Josh Megnauth
284 lines
9.0 KiB
Rust
284 lines
9.0 KiB
Rust
// strftime implementation for Redox, following the POSIX standard.
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// Following https://pubs.opengroup.org/onlinepubs/7908799/xsh/strftime.html
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use alloc::string::String;
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use super::tm;
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use crate::platform::{self, types::*, WriteByte};
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// We use the langinfo constants
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use crate::header::langinfo::{
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nl_item,
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nl_langinfo,
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ABDAY_1,
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ABMON_1,
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AM_STR,
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DAY_1,
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MON_1,
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PM_STR,
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// TODO : other constants if needed
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};
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/// A helper that calls `nl_langinfo(item)` and converts the returned pointer
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/// into a `&str`. If it fails or is null, returns an empty string "".
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unsafe fn langinfo_to_str(item: nl_item) -> &'static str {
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use core::ffi::CStr;
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let ptr = nl_langinfo(item);
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if ptr.is_null() {
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return "";
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}
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match CStr::from_ptr(ptr).to_str() {
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Ok(s) => s,
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Err(_) => "",
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}
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}
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/// Formats time data according to the given `format` string.
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///
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/// Use `langinfo` for locale-based day/month names,
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/// but still hard-codes other aspects of the "C" locale (like numeric/date
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/// formats) and ignores `%E` / `%O` variations.
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pub unsafe fn strftime<W: WriteByte>(w: &mut W, format: *const c_char, t: *const tm) -> size_t {
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/// Helper that actually parses the format string and writes output.
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pub unsafe fn inner_strftime<W: WriteByte>(
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w: &mut W,
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mut format: *const c_char,
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t: *const tm,
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) -> bool {
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macro_rules! w {
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(byte $b:expr) => {{
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if w.write_u8($b).is_err() {
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return false;
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}
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}};
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(char $chr:expr) => {{
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if w.write_char($chr).is_err() {
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return false;
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}
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}};
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(recurse $fmt:expr) => {{
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let mut tmp = String::with_capacity($fmt.len() + 1);
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tmp.push_str($fmt);
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tmp.push('\0');
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if !inner_strftime(w, tmp.as_ptr() as *mut c_char, t) {
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return false;
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}
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}};
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($str:expr) => {{
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if w.write_str($str).is_err() {
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return false;
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}
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}};
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($fmt:expr, $($args:expr),+) => {{
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// Could use write!() if we didn't need the exact count
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if write!(w, $fmt, $($args),+).is_err() {
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return false;
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}
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}};
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}
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while *format != 0 {
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// If the character isn't '%', just copy it out.
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if *format as u8 != b'%' {
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w!(byte * format as u8);
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format = format.offset(1);
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continue;
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}
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// Skip '%'
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format = format.offset(1);
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// POSIX says '%E' and '%O' can modify numeric formats for locales,
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// but we ignore them in this minimal "C" locale approach.
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if *format as u8 == b'E' || *format as u8 == b'O' {
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format = format.offset(1);
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}
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match *format as u8 {
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// Literal '%'
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b'%' => w!(byte b'%'),
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// Newline and tab expansions
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b'n' => w!(byte b'\n'),
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b't' => w!(byte b'\t'),
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// Abbreviated weekday name: %a
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b'a' => {
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// `ABDAY_1 + tm_wday` is the correct langinfo ID for abbreviated weekdays
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let s = langinfo_to_str(ABDAY_1 + (*t).tm_wday as i32);
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w!(s);
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}
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// Full weekday name: %A
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b'A' => {
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// `DAY_1 + tm_wday` is the correct langinfo ID for full weekdays
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let s = langinfo_to_str(DAY_1 + (*t).tm_wday as i32);
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w!(s);
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}
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// Abbreviated month name: %b or %h
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b'b' | b'h' => {
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let s = langinfo_to_str(ABMON_1 + (*t).tm_mon as i32);
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w!(s);
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}
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// Full month name: %B
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b'B' => {
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let s = langinfo_to_str(MON_1 + (*t).tm_mon as i32);
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w!(s);
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}
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// Century: %C
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b'C' => {
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let mut year = (*t).tm_year / 100;
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if (*t).tm_year % 100 != 0 {
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year += 1;
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}
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w!("{:02}", year + 19);
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}
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// Day of month: %d
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b'd' => w!("{:02}", (*t).tm_mday),
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// %D => same as %m/%d/%y
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b'D' => w!(recurse "%m/%d/%y"),
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// Day of month, space-padded: %e
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b'e' => w!("{:2}", (*t).tm_mday),
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// ISO 8601 date: %F => %Y-%m-%d
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b'F' => w!(recurse "%Y-%m-%d"),
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// Hour (00-23): %H
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b'H' => w!("{:02}", (*t).tm_hour),
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// Hour (01-12): %I
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b'I' => w!("{:02}", ((*t).tm_hour + 12 - 1) % 12 + 1),
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// Day of year: %j
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b'j' => w!("{:03}", (*t).tm_yday),
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// etc.
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b'k' => w!("{:2}", (*t).tm_hour),
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b'l' => w!("{:2}", ((*t).tm_hour + 12 - 1) % 12 + 1),
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b'm' => w!("{:02}", (*t).tm_mon + 1),
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b'M' => w!("{:02}", (*t).tm_min),
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// AM/PM (uppercase): %p
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b'p' => {
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// Get "AM" / "PM" from langinfo
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if (*t).tm_hour < 12 {
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w!(langinfo_to_str(AM_STR));
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} else {
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w!(langinfo_to_str(PM_STR));
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}
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}
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// am/pm (lowercase): %P
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b'P' => {
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// Convert the AM_STR / PM_STR to lowercase
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if (*t).tm_hour < 12 {
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let am = langinfo_to_str(AM_STR).to_ascii_lowercase();
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w!(&am);
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} else {
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let pm = langinfo_to_str(PM_STR).to_ascii_lowercase();
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w!(&pm);
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}
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}
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// 12-hour clock with seconds + AM/PM: %r => %I:%M:%S %p
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b'r' => w!(recurse "%I:%M:%S %p"),
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// 24-hour clock without seconds: %R => %H:%M
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b'R' => w!(recurse "%H:%M"),
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// Seconds since the Epoch: %s => calls mktime() to convert tm to time_t
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b's' => w!("{}", super::mktime(t as *mut tm)),
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// Seconds (00-60): %S (unchanged)
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b'S' => w!("{:02}", (*t).tm_sec),
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// 24-hour clock with seconds: %T => %H:%M:%S
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b'T' => w!(recurse "%H:%M:%S"),
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// Weekday (1-7, Monday=1): %u
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b'u' => w!("{}", ((*t).tm_wday + 7 - 1) % 7 + 1),
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// Sunday-based week of year: %U
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b'U' => w!("{}", ((*t).tm_yday + 7 - (*t).tm_wday) / 7),
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// ISO-8601 week of year
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b'V' => w!("{}", week_of_year(unsafe { &*t })),
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// Weekday (0-6, Sunday=0): %w
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b'w' => w!("{}", (*t).tm_wday),
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// Monday-based week of year: %W
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b'W' => w!("{}", ((*t).tm_yday + 7 - ((*t).tm_wday + 6) % 7) / 7),
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// Last two digits of year: %y
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b'y' => w!("{:02}", (*t).tm_year % 100),
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// Full year: %Y
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b'Y' => w!("{}", (*t).tm_year + 1900),
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// Timezone offset: %z => currently hard-coded "+0000"
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b'z' => w!("+0000"), // TODO: Add real timezone support
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// Timezone name: %Z => currently "UTC"
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b'Z' => w!("UTC"), // TODO: Add real timezone name support
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// Date+time+TZ: %+
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b'+' => w!(recurse "%a %b %d %T %Z %Y"),
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// Unrecognized format specifier => fail
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_ => return false,
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}
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// Move past the format specifier
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format = format.offset(1);
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}
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true
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}
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// Wrap the writer in a CountingWriter to return how many bytes were written.
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let mut cw = platform::CountingWriter::new(w);
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if !inner_strftime(&mut cw, format, t) {
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return 0;
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}
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cw.written
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}
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/// Calculate number of weeks in a year as defined by ISO 8601
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///
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/// ## Source
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/// https://en.wikipedia.org/wiki/ISO_week_date
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fn weeks_per_year(year: c_int) -> c_int {
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let year = year as f64;
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// TODO: This function can be made const on newer Rust compilers but this line prevents it on
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// our version in CI
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let p_y = (year + (year / 4.) - (year / 100.) + (year / 400.)) as c_int % 7;
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if p_y == 4 {
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53
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} else {
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52
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}
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}
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/// Calculate the week of the year accounting for leap weeks (ISO 8601)
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///
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/// ## Source
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/// https://en.wikipedia.org/wiki/ISO_week_date
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fn week_of_year(time: &tm) -> c_int {
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let week = (10 + time.tm_yday - time.tm_wday) / 7;
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if week <= 1 {
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weeks_per_year(time.tm_year - 1)
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} else if week > weeks_per_year(time.tm_year) {
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1
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} else {
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week
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}
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}
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