handle error codes more often

src/error.rs

@@ -1,21 +1,39 @@
 use std::ffi::{c_int, NulError};
 use std::str::Utf8Error;
 
+/// Whisper tends to output errors to stderr, so if an error occurs, check stderr.
 #[derive(Debug, Copy, Clone)]
 pub enum WhisperError {
+    /// Failed to create a new context.
     InitError,
+    /// User didn't initialize spectrogram
     SpectrogramNotInitialized,
+    /// Encode was not called.
     EncodeNotComplete,
+    /// Decode was not called.
     DecodeNotComplete,
+    /// Failed to calculate the spectrogram for some reason.
+    UnableToCalculateSpectrogram,
+    /// Failed to evaluate model.
+    UnableToCalculateEvaluation,
+    /// Failed to run the encoder
+    FailedToEncode,
+    /// Failed to run the decoder
+    FailedToDecode,
+    /// Invalid number of mel bands.
+    InvalidMelBands,
+    /// Invalid thread count
     InvalidThreadCount,
+    /// Invalid UTF-8 detected in a string from Whisper.
     InvalidUtf8 {
         error_len: Option<usize>,
         valid_up_to: usize,
     },
-    NullByteInString {
-        idx: usize,
-    },
+    /// A null byte was detected in a user-provided string.
+    NullByteInString { idx: usize },
+    /// Whisper returned a null pointer.
     NullPointer,
+    /// Generic whisper error. Varies depending on the function.
     GenericError(c_int),
 }