feat: Add datetime and OS information libraries with formatting and retrieval functions

1 files changed, 111 insertions, 0 deletions

diff --git a/system/libraries/datetime/format.zig b/system/libraries/datetime/format.zig
new file mode 100644
index 0000000..daebd10
--- /dev/null
+++ b/system/libraries/datetime/format.zig
@@ -0,0 +1,111 @@
+//! Date/time formatting
+
+const time = @import("time.zig");
+
+const MONTH_NAMES = [_][]const u8{ "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
+
+pub fn date(timestamp: u64, buf: []u8) []const u8 {
+    if (timestamp == 0) {
+        const default = "01 Jan 1970 00:00";
+        for (default, 0..) |c, i| {
+            buf[i] = c;
+        }
+        return buf[0..default.len];
+    }
+
+    const dt = time.parts(timestamp);
+    var pos: usize = 0;
+
+    // Day
+    if (dt.day < 10) {
+        buf[pos] = '0';
+        pos += 1;
+    }
+    pos += writeInt(dt.day, buf[pos..]);
+
+    buf[pos] = ' ';
+    pos += 1;
+
+    // Month name
+    const month_idx = if (dt.month > 0 and dt.month <= 12) dt.month - 1 else 0;
+    for (MONTH_NAMES[month_idx]) |c| {
+        buf[pos] = c;
+        pos += 1;
+    }
+
+    buf[pos] = ' ';
+    pos += 1;
+
+    // Year
+    pos += writeInt(dt.year, buf[pos..]);
+
+    buf[pos] = ' ';
+    pos += 1;
+
+    // Hour
+    if (dt.hour < 10) {
+        buf[pos] = '0';
+        pos += 1;
+    }
+    pos += writeInt(dt.hour, buf[pos..]);
+
+    buf[pos] = ':';
+    pos += 1;
+
+    // Minute
+    if (dt.minute < 10) {
+        buf[pos] = '0';
+        pos += 1;
+    }
+    pos += writeInt(dt.minute, buf[pos..]);
+
+    return buf[0..pos];
+}
+
+pub fn duration(total_secs: u64, buf: []u8) []const u8 {
+    const hours = total_secs / 3600;
+    const mins = (total_secs % 3600) / 60;
+    const secs = total_secs % 60;
+
+    var pos: usize = 0;
+
+    pos += writeInt(hours, buf[pos..]);
+    buf[pos] = 'h';
+    pos += 1;
+    buf[pos] = ' ';
+    pos += 1;
+
+    pos += writeInt(mins, buf[pos..]);
+    buf[pos] = 'm';
+    pos += 1;
+    buf[pos] = ' ';
+    pos += 1;
+
+    pos += writeInt(secs, buf[pos..]);
+    buf[pos] = 's';
+    pos += 1;
+
+    return buf[0..pos];
+}
+
+fn writeInt(value: u64, buf: []u8) usize {
+    if (value == 0) {
+        buf[0] = '0';
+        return 1;
+    }
+
+    var temp: [20]u8 = undefined;
+    var len: usize = 0;
+    var v = value;
+
+    while (v > 0) : (v /= 10) {
+        temp[len] = @intCast('0' + (v % 10));
+        len += 1;
+    }
+
+    for (0..len) |i| {
+        buf[i] = temp[len - 1 - i];
+    }
+
+    return len;
+}