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use memmap::Mmap;
use std::fs::File;
use core::slice::Iter;
use boyer_moore_magiclen::{BMByte, BMByteSearchable};
use mp4parse::MediaContext;
use std::io::{Write};
pub struct Bytes<'a> {
bytes: &'a [u8]
}
impl<'a> Bytes<'a> {
fn new(bytes: &'a[u8]) -> Self {
Bytes { bytes }
}
}
impl<'a> BMByteSearchable for Bytes<'a> {
fn len(&self) -> usize {
self.bytes.len()
}
fn value_at(&self, index: usize) -> u8 {
self.bytes[index]
}
fn iter(&self) -> Iter<u8> {
self.bytes.iter()
}
}
pub struct SmMotion {
mmap: Mmap,
pub video_index: Option<usize>
}
impl SmMotion {
pub fn with(file: &File) -> Option<SmMotion>{
Some(SmMotion {
video_index: None,
mmap: match unsafe { Mmap::map(&file) } {
Ok(m) => m,
_ => return None
}
})
}
pub fn find_video_index(&mut self) -> Result<Option<usize>, &'static str> {
let indicator: Vec<u8> = vec![0x4D, 0x6F, 0x74, 0x69, 0x6F, 0x6E, 0x50, 0x68,
0x6F, 0x74, 0x6F, 0x5F, 0x44, 0x61, 0x74, 0x61];
let bmb = BMByte::from(&indicator).unwrap();
let bytes = Bytes::new(&self.mmap[..]);
self.video_index = match bmb.find_first_in(bytes){
Some(index) => Some(index+16),
None => None
};
return Ok(self.video_index);
}
pub fn has_video(&mut self) -> bool{
match self.video_index {
Some(_) => true,
None => {
match self.find_video_index(){
Ok(_) => self.has_video(),
Err(_) => false
}
}
}
}
pub fn find_video_context(&mut self) -> Option<MediaContext> {
match self.video_index {
Some(index) => {
let mut video_content = &self.mmap[index..];
let mut context = mp4parse::MediaContext::new();
let _ = mp4parse::read_mp4(&mut video_content, &mut context);
Some(context)
},
None => {
match &self.find_video_index() {
Ok(_) => {
self.find_video_context()
},
Err(_) => None
}
}
}
}
pub fn get_video_file_duration(&mut self) -> Option<u64> {
let context = self.find_video_context()?;
if context.tracks.len() != 1 {
return None
}
match context.tracks[0].tkhd.as_ref() {
Some(tkhd) => Some(tkhd.duration),
None => None
}
}
pub fn dump_video_file(&mut self, file: &mut File) -> Result<(), &str>{
match self.video_index {
Some(index) => {
let video_content = &self.mmap[index..];
match file.write_all(&video_content){
Ok(()) => Ok(()),
Err(_) => Err("Can't write to file")
}
},
None => {
match self.find_video_index() {
Ok(_) =>
self.dump_video_file(file),
Err(e) => Err(e)
}
}
}
}
}