76 lines
1.6 KiB
Rust
76 lines
1.6 KiB
Rust
use std::ops::Range;
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use regex::Regex;
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pub fn parse_range_header (range_str: &str) -> (Option <u64>, Option <u64>) {
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use lazy_static::lazy_static;
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lazy_static! {
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static ref RE: Regex = Regex::new (r"^bytes=(\d*)-(\d*)$").expect ("Couldn't compile regex for Range header");
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}
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let caps = match RE.captures (range_str) {
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Some (x) => x,
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None => return (None, None),
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};
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let start = caps.get (1).map (|x| x.as_str ());
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let end = caps.get (2).map (|x| x.as_str ());
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let start = start.and_then (|x| u64::from_str_radix (x, 10).ok ());
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// HTTP specifies ranges as [start inclusive, end inclusive]
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// But that's dumb and [start inclusive, end exclusive) is better
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let end = end.and_then (|x| u64::from_str_radix (x, 10).ok ().map (|x| x + 1));
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(start, end)
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}
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#[derive (Debug, PartialEq)]
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pub struct ValidParsedRange {
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pub range: Range <u64>,
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pub range_requested: bool,
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}
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#[derive (Debug, PartialEq)]
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pub enum ParsedRange {
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Valid (ValidParsedRange),
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RangeNotSatisfiable (u64),
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}
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pub fn check_range (range_str: Option <&str>, file_len: u64)
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-> ParsedRange
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{
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use ParsedRange::*;
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let not_satisfiable = RangeNotSatisfiable (file_len);
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let range_str = match range_str {
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None => return Valid (ValidParsedRange {
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range: 0..file_len,
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range_requested: false,
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}),
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Some (x) => x,
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};
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let (start, end) = parse_range_header (range_str);
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let start = start.unwrap_or (0);
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if start >= file_len {
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return not_satisfiable;
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}
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let end = end.unwrap_or (file_len);
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if end > file_len {
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return not_satisfiable;
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}
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if end < start {
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return not_satisfiable;
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}
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Valid (ValidParsedRange {
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range: start..end,
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range_requested: true,
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})
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}
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