//! Functions for parsing DWARF debugging information.

use leb128;
use nom::{Err, ErrorKind, IResult, le_u8, Needed};
use std::fmt;
use types::{Abbreviation, AbbreviationHasChildren, Abbreviations, AbbreviationTag, AttributeForm,
            AttributeName, AttributeSpecification};

/// A parse error.
#[derive(Debug)]
pub enum Error {
    /// A malformed LEB128 value.
    LebError(leb128::read::Error),

    /// Zero is an illegal value for an abbreviation code.
    AbbreviationCodeZero,

    /// The abbreviation's tag is not a known variant of `AbbreviationTag` (aka
    /// `DW_TAG_*`).
    InvalidAbbreviationTag,

    /// The abbreviation's "does the abbreviated type have children?" byte was
    /// not one of `DW_CHILDREN_yes` or `DW_CHILDREN_no`.
    InvalidAbbreviationHasChildren,

    /// The abbreviation's attribute name is not a valid variant of
    /// `AttributeName` (aka `DW_AT_*`).
    InvalidAttributeName,

    /// The abbreviation's attribute form is not a valid variant of
    /// `AttributeForm` (aka `DW_FORM_*`).
    InvalidAttributeForm,

    /// Expected a zero byte, but did not find one.
    ExpectedZero,

    /// An abbreviation attempted to declare a code that is already in use by an
    /// earlier abbreviation definition.
    DuplicateAbbreviationCode,
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        write!(f, "gimli::parser::Error")
    }
}

impl ::std::error::Error for Error {
    fn description(&self) -> &str {
        match *self {
            Error::LebError(_) =>
                "Error parsing LEB128 value",
            Error::AbbreviationCodeZero =>
                "Abbreviation declared its code to be the reserved code 0",
            Error::InvalidAbbreviationTag =>
                "The abbreviation tag is invalid",
            Error::InvalidAbbreviationHasChildren =>
                "The \"does-the-abbreviated-type-have-children?\" byte is not DW_CHILDREN_yes or DW_CHILDREN_no",
            Error::InvalidAttributeName =>
                "The abbreviation's attribute name is invalid",
            Error::InvalidAttributeForm =>
                "The abbreviation's attribute form is invalid",
            Error::ExpectedZero =>
                "Expected zero",
            Error::DuplicateAbbreviationCode =>
                "Found an abbreviation with a code that has already been used"
        }
    }

    fn cause(&self) -> Option<&::std::error::Error> {
        match *self {
            Error::LebError(ref e) => Some(e),
            Error::AbbreviationCodeZero => None,
            Error::InvalidAbbreviationTag => None,
            Error::InvalidAbbreviationHasChildren => None,
            Error::InvalidAttributeName => None,
            Error::InvalidAttributeForm => None,
            Error::ExpectedZero => None,
            Error::DuplicateAbbreviationCode => None,
        }
    }
}

/// The result of an attempted parse.
pub type ParseResult<'a, T> = IResult<&'a [u8], T, Error>;

/// Parse an unsigned LEB128 encoded integer.
fn parse_unsigned_leb(mut input: &[u8]) -> ParseResult<u64> {
    match leb128::read::unsigned(&mut input) {
        Ok(val) =>
            IResult::Done(input, val),
        Err(leb128::read::Error::UnexpectedEndOfData) =>
            IResult::Incomplete(Needed::Unknown),
        Err(e) =>
            IResult::Error(Err::Position(ErrorKind::Custom(Error::LebError(e)), input)),
    }
}

// /// TODO FITZGEN
// fn parse_signed_leb(mut input: &[u8]) -> ParseResult<i64> {
//     match leb128::read::signed(&mut input) {
//         Ok(val) =>
//             IResult::Done(input, val),
//         Err(leb128::read::Error::UnexpectedEndOfData) =>
//             IResult::Incomplete(Needed::Unknown),
//         Err(e) =>
//             IResult::Error(Err::Position(ErrorKind::Custom(Error::LebError(e)), input)),
//     }
// }

/// Parse an abbreviation's code.
fn parse_abbreviation_code(mut input: &[u8]) -> ParseResult<u64> {
    match parse_unsigned_leb(&mut input) {
        IResult::Done(input, val) =>
            if val == 0 {
                IResult::Error(Err::Position(ErrorKind::Custom(Error::AbbreviationCodeZero),
                                             input))
            } else {
                IResult::Done(input, val)
            },
        res =>
            res,
    }
}

/// Parse an abbreviation's tag.
fn parse_abbreviation_tag(mut input: &[u8]) -> ParseResult<AbbreviationTag> {
    match parse_unsigned_leb(&mut input) {
        IResult::Done(input, val) if AbbreviationTag::ArrayType as u64 == val =>
            IResult::Done(input, AbbreviationTag::ArrayType),

        IResult::Done(input, val) if AbbreviationTag::ClassType as u64 == val =>
            IResult::Done(input, AbbreviationTag::ClassType),

        IResult::Done(input, val) if AbbreviationTag::EntryPoint as u64 == val =>
            IResult::Done(input, AbbreviationTag::EntryPoint),

        IResult::Done(input, val) if AbbreviationTag::EnumerationType as u64 == val =>
            IResult::Done(input, AbbreviationTag::EnumerationType),

        IResult::Done(input, val) if AbbreviationTag::FormalParameter as u64 == val =>
            IResult::Done(input, AbbreviationTag::FormalParameter),

        IResult::Done(input, val) if AbbreviationTag::ImportedDeclaration as u64 == val =>
            IResult::Done(input, AbbreviationTag::ImportedDeclaration),

        IResult::Done(input, val) if AbbreviationTag::Label as u64 == val =>
            IResult::Done(input, AbbreviationTag::Label),

        IResult::Done(input, val) if AbbreviationTag::LexicalBlock as u64 == val =>
            IResult::Done(input, AbbreviationTag::LexicalBlock),

        IResult::Done(input, val) if AbbreviationTag::Member as u64 == val =>
            IResult::Done(input, AbbreviationTag::Member),

        IResult::Done(input, val) if AbbreviationTag::PointerType as u64 == val =>
            IResult::Done(input, AbbreviationTag::PointerType),

        IResult::Done(input, val) if AbbreviationTag::ReferenceType as u64 == val =>
            IResult::Done(input, AbbreviationTag::ReferenceType),

        IResult::Done(input, val) if AbbreviationTag::CompileUnit as u64 == val =>
            IResult::Done(input, AbbreviationTag::CompileUnit),

        IResult::Done(input, val) if AbbreviationTag::StringType as u64 == val =>
            IResult::Done(input, AbbreviationTag::StringType),

        IResult::Done(input, val) if AbbreviationTag::StructureType as u64 == val =>
            IResult::Done(input, AbbreviationTag::StructureType),

        IResult::Done(input, val) if AbbreviationTag::SubroutineType as u64 == val =>
            IResult::Done(input, AbbreviationTag::SubroutineType),

        IResult::Done(input, val) if AbbreviationTag::Typedef as u64 == val =>
            IResult::Done(input, AbbreviationTag::Typedef),

        IResult::Done(input, val) if AbbreviationTag::UnionType as u64 == val =>
            IResult::Done(input, AbbreviationTag::UnionType),

        IResult::Done(input, val) if AbbreviationTag::UnspecifiedParameters as u64 == val =>
            IResult::Done(input, AbbreviationTag::UnspecifiedParameters),

        IResult::Done(input, val) if AbbreviationTag::Variant as u64 == val =>
            IResult::Done(input, AbbreviationTag::Variant),

        IResult::Done(input, val) if AbbreviationTag::CommonBlock as u64 == val =>
            IResult::Done(input, AbbreviationTag::CommonBlock),

        IResult::Done(input, val) if AbbreviationTag::CommonInclusion as u64 == val =>
            IResult::Done(input, AbbreviationTag::CommonInclusion),

        IResult::Done(input, val) if AbbreviationTag::Inheritance as u64 == val =>
            IResult::Done(input, AbbreviationTag::Inheritance),

        IResult::Done(input, val) if AbbreviationTag::InlinedSubroutine as u64 == val =>
            IResult::Done(input, AbbreviationTag::InlinedSubroutine),

        IResult::Done(input, val) if AbbreviationTag::Module as u64 == val =>
            IResult::Done(input, AbbreviationTag::Module),

        IResult::Done(input, val) if AbbreviationTag::PtrToMemberType as u64 == val =>
            IResult::Done(input, AbbreviationTag::PtrToMemberType),

        IResult::Done(input, val) if AbbreviationTag::SetType as u64 == val =>
            IResult::Done(input, AbbreviationTag::SetType),

        IResult::Done(input, val) if AbbreviationTag::SubrangeType as u64 == val =>
            IResult::Done(input, AbbreviationTag::SubrangeType),

        IResult::Done(input, val) if AbbreviationTag::WithStmt as u64 == val =>
            IResult::Done(input, AbbreviationTag::WithStmt),

        IResult::Done(input, val) if AbbreviationTag::AccessDeclaration as u64 == val =>
            IResult::Done(input, AbbreviationTag::AccessDeclaration),

        IResult::Done(input, val) if AbbreviationTag::BaseType as u64 == val =>
            IResult::Done(input, AbbreviationTag::BaseType),

        IResult::Done(input, val) if AbbreviationTag::CatchBlock as u64 == val =>
            IResult::Done(input, AbbreviationTag::CatchBlock),

        IResult::Done(input, val) if AbbreviationTag::ConstType as u64 == val =>
            IResult::Done(input, AbbreviationTag::ConstType),

        IResult::Done(input, val) if AbbreviationTag::Constant as u64 == val =>
            IResult::Done(input, AbbreviationTag::Constant),

        IResult::Done(input, val) if AbbreviationTag::Enumerator as u64 == val =>
            IResult::Done(input, AbbreviationTag::Enumerator),

        IResult::Done(input, val) if AbbreviationTag::FileType as u64 == val =>
            IResult::Done(input, AbbreviationTag::FileType),

        IResult::Done(input, val) if AbbreviationTag::Friend as u64 == val =>
            IResult::Done(input, AbbreviationTag::Friend),

        IResult::Done(input, val) if AbbreviationTag::Namelist as u64 == val =>
            IResult::Done(input, AbbreviationTag::Namelist),

        IResult::Done(input, val) if AbbreviationTag::NamelistItem as u64 == val =>
            IResult::Done(input, AbbreviationTag::NamelistItem),

        IResult::Done(input, val) if AbbreviationTag::PackedType as u64 == val =>
            IResult::Done(input, AbbreviationTag::PackedType),

        IResult::Done(input, val) if AbbreviationTag::Subprogram as u64 == val =>
            IResult::Done(input, AbbreviationTag::Subprogram),

        IResult::Done(input, val) if AbbreviationTag::TemplateTypeParameter as u64 == val =>
            IResult::Done(input, AbbreviationTag::TemplateTypeParameter),

        IResult::Done(input, val) if AbbreviationTag::TemplateValueParameter as u64 == val =>
            IResult::Done(input, AbbreviationTag::TemplateValueParameter),

        IResult::Done(input, val) if AbbreviationTag::ThrownType as u64 == val =>
            IResult::Done(input, AbbreviationTag::ThrownType),

        IResult::Done(input, val) if AbbreviationTag::TryBlock as u64 == val =>
            IResult::Done(input, AbbreviationTag::TryBlock),

        IResult::Done(input, val) if AbbreviationTag::VariantPart as u64 == val =>
            IResult::Done(input, AbbreviationTag::VariantPart),

        IResult::Done(input, val) if AbbreviationTag::Variable as u64 == val =>
            IResult::Done(input, AbbreviationTag::Variable),

        IResult::Done(input, val) if AbbreviationTag::VolatileType as u64 == val =>
            IResult::Done(input, AbbreviationTag::VolatileType),

        IResult::Done(input, val) if AbbreviationTag::RestrictType as u64 == val =>
            IResult::Done(input, AbbreviationTag::RestrictType),

        IResult::Done(input, val) if AbbreviationTag::InterfaceType as u64 == val =>
            IResult::Done(input, AbbreviationTag::InterfaceType),

        IResult::Done(input, val) if AbbreviationTag::Namespace as u64 == val =>
            IResult::Done(input, AbbreviationTag::Namespace),

        IResult::Done(input, val) if AbbreviationTag::ImportedModule as u64 == val =>
            IResult::Done(input, AbbreviationTag::ImportedModule),

        IResult::Done(input, val) if AbbreviationTag::UnspecifiedType as u64 == val =>
            IResult::Done(input, AbbreviationTag::UnspecifiedType),

        IResult::Done(input, val) if AbbreviationTag::PartialUnit as u64 == val =>
            IResult::Done(input, AbbreviationTag::PartialUnit),

        IResult::Done(input, val) if AbbreviationTag::ImportedUnit as u64 == val =>
            IResult::Done(input, AbbreviationTag::ImportedUnit),

        IResult::Done(input, val) if AbbreviationTag::Condition as u64 == val =>
            IResult::Done(input, AbbreviationTag::Condition),

        IResult::Done(input, val) if AbbreviationTag::SharedType as u64 == val =>
            IResult::Done(input, AbbreviationTag::SharedType),

        IResult::Done(input, val) if AbbreviationTag::TypeUnit as u64 == val =>
            IResult::Done(input, AbbreviationTag::TypeUnit),

        IResult::Done(input, val) if AbbreviationTag::RvalueReferenceType as u64 == val =>
            IResult::Done(input, AbbreviationTag::RvalueReferenceType),

        IResult::Done(input, val) if AbbreviationTag::TemplateAlias as u64 == val =>
            IResult::Done(input, AbbreviationTag::TemplateAlias),

        IResult::Done(input, val) if AbbreviationTag::LoUser as u64 == val =>
            IResult::Done(input, AbbreviationTag::LoUser),

        IResult::Done(input, val) if AbbreviationTag::HiUser as u64 == val =>
            IResult::Done(input, AbbreviationTag::HiUser),

        IResult::Done(input, _) =>
            IResult::Error(Err::Position(ErrorKind::Custom(Error::InvalidAbbreviationTag), input)),

        IResult::Incomplete(needed) =>
            IResult::Incomplete(needed),

        IResult::Error(error) =>
            IResult::Error(error),
    }
}

/// Parse an abbreviation's "does the type have children?" byte.
fn parse_abbreviation_has_children(input: &[u8]) -> ParseResult<AbbreviationHasChildren> {
    match le_u8(input) {
        IResult::Done(input, val) if AbbreviationHasChildren::Yes as u8 == val =>
            IResult::Done(input, AbbreviationHasChildren::Yes),

        IResult::Done(input, val) if AbbreviationHasChildren::No as u8 == val =>
            IResult::Done(input, AbbreviationHasChildren::No),

        IResult::Done(input, _) =>
            IResult::Error(
                Err::Position(ErrorKind::Custom(Error::InvalidAbbreviationHasChildren), input)),

        IResult::Incomplete(needed) =>
            IResult::Incomplete(needed),

        IResult::Error(_) =>
            IResult::Error(Err::Code(ErrorKind::Custom(Error::InvalidAbbreviationHasChildren))),
    }
}

/// Parse an attribute's name.
fn parse_attribute_name(input: &[u8]) -> ParseResult<AttributeName> {
    match parse_unsigned_leb(input) {
        IResult::Done(input, val) if AttributeName::Sibling as u64 == val =>
            IResult::Done(input, AttributeName::Sibling),

        IResult::Done(input, val) if AttributeName::Location as u64 == val =>
            IResult::Done(input, AttributeName::Location),

        IResult::Done(input, val) if AttributeName::Name as u64 == val =>
            IResult::Done(input, AttributeName::Name),

        IResult::Done(input, val) if AttributeName::Ordering as u64 == val =>
            IResult::Done(input, AttributeName::Ordering),

        IResult::Done(input, val) if AttributeName::ByteSize as u64 == val =>
            IResult::Done(input, AttributeName::ByteSize),

        IResult::Done(input, val) if AttributeName::BitOffset as u64 == val =>
            IResult::Done(input, AttributeName::BitOffset),

        IResult::Done(input, val) if AttributeName::BitSize as u64 == val =>
            IResult::Done(input, AttributeName::BitSize),

        IResult::Done(input, val) if AttributeName::StmtList as u64 == val =>
            IResult::Done(input, AttributeName::StmtList),

        IResult::Done(input, val) if AttributeName::LowPc as u64 == val =>
            IResult::Done(input, AttributeName::LowPc),

        IResult::Done(input, val) if AttributeName::HighPc as u64 == val =>
            IResult::Done(input, AttributeName::HighPc),

        IResult::Done(input, val) if AttributeName::Language as u64 == val =>
            IResult::Done(input, AttributeName::Language),

        IResult::Done(input, val) if AttributeName::Discr as u64 == val =>
            IResult::Done(input, AttributeName::Discr),

        IResult::Done(input, val) if AttributeName::DiscrValue as u64 == val =>
            IResult::Done(input, AttributeName::DiscrValue),

        IResult::Done(input, val) if AttributeName::Visibility as u64 == val =>
            IResult::Done(input, AttributeName::Visibility),

        IResult::Done(input, val) if AttributeName::Import as u64 == val =>
            IResult::Done(input, AttributeName::Import),

        IResult::Done(input, val) if AttributeName::StringLength as u64 == val =>
            IResult::Done(input, AttributeName::StringLength),

        IResult::Done(input, val) if AttributeName::CommonReference as u64 == val =>
            IResult::Done(input, AttributeName::CommonReference),

        IResult::Done(input, val) if AttributeName::CompDir as u64 == val =>
            IResult::Done(input, AttributeName::CompDir),

        IResult::Done(input, val) if AttributeName::ConstValue as u64 == val =>
            IResult::Done(input, AttributeName::ConstValue),

        IResult::Done(input, val) if AttributeName::ContainingType as u64 == val =>
            IResult::Done(input, AttributeName::ContainingType),

        IResult::Done(input, val) if AttributeName::DefaultValue as u64 == val =>
            IResult::Done(input, AttributeName::DefaultValue),

        IResult::Done(input, val) if AttributeName::Inline as u64 == val =>
            IResult::Done(input, AttributeName::Inline),

        IResult::Done(input, val) if AttributeName::IsOptional as u64 == val =>
            IResult::Done(input, AttributeName::IsOptional),

        IResult::Done(input, val) if AttributeName::LowerBound as u64 == val =>
            IResult::Done(input, AttributeName::LowerBound),

        IResult::Done(input, val) if AttributeName::Producer as u64 == val =>
            IResult::Done(input, AttributeName::Producer),

        IResult::Done(input, val) if AttributeName::Prototyped as u64 == val =>
            IResult::Done(input, AttributeName::Prototyped),

        IResult::Done(input, val) if AttributeName::ReturnAddr as u64 == val =>
            IResult::Done(input, AttributeName::ReturnAddr),

        IResult::Done(input, val) if AttributeName::StartScope as u64 == val =>
            IResult::Done(input, AttributeName::StartScope),

        IResult::Done(input, val) if AttributeName::BitStride as u64 == val =>
            IResult::Done(input, AttributeName::BitStride),

        IResult::Done(input, val) if AttributeName::UpperBound as u64 == val =>
            IResult::Done(input, AttributeName::UpperBound),

        IResult::Done(input, val) if AttributeName::AbstractOrigin as u64 == val =>
            IResult::Done(input, AttributeName::AbstractOrigin),

        IResult::Done(input, val) if AttributeName::Accessibility as u64 == val =>
            IResult::Done(input, AttributeName::Accessibility),

        IResult::Done(input, val) if AttributeName::AddressClass as u64 == val =>
            IResult::Done(input, AttributeName::AddressClass),

        IResult::Done(input, val) if AttributeName::Artificial as u64 == val =>
            IResult::Done(input, AttributeName::Artificial),

        IResult::Done(input, val) if AttributeName::BaseTypes as u64 == val =>
            IResult::Done(input, AttributeName::BaseTypes),

        IResult::Done(input, val) if AttributeName::CallingConvention as u64 == val =>
            IResult::Done(input, AttributeName::CallingConvention),

        IResult::Done(input, val) if AttributeName::Count as u64 == val =>
            IResult::Done(input, AttributeName::Count),

        IResult::Done(input, val) if AttributeName::DataMemberLocation as u64 == val =>
            IResult::Done(input, AttributeName::DataMemberLocation),

        IResult::Done(input, val) if AttributeName::DeclColumn as u64 == val =>
            IResult::Done(input, AttributeName::DeclColumn),

        IResult::Done(input, val) if AttributeName::DeclFile as u64 == val =>
            IResult::Done(input, AttributeName::DeclFile),

        IResult::Done(input, val) if AttributeName::DeclLine as u64 == val =>
            IResult::Done(input, AttributeName::DeclLine),

        IResult::Done(input, val) if AttributeName::Declaration as u64 == val =>
            IResult::Done(input, AttributeName::Declaration),

        IResult::Done(input, val) if AttributeName::DiscrList as u64 == val =>
            IResult::Done(input, AttributeName::DiscrList),

        IResult::Done(input, val) if AttributeName::Encoding as u64 == val =>
            IResult::Done(input, AttributeName::Encoding),

        IResult::Done(input, val) if AttributeName::External as u64 == val =>
            IResult::Done(input, AttributeName::External),

        IResult::Done(input, val) if AttributeName::FrameBase as u64 == val =>
            IResult::Done(input, AttributeName::FrameBase),

        IResult::Done(input, val) if AttributeName::Friend as u64 == val =>
            IResult::Done(input, AttributeName::Friend),

        IResult::Done(input, val) if AttributeName::IdentifierCase as u64 == val =>
            IResult::Done(input, AttributeName::IdentifierCase),

        IResult::Done(input, val) if AttributeName::MacroInfo as u64 == val =>
            IResult::Done(input, AttributeName::MacroInfo),

        IResult::Done(input, val) if AttributeName::NamelistItem as u64 == val =>
            IResult::Done(input, AttributeName::NamelistItem),

        IResult::Done(input, val) if AttributeName::Priority as u64 == val =>
            IResult::Done(input, AttributeName::Priority),

        IResult::Done(input, val) if AttributeName::Segment as u64 == val =>
            IResult::Done(input, AttributeName::Segment),

        IResult::Done(input, val) if AttributeName::Specification as u64 == val =>
            IResult::Done(input, AttributeName::Specification),

        IResult::Done(input, val) if AttributeName::StaticLink as u64 == val =>
            IResult::Done(input, AttributeName::StaticLink),

        IResult::Done(input, val) if AttributeName::Type as u64 == val =>
            IResult::Done(input, AttributeName::Type),

        IResult::Done(input, val) if AttributeName::UseLocation as u64 == val =>
            IResult::Done(input, AttributeName::UseLocation),

        IResult::Done(input, val) if AttributeName::VariableParameter as u64 == val =>
            IResult::Done(input, AttributeName::VariableParameter),

        IResult::Done(input, val) if AttributeName::Virtuality as u64 == val =>
            IResult::Done(input, AttributeName::Virtuality),

        IResult::Done(input, val) if AttributeName::VtableElemLocation as u64 == val =>
            IResult::Done(input, AttributeName::VtableElemLocation),

        IResult::Done(input, val) if AttributeName::Allocated as u64 == val =>
            IResult::Done(input, AttributeName::Allocated),

        IResult::Done(input, val) if AttributeName::Associated as u64 == val =>
            IResult::Done(input, AttributeName::Associated),

        IResult::Done(input, val) if AttributeName::DataLocation as u64 == val =>
            IResult::Done(input, AttributeName::DataLocation),

        IResult::Done(input, val) if AttributeName::ByteStride as u64 == val =>
            IResult::Done(input, AttributeName::ByteStride),

        IResult::Done(input, val) if AttributeName::EntryPc as u64 == val =>
            IResult::Done(input, AttributeName::EntryPc),

        IResult::Done(input, val) if AttributeName::UseUtf8 as u64 == val =>
            IResult::Done(input, AttributeName::UseUtf8),

        IResult::Done(input, val) if AttributeName::Extension as u64 == val =>
            IResult::Done(input, AttributeName::Extension),

        IResult::Done(input, val) if AttributeName::Ranges as u64 == val =>
            IResult::Done(input, AttributeName::Ranges),

        IResult::Done(input, val) if AttributeName::Trampoline as u64 == val =>
            IResult::Done(input, AttributeName::Trampoline),

        IResult::Done(input, val) if AttributeName::CallColumn as u64 == val =>
            IResult::Done(input, AttributeName::CallColumn),

        IResult::Done(input, val) if AttributeName::CallFile as u64 == val =>
            IResult::Done(input, AttributeName::CallFile),

        IResult::Done(input, val) if AttributeName::CallLine as u64 == val =>
            IResult::Done(input, AttributeName::CallLine),

        IResult::Done(input, val) if AttributeName::Description as u64 == val =>
            IResult::Done(input, AttributeName::Description),

        IResult::Done(input, val) if AttributeName::BinaryScale as u64 == val =>
            IResult::Done(input, AttributeName::BinaryScale),

        IResult::Done(input, val) if AttributeName::DecimalScale as u64 == val =>
            IResult::Done(input, AttributeName::DecimalScale),

        IResult::Done(input, val) if AttributeName::Small as u64 == val =>
            IResult::Done(input, AttributeName::Small),

        IResult::Done(input, val) if AttributeName::DecimalSign as u64 == val =>
            IResult::Done(input, AttributeName::DecimalSign),

        IResult::Done(input, val) if AttributeName::DigitCount as u64 == val =>
            IResult::Done(input, AttributeName::DigitCount),

        IResult::Done(input, val) if AttributeName::PictureString as u64 == val =>
            IResult::Done(input, AttributeName::PictureString),

        IResult::Done(input, val) if AttributeName::Mutable as u64 == val =>
            IResult::Done(input, AttributeName::Mutable),

        IResult::Done(input, val) if AttributeName::ThreadsScaled as u64 == val =>
            IResult::Done(input, AttributeName::ThreadsScaled),

        IResult::Done(input, val) if AttributeName::Explicit as u64 == val =>
            IResult::Done(input, AttributeName::Explicit),

        IResult::Done(input, val) if AttributeName::ObjectPointer as u64 == val =>
            IResult::Done(input, AttributeName::ObjectPointer),

        IResult::Done(input, val) if AttributeName::Endianity as u64 == val =>
            IResult::Done(input, AttributeName::Endianity),

        IResult::Done(input, val) if AttributeName::Elemental as u64 == val =>
            IResult::Done(input, AttributeName::Elemental),

        IResult::Done(input, val) if AttributeName::Pure as u64 == val =>
            IResult::Done(input, AttributeName::Pure),

        IResult::Done(input, val) if AttributeName::Recursive as u64 == val =>
            IResult::Done(input, AttributeName::Recursive),

        IResult::Done(input, val) if AttributeName::Signature as u64 == val =>
            IResult::Done(input, AttributeName::Signature),

        IResult::Done(input, val) if AttributeName::MainSubprogram as u64 == val =>
            IResult::Done(input, AttributeName::MainSubprogram),

        IResult::Done(input, val) if AttributeName::DataBitOffset as u64 == val =>
            IResult::Done(input, AttributeName::DataBitOffset),

        IResult::Done(input, val) if AttributeName::ConstExpr as u64 == val =>
            IResult::Done(input, AttributeName::ConstExpr),

        IResult::Done(input, val) if AttributeName::EnumClass as u64 == val =>
            IResult::Done(input, AttributeName::EnumClass),

        IResult::Done(input, val) if AttributeName::LinkageName as u64 == val =>
            IResult::Done(input, AttributeName::LinkageName),

        IResult::Done(input, val) if AttributeName::LoUser as u64 == val =>
            IResult::Done(input, AttributeName::LoUser),

        IResult::Done(input, val) if AttributeName::HiUser as u64 == val =>
            IResult::Done(input, AttributeName::HiUser),

        IResult::Done(input, _) =>
            IResult::Error(
                Err::Position(ErrorKind::Custom(Error::InvalidAttributeName), input)),

        IResult::Incomplete(needed) =>
            IResult::Incomplete(needed),

        IResult::Error(error) =>
            IResult::Error(error),
    }
}

/// Parse an attribute's form.
fn parse_attribute_form(input: &[u8]) -> ParseResult<AttributeForm> {
    match parse_unsigned_leb(input) {
        IResult::Done(input, val) if AttributeForm::Addr as u64 == val =>
            IResult::Done(input, AttributeForm::Addr),

        IResult::Done(input, val) if AttributeForm::Block2 as u64 == val =>
            IResult::Done(input, AttributeForm::Block2),

        IResult::Done(input, val) if AttributeForm::Block4 as u64 == val =>
            IResult::Done(input, AttributeForm::Block4),

        IResult::Done(input, val) if AttributeForm::Data2 as u64 == val =>
            IResult::Done(input, AttributeForm::Data2),

        IResult::Done(input, val) if AttributeForm::Data4 as u64 == val =>
            IResult::Done(input, AttributeForm::Data4),

        IResult::Done(input, val) if AttributeForm::Data8 as u64 == val =>
            IResult::Done(input, AttributeForm::Data8),

        IResult::Done(input, val) if AttributeForm::String as u64 == val =>
            IResult::Done(input, AttributeForm::String),

        IResult::Done(input, val) if AttributeForm::Block as u64 == val =>
            IResult::Done(input, AttributeForm::Block),

        IResult::Done(input, val) if AttributeForm::Block1 as u64 == val =>
            IResult::Done(input, AttributeForm::Block1),

        IResult::Done(input, val) if AttributeForm::Data1 as u64 == val =>
            IResult::Done(input, AttributeForm::Data1),

        IResult::Done(input, val) if AttributeForm::Flag as u64 == val =>
            IResult::Done(input, AttributeForm::Flag),

        IResult::Done(input, val) if AttributeForm::Sdata as u64 == val =>
            IResult::Done(input, AttributeForm::Sdata),

        IResult::Done(input, val) if AttributeForm::Strp as u64 == val =>
            IResult::Done(input, AttributeForm::Strp),

        IResult::Done(input, val) if AttributeForm::Udata as u64 == val =>
            IResult::Done(input, AttributeForm::Udata),

        IResult::Done(input, val) if AttributeForm::RefAddr as u64 == val =>
            IResult::Done(input, AttributeForm::RefAddr),

        IResult::Done(input, val) if AttributeForm::Ref1 as u64 == val =>
            IResult::Done(input, AttributeForm::Ref1),

        IResult::Done(input, val) if AttributeForm::Ref2 as u64 == val =>
            IResult::Done(input, AttributeForm::Ref2),

        IResult::Done(input, val) if AttributeForm::Ref4 as u64 == val =>
            IResult::Done(input, AttributeForm::Ref4),

        IResult::Done(input, val) if AttributeForm::Ref8 as u64 == val =>
            IResult::Done(input, AttributeForm::Ref8),

        IResult::Done(input, val) if AttributeForm::RefUdata as u64 == val =>
            IResult::Done(input, AttributeForm::RefUdata),

        IResult::Done(input, val) if AttributeForm::Indirect as u64 == val =>
            IResult::Done(input, AttributeForm::Indirect),

        IResult::Done(input, val) if AttributeForm::SecOffset as u64 == val =>
            IResult::Done(input, AttributeForm::SecOffset),

        IResult::Done(input, val) if AttributeForm::Exprloc as u64 == val =>
            IResult::Done(input, AttributeForm::Exprloc),

        IResult::Done(input, val) if AttributeForm::FlagPresent as u64 == val =>
            IResult::Done(input, AttributeForm::FlagPresent),

        IResult::Done(input, val) if AttributeForm::RefSig8 as u64 == val =>
            IResult::Done(input, AttributeForm::RefSig8),

        IResult::Done(input, _) =>
            IResult::Error(
                Err::Position(ErrorKind::Custom(Error::InvalidAttributeForm), input)),

        IResult::Incomplete(needed) =>
            IResult::Incomplete(needed),

        IResult::Error(error) =>
            IResult::Error(error),
    }
}

/// Parse a non-null attribute specification.
fn parse_attribute_specification(input: &[u8]) -> ParseResult<AttributeSpecification> {
    chain!(input,
           name: parse_attribute_name ~
           form: parse_attribute_form,
           || AttributeSpecification::new(name, form))
}

/// Parse the null attribute specification.
fn parse_null_attribute_specification(input: &[u8]) -> ParseResult<()> {
    let (input1, name) = try_parse!(input, parse_unsigned_leb);
    if name != 0 {
        return IResult::Error(Err::Position(ErrorKind::Custom(Error::ExpectedZero), input));
    }

    let (input2, form) = try_parse!(input1, parse_unsigned_leb);
    if form != 0 {
        return IResult::Error(Err::Position(ErrorKind::Custom(Error::ExpectedZero), input1));
    }

    IResult::Done(input2, ())
}

/// Parse a series of attribute specifications, terminated by a null attribute
/// specification.
fn parse_attribute_specifications(mut input: &[u8]) -> ParseResult<Vec<AttributeSpecification>> {
    // There has to be a better way to keep parsing attributes until we see two
    // 0 LEB128s, but take_until!/take_while! aren't quite expressive enough for
    // this case.

    let mut results = Vec::new();

    loop {
        let (input1, attribute) = try_parse!(
            input,
            alt!(parse_null_attribute_specification => { |_| None } |
                 parse_attribute_specification      => { |a| Some(a) }));

        input = input1;

        match attribute {
            None => break,
            Some(attr) => results.push(attr),
        };
    }

    IResult::Done(input, results)
}

/// Parse a non-null abbreviation.
fn parse_abbreviation(input: &[u8]) -> ParseResult<Abbreviation> {
    chain!(input,
           code: parse_abbreviation_code ~
           tag: parse_abbreviation_tag ~
           has_children: parse_abbreviation_has_children ~
           attributes: parse_attribute_specifications,
           || Abbreviation::new(code, tag, has_children, attributes))
}

/// Parse a null abbreviation.
fn parse_null_abbreviation(input: &[u8]) -> ParseResult<()> {
    let (input1, name) = try_parse!(input, parse_unsigned_leb);
    if name == 0 {
        IResult::Done(input1, ())
    } else {
        IResult::Error(Err::Position(ErrorKind::Custom(Error::ExpectedZero), input))
    }

}

/// Parse a series of abbreviations, terminated by a null abbreviation.
pub fn parse_abbreviations(mut input: &[u8]) -> ParseResult<Abbreviations> {
    // Again with the super funky keep-parsing-X-while-we-can't-parse-a-Y
    // thing... This should definitely be abstracted out.

    let mut results = Abbreviations::new();

    loop {
        let (input1, abbrev) = try_parse!(input,
                                          alt!(parse_null_abbreviation => { |_| None } |
                                               parse_abbreviation      => { |a| Some(a) }));

        match abbrev {
            None => break,
            Some(abbrev) => {
                match results.insert(abbrev) {
                    Ok(_) =>
                        input = input1,
                    Err(_) =>
                        return IResult::Error(
                            Err::Position(
                                ErrorKind::Custom(Error::DuplicateAbbreviationCode),
                                input)),
                }
            }
        }
    }

    IResult::Done(input, results)
}