string:
+            ret += ' ' + n.string
+        return ret
+
+    def visit_ArrayRef(self, n):
+        arrref = self._parenthesize_unless_simple(n.name)
+        return arrref + '[' + self.visit(n.subscript) + ']'
+
+    def visit_StructRef(self, n):
+        sref = self._parenthesize_unless_simple(n.name)
+        return sref + n.type + self.visit(n.field)
+
+    def visit_FuncCall(self, n):
+        fref = self._parenthesize_unless_simple(n.name)
+        return fref + '(' + self.visit(n.args) + ')'
+
+    def visit_UnaryOp(self, n):
+        if n.op == 'sizeof':
+            # Always parenthesize the argument of sizeof since it can be
+            # a name.
+            return 'sizeof(%s)' % self.visit(n.expr)
+        else:
+            operand = self._parenthesize_unless_simple(n.expr)
+            if n.op == 'p++':
+                return '%s++' % operand
+            elif n.op == 'p--':
+                return '%s--' % operand
+            else:
+                return '%s%s' % (n.op, operand)
+
+    # Precedence map of binary operators:
+    precedence_map = {
+        # Should be in sync with c_parser.CParser.precedence
+        # Higher numbers are stronger binding
+        '||': 0,  # weakest binding
+        '&&': 1,
+        '|': 2,
+        '^': 3,
+        '&': 4,
+        '==': 5, '!=': 5,
+        '>': 6, '>=': 6, '<': 6, '<=': 6,
+        '>>': 7, '<<': 7,
+        '+': 8, '-': 8,
+        '*': 9, '/': 9, '%': 9  # strongest binding
+    }
+
+    def visit_BinaryOp(self, n):
+        # Note: all binary operators are left-to-right associative
+        #
+        # If `n.left.op` has a stronger or equally binding precedence in
+        # comparison to `n.op`, no parenthesis are needed for the left:
+        # e.g., `(a*b) + c` is equivalent to `a*b + c`, as well as
+        #       `(a+b) - c` is equivalent to `a+b - c` (same precedence).
+        # If the left operator is weaker binding than the current, then
+        # parentheses are necessary:
+        # e.g., `(a+b) * c` is NOT equivalent to `a+b * c`.
+        lval_str = self._parenthesize_if(
+            n.left,
+            lambda d: not (self._is_simple_node(d) or
+                      self.reduce_parentheses and isinstance(d, c_ast.BinaryOp) and
+                      self.precedence_map[d.op] >= self.precedence_map[n.op]))
+        # If `n.right.op` has a stronger -but not equal- binding precedence,
+        # parenthesis can be omitted on the right:
+        # e.g., `a + (b*c)` is equivalent to `a + b*c`.
+        # If the right operator is weaker or equally binding, then parentheses
+        # are necessary:
+        # e.g., `a * (b+c)` is NOT equivalent to `a * b+c` and
+        #       `a - (b+c)` is NOT equivalent to `a - b+c` (same precedence).
+        rval_str = self._parenthesize_if(
+            n.right,
+            lambda d: not (self._is_simple_node(d) or
+                      self.reduce_parentheses and isinstance(d, c_ast.BinaryOp) and
+                      self.precedence_map[d.op] > self.precedence_map[n.op]))
+        return '%s %s %s' % (lval_str, n.op, rval_str)
+
+    def visit_Assignment(self, n):
+        rval_str = self._parenthesize_if(
+                            n.rvalue,
+                            lambda n: isinstance(n, c_ast.Assignment))
+        return '%s %s %s' % (self.visit(n.lvalue), n.op, rval_str)
+
+    def visit_IdentifierType(self, n):
+        return ' '.join(n.names)
+
+    def _visit_expr(self, n):
+        if isinstance(n, c_ast.InitList):
+            return '{' + self.visit(n) + '}'
+        elif isinstance(n, c_ast.ExprList):
+            return '(' + self.visit(n) + ')'
+        else:
+            return self.visit(n)
+
+    def visit_Decl(self, n, no_type=False):
+        # no_type is used when a Decl is part of a DeclList, where the type is
+        # explicitly only for the first declaration in a list.
+        #
+        s = n.name if no_type else self._generate_decl(n)
+        if n.bitsize: s += ' : ' + self.visit(n.bitsize)
+        if n.init:
+            s += ' = ' + self._visit_expr(n.init)
+        return s
+
+    def visit_DeclList(self, n):
+        s = self.visit(n.decls[0])
+        if len(n.decls) > 1:
+            s += ', ' + ', '.join(self.visit_Decl(decl, no_type=True)
+                                    for decl in n.decls[1:])
+        return s
+
+    def visit_Typedef(self, n):
+        s = ''
+        if n.storage: s += ' '.join(n.storage) + ' '
+        s += self._generate_type(n.type)
+        return s
+
+    def visit_Cast(self, n):
+        s = '(' + self._generate_type(n.to_type, emit_declname=False) + ')'
+        return s + ' ' + self._parenthesize_unless_simple(n.expr)
+
+    def visit_ExprList(self, n):
+        visited_subexprs = []
+        for expr in n.exprs:
+            visited_subexprs.append(self._visit_expr(expr))
+        return ', '.join(visited_subexprs)
+
+    def visit_InitList(self, n):
+        visited_subexprs = []
+        for expr in n.exprs:
+            visited_subexprs.append(self._visit_expr(expr))
+        return ', '.join(visited_subexprs)
+
+    def visit_Enum(self, n):
+        return self._generate_struct_union_enum(n, name='enum')
+
+    def visit_Alignas(self, n):
+        return '_Alignas({})'.format(self.visit(n.alignment))
+
+    def visit_Enumerator(self, n):
+        if not n.value:
+            return '{indent}{name},\n'.format(
+                indent=self._make_indent(),
+                name=n.name,
+            )
+        else:
+            return '{indent}{name} = {value},\n'.format(
+                indent=self._make_indent(),
+                name=n.name,
+                value=self.visit(n.value),
+            )
+
+    def visit_FuncDef(self, n):
+        decl = self.visit(n.decl)
+        self.indent_level = 0
+        body = self.visit(n.body)
+        if n.param_decls:
+            knrdecls = ';\n'.join(self.visit(p) for p in n.param_decls)
+            return decl + '\n' + knrdecls + ';\n' + body + '\n'
+        else:
+            return decl + '\n' + body + '\n'
+
+    def visit_FileAST(self, n):
+        s = ''
+        for ext in n.ext:
+            if isinstance(ext, c_ast.FuncDef):
+                s += self.visit(ext)
+            elif isinstance(ext, c_ast.Pragma):
+                s += self.visit(ext) + '\n'
+            else:
+                s += self.visit(ext) + ';\n'
+        return s
+
+    def visit_Compound(self, n):
+        s = self._make_indent() + '{\n'
+        self.indent_level += 2
+        if n.block_items:
+            s += ''.join(self._generate_stmt(stmt) for stmt in n.block_items)
+        self.indent_level -= 2
+        s += self._make_indent() + '}\n'
+        return s
+
+    def visit_CompoundLiteral(self, n):
+        return '(' + self.visit(n.type) + '){' + self.visit(n.init) + '}'
+
+
+    def visit_EmptyStatement(self, n):
+        return ';'
+
+    def visit_ParamList(self, n):
+        return ', '.join(self.visit(param) for param in n.params)
+
+    def visit_Return(self, n):
+        s = 'return'
+        if n.expr: s += ' ' + self.visit(n.expr)
+        return s + ';'
+
+    def visit_Break(self, n):
+        return 'break;'
+
+    def visit_Continue(self, n):
+        return 'continue;'
+
+    def visit_TernaryOp(self, n):
+        s  = '(' + self._visit_expr(n.cond) + ') ? '
+        s += '(' + self._visit_expr(n.iftrue) + ') : '
+        s += '(' + self._visit_expr(n.iffalse) + ')'
+        return s
+
+    def visit_If(self, n):
+        s = 'if ('
+        if n.cond: s += self.visit(n.cond)
+        s += ')\n'
+        s += self._generate_stmt(n.iftrue, add_indent=True)
+        if n.iffalse:
+            s += self._make_indent() + 'else\n'
+            s += self._generate_stmt(n.iffalse, add_indent=True)
+        return s
+
+    def visit_For(self, n):
+        s = 'for ('
+        if n.init: s += self.visit(n.init)
+        s += ';'
+        if n.cond: s += ' ' + self.visit(n.cond)
+        s += ';'
+        if n.next: s += ' ' + self.visit(n.next)
+        s += ')\n'
+        s += self._generate_stmt(n.stmt, add_indent=True)
+        return s
+
+    def visit_While(self, n):
+        s = 'while ('
+        if n.cond: s += self.visit(n.cond)
+        s += ')\n'
+        s += self._generate_stmt(n.stmt, add_indent=True)
+        return s
+
+    def visit_DoWhile(self, n):
+        s = 'do\n'
+        s += self._generate_stmt(n.stmt, add_indent=True)
+        s += self._make_indent() + 'while ('
+        if n.cond: s += self.visit(n.cond)
+        s += ');'
+        return s
+
+    def visit_StaticAssert(self, n):
+        s = '_Static_assert('
+        s += self.visit(n.cond)
+        if n.message:
+            s += ','
+            s += self.visit(n.message)
+        s += ')'
+        return s
+
+    def visit_Switch(self, n):
+        s = 'switch (' + self.visit(n.cond) + ')\n'
+        s += self._generate_stmt(n.stmt, add_indent=True)
+        return s
+
+    def visit_Case(self, n):
+        s = 'case ' + self.visit(n.expr) + ':\n'
+        for stmt in n.stmts:
+            s += self._generate_stmt(stmt, add_indent=True)
+        return s
+
+    def visit_Default(self, n):
+        s = 'default:\n'
+        for stmt in n.stmts:
+            s += self._generate_stmt(stmt, add_indent=True)
+        return s
+
+    def visit_Label(self, n):
+        return n.name + ':\n' + self._generate_stmt(n.stmt)
+
+    def visit_Goto(self, n):
+        return 'goto ' + n.name + ';'
+
+    def visit_EllipsisParam(self, n):
+        return '...'
+
+    def visit_Struct(self, n):
+        return self._generate_struct_union_enum(n, 'struct')
+
+    def visit_Typename(self, n):
+        return self._generate_type(n.type)
+
+    def visit_Union(self, n):
+        return self._generate_struct_union_enum(n, 'union')
+
+    def visit_NamedInitializer(self, n):
+        s = ''
+        for name in n.name:
+            if isinstance(name, c_ast.ID):
+                s += '.' + name.name
+            else:
+                s += '[' + self.visit(name) + ']'
+        s += ' = ' + self._visit_expr(n.expr)
+        return s
+
+    def visit_FuncDecl(self, n):
+        return self._generate_type(n)
+
+    def visit_ArrayDecl(self, n):
+        return self._generate_type(n, emit_declname=False)
+
+    def visit_TypeDecl(self, n):
+        return self._generate_type(n, emit_declname=False)
+
+    def visit_PtrDecl(self, n):
+        return self._generate_type(n, emit_declname=False)
+
+    def _generate_struct_union_enum(self, n, name):
+        """ Generates code for structs, unions, and enums. name should be
+            'struct', 'union', or 'enum'.
+        """
+        if name in ('struct', 'union'):
+            members = n.decls
+            body_function = self._generate_struct_union_body
+        else:
+            assert name == 'enum'
+            members = None if n.values is None else n.values.enumerators
+            body_function = self._generate_enum_body
+        s = name + ' ' + (n.name or '')
+        if members is not None:
+            # None means no members
+            # Empty sequence means an empty list of members
+            s += '\n'
+            s += self._make_indent()
+            self.indent_level += 2
+            s += '{\n'
+            s += body_function(members)
+            self.indent_level -= 2
+            s += self._make_indent() + '}'
+        return s
+
+    def _generate_struct_union_body(self, members):
+        return ''.join(self._generate_stmt(decl) for decl in members)
+
+    def _generate_enum_body(self, members):
+        # `[:-2] + '\n'` removes the final `,` from the enumerator list
+        return ''.join(self.visit(value) for value in members)[:-2] + '\n'
+
+    def _generate_stmt(self, n, add_indent=False):
+        """ Generation from a statement node. This method exists as a wrapper
+            for individual visit_* methods to handle different treatment of
+            some statements in this context.
+        """
+        typ = type(n)
+        if add_indent: self.indent_level += 2
+        indent = self._make_indent()
+        if add_indent: self.indent_level -= 2
+
+        if typ in (
+                c_ast.Decl, c_ast.Assignment, c_ast.Cast, c_ast.UnaryOp,
+                c_ast.BinaryOp, c_ast.TernaryOp, c_ast.FuncCall, c_ast.ArrayRef,
+                c_ast.StructRef, c_ast.Constant, c_ast.ID, c_ast.Typedef,
+                c_ast.ExprList):
+            # These can also appear in an expression context so no semicolon
+            # is added to them automatically
+            #
+            return indent + self.visit(n) + ';\n'
+        elif typ in (c_ast.Compound,):
+            # No extra indentation required before the opening brace of a
+            # compound - because it consists of multiple lines it has to
+            # compute its own indentation.
+            #
+            return self.visit(n)
+        elif typ in (c_ast.If,):
+            return indent + self.visit(n)
+        else:
+            return indent + self.visit(n) + '\n'
+
+    def _generate_decl(self, n):
+        """ Generation from a Decl node.
+        """
+        s = ''
+        if n.funcspec: s = ' '.join(n.funcspec) + ' '
+        if n.storage: s += ' '.join(n.storage) + ' '
+        if n.align: s += self.visit(n.align[0]) + ' '
+        s += self._generate_type(n.type)
+        return s
+
+    def _generate_type(self, n, modifiers=[], emit_declname = True):
+        """ Recursive generation from a type node. n is the type node.
+            modifiers collects the PtrDecl, ArrayDecl and FuncDecl modifiers
+            encountered on the way down to a TypeDecl, to allow proper
+            generation from it.
+        """
+        typ = type(n)
+        #~ print(n, modifiers)
+
+        if typ == c_ast.TypeDecl:
+            s = ''
+            if n.quals: s += ' '.join(n.quals) + ' '
+            s += self.visit(n.type)
+
+            nstr = n.declname if n.declname and emit_declname else ''
+            # Resolve modifiers.
+            # Wrap in parens to distinguish pointer to array and pointer to
+            # function syntax.
+            #
+            for i, modifier in enumerate(modifiers):
+                if isinstance(modifier, c_ast.ArrayDecl):
+                    if (i != 0 and
+                        isinstance(modifiers[i - 1], c_ast.PtrDecl)):
+                            nstr = '(' + nstr + ')'
+                    nstr += '['
+                    if modifier.dim_quals:
+                        nstr += ' '.join(modifier.dim_quals) + ' '
+                    nstr += self.visit(modifier.dim) + ']'
+                elif isinstance(modifier, c_ast.FuncDecl):
+                    if (i != 0 and
+                        isinstance(modifiers[i - 1], c_ast.PtrDecl)):
+                            nstr = '(' + nstr + ')'
+                    nstr += '(' + self.visit(modifier.args) + ')'
+                elif isinstance(modifier, c_ast.PtrDecl):
+                    if modifier.quals:
+                        nstr = '* %s%s' % (' '.join(modifier.quals),
+                                           ' ' + nstr if nstr else '')
+                    else:
+                        nstr = '*' + nstr
+            if nstr: s += ' ' + nstr
+            return s
+        elif typ == c_ast.Decl:
+            return self._generate_decl(n.type)
+        elif typ == c_ast.Typename:
+            return self._generate_type(n.type, emit_declname = emit_declname)
+        elif typ == c_ast.IdentifierType:
+            return ' '.join(n.names) + ' '
+        elif typ in (c_ast.ArrayDecl, c_ast.PtrDecl, c_ast.FuncDecl):
+            return self._generate_type(n.type, modifiers + [n],
+                                       emit_declname = emit_declname)
+        else:
+            return self.visit(n)
+
+    def _parenthesize_if(self, n, condition):
+        """ Visits 'n' and returns its string representation, parenthesized
+            if the condition function applied to the node returns True.
+        """
+        s = self._visit_expr(n)
+        if condition(n):
+            return '(' + s + ')'
+        else:
+            return s
+
+    def _parenthesize_unless_simple(self, n):
+        """ Common use case for _parenthesize_if
+        """
+        return self._parenthesize_if(n, lambda d: not self._is_simple_node(d))
+
+    def _is_simple_node(self, n):
+        """ Returns True for nodes that are "simple" - i.e. nodes that always
+            have higher precedence than operators.
+        """
+        return isinstance(n, (c_ast.Constant, c_ast.ID, c_ast.ArrayRef,
+                              c_ast.StructRef, c_ast.FuncCall))