libmagic_rs/evaluator/

types.rs

// Copyright (c) 2025-2026 the libmagic-rs contributors
// SPDX-License-Identifier: Apache-2.0

//! Type interpretation for reading and converting bytes from file buffers
//!
//! This module provides functions for safely reading different data types from byte buffers
//! with proper bounds checking and error handling.

use crate::parser::ast::{Endianness, TypeKind, Value};
use byteorder::{BigEndian, ByteOrder, LittleEndian, NativeEndian};
use thiserror::Error;

/// Errors that can occur during type reading operations
#[derive(Debug, Error, PartialEq, Eq)]
pub enum TypeReadError {
    /// Buffer access beyond available data
    #[error(
        "Buffer overrun: attempted to read at offset {offset} but buffer length is {buffer_len}"
    )]
    BufferOverrun {
        /// The offset that was attempted to be accessed
        offset: usize,
        /// The actual length of the buffer
        buffer_len: usize,
    },
    /// Unsupported type variant
    #[error("Unsupported type: {type_name}")]
    UnsupportedType {
        /// The name of the unsupported type
        type_name: String,
    },
}

/// Safely reads a single byte from the buffer at the specified offset
///
/// This function provides secure byte reading with comprehensive bounds checking
/// to prevent buffer overruns and potential security vulnerabilities.
///
/// # Arguments
///
/// * `buffer` - The byte buffer to read from
/// * `offset` - The offset position to read the byte from
/// * `signed` - Whether to interpret the byte as signed (`i8`) or unsigned (`u8`)
///
/// # Returns
///
/// Returns `Ok(Value::Uint(byte_value))` for unsigned reads or
/// `Ok(Value::Int(byte_value))` for signed reads if the read is successful, or
/// `Err(TypeReadError::BufferOverrun)` if the offset is beyond the buffer bounds.
///
/// # Security
///
/// This function performs strict bounds checking to prevent:
/// - Buffer overruns that could lead to memory safety issues
/// - Reading uninitialized or out-of-bounds memory
/// - Integer overflow in offset calculations
///
/// # Examples
///
/// ```
/// use libmagic_rs::evaluator::types::read_byte;
/// use libmagic_rs::parser::ast::Value;
///
/// let buffer = &[0x7f, 0x80, 0x4c, 0x46]; // example bytes
///
/// // Read unsigned byte (0x80 = 128)
/// let result = read_byte(buffer, 1, false).unwrap();
/// assert_eq!(result, Value::Uint(0x80));
///
/// // Read signed byte (0x80 = -128)
/// let result = read_byte(buffer, 1, true).unwrap();
/// assert_eq!(result, Value::Int(-128));
/// ```
///
/// # Errors
///
/// Returns `TypeReadError::BufferOverrun` if the offset is greater than or equal to
/// the buffer length.
pub fn read_byte(buffer: &[u8], offset: usize, signed: bool) -> Result<Value, TypeReadError> {
    buffer
        .get(offset)
        .map(|&byte| {
            if signed {
                // Wrapping is intentional: e.g., 0x80 -> -128 as i8
                #[allow(clippy::cast_possible_wrap)]
                Value::Int(i64::from(byte as i8))
            } else {
                Value::Uint(u64::from(byte))
            }
        })
        .ok_or(TypeReadError::BufferOverrun {
            offset,
            buffer_len: buffer.len(),
        })
}

/// Safely reads a 16-bit integer from the buffer at the specified offset
///
/// # Arguments
///
/// * `buffer` - The byte buffer to read from
/// * `offset` - The offset position to read the 16-bit value from
/// * `endian` - The byte order to use for interpretation
/// * `signed` - Whether to interpret the value as signed or unsigned
///
/// # Returns
///
/// Returns `Ok(Value::Uint(value))` for unsigned values or `Ok(Value::Int(value))` for signed values
/// if the read is successful, or `Err(TypeReadError::BufferOverrun)` if there are insufficient bytes.
///
/// # Examples
///
/// ```
/// use libmagic_rs::evaluator::types::read_short;
/// use libmagic_rs::parser::ast::{Endianness, Value};
///
/// let buffer = &[0x34, 0x12, 0xff, 0x7f]; // Little-endian data
///
/// // Read unsigned little-endian short (0x1234)
/// let result = read_short(buffer, 0, Endianness::Little, false).unwrap();
/// assert_eq!(result, Value::Uint(0x1234));
///
/// // Read signed little-endian short (0x7fff = 32767)
/// let result = read_short(buffer, 2, Endianness::Little, true).unwrap();
/// assert_eq!(result, Value::Int(32767));
/// ```
///
/// # Errors
///
/// Returns `TypeReadError::BufferOverrun` if there are fewer than 2 bytes available
/// starting at the specified offset.
pub fn read_short(
    buffer: &[u8],
    offset: usize,
    endian: Endianness,
    signed: bool,
) -> Result<Value, TypeReadError> {
    let bytes = buffer
        .get(offset..offset + 2)
        .ok_or(TypeReadError::BufferOverrun {
            offset,
            buffer_len: buffer.len(),
        })?;

    let value = match endian {
        Endianness::Little => LittleEndian::read_u16(bytes),
        Endianness::Big => BigEndian::read_u16(bytes),
        Endianness::Native => NativeEndian::read_u16(bytes),
    };

    if signed {
        #[allow(clippy::cast_possible_wrap)]
        Ok(Value::Int(i64::from(value as i16)))
    } else {
        Ok(Value::Uint(u64::from(value)))
    }
}

/// Safely reads a 32-bit integer from the buffer at the specified offset
///
/// # Arguments
///
/// * `buffer` - The byte buffer to read from
/// * `offset` - The offset position to read the 32-bit value from
/// * `endian` - The byte order to use for interpretation
/// * `signed` - Whether to interpret the value as signed or unsigned
///
/// # Returns
///
/// Returns `Ok(Value::Uint(value))` for unsigned values or `Ok(Value::Int(value))` for signed values
/// if the read is successful, or `Err(TypeReadError::BufferOverrun)` if there are insufficient bytes.
///
/// # Examples
///
/// ```
/// use libmagic_rs::evaluator::types::read_long;
/// use libmagic_rs::parser::ast::{Endianness, Value};
///
/// let buffer = &[0x78, 0x56, 0x34, 0x12, 0xff, 0xff, 0xff, 0x7f];
///
/// // Read unsigned little-endian long (0x12345678)
/// let result = read_long(buffer, 0, Endianness::Little, false).unwrap();
/// assert_eq!(result, Value::Uint(0x12345678));
///
/// // Read signed little-endian long (0x7fffffff = 2147483647)
/// let result = read_long(buffer, 4, Endianness::Little, true).unwrap();
/// assert_eq!(result, Value::Int(2147483647));
/// ```
///
/// # Errors
///
/// Returns `TypeReadError::BufferOverrun` if there are fewer than 4 bytes available
/// starting at the specified offset.
pub fn read_long(
    buffer: &[u8],
    offset: usize,
    endian: Endianness,
    signed: bool,
) -> Result<Value, TypeReadError> {
    let bytes = buffer
        .get(offset..offset + 4)
        .ok_or(TypeReadError::BufferOverrun {
            offset,
            buffer_len: buffer.len(),
        })?;

    let value = match endian {
        Endianness::Little => LittleEndian::read_u32(bytes),
        Endianness::Big => BigEndian::read_u32(bytes),
        Endianness::Native => NativeEndian::read_u32(bytes),
    };

    if signed {
        #[allow(clippy::cast_possible_wrap)]
        Ok(Value::Int(i64::from(value as i32)))
    } else {
        Ok(Value::Uint(u64::from(value)))
    }
}

/// Safely reads a null-terminated string from the buffer at the specified offset
///
/// This function reads bytes from the buffer starting at the given offset until it encounters
/// a null byte (0x00) or reaches the maximum length limit. The resulting bytes are converted
/// to a UTF-8 string with proper error handling for invalid sequences.
///
/// # Arguments
///
/// * `buffer` - The byte buffer to read from
/// * `offset` - The offset position to start reading the string from
/// * `max_length` - Optional maximum number of bytes to read excluding the null terminator.
///   If a NUL is found within `max_length` bytes, it is not counted in the result length.
///   If no NUL is found, up to `max_length` bytes are returned with no trailing NUL.
///   When `None`, reads until the first NUL or end of buffer.
///
/// # Returns
///
/// Returns `Ok(Value::String(string))` if the read is successful, or an appropriate error
/// if the read fails due to buffer overrun or invalid UTF-8 sequences.
///
/// # Security
///
/// This function provides several security guarantees:
/// - Bounds checking prevents reading beyond buffer limits
/// - Length limits prevent excessive memory allocation
/// - UTF-8 validation ensures string safety
/// - Null termination handling prevents runaway reads
///
/// # Examples
///
/// ```
/// use libmagic_rs::evaluator::types::read_string;
/// use libmagic_rs::parser::ast::Value;
///
/// // Null-terminated string
/// let buffer = b"Hello\x00World";
/// let result = read_string(buffer, 0, None).unwrap();
/// assert_eq!(result, Value::String("Hello".to_string()));
///
/// // String with length limit
/// let buffer = b"VeryLongString\x00";
/// let result = read_string(buffer, 0, Some(4)).unwrap();
/// assert_eq!(result, Value::String("Very".to_string()));
///
/// // String without null terminator (reads to max_length)
/// let buffer = b"NoNull";
/// let result = read_string(buffer, 0, Some(6)).unwrap();
/// assert_eq!(result, Value::String("NoNull".to_string()));
///
/// // NUL found within max_length (NUL not counted in result)
/// let buffer = b"Hello\x00World";
/// let result = read_string(buffer, 0, Some(10)).unwrap();
/// assert_eq!(result, Value::String("Hello".to_string()));
///
/// // No NUL found, returns exactly max_length bytes
/// let buffer = b"ABCDEF";
/// let result = read_string(buffer, 0, Some(4)).unwrap();
/// assert_eq!(result, Value::String("ABCD".to_string()));
/// ```
///
/// # Errors
///
/// Returns `TypeReadError::BufferOverrun` if the offset is greater than or equal to the buffer length.
pub fn read_string(
    buffer: &[u8],
    offset: usize,
    max_length: Option<usize>,
) -> Result<Value, TypeReadError> {
    // Check if offset is within buffer bounds
    if offset >= buffer.len() {
        return Err(TypeReadError::BufferOverrun {
            offset,
            buffer_len: buffer.len(),
        });
    }

    // Get the slice starting from offset
    let remaining_buffer = &buffer[offset..];

    // Determine the actual length to read (uses memchr for efficient null byte scanning)
    let read_length = if let Some(max_len) = max_length {
        // Find null terminator within max_length, or use max_length if no null found
        let search_len = std::cmp::min(max_len, remaining_buffer.len());
        memchr::memchr(0, &remaining_buffer[..search_len]).unwrap_or(search_len)
    } else {
        // Find null terminator in entire remaining buffer
        memchr::memchr(0, remaining_buffer).unwrap_or(remaining_buffer.len())
    };

    // Extract the string bytes (excluding null terminator)
    let string_bytes = &remaining_buffer[..read_length];

    // Convert to UTF-8 string, replacing invalid sequences with replacement character
    let string_value = String::from_utf8_lossy(string_bytes).into_owned();

    Ok(Value::String(string_value))
}

/// Reads and interprets bytes according to the specified `TypeKind`
///
/// This is the main interface for type interpretation that dispatches to the appropriate
/// reading function based on the `TypeKind` variant.
///
/// # Arguments
///
/// * `buffer` - The byte buffer to read from
/// * `offset` - The offset position to read from
/// * `type_kind` - The type specification that determines how to interpret the bytes
///
/// # Returns
///
/// Returns the interpreted value as a `Value` enum variant, or an error if the read fails.
///
/// # Examples
///
/// ```
/// use libmagic_rs::evaluator::types::read_typed_value;
/// use libmagic_rs::parser::ast::{TypeKind, Endianness, Value};
///
/// let buffer = &[0x7f, 0x45, 0x4c, 0x46, 0x34, 0x12];
///
/// // Read an unsigned byte
/// let byte_result = read_typed_value(buffer, 0, &TypeKind::Byte { signed: false }).unwrap();
/// assert_eq!(byte_result, Value::Uint(0x7f));
///
/// // Read a little-endian short
/// let short_type = TypeKind::Short {
///     endian: Endianness::Little,
///     signed: false,
/// };
/// let short_result = read_typed_value(buffer, 4, &short_type).unwrap();
/// assert_eq!(short_result, Value::Uint(0x1234));
/// ```
///
/// # Errors
///
/// Returns `TypeReadError::BufferOverrun` if there are insufficient bytes for the requested type,
/// or `TypeReadError::UnsupportedType` for type variants that are not yet implemented.
pub fn read_typed_value(
    buffer: &[u8],
    offset: usize,
    type_kind: &TypeKind,
) -> Result<Value, TypeReadError> {
    match type_kind {
        TypeKind::Byte { signed } => read_byte(buffer, offset, *signed),
        TypeKind::Short { endian, signed } => read_short(buffer, offset, *endian, *signed),
        TypeKind::Long { endian, signed } => read_long(buffer, offset, *endian, *signed),
        TypeKind::String { max_length } => read_string(buffer, offset, *max_length),
    }
}

/// Coerce a rule's expected value to match the type's signedness and width.
///
/// In libmagic, comparison values like `0xff` in `0 byte =0xff` are interpreted
/// at the type's bit width. For a signed byte, `0xff` means `-1` (the signed
/// interpretation of that bit pattern). This function performs that coercion so
/// that comparisons work correctly regardless of how the value was parsed.
///
/// Only affects `Value::Uint` values paired with signed types whose values exceed
/// the signed range. All other combinations pass through unchanged.
///
/// # Examples
///
/// ```
/// use libmagic_rs::evaluator::types::coerce_value_to_type;
/// use libmagic_rs::parser::ast::{TypeKind, Value};
///
/// // 0xff for signed byte -> -1
/// let coerced = coerce_value_to_type(&Value::Uint(0xff), &TypeKind::Byte { signed: true });
/// assert_eq!(coerced, Value::Int(-1));
///
/// // 0x7f for signed byte -> unchanged (fits in signed range)
/// let coerced = coerce_value_to_type(&Value::Uint(0x7f), &TypeKind::Byte { signed: true });
/// assert_eq!(coerced, Value::Uint(0x7f));
///
/// // Unsigned types pass through unchanged
/// let coerced = coerce_value_to_type(&Value::Uint(0xff), &TypeKind::Byte { signed: false });
/// assert_eq!(coerced, Value::Uint(0xff));
/// ```
#[must_use]
pub fn coerce_value_to_type(value: &Value, type_kind: &TypeKind) -> Value {
    match (value, type_kind) {
        (Value::Uint(v), TypeKind::Byte { signed: true }) if *v > i8::MAX as u64 =>
        {
            #[allow(clippy::cast_possible_truncation, clippy::cast_possible_wrap)]
            Value::Int(i64::from(*v as u8 as i8))
        }
        (Value::Uint(v), TypeKind::Short { signed: true, .. }) if *v > i16::MAX as u64 =>
        {
            #[allow(clippy::cast_possible_truncation, clippy::cast_possible_wrap)]
            Value::Int(i64::from(*v as u16 as i16))
        }
        (Value::Uint(v), TypeKind::Long { signed: true, .. }) if *v > i32::MAX as u64 =>
        {
            #[allow(clippy::cast_possible_truncation, clippy::cast_possible_wrap)]
            Value::Int(i64::from(*v as u32 as i32))
        }
        _ => value.clone(),
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_read_byte_values() {
        // All 256 unsigned values
        let buffer: Vec<u8> = (0..=255).collect();
        for (i, &byte) in buffer.iter().enumerate() {
            assert_eq!(
                read_byte(&buffer, i, false).unwrap(),
                Value::Uint(u64::from(byte))
            );
        }
    }

    #[test]
    fn test_read_byte_out_of_bounds() {
        // Empty buffer
        assert_eq!(
            read_byte(&[], 0, false).unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 0,
                buffer_len: 0
            }
        );
        // Just past end
        assert_eq!(
            read_byte(&[0x42], 1, false).unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 1,
                buffer_len: 1
            }
        );
        // Way past end
        assert_eq!(
            read_byte(&[1, 2, 3], 100, false).unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 100,
                buffer_len: 3
            }
        );
    }

    #[test]
    fn test_read_byte_signedness() {
        let cases: Vec<(u8, bool, Value)> = vec![
            (0x00, false, Value::Uint(0)),
            (0x7f, false, Value::Uint(127)),
            (0x80, false, Value::Uint(128)),
            (0xff, false, Value::Uint(255)),
            (0x00, true, Value::Int(0)),
            (0x7f, true, Value::Int(127)),
            (0x80, true, Value::Int(-128)),
            (0xff, true, Value::Int(-1)),
        ];
        for (byte, signed, expected) in cases {
            let result = read_byte(&[byte], 0, signed).unwrap();
            assert_eq!(result, expected, "byte=0x{byte:02x}, signed={signed}");
        }
    }

    #[test]
    fn test_type_read_error_display() {
        let error = TypeReadError::BufferOverrun {
            offset: 10,
            buffer_len: 5,
        };
        let msg = format!("{error}");
        assert!(msg.contains("offset 10"));
        assert!(msg.contains("buffer length is 5"));
    }

    // Tests for read_short function
    #[test]
    fn test_read_short_little_endian_unsigned() {
        let buffer = &[0x34, 0x12, 0x78, 0x56]; // 0x1234, 0x5678 in little-endian

        // Read first short (0x1234)
        let result = read_short(buffer, 0, Endianness::Little, false).unwrap();
        assert_eq!(result, Value::Uint(0x1234));

        // Read second short (0x5678)
        let result = read_short(buffer, 2, Endianness::Little, false).unwrap();
        assert_eq!(result, Value::Uint(0x5678));
    }

    #[test]
    fn test_read_short_big_endian_unsigned() {
        let buffer = &[0x12, 0x34, 0x56, 0x78]; // 0x1234, 0x5678 in big-endian

        // Read first short (0x1234)
        let result = read_short(buffer, 0, Endianness::Big, false).unwrap();
        assert_eq!(result, Value::Uint(0x1234));

        // Read second short (0x5678)
        let result = read_short(buffer, 2, Endianness::Big, false).unwrap();
        assert_eq!(result, Value::Uint(0x5678));
    }

    #[test]
    fn test_read_short_native_endian_unsigned() {
        let buffer = &[0x34, 0x12, 0x78, 0x56];

        // Read using native endianness
        let result = read_short(buffer, 0, Endianness::Native, false).unwrap();

        // The exact value depends on the system's endianness, but it should be valid
        match result {
            Value::Uint(val) => {
                // Should be either 0x1234 (little-endian) or 0x3412 (big-endian)
                assert!(val == 0x1234 || val == 0x3412);
            }
            _ => panic!("Expected Value::Uint variant"),
        }
    }

    #[test]
    fn test_read_short_signed_positive() {
        let buffer = &[0xff, 0x7f]; // 0x7fff = 32767 in little-endian

        let result = read_short(buffer, 0, Endianness::Little, true).unwrap();
        assert_eq!(result, Value::Int(32767));
    }

    #[test]
    fn test_read_short_signed_negative() {
        let buffer = &[0x00, 0x80]; // 0x8000 = -32768 in little-endian (signed)

        let result = read_short(buffer, 0, Endianness::Little, true).unwrap();
        assert_eq!(result, Value::Int(-32768));
    }

    #[test]
    fn test_read_short_signed_vs_unsigned() {
        let buffer = &[0xff, 0xff]; // 0xffff

        // Unsigned interpretation
        let unsigned_result = read_short(buffer, 0, Endianness::Little, false).unwrap();
        assert_eq!(unsigned_result, Value::Uint(65535));

        // Signed interpretation
        let signed_result = read_short(buffer, 0, Endianness::Little, true).unwrap();
        assert_eq!(signed_result, Value::Int(-1));
    }

    #[test]
    fn test_read_short_buffer_overrun() {
        let buffer = &[0x12]; // Only 1 byte available

        // Should fail when trying to read 2 bytes
        let result = read_short(buffer, 0, Endianness::Little, false);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 0,
                buffer_len: 1
            }
        );
    }

    #[test]
    fn test_read_short_offset_out_of_bounds() {
        let buffer = &[0x12, 0x34, 0x56];

        // Should fail when trying to read 2 bytes starting at offset 2 (only 1 byte left)
        let result = read_short(buffer, 2, Endianness::Little, false);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 2,
                buffer_len: 3
            }
        );
    }

    #[test]
    fn test_read_short_empty_buffer() {
        let buffer = &[];

        let result = read_short(buffer, 0, Endianness::Little, false);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 0,
                buffer_len: 0
            }
        );
    }

    #[test]
    fn test_read_short_all_endianness_variants() {
        let buffer = &[0x12, 0x34];

        // Test all endianness variants
        let little = read_short(buffer, 0, Endianness::Little, false).unwrap();
        let big = read_short(buffer, 0, Endianness::Big, false).unwrap();
        let native = read_short(buffer, 0, Endianness::Native, false).unwrap();

        // Little-endian: 0x3412, Big-endian: 0x1234
        assert_eq!(little, Value::Uint(0x3412));
        assert_eq!(big, Value::Uint(0x1234));

        // Native should match one of them
        match native {
            Value::Uint(val) => assert!(val == 0x1234 || val == 0x3412),
            _ => panic!("Expected Value::Uint variant"),
        }
    }

    // Tests for read_long function
    #[test]
    fn test_read_long_little_endian_unsigned() {
        let buffer = &[0x78, 0x56, 0x34, 0x12, 0xbc, 0x9a, 0x78, 0x56]; // 0x12345678, 0x56789abc

        // Read first long (0x12345678)
        let result = read_long(buffer, 0, Endianness::Little, false).unwrap();
        assert_eq!(result, Value::Uint(0x1234_5678));

        // Read second long (0x56789abc)
        let result = read_long(buffer, 4, Endianness::Little, false).unwrap();
        assert_eq!(result, Value::Uint(0x5678_9abc));
    }

    #[test]
    fn test_read_long_big_endian_unsigned() {
        let buffer = &[0x12, 0x34, 0x56, 0x78, 0x56, 0x78, 0x9a, 0xbc]; // 0x12345678, 0x56789abc

        // Read first long (0x12345678)
        let result = read_long(buffer, 0, Endianness::Big, false).unwrap();
        assert_eq!(result, Value::Uint(0x1234_5678));

        // Read second long (0x56789abc)
        let result = read_long(buffer, 4, Endianness::Big, false).unwrap();
        assert_eq!(result, Value::Uint(0x5678_9abc));
    }

    #[test]
    fn test_read_long_native_endian_unsigned() {
        let buffer = &[0x78, 0x56, 0x34, 0x12];

        // Read using native endianness
        let result = read_long(buffer, 0, Endianness::Native, false).unwrap();

        // The exact value depends on the system's endianness, but it should be valid
        match result {
            Value::Uint(val) => {
                // Should be either 0x12345678 (little-endian) or 0x78563412 (big-endian)
                assert!(val == 0x1234_5678 || val == 0x7856_3412);
            }
            _ => panic!("Expected Value::Uint variant"),
        }
    }

    #[test]
    fn test_read_long_signed_positive() {
        let buffer = &[0xff, 0xff, 0xff, 0x7f]; // 0x7fffffff = 2147483647 in little-endian

        let result = read_long(buffer, 0, Endianness::Little, true).unwrap();
        assert_eq!(result, Value::Int(2_147_483_647));
    }

    #[test]
    fn test_read_long_signed_negative() {
        let buffer = &[0x00, 0x00, 0x00, 0x80]; // 0x80000000 = -2147483648 in little-endian (signed)

        let result = read_long(buffer, 0, Endianness::Little, true).unwrap();
        assert_eq!(result, Value::Int(-2_147_483_648));
    }

    #[test]
    fn test_read_long_signed_vs_unsigned() {
        let buffer = &[0xff, 0xff, 0xff, 0xff]; // 0xffffffff

        // Unsigned interpretation
        let unsigned_result = read_long(buffer, 0, Endianness::Little, false).unwrap();
        assert_eq!(unsigned_result, Value::Uint(4_294_967_295));

        // Signed interpretation
        let signed_result = read_long(buffer, 0, Endianness::Little, true).unwrap();
        assert_eq!(signed_result, Value::Int(-1));
    }

    #[test]
    fn test_read_long_buffer_overrun() {
        let buffer = &[0x12, 0x34, 0x56]; // Only 3 bytes available

        // Should fail when trying to read 4 bytes
        let result = read_long(buffer, 0, Endianness::Little, false);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 0,
                buffer_len: 3
            }
        );
    }

    #[test]
    fn test_read_long_offset_out_of_bounds() {
        let buffer = &[0x12, 0x34, 0x56, 0x78, 0x9a];

        // Should fail when trying to read 4 bytes starting at offset 2 (only 3 bytes left)
        let result = read_long(buffer, 2, Endianness::Little, false);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 2,
                buffer_len: 5
            }
        );
    }

    #[test]
    fn test_read_long_empty_buffer() {
        let buffer = &[];

        let result = read_long(buffer, 0, Endianness::Little, false);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 0,
                buffer_len: 0
            }
        );
    }

    #[test]
    fn test_read_long_all_endianness_variants() {
        let buffer = &[0x12, 0x34, 0x56, 0x78];

        // Test all endianness variants
        let little = read_long(buffer, 0, Endianness::Little, false).unwrap();
        let big = read_long(buffer, 0, Endianness::Big, false).unwrap();
        let native = read_long(buffer, 0, Endianness::Native, false).unwrap();

        // Little-endian: 0x78563412, Big-endian: 0x12345678
        assert_eq!(little, Value::Uint(0x7856_3412));
        assert_eq!(big, Value::Uint(0x1234_5678));

        // Native should match one of them
        match native {
            Value::Uint(val) => assert!(val == 0x1234_5678 || val == 0x7856_3412),
            _ => panic!("Expected Value::Uint variant"),
        }
    }

    #[test]
    fn test_read_long_extreme_values() {
        // Test maximum unsigned 32-bit value
        let max_buffer = &[0xff, 0xff, 0xff, 0xff];
        let max_result = read_long(max_buffer, 0, Endianness::Little, false).unwrap();
        assert_eq!(max_result, Value::Uint(u64::from(u32::MAX)));

        // Test zero value
        let zero_buffer = &[0x00, 0x00, 0x00, 0x00];
        let zero_result = read_long(zero_buffer, 0, Endianness::Little, false).unwrap();
        assert_eq!(zero_result, Value::Uint(0));
    }

    #[test]
    fn test_read_short_extreme_values() {
        // Test maximum unsigned 16-bit value
        let max_buffer = &[0xff, 0xff];
        let max_result = read_short(max_buffer, 0, Endianness::Little, false).unwrap();
        assert_eq!(max_result, Value::Uint(u64::from(u16::MAX)));

        // Test zero value
        let zero_buffer = &[0x00, 0x00];
        let zero_result = read_short(zero_buffer, 0, Endianness::Little, false).unwrap();
        assert_eq!(zero_result, Value::Uint(0));
    }

    #[test]
    fn test_multi_byte_reading_consistency() {
        // Test that reading the same bytes with different functions gives consistent results
        let buffer = &[0x34, 0x12, 0x78, 0x56, 0xbc, 0x9a, 0xde, 0xf0];

        // Read as individual bytes
        let byte0 = read_byte(buffer, 0, false).unwrap();
        let byte1 = read_byte(buffer, 1, false).unwrap();

        // Read as short
        let short = read_short(buffer, 0, Endianness::Little, false).unwrap();

        // Verify consistency
        match (byte0, byte1, short) {
            (Value::Uint(b0), Value::Uint(b1), Value::Uint(s)) => {
                assert_eq!(s, b0 + (b1 << 8)); // Little-endian composition
            }
            _ => panic!("Expected all Uint values"),
        }
    }

    // Tests for UnsupportedType error
    #[test]
    fn test_unsupported_type_error() {
        let error = TypeReadError::UnsupportedType {
            type_name: "CustomType".to_string(),
        };

        let error_string = format!("{error}");
        assert!(error_string.contains("Unsupported type"));
        assert!(error_string.contains("CustomType"));
    }

    #[test]
    fn test_unsupported_type_error_debug() {
        let error = TypeReadError::UnsupportedType {
            type_name: "TestType".to_string(),
        };

        let debug_string = format!("{error:?}");
        assert!(debug_string.contains("UnsupportedType"));
        assert!(debug_string.contains("TestType"));
    }

    #[test]
    fn test_unsupported_type_error_equality() {
        let error1 = TypeReadError::UnsupportedType {
            type_name: "Type1".to_string(),
        };
        let error2 = TypeReadError::UnsupportedType {
            type_name: "Type1".to_string(),
        };
        let error3 = TypeReadError::UnsupportedType {
            type_name: "Type2".to_string(),
        };

        assert_eq!(error1, error2);
        assert_ne!(error1, error3);
    }

    // Tests for read_typed_value function
    #[test]
    fn test_read_typed_value_byte() {
        let buffer = &[0x7f, 0x45, 0x4c, 0x46];
        let type_kind = TypeKind::Byte { signed: false };

        let result = read_typed_value(buffer, 0, &type_kind).unwrap();
        assert_eq!(result, Value::Uint(0x7f));

        let result = read_typed_value(buffer, 3, &type_kind).unwrap();
        assert_eq!(result, Value::Uint(0x46));
    }

    #[test]
    fn test_read_typed_value_short_unsigned_little_endian() {
        let buffer = &[0x34, 0x12, 0x78, 0x56];
        let type_kind = TypeKind::Short {
            endian: Endianness::Little,
            signed: false,
        };

        let result = read_typed_value(buffer, 0, &type_kind).unwrap();
        assert_eq!(result, Value::Uint(0x1234));

        let result = read_typed_value(buffer, 2, &type_kind).unwrap();
        assert_eq!(result, Value::Uint(0x5678));
    }

    #[test]
    fn test_read_typed_value_short_signed_big_endian() {
        let buffer = &[0x80, 0x00, 0x7f, 0xff];
        let type_kind = TypeKind::Short {
            endian: Endianness::Big,
            signed: true,
        };

        // 0x8000 = -32768 in signed 16-bit
        let result = read_typed_value(buffer, 0, &type_kind).unwrap();
        assert_eq!(result, Value::Int(-32768));

        // 0x7fff = 32767 in signed 16-bit
        let result = read_typed_value(buffer, 2, &type_kind).unwrap();
        assert_eq!(result, Value::Int(32767));
    }

    #[test]
    fn test_read_typed_value_long_unsigned_little_endian() {
        let buffer = &[0x78, 0x56, 0x34, 0x12, 0xbc, 0x9a, 0x78, 0x56];
        let type_kind = TypeKind::Long {
            endian: Endianness::Little,
            signed: false,
        };

        let result = read_typed_value(buffer, 0, &type_kind).unwrap();
        assert_eq!(result, Value::Uint(0x1234_5678));

        let result = read_typed_value(buffer, 4, &type_kind).unwrap();
        assert_eq!(result, Value::Uint(0x5678_9abc));
    }

    #[test]
    fn test_read_typed_value_long_signed_big_endian() {
        let buffer = &[0x80, 0x00, 0x00, 0x00, 0x7f, 0xff, 0xff, 0xff];
        let type_kind = TypeKind::Long {
            endian: Endianness::Big,
            signed: true,
        };

        // 0x80000000 = -2147483648 in signed 32-bit
        let result = read_typed_value(buffer, 0, &type_kind).unwrap();
        assert_eq!(result, Value::Int(-2_147_483_648));

        // 0x7fffffff = 2147483647 in signed 32-bit
        let result = read_typed_value(buffer, 4, &type_kind).unwrap();
        assert_eq!(result, Value::Int(2_147_483_647));
    }

    #[test]
    fn test_read_typed_value_native_endian() {
        let buffer = &[0x34, 0x12, 0x78, 0x56, 0xbc, 0x9a, 0xde, 0xf0];

        // Test short with native endianness
        let short_type = TypeKind::Short {
            endian: Endianness::Native,
            signed: false,
        };

        let result = read_typed_value(buffer, 0, &short_type).unwrap();
        match result {
            Value::Uint(val) => {
                // Should be either 0x1234 (little-endian) or 0x3412 (big-endian)
                assert!(val == 0x1234 || val == 0x3412);
            }
            _ => panic!("Expected Value::Uint variant"),
        }
    }

    #[test]
    fn test_read_typed_value_string() {
        let buffer = b"Hello\x00World\x00";
        let type_kind = TypeKind::String { max_length: None };

        let result = read_typed_value(buffer, 0, &type_kind).unwrap();
        assert_eq!(result, Value::String("Hello".to_string()));

        let result = read_typed_value(buffer, 6, &type_kind).unwrap();
        assert_eq!(result, Value::String("World".to_string()));
    }

    #[test]
    fn test_read_typed_value_string_with_max_length() {
        let buffer = b"VeryLongString\x00";
        let type_kind = TypeKind::String {
            max_length: Some(4),
        };

        let result = read_typed_value(buffer, 0, &type_kind).unwrap();
        assert_eq!(result, Value::String("Very".to_string()));
    }

    #[test]
    fn test_read_typed_value_buffer_overrun() {
        let buffer = &[0x12];
        let type_kind = TypeKind::Short {
            endian: Endianness::Little,
            signed: false,
        };

        let result = read_typed_value(buffer, 0, &type_kind);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 0,
                buffer_len: 1
            }
        );
    }

    // Tests for read_string function
    #[test]
    fn test_read_string_null_terminated() {
        let buffer = b"Hello\x00World";

        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String("Hello".to_string()));
    }

    #[test]
    fn test_read_string_null_terminated_at_offset() {
        let buffer = b"Prefix\x00Hello\x00Suffix";

        let result = read_string(buffer, 7, None).unwrap();
        assert_eq!(result, Value::String("Hello".to_string()));
    }

    #[test]
    fn test_read_string_with_max_length_shorter_than_null() {
        let buffer = b"VeryLongString\x00";

        // Max length is shorter than the null terminator position
        let result = read_string(buffer, 0, Some(4)).unwrap();
        assert_eq!(result, Value::String("Very".to_string()));
    }

    #[test]
    fn test_read_string_with_max_length_longer_than_null() {
        let buffer = b"Short\x00LongerSuffix";

        // Max length is longer than the null terminator position
        let result = read_string(buffer, 0, Some(10)).unwrap();
        assert_eq!(result, Value::String("Short".to_string()));
    }

    #[test]
    fn test_read_string_no_null_terminator_with_max_length() {
        let buffer = b"NoNullTerminator";

        // Should read up to max_length when no null terminator is found
        let result = read_string(buffer, 0, Some(6)).unwrap();
        assert_eq!(result, Value::String("NoNull".to_string()));
    }

    #[test]
    fn test_read_string_no_null_terminator_no_max_length() {
        let buffer = b"NoNullTerminator";

        // Should read entire remaining buffer when no null terminator and no max_length
        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String("NoNullTerminator".to_string()));
    }

    #[test]
    fn test_read_string_empty_string() {
        let buffer = b"\x00Hello";

        // Should return empty string when null terminator is at offset
        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String(String::new()));
    }

    #[test]
    fn test_read_string_empty_buffer() {
        let buffer = b"";

        // Should fail with buffer overrun for empty buffer
        let result = read_string(buffer, 0, None);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 0,
                buffer_len: 0
            }
        );
    }

    #[test]
    fn test_read_string_offset_out_of_bounds() {
        let buffer = b"Hello";

        // Should fail when offset is beyond buffer length
        let result = read_string(buffer, 10, None);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 10,
                buffer_len: 5
            }
        );
    }

    #[test]
    fn test_read_string_offset_at_buffer_end() {
        let buffer = b"Hello";

        // Should fail when offset equals buffer length
        let result = read_string(buffer, 5, None);
        assert!(result.is_err());
        assert_eq!(
            result.unwrap_err(),
            TypeReadError::BufferOverrun {
                offset: 5,
                buffer_len: 5
            }
        );
    }

    #[test]
    fn test_read_string_max_length_zero() {
        let buffer = b"Hello\x00World";

        // Should return empty string when max_length is 0
        let result = read_string(buffer, 0, Some(0)).unwrap();
        assert_eq!(result, Value::String(String::new()));
    }

    #[test]
    fn test_read_string_max_length_larger_than_buffer() {
        let buffer = b"Short";

        // Should read entire buffer when max_length exceeds buffer size
        let result = read_string(buffer, 0, Some(100)).unwrap();
        assert_eq!(result, Value::String("Short".to_string()));
    }

    #[test]
    fn test_read_string_utf8_valid() {
        let buffer = b"Caf\xc3\xa9\x00"; // "Café" in UTF-8

        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String("Café".to_string()));
    }

    #[test]
    fn test_read_string_utf8_invalid() {
        let buffer = b"Invalid\xff\xfe\x00"; // Invalid UTF-8 sequence

        let result = read_string(buffer, 0, None).unwrap();
        // Should use replacement characters for invalid UTF-8
        assert!(matches!(result, Value::String(_)));
        if let Value::String(s) = result {
            assert!(s.starts_with("Invalid"));
            assert!(s.contains('\u{FFFD}')); // UTF-8 replacement character
        }
    }

    #[test]
    fn test_read_string_binary_data() {
        let buffer = &[0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x00, 0x80, 0x90]; // "Hello" + binary

        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String("Hello".to_string()));
    }

    #[test]
    fn test_read_string_multiple_nulls() {
        let buffer = b"First\x00\x00Second\x00";

        // Should stop at first null terminator
        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String("First".to_string()));

        // Reading from second null should return empty string
        let result = read_string(buffer, 6, None).unwrap();
        assert_eq!(result, Value::String(String::new()));
    }

    #[test]
    fn test_read_string_ascii_control_characters() {
        let buffer = b"Hello\x09World\x00"; // Tab character in string

        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String("Hello\tWorld".to_string()));
    }

    #[test]
    fn test_read_string_single_character() {
        let buffer = b"A\x00";

        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String("A".to_string()));
    }

    #[test]
    fn test_read_string_max_length_exact_match() {
        let buffer = b"Exact\x00";

        // Max length exactly matches string length (excluding null)
        let result = read_string(buffer, 0, Some(5)).unwrap();
        assert_eq!(result, Value::String("Exact".to_string()));
    }

    #[test]
    fn test_read_string_at_buffer_boundary() {
        let buffer = b"Hello";

        // Reading from last character position
        let result = read_string(buffer, 4, Some(1)).unwrap();
        assert_eq!(result, Value::String("o".to_string()));
    }

    #[test]
    fn test_read_string_whitespace_handling() {
        let buffer = b"  Spaces  \x00";

        // Should preserve whitespace in strings
        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String("  Spaces  ".to_string()));
    }

    #[test]
    fn test_read_string_newline_characters() {
        let buffer = b"Line1\nLine2\r\n\x00";

        let result = read_string(buffer, 0, None).unwrap();
        assert_eq!(result, Value::String("Line1\nLine2\r\n".to_string()));
    }

    #[test]
    fn test_read_string_consistency_with_typed_value() {
        let buffer = b"Test\x00String";

        // Test that read_string and read_typed_value produce same results
        let direct_result = read_string(buffer, 0, None).unwrap();

        let type_kind = TypeKind::String { max_length: None };
        let typed_result = read_typed_value(buffer, 0, &type_kind).unwrap();

        assert_eq!(direct_result, typed_result);
        assert_eq!(typed_result, Value::String("Test".to_string()));
    }

    #[test]
    fn test_read_string_consistency_with_max_length() {
        let buffer = b"LongString\x00";

        // Test consistency between direct call and typed_value call with max_length
        let direct_result = read_string(buffer, 0, Some(4)).unwrap();

        let type_kind = TypeKind::String {
            max_length: Some(4),
        };
        let typed_result = read_typed_value(buffer, 0, &type_kind).unwrap();

        assert_eq!(direct_result, typed_result);
        assert_eq!(typed_result, Value::String("Long".to_string()));
    }

    #[test]
    fn test_read_string_edge_case_combinations() {
        // Test various edge case combinations
        let test_cases = [
            (b"" as &[u8], 0, None, true), // Empty buffer should fail
            (b"\x00", 0, None, false),     // Just null terminator
            (b"A", 0, Some(0), false),     // Zero max length
            (b"AB", 1, Some(1), false),    // Single char at offset
        ];

        for (buffer, offset, max_length, should_fail) in test_cases {
            let result = read_string(buffer, offset, max_length);

            if should_fail {
                assert!(
                    result.is_err(),
                    "Expected failure for buffer {buffer:?}, offset {offset}, max_length {max_length:?}"
                );
            } else {
                assert!(
                    result.is_ok(),
                    "Expected success for buffer {buffer:?}, offset {offset}, max_length {max_length:?}"
                );
            }
        }
    }
}

#[test]
fn test_read_typed_value_buffer_overrun() {
    let buffer = &[0x12, 0x34];

    // Try to read a long (4 bytes) from a 2-byte buffer
    let long_type = TypeKind::Long {
        endian: Endianness::Little,
        signed: false,
    };
    let result = read_typed_value(buffer, 0, &long_type);
    assert!(result.is_err());
    assert_eq!(
        result.unwrap_err(),
        TypeReadError::BufferOverrun {
            offset: 0,
            buffer_len: 2
        }
    );

    // Try to read a short (2 bytes) at offset 1 from a 2-byte buffer
    let short_type = TypeKind::Short {
        endian: Endianness::Little,
        signed: false,
    };
    let result = read_typed_value(buffer, 1, &short_type);
    assert!(result.is_err());
    assert_eq!(
        result.unwrap_err(),
        TypeReadError::BufferOverrun {
            offset: 1,
            buffer_len: 2
        }
    );
}

#[test]
fn test_read_typed_value_all_supported_types() {
    let buffer = &[0x7f, 0x34, 0x12, 0x78, 0x56, 0x34, 0x12, 0xbc, 0x9a];

    // Test all supported TypeKind variants
    let test_cases = vec![
        (TypeKind::Byte { signed: false }, 0, Value::Uint(0x7f)),
        (
            TypeKind::Short {
                endian: Endianness::Little,
                signed: false,
            },
            1,
            Value::Uint(0x1234), // bytes [0x34, 0x12] -> 0x1234 little-endian
        ),
        (
            TypeKind::Short {
                endian: Endianness::Big,
                signed: false,
            },
            1,
            Value::Uint(0x3412), // bytes [0x34, 0x12] -> 0x3412 big-endian
        ),
        (
            TypeKind::Long {
                endian: Endianness::Little,
                signed: false,
            },
            1,
            Value::Uint(0x5678_1234), // bytes [0x34, 0x12, 0x78, 0x56] -> 0x56781234 little-endian
        ),
        (
            TypeKind::Long {
                endian: Endianness::Big,
                signed: false,
            },
            1,
            Value::Uint(0x3412_7856), // bytes [0x34, 0x12, 0x78, 0x56] -> 0x34127856 big-endian
        ),
    ];

    for (type_kind, offset, expected) in test_cases {
        let result = read_typed_value(buffer, offset, &type_kind).unwrap();
        assert_eq!(result, expected, "Failed for type: {type_kind:?}");
    }
}

#[test]
fn test_read_typed_value_signed_vs_unsigned() {
    let buffer = &[0xff, 0xff, 0xff, 0xff, 0xff, 0xff];

    // Test signed vs unsigned interpretation for shorts
    let unsigned_short = TypeKind::Short {
        endian: Endianness::Little,
        signed: false,
    };
    let signed_short = TypeKind::Short {
        endian: Endianness::Little,
        signed: true,
    };

    let unsigned_result = read_typed_value(buffer, 0, &unsigned_short).unwrap();
    let signed_result = read_typed_value(buffer, 0, &signed_short).unwrap();

    assert_eq!(unsigned_result, Value::Uint(65535));
    assert_eq!(signed_result, Value::Int(-1));

    // Test signed vs unsigned interpretation for longs
    let unsigned_long = TypeKind::Long {
        endian: Endianness::Little,
        signed: false,
    };
    let signed_long = TypeKind::Long {
        endian: Endianness::Little,
        signed: true,
    };

    let unsigned_result = read_typed_value(buffer, 0, &unsigned_long).unwrap();
    let signed_result = read_typed_value(buffer, 0, &signed_long).unwrap();

    assert_eq!(unsigned_result, Value::Uint(4_294_967_295));
    assert_eq!(signed_result, Value::Int(-1));
}

#[test]
fn test_read_typed_value_consistency_with_direct_calls() {
    let buffer = &[0x34, 0x12, 0x78, 0x56, 0xbc, 0x9a, 0xde, 0xf0];

    // Test that read_typed_value gives same results as direct function calls
    let byte_type = TypeKind::Byte { signed: false };
    let direct_byte = read_byte(buffer, 0, false).unwrap();
    let typed_byte = read_typed_value(buffer, 0, &byte_type).unwrap();
    assert_eq!(direct_byte, typed_byte);

    let short_type = TypeKind::Short {
        endian: Endianness::Little,
        signed: false,
    };
    let direct_short = read_short(buffer, 0, Endianness::Little, false).unwrap();
    let typed_short = read_typed_value(buffer, 0, &short_type).unwrap();
    assert_eq!(direct_short, typed_short);

    let long_type = TypeKind::Long {
        endian: Endianness::Big,
        signed: true,
    };
    let direct_long = read_long(buffer, 0, Endianness::Big, true).unwrap();
    let typed_long = read_typed_value(buffer, 0, &long_type).unwrap();
    assert_eq!(direct_long, typed_long);
}

#[test]
fn test_read_typed_value_empty_buffer() {
    let buffer = &[];

    // All types should fail on empty buffer
    let types = vec![
        TypeKind::Byte { signed: false },
        TypeKind::Short {
            endian: Endianness::Little,
            signed: false,
        },
        TypeKind::Long {
            endian: Endianness::Little,
            signed: false,
        },
    ];

    for type_kind in types {
        let result = read_typed_value(buffer, 0, &type_kind);
        assert!(result.is_err());
        match result.unwrap_err() {
            TypeReadError::BufferOverrun { offset, buffer_len } => {
                assert_eq!(offset, 0);
                assert_eq!(buffer_len, 0);
            }
            TypeReadError::UnsupportedType { .. } => panic!("Expected BufferOverrun error"),
        }
    }
}

#[test]
#[allow(clippy::too_many_lines)]
fn test_coerce_value_to_type() {
    let cases = [
        // Signed byte: values above i8::MAX get coerced
        (
            Value::Uint(0xff),
            TypeKind::Byte { signed: true },
            Value::Int(-1),
        ),
        (
            Value::Uint(0x80),
            TypeKind::Byte { signed: true },
            Value::Int(-128),
        ),
        (
            Value::Uint(0xfe),
            TypeKind::Byte { signed: true },
            Value::Int(-2),
        ),
        // Signed byte: values in signed range pass through
        (
            Value::Uint(0x7f),
            TypeKind::Byte { signed: true },
            Value::Uint(0x7f),
        ),
        (
            Value::Uint(0),
            TypeKind::Byte { signed: true },
            Value::Uint(0),
        ),
        (
            Value::Uint(1),
            TypeKind::Byte { signed: true },
            Value::Uint(1),
        ),
        // Unsigned byte: all values pass through
        (
            Value::Uint(0xff),
            TypeKind::Byte { signed: false },
            Value::Uint(0xff),
        ),
        (
            Value::Uint(0x80),
            TypeKind::Byte { signed: false },
            Value::Uint(0x80),
        ),
        // Signed short: values above i16::MAX get coerced
        (
            Value::Uint(0xffff),
            TypeKind::Short {
                endian: Endianness::Native,
                signed: true,
            },
            Value::Int(-1),
        ),
        (
            Value::Uint(0x8000),
            TypeKind::Short {
                endian: Endianness::Native,
                signed: true,
            },
            Value::Int(-32768),
        ),
        (
            Value::Uint(0xffd8),
            TypeKind::Short {
                endian: Endianness::Big,
                signed: true,
            },
            Value::Int(-40),
        ),
        // Signed short: values in signed range pass through
        (
            Value::Uint(0x7fff),
            TypeKind::Short {
                endian: Endianness::Native,
                signed: true,
            },
            Value::Uint(0x7fff),
        ),
        // Unsigned short: all values pass through
        (
            Value::Uint(0xffff),
            TypeKind::Short {
                endian: Endianness::Native,
                signed: false,
            },
            Value::Uint(0xffff),
        ),
        // Signed long: values above i32::MAX get coerced
        (
            Value::Uint(0xffff_ffff),
            TypeKind::Long {
                endian: Endianness::Native,
                signed: true,
            },
            Value::Int(-1),
        ),
        (
            Value::Uint(0x8000_0000),
            TypeKind::Long {
                endian: Endianness::Native,
                signed: true,
            },
            Value::Int(-2_147_483_648),
        ),
        (
            Value::Uint(0x8950_4e47),
            TypeKind::Long {
                endian: Endianness::Big,
                signed: true,
            },
            Value::Int(-1_991_225_785),
        ),
        // Signed long: values in signed range pass through
        (
            Value::Uint(0x7fff_ffff),
            TypeKind::Long {
                endian: Endianness::Native,
                signed: true,
            },
            Value::Uint(0x7fff_ffff),
        ),
        // Unsigned long: all values pass through
        (
            Value::Uint(0xffff_ffff),
            TypeKind::Long {
                endian: Endianness::Native,
                signed: false,
            },
            Value::Uint(0xffff_ffff),
        ),
        // Non-Uint values pass through unchanged
        (
            Value::Int(-1),
            TypeKind::Byte { signed: true },
            Value::Int(-1),
        ),
        (
            Value::Int(42),
            TypeKind::Long {
                endian: Endianness::Native,
                signed: true,
            },
            Value::Int(42),
        ),
        // String type: values pass through
        (
            Value::Uint(0xff),
            TypeKind::String { max_length: None },
            Value::Uint(0xff),
        ),
    ];

    for (i, (input, type_kind, expected)) in cases.iter().enumerate() {
        let result = coerce_value_to_type(input, type_kind);
        assert_eq!(
            result, *expected,
            "Case {i}: coerce({input:?}, {type_kind:?})"
        );
    }
}