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use std::io::SeekFrom;
use crate::io::byteio::ByteReader;
#[derive(Debug,Clone,Copy,PartialEq)]
pub enum DetectionScore {
No,
ExtensionMatches,
MagicMatches,
}
impl DetectionScore {
pub fn less(&self, other: DetectionScore) -> bool {
(*self as i32) < (other as i32)
}
}
#[allow(dead_code)]
enum Arg {
Byte(u8),
U16BE(u16),
U16LE(u16),
U24BE(u32),
U24LE(u32),
U32BE(u32),
U32LE(u32),
U64BE(u64),
U64LE(u64),
}
impl Arg {
fn val(&self) -> u64 {
match *self {
Arg::Byte(b) => { b as u64 }
Arg::U16BE(v) => { v as u64 }
Arg::U16LE(v) => { v as u64 }
Arg::U24BE(v) => { v as u64 }
Arg::U24LE(v) => { v as u64 }
Arg::U32BE(v) => { v as u64 }
Arg::U32LE(v) => { v as u64 }
Arg::U64BE(v) => { v }
Arg::U64LE(v) => { v }
}
}
fn read_val(&self, src: &mut ByteReader) -> Option<u64> {
match *self {
Arg::Byte(_) => {
let res = src.peek_byte();
if let Err(_) = res { return None; }
Some(res.unwrap() as u64)
}
Arg::U16BE(_) => {
let res = src.peek_u16be();
if let Err(_) = res { return None; }
Some(res.unwrap() as u64)
}
Arg::U16LE(_) => {
let res = src.peek_u16le();
if let Err(_) = res { return None; }
Some(res.unwrap() as u64)
}
Arg::U24BE(_) => {
let res = src.peek_u24be();
if let Err(_) = res { return None; }
Some(res.unwrap() as u64)
}
Arg::U24LE(_) => {
let res = src.peek_u24le();
if let Err(_) = res { return None; }
Some(res.unwrap() as u64)
}
Arg::U32BE(_) => {
let res = src.peek_u32be();
if let Err(_) = res { return None; }
Some(res.unwrap() as u64)
}
Arg::U32LE(_) => {
let res = src.peek_u32le();
if let Err(_) = res { return None; }
Some(res.unwrap() as u64)
}
Arg::U64BE(_) => {
let res = src.peek_u64be();
if let Err(_) = res { return None; }
Some(res.unwrap())
}
Arg::U64LE(_) => {
let res = src.peek_u64le();
if let Err(_) = res { return None; }
Some(res.unwrap())
}
}
}
fn eq(&self, src: &mut ByteReader) -> bool {
let val = self.read_val(src);
if let None = val { false }
else { val.unwrap() == self.val() }
}
fn ge(&self, src: &mut ByteReader) -> bool {
let val = self.read_val(src);
if let None = val { false }
else { val.unwrap() >= self.val() }
}
fn gt(&self, src: &mut ByteReader) -> bool {
let val = self.read_val(src);
if let None = val { false }
else { val.unwrap() > self.val() }
}
fn le(&self, src: &mut ByteReader) -> bool {
let val = self.read_val(src);
if let None = val { false }
else { val.unwrap() <= self.val() }
}
fn lt(&self, src: &mut ByteReader) -> bool {
let val = self.read_val(src);
if let None = val { false }
else { val.unwrap() < self.val() }
}
}
#[allow(dead_code)]
enum CC<'a> {
Or(&'a CC<'a>, &'a CC<'a>),
Eq(Arg),
Str(&'static [u8]),
In(Arg, Arg),
Lt(Arg),
Le(Arg),
Gt(Arg),
Ge(Arg),
}
impl<'a> CC<'a> {
fn eval(&self, src: &mut ByteReader) -> bool {
match *self {
CC::Or (ref a, ref b) => { a.eval(src) || b.eval(src) },
CC::Eq(ref arg) => { arg.eq(src) },
CC::In(ref a, ref b) => { a.le(src) && b.ge(src) },
CC::Lt(ref arg) => { arg.lt(src) },
CC::Le(ref arg) => { arg.le(src) },
CC::Gt(ref arg) => { arg.gt(src) },
CC::Ge(ref arg) => { arg.ge(src) },
CC::Str(str) => {
let mut val: Vec<u8> = Vec::with_capacity(str.len());
val.resize(str.len(), 0);
let res = src.peek_buf(val.as_mut_slice());
if let Err(_) = res { return false; }
val == str
}
}
}
}
struct CheckItem<'a> {
offs: u32,
cond: &'a CC<'a>,
}
#[allow(dead_code)]
struct DetectConditions<'a> {
demux_name: &'static str,
extensions: &'static str,
conditions: &'a [CheckItem<'a>],
}
const DETECTORS: &[DetectConditions] = &[
DetectConditions {
demux_name: "avi",
extensions: ".avi",
conditions: &[CheckItem{offs: 0, cond: &CC::Or(&CC::Str(b"RIFF"), &CC::Str(b"ON2 ")) },
CheckItem{offs: 8, cond: &CC::Or(&CC::Or(&CC::Str(b"AVI LIST"),
&CC::Str(b"AVIXLIST")),
&CC::Str(b"ON2fLIST")) },
]
},
DetectConditions {
demux_name: "gdv",
extensions: ".gdv",
conditions: &[CheckItem{offs: 0, cond: &CC::Eq(Arg::U32LE(0x29111994))}],
},
DetectConditions {
demux_name: "realaudio",
extensions: ".ra,.ram",
conditions: &[CheckItem{offs: 0, cond: &CC::Str(b".ra\xFD")}],
},
DetectConditions {
demux_name: "realmedia",
extensions: ".rm,.rmvb,.rma,.ra,.ram",
conditions: &[CheckItem{offs: 0, cond: &CC::Or(&CC::Str(b".RMF"), &CC::Str(b".RMP")) },
CheckItem{offs: 4, cond: &CC::Ge(Arg::U32BE(10))}],
},
DetectConditions {
demux_name: "real_ivr",
extensions: ".ivr",
conditions: &[CheckItem{offs: 0, cond: &CC::Or(&CC::Str(b".R1M"), &CC::Str(b".REC"))}],
},
];
pub fn detect_format(name: &str, src: &mut ByteReader) -> Option<(&'static str, DetectionScore)> {
let mut result = None;
let lname = name.to_lowercase();
for detector in DETECTORS {
let mut score = DetectionScore::No;
if name.len() > 0 {
for ext in detector.extensions.split(',') {
if lname.ends_with(ext) {
score = DetectionScore::ExtensionMatches;
break;
}
}
}
let mut passed = detector.conditions.len() > 0;
for ck in detector.conditions {
let ret = src.seek(SeekFrom::Start(ck.offs as u64));
if let Err(_) = ret {
passed = false;
break;
}
if !ck.cond.eval(src) {
passed = false;
break;
}
}
if passed {
score = DetectionScore::MagicMatches;
}
if score == DetectionScore::MagicMatches {
return Some((detector.demux_name, score));
}
if let None = result {
result = Some((detector.demux_name, score));
} else {
let (_, oldsc) = result.unwrap();
if oldsc.less(score) {
result = Some((detector.demux_name, score));
}
}
}
result
}
#[cfg(test)]
mod test {
use super::*;
use std::fs::File;
use crate::io::byteio::*;
#[test]
fn test_avi_detect() {
let name = "assets/laser05.avi";
let mut file = File::open(name).unwrap();
let mut fr = FileReader::new_read(&mut file);
let mut br = ByteReader::new(&mut fr);
let (name, score) = detect_format(name, &mut br).unwrap();
assert_eq!(name, "avi");
assert_eq!(score, DetectionScore::MagicMatches);
}
#[test]
fn test_gdv_detect() {
let name = "assets/intro1.gdv";
let mut file = File::open(name).unwrap();
let mut fr = FileReader::new_read(&mut file);
let mut br = ByteReader::new(&mut fr);
let (name, score) = detect_format(name, &mut br).unwrap();
assert_eq!(name, "gdv");
assert_eq!(score, DetectionScore::MagicMatches);
}
}
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