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#[derive(PartialEq, Debug)]
pub struct CMacro {
pub name: String,
pub args: Option<Vec<String>>,
pub body: Option<String>
}
pub struct ConstDecl {
pub name: String,
pub type_name: String,
pub expr: String
}
pub enum TranslateAction {
TypedConst(ConstDecl),
Skip
}
struct CharStream<'a> {
input: &'a str,
pos: usize
}
impl<'a> CharStream<'a> {
fn new(input: &str) -> CharStream {
CharStream{input: input, pos: 0}
}
fn at_end(&self) -> bool {
self.pos >= self.input.len()
}
fn peek(&self, offset: usize) -> char {
self.tail().chars().nth(offset).unwrap_or(0 as char)
}
fn next(&mut self) -> char {
let ch = self.peek(0);
self.pos += ch.len_utf8();
ch
}
fn consume(&mut self, text: &str) -> bool {
if self.tail().starts_with(text) {
self.pos += text.len();
true
} else {
false
}
}
fn consume_char(&mut self, required: char) -> bool {
self.consume_while(|ch| ch == required).len() > 0
}
fn consume_while<Predicate>(&mut self, test: Predicate) -> &'a str
where Predicate: Fn(char) -> bool {
let start_pos = self.pos;
while test(self.peek(0)) {
self.next();
}
&self.input[start_pos..self.pos]
}
fn skip_whitespace(&mut self) -> &str {
self.consume_while(|ch| ch.is_whitespace())
}
fn tail(&self) -> &str {
&self.input[self.pos..]
}
}
struct CHeaderLineIter<'a> {
input: CharStream<'a>
}
impl<'a> Iterator for CHeaderLineIter<'a> {
type Item = String;
fn next(&mut self) -> Option<Self::Item> {
if self.input.at_end() {
None
} else {
self.input.skip_whitespace();
let mut line = String::new();
while !self.input.at_end() {
let ch = self.input.peek(0);
if ch == '\n' {
self.input.next();
break;
} else if ch == '\\' && self.input.peek(1) == '\n' {
self.input.next();
self.input.next();
} else {
self.input.next();
line.push(ch);
}
}
Some(line)
}
}
}
fn is_ident_char(ch: char) -> bool {
match ch {
'0'...'9' | 'A'...'Z' | 'a'...'z' | '_' => true,
_ => false
}
}
fn parse_c_style_comment(input: &mut CharStream) -> bool {
if !input.consume("/*") {
return false;
}
while !input.at_end() {
if input.consume("*/") {
break;
}
input.next();
}
true
}
fn parse_arg_list(input: &mut CharStream) -> Result<Vec<String>,String> {
let mut args: Vec<String> = vec![];
input.consume_char('(');
loop {
match input.peek(0) {
',' => { input.next(); }
')' => { input.next(); return Ok(args) },
'.' => {
if input.consume("...") {
args.push("...".to_string());
} else {
return Err(format!("Expected '...' in macro argument list"))
}
},
'/' => {
if parse_c_style_comment(input) {
continue;
} else {
return Err(format!("Expected C-style comment after '/' in argument list"));
}
},
ch if ch.is_whitespace() => { input.next(); }
ch if is_ident_char(ch) => {
args.push(parse_ident(input).to_string());
},
ch => return Err(format!("Unexpected char {} in macro argument list", ch))
}
}
}
fn parse_ident<'a>(input: &mut CharStream<'a>) -> &'a str {
input.consume_while(|ch| is_ident_char(ch))
}
fn parse_macro(input: &mut CharStream) -> Result<CMacro,String> {
let name = parse_ident(input);
if name.len() == 0 {
return Err(format!("Could not parse macro name from {}", input.tail()))
}
let args = if input.peek(0) == '(' {
Some(try!(parse_arg_list(input)))
} else {
None
};
let body = input.tail().trim();
Ok(CMacro {
name: name.to_string(),
args: args,
body: if body.len() > 0 {
Some(body.to_string())
} else {
None
}
})
}
pub fn extract_macros(src: &str) -> Result<Vec<CMacro>,String> {
let mut macros: Vec<CMacro> = vec![];
let line_iter = CHeaderLineIter{input: CharStream::new(src)};
for line in line_iter {
let mut macro_def = CharStream{input: &line, pos: 0};
if !macro_def.consume_char('#') {
continue;
}
macro_def.skip_whitespace();
if !macro_def.consume("define") || !macro_def.peek(0).is_whitespace() {
continue
}
macro_def.skip_whitespace();
match parse_macro(&mut macro_def) {
Ok(cmacro) => macros.push(cmacro),
Err(err) => return Err(err)
}
}
Ok(macros)
}
pub fn generate_rust_src<TranslateFn>(defs: &[CMacro], translate_fn: TranslateFn) -> String
where TranslateFn: Fn(&CMacro) -> TranslateAction {
let decl_lines: Vec<String> = defs.iter()
.filter_map(|def| {
match translate_fn(def) {
TranslateAction::TypedConst(decl) => {
Some(format!("pub const {}: {} = {};", decl.name, decl.type_name, decl.expr))
},
TranslateAction::Skip => None
}
})
.collect();
decl_lines.connect("\n")
}
impl CMacro {
pub fn new(name: &str, body: Option<&str>) -> CMacro {
CMacro{ name: name.to_string(), args: None, body: body.map(|s| s.to_string())}
}
pub fn new_with_args(name: &str, args: Vec<&str>, body: &str) -> CMacro {
let arg_strings: Vec<String> = args.iter().map(|s| s.to_string()).collect();
CMacro{ name: name.to_string(), args: Some(arg_strings), body: Some(body.to_string()) }
}
}
pub fn guess_type(body: &str) -> &str {
if body.starts_with("\"") {
"&'static str"
} else if body.contains("0x") {
"u32"
} else {
"i32"
}
}
pub fn translate_macro(def: &CMacro) -> TranslateAction {
if def.args.is_none() && def.body.is_some() {
let body = def.body.as_ref().unwrap().clone();
TranslateAction::TypedConst(ConstDecl{
name: def.name.clone(),
type_name: guess_type(&body).to_string(),
expr: body
})
} else {
TranslateAction::Skip
}
}
#[test]
fn test_extract_macros() {
let src = r"
#define CONST_1 1
#define CONST_2 2
#define CONST_3 3
#define NO_BODY
#define EXTRA_SPACES 4
#define MACRO_WITH_ARGS(a,b,c) ((a) + (b) + (c))
#define MACRO_WITH_ARGS_2( a , b , c ) ((a) + (b) + (c))
// commented out macros
//#define IGNORE_ME_2
#define MULTI_LINE_MACRO(a,b) \
a + b
#define PRECEDING_SPACES
# define SPACE_AFTER_HASH
#define VARIADIC_MACRO(...) __VA_ARGS__
#define COMMENT_IN_ARGS(/* foo */ a) bar
";
let expected_macros: Vec<CMacro> = vec![
CMacro::new("CONST_1", Some("1")),
CMacro::new("CONST_2", Some("2")),
CMacro::new("CONST_3", Some("3")),
CMacro::new("NO_BODY", None),
CMacro::new("EXTRA_SPACES", Some("4")),
CMacro::new_with_args("MACRO_WITH_ARGS", vec!["a","b","c"], "((a) + (b) + (c))"),
CMacro::new_with_args("MACRO_WITH_ARGS_2", vec!["a","b","c"], "((a) + (b) + (c))"),
CMacro::new_with_args("MULTI_LINE_MACRO", vec!["a","b"], "a + b"),
CMacro::new("PRECEDING_SPACES", None),
CMacro::new("SPACE_AFTER_HASH", None),
CMacro::new_with_args("VARIADIC_MACRO", vec!["..."], "__VA_ARGS__"),
CMacro::new_with_args("COMMENT_IN_ARGS", vec!["a"], "bar")
];
let actual_macros = extract_macros(src).unwrap();
let expected_macro_names: Vec<&str> = expected_macros.iter().map(|m| &m.name[..]).collect();
let actual_macro_names: Vec<&str> = actual_macros.iter().map(|m| &m.name[..]).collect();
assert_eq!(expected_macro_names, actual_macro_names);
for (actual, expected) in expected_macros.iter().zip(actual_macros.iter()) {
assert_eq!(actual, expected);
}
}
#[test]
#[ignore]
fn test_skip_macros_in_comments() {
let src = r"
#define NOT_IN_COMMENT
/*
#define IN_C_STYLE_COMMENT
*/";
let macros = extract_macros(src).unwrap();
let macro_names: Vec<&str> = macros.iter().map(|m| &m.name[..]).collect();
assert_eq!(macro_names, vec!["NOT_IN_COMMENT"]);
}
#[test]
fn test_generate_rust_src() {
let macros: Vec<CMacro> = vec![
CMacro::new("USED_CONST", Some("1")),
CMacro::new("USED_CONST_2", Some("2")),
CMacro::new("SKIPPED_CONST", Some("3"))
];
let src = generate_rust_src(¯os, |ref def| {
if def.name.starts_with("USED") {
TranslateAction::TypedConst(ConstDecl{
name: def.name.clone(),
type_name: guess_type(&def.body.as_ref().unwrap()).to_string(),
expr: def.body.as_ref().unwrap().clone()
})
} else {
TranslateAction::Skip
}
});
assert_eq!(src, vec![
"pub const USED_CONST: i32 = 1;",
"pub const USED_CONST_2: i32 = 2;"
].connect("\n"))
}