##// END OF EJS Templates
templates: add filter to reverse list...
templates: add filter to reverse list The filter supports only lists because for lists, it’s straightforward to implement. Reversing text doesn’t seem very useful and is hard to implement. Reversing the bytes would break multi-bytes encodings. Reversing the code points would break characters consisting of multiple code points. Reversing graphemes is non-trivial without using a library not included in the standard library.

File last commit:

r48171:fad504cf default
r50389:c96ed402 default
Show More
path_encode.rs
646 lines | 20.7 KiB | application/rls-services+xml | RustLexer
use sha1::{Digest, Sha1};
#[derive(PartialEq, Debug)]
#[allow(non_camel_case_types)]
enum path_state {
START, /* first byte of a path component */
A, /* "AUX" */
AU,
THIRD, /* third of a 3-byte sequence, e.g. "AUX", "NUL" */
C, /* "CON" or "COMn" */
CO,
COMLPT, /* "COM" or "LPT" */
COMLPTn,
L,
LP,
N,
NU,
P, /* "PRN" */
PR,
LDOT, /* leading '.' */
DOT, /* '.' in a non-leading position */
H, /* ".h" */
HGDI, /* ".hg", ".d", or ".i" */
SPACE,
DEFAULT, /* byte of a path component after the first */
}
/* state machine for dir-encoding */
#[allow(non_camel_case_types)]
enum dir_state {
DDOT,
DH,
DHGDI,
DDEFAULT,
}
fn inset(bitset: &[u32; 8], c: u8) -> bool {
bitset[(c as usize) >> 5] & (1 << (c & 31)) != 0
}
fn charcopy(dest: Option<&mut [u8]>, destlen: &mut usize, c: u8) {
if let Some(slice) = dest {
slice[*destlen] = c
}
*destlen += 1
}
fn memcopy(dest: Option<&mut [u8]>, destlen: &mut usize, src: &[u8]) {
if let Some(slice) = dest {
slice[*destlen..*destlen + src.len()].copy_from_slice(src)
}
*destlen += src.len();
}
fn rewrap_option<'a, 'b: 'a>(
x: &'a mut Option<&'b mut [u8]>,
) -> Option<&'a mut [u8]> {
match x {
None => None,
Some(y) => Some(y),
}
}
fn hexencode<'a>(mut dest: Option<&'a mut [u8]>, destlen: &mut usize, c: u8) {
let hexdigit = b"0123456789abcdef";
charcopy(
rewrap_option(&mut dest),
destlen,
hexdigit[(c as usize) >> 4],
);
charcopy(dest, destlen, hexdigit[(c as usize) & 15]);
}
/* 3-byte escape: tilde followed by two hex digits */
fn escape3(mut dest: Option<&mut [u8]>, destlen: &mut usize, c: u8) {
charcopy(rewrap_option(&mut dest), destlen, b'~');
hexencode(dest, destlen, c);
}
fn encode_dir(mut dest: Option<&mut [u8]>, src: &[u8]) -> usize {
let mut state = dir_state::DDEFAULT;
let mut i = 0;
let mut destlen = 0;
while i < src.len() {
match state {
dir_state::DDOT => match src[i] {
b'd' | b'i' => {
state = dir_state::DHGDI;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'h' => {
state = dir_state::DH;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
_ => {
state = dir_state::DDEFAULT;
}
},
dir_state::DH => {
if src[i] == b'g' {
state = dir_state::DHGDI;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
} else {
state = dir_state::DDEFAULT;
}
}
dir_state::DHGDI => {
if src[i] == b'/' {
memcopy(rewrap_option(&mut dest), &mut destlen, b".hg");
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
state = dir_state::DDEFAULT;
}
dir_state::DDEFAULT => {
if src[i] == b'.' {
state = dir_state::DDOT
}
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
}
}
destlen
}
fn _encode(
twobytes: &[u32; 8],
onebyte: &[u32; 8],
mut dest: Option<&mut [u8]>,
src: &[u8],
encodedir: bool,
) -> usize {
let mut state = path_state::START;
let mut i = 0;
let mut destlen = 0;
let len = src.len();
while i < len {
match state {
path_state::START => match src[i] {
b'/' => {
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'.' => {
state = path_state::LDOT;
escape3(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b' ' => {
state = path_state::DEFAULT;
escape3(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'a' => {
state = path_state::A;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'c' => {
state = path_state::C;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'l' => {
state = path_state::L;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'n' => {
state = path_state::N;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'p' => {
state = path_state::P;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
_ => {
state = path_state::DEFAULT;
}
},
path_state::A => {
if src[i] == b'u' {
state = path_state::AU;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::AU => {
if src[i] == b'x' {
state = path_state::THIRD;
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::THIRD => {
state = path_state::DEFAULT;
match src[i] {
b'.' | b'/' | b'\0' => escape3(
rewrap_option(&mut dest),
&mut destlen,
src[i - 1],
),
_ => i -= 1,
}
}
path_state::C => {
if src[i] == b'o' {
state = path_state::CO;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::CO => {
if src[i] == b'm' {
state = path_state::COMLPT;
i += 1;
} else if src[i] == b'n' {
state = path_state::THIRD;
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::COMLPT => {
if src[i] >= b'1' && src[i] <= b'9' {
state = path_state::COMLPTn;
i += 1;
} else {
state = path_state::DEFAULT;
charcopy(
rewrap_option(&mut dest),
&mut destlen,
src[i - 1],
);
}
}
path_state::COMLPTn => {
state = path_state::DEFAULT;
match src[i] {
b'.' | b'/' | b'\0' => {
escape3(
rewrap_option(&mut dest),
&mut destlen,
src[i - 2],
);
charcopy(
rewrap_option(&mut dest),
&mut destlen,
src[i - 1],
);
}
_ => {
memcopy(
rewrap_option(&mut dest),
&mut destlen,
&src[i - 2..i],
);
}
}
}
path_state::L => {
if src[i] == b'p' {
state = path_state::LP;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::LP => {
if src[i] == b't' {
state = path_state::COMLPT;
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::N => {
if src[i] == b'u' {
state = path_state::NU;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::NU => {
if src[i] == b'l' {
state = path_state::THIRD;
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::P => {
if src[i] == b'r' {
state = path_state::PR;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::PR => {
if src[i] == b'n' {
state = path_state::THIRD;
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::LDOT => match src[i] {
b'd' | b'i' => {
state = path_state::HGDI;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'h' => {
state = path_state::H;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
_ => {
state = path_state::DEFAULT;
}
},
path_state::DOT => match src[i] {
b'/' | b'\0' => {
state = path_state::START;
memcopy(rewrap_option(&mut dest), &mut destlen, b"~2e");
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'd' | b'i' => {
state = path_state::HGDI;
charcopy(rewrap_option(&mut dest), &mut destlen, b'.');
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
b'h' => {
state = path_state::H;
memcopy(rewrap_option(&mut dest), &mut destlen, b".h");
i += 1;
}
_ => {
state = path_state::DEFAULT;
charcopy(rewrap_option(&mut dest), &mut destlen, b'.');
}
},
path_state::H => {
if src[i] == b'g' {
state = path_state::HGDI;
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
} else {
state = path_state::DEFAULT;
}
}
path_state::HGDI => {
if src[i] == b'/' {
state = path_state::START;
if encodedir {
memcopy(
rewrap_option(&mut dest),
&mut destlen,
b".hg",
);
}
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1
} else {
state = path_state::DEFAULT;
}
}
path_state::SPACE => match src[i] {
b'/' | b'\0' => {
state = path_state::START;
memcopy(rewrap_option(&mut dest), &mut destlen, b"~20");
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
_ => {
state = path_state::DEFAULT;
charcopy(rewrap_option(&mut dest), &mut destlen, b' ');
}
},
path_state::DEFAULT => {
while i != len && inset(onebyte, src[i]) {
charcopy(rewrap_option(&mut dest), &mut destlen, src[i]);
i += 1;
}
if i == len {
break;
}
match src[i] {
b'.' => {
state = path_state::DOT;
i += 1
}
b' ' => {
state = path_state::SPACE;
i += 1
}
b'/' => {
state = path_state::START;
charcopy(rewrap_option(&mut dest), &mut destlen, b'/');
i += 1;
}
_ => {
if inset(onebyte, src[i]) {
loop {
charcopy(
rewrap_option(&mut dest),
&mut destlen,
src[i],
);
i += 1;
if !(i < len && inset(onebyte, src[i])) {
break;
}
}
} else if inset(twobytes, src[i]) {
let c = src[i];
i += 1;
charcopy(
rewrap_option(&mut dest),
&mut destlen,
b'_',
);
charcopy(
rewrap_option(&mut dest),
&mut destlen,
if c == b'_' { b'_' } else { c + 32 },
);
} else {
escape3(
rewrap_option(&mut dest),
&mut destlen,
src[i],
);
i += 1;
}
}
}
}
}
}
match state {
path_state::START => (),
path_state::A => (),
path_state::AU => (),
path_state::THIRD => {
escape3(rewrap_option(&mut dest), &mut destlen, src[i - 1])
}
path_state::C => (),
path_state::CO => (),
path_state::COMLPT => {
charcopy(rewrap_option(&mut dest), &mut destlen, src[i - 1])
}
path_state::COMLPTn => {
escape3(rewrap_option(&mut dest), &mut destlen, src[i - 2]);
charcopy(rewrap_option(&mut dest), &mut destlen, src[i - 1]);
}
path_state::L => (),
path_state::LP => (),
path_state::N => (),
path_state::NU => (),
path_state::P => (),
path_state::PR => (),
path_state::LDOT => (),
path_state::DOT => {
memcopy(rewrap_option(&mut dest), &mut destlen, b"~2e");
}
path_state::H => (),
path_state::HGDI => (),
path_state::SPACE => {
memcopy(rewrap_option(&mut dest), &mut destlen, b"~20");
}
path_state::DEFAULT => (),
};
destlen
}
fn basic_encode(dest: Option<&mut [u8]>, src: &[u8]) -> usize {
let twobytes: [u32; 8] = [0, 0, 0x87ff_fffe, 0, 0, 0, 0, 0];
let onebyte: [u32; 8] =
[1, 0x2bff_3bfa, 0x6800_0001, 0x2fff_ffff, 0, 0, 0, 0];
_encode(&twobytes, &onebyte, dest, src, true)
}
const MAXSTOREPATHLEN: usize = 120;
fn lower_encode(mut dest: Option<&mut [u8]>, src: &[u8]) -> usize {
let onebyte: [u32; 8] =
[1, 0x2bff_fbfb, 0xe800_0001, 0x2fff_ffff, 0, 0, 0, 0];
let lower: [u32; 8] = [0, 0, 0x07ff_fffe, 0, 0, 0, 0, 0];
let mut destlen = 0;
for c in src {
if inset(&onebyte, *c) {
charcopy(rewrap_option(&mut dest), &mut destlen, *c)
} else if inset(&lower, *c) {
charcopy(rewrap_option(&mut dest), &mut destlen, *c + 32)
} else {
escape3(rewrap_option(&mut dest), &mut destlen, *c)
}
}
destlen
}
fn aux_encode(dest: Option<&mut [u8]>, src: &[u8]) -> usize {
let twobytes = [0; 8];
let onebyte: [u32; 8] = [!0, 0xffff_3ffe, !0, !0, !0, !0, !0, !0];
_encode(&twobytes, &onebyte, dest, src, false)
}
fn hash_mangle(src: &[u8], sha: &[u8]) -> Vec<u8> {
let dirprefixlen = 8;
let maxshortdirslen = 68;
let mut destlen = 0;
let last_slash = src.iter().rposition(|b| *b == b'/');
let last_dot: Option<usize> = {
let s = last_slash.unwrap_or(0);
src[s..]
.iter()
.rposition(|b| *b == b'.')
.and_then(|i| Some(i + s))
};
let mut dest = vec![0; MAXSTOREPATHLEN];
memcopy(Some(&mut dest), &mut destlen, b"dh/");
{
let mut first = true;
for slice in src[..last_slash.unwrap_or_else(|| src.len())]
.split(|b| *b == b'/')
{
let slice = &slice[..std::cmp::min(slice.len(), dirprefixlen)];
if destlen + (slice.len() + if first { 0 } else { 1 })
> maxshortdirslen + 3
{
break;
} else {
if !first {
charcopy(Some(&mut dest), &mut destlen, b'/')
};
memcopy(Some(&mut dest), &mut destlen, slice);
if dest[destlen - 1] == b'.' || dest[destlen - 1] == b' ' {
dest[destlen - 1] = b'_'
}
}
first = false;
}
if !first {
charcopy(Some(&mut dest), &mut destlen, b'/');
}
}
let used = destlen + 40 + {
if let Some(l) = last_dot {
src.len() - l
} else {
0
}
};
if MAXSTOREPATHLEN > used {
let slop = MAXSTOREPATHLEN - used;
let basenamelen = match last_slash {
Some(l) => src.len() - l - 1,
None => src.len(),
};
let basenamelen = std::cmp::min(basenamelen, slop);
if basenamelen > 0 {
let start = match last_slash {
Some(l) => l + 1,
None => 0,
};
memcopy(
Some(&mut dest),
&mut destlen,
&src[start..][..basenamelen],
)
}
}
for c in sha {
hexencode(Some(&mut dest), &mut destlen, *c);
}
if let Some(l) = last_dot {
memcopy(Some(&mut dest), &mut destlen, &src[l..]);
}
if destlen == dest.len() {
dest
} else {
// sometimes the path are shorter than MAXSTOREPATHLEN
dest[..destlen].to_vec()
}
}
const MAXENCODE: usize = 4096 * 4;
fn hash_encode(src: &[u8]) -> Vec<u8> {
let dired = &mut [0; MAXENCODE];
let lowered = &mut [0; MAXENCODE];
let auxed = &mut [0; MAXENCODE];
let baselen = (src.len() - 5) * 3;
if baselen >= MAXENCODE {
panic!("path_encode::hash_encore: string too long: {}", baselen)
};
let dirlen = encode_dir(Some(&mut dired[..]), src);
let sha = Sha1::digest(&dired[..dirlen]);
let lowerlen = lower_encode(Some(&mut lowered[..]), &dired[..dirlen][5..]);
let auxlen = aux_encode(Some(&mut auxed[..]), &lowered[..lowerlen]);
hash_mangle(&auxed[..auxlen], &sha)
}
pub fn path_encode(path: &[u8]) -> Vec<u8> {
let newlen = if path.len() <= MAXSTOREPATHLEN {
basic_encode(None, path)
} else {
MAXSTOREPATHLEN + 1
};
if newlen <= MAXSTOREPATHLEN {
if newlen == path.len() {
path.to_vec()
} else {
let mut res = vec![0; newlen];
basic_encode(Some(&mut res), path);
res
}
} else {
hash_encode(&path)
}
}