initial

1 files changed, 71 insertions, 0 deletions

diff --git a/src/parse.rs b/src/parse.rs
new file mode 100644
index 0000000..edfd9c5
--- /dev/null
+++ b/src/parse.rs
@@ -0,0 +1,71 @@
+use std::str::FromStr;
+use crate::{error::PissError, PissAmount};
+
+impl<T> From<T> for PissAmount 
+where T: Into<u128> {
+    fn from(num: T) -> PissAmount {
+        PissAmount {
+            to_piss: num.into()
+        } 
+    }  
+}
+
+fn parse_suffix(s: &str) -> Result<u128, PissError> {
+    Ok(match s { // nepal
+        "k" | "kb" => 1_000,
+        "m" | "mb" => 1_000_000,
+        "g" | "gb" => 1_000_000_000,
+        "t" | "tb" => 1_000_000_000_000,
+        "p" | "pb" => 1_000_000_000_000_000,
+        "e" | "eb" => 1_000_000_000_000_000_000,
+        "x" | "xb" => 1_000_000_000_000_000_000_000,
+        "y" | "yb" => 1_000_000_000_000_000_000_000_000,
+        "r" | "rb" => 1_000_000_000_000_000_000_000_000_000,
+        "q" | "qb" => 1_000_000_000_000_000_000_000_000_000_000,
+        "ki" | "kib" => 0x400,
+        "mi" | "mib" => 0x100000,
+        "gi" | "gib" => 0x40000000,
+        "ti" | "tib" => 0x10000000000,
+        "pi" | "pib" => 0x4000000000000,
+        "ei" | "eib" => 0x1000000000000000,
+        "xi" | "xib" => 0x400000000000000000,
+        "yi" | "yib" => 0x100000000000000000000,
+        "ri" | "rib" => 0x40000000000000000000000,
+        "qi" | "qib" => 0x10000000000000000000000000,
+        "" | "b" => 1, // uwu
+        _ => return Err(PissError::InvalidSuffix(s.into())) // such nepal
+    })
+}
+
+fn parse_file_size(s: &str) -> Result<PissAmount, PissError> {
+    let mut end = 0;
+    for (i, c) in s.char_indices() {
+        if c.is_digit(10) || c == '.' { continue; }
+        end = i;
+        break;
+    }
+
+    let num_text = &s[..end];
+    let suffix_text = &s[end..];
+    
+    let Ok(num) = num_text.parse::<f64>() else {
+        return Err(PissError::InvalidNumber(num_text.into()))
+    };
+
+    if num <= 0f64 {
+        return Err(PissError::NumberNotPositive)
+    } 
+
+    let multiplier = parse_suffix(suffix_text)?;
+    
+    Ok(PissAmount {
+        to_piss: (num * multiplier as f64) as u128
+    })
+}
+
+impl FromStr for PissAmount {
+    type Err = PissError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        parse_file_size(s)
+    }
+}