Enum tfm::format::DeserializationError

pub enum DeserializationError {
    FileIsEmpty,
    FileHasOneByte(u8),
    InternalFileLengthIsZero,
    InternalFileLengthIsNegative(i16),
    InternalFileLengthIsTooBig(i16, usize),
    InternalFileLengthIsTooSmall(i16, usize),
    SubFileSizeIsNegative(SubFileSizes),
    HeaderLengthIsTooSmall(i16),
    InvalidCharacterRange(i16, i16),
    IncompleteSubFiles(SubFileSizes),
    TooManyExtensibleCharacters(i16),
    InconsistentSubFileSizes(SubFileSizes),
}

Variants

FileIsEmpty

The TFM file is empty (i.e., 0 bytes).

Knuth’s TFToPL doesn’t handle this case explicitly. Providing an empty file to the TFtoPL always returns an error. However, the error message is non-deterministic and depends on the initial value of a specific byte of memory (tfm[0]). If that byte is greater than 127 the message for DeserializationError::InternalFileLengthIsNegative is printed; otherwise the message for DeserializationError::FileHasOneByte is printed.

FileHasOneByte(u8)

The TFM file consists of a single byte.

InternalFileLengthIsZero

The file length specified inside the TFM file is invalid because it is zero.

InternalFileLengthIsNegative(i16)

The file length specified inside the TFM file is invalid because it is negative.

The variant payload is the invalid length in this file.

InternalFileLengthIsTooBig(i16, usize)

The file length specified inside the TFM file is invalid because the file is smaller than it claims.

The variant payload is the invalid length of this file (in words) and the actual file size (in bytes). One word is 4 bytes.

InternalFileLengthIsTooSmall(i16, usize)

The file length specified inside the TFM file is invalid because it is too small.

TFM files must contain at least 24 bytes of data: the 16-bit file size and the 11 16-bit numbers in the sub file sizes section.

Knuth’s TFToPL doesn’t handle this case explicitly. When this buggy input is provided, a DeserializationError::SubFileSizeIsNegative error is thrown in some cases, and a DeserializationError::HeaderLengthIsTooSmall in other cases. Although the result is deterministic, there seems to be undefined behavior here because it seems to depend on the value of uninitialized memory.

SubFileSizeIsNegative(SubFileSizes)

One of the sub file sizes is negative.

HeaderLengthIsTooSmall(i16)

The header length is too small (either 0 or 1).

InvalidCharacterRange(i16, i16)

The character range is invalid.

This means either that the lower bound of the range (the smallest character) is not smaller than the upper bound of the range (the largest character), or the upper bound is bigger than 255.

IncompleteSubFiles(SubFileSizes)

The character dimension sub-files are incomplete.

This means the sub-file for either widths, heights, depths or italic corrections is empty.

TooManyExtensibleCharacters(i16)

There are more than 256 extensible characters.

InconsistentSubFileSizes(SubFileSizes)

The sub-file sizes are inconsistent.

Implementations

impl DeserializationError

pub fn tftopl_message(&self) -> String

Returns the error message the TFtoPL program prints for this kind of error.

pub fn tftopl_section(&self) -> usize

Returns the section in Knuth’s TFtoPL (version 2014) in which this error occurs.

Trait Implementations

impl Debug for DeserializationError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for DeserializationError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for DeserializationError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for DeserializationError

fn eq(&self, other: &DeserializationError) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for DeserializationError

impl StructuralPartialEq for DeserializationError