Struct TablesHeader 

pub struct TablesHeader<'a> {
    pub major_version: u8,
    pub minor_version: u8,
    pub valid: u64,
    pub sorted: u64,
    pub info: TableInfoRef,
    /* private fields */
}

ECMA-335 compliant metadata tables header providing efficient access to .NET assembly metadata.

The crate::metadata::streams::tablesheader::TablesHeader struct represents the compressed metadata tables stream (#~) header and provides type-safe, memory-efficient access to all metadata tables within a .NET assembly. This is the primary interface for reflection, analysis, and runtime operations on .NET metadata.

Architecture and Design

crate::metadata::streams::tablesheader::TablesHeader implements a lazy-loading design that maximizes performance while maintaining memory safety through Rust’s lifetime system:

• Lazy parsing: Table rows are parsed only when accessed
• Type safety: Generic type parameters prevent incorrect table access
• Lifetime safety: Rust borrow checker prevents dangling references
• ECMA-335 compliance: Full specification adherence for all table formats

Metadata Tables Overview

The metadata tables system contains 45 different table types defined by ECMA-335, each serving specific purposes in the .NET type system:

Core Tables (Always Present)

• Module: Assembly module identification and versioning
• TypeDef: Type definitions declared in this assembly
• MethodDef: Method definitions and IL code references
• Field: Field definitions and attributes

Reference Tables (External Dependencies)

• TypeRef: References to types in other assemblies
• MemberRef: References to methods/fields in external types
• AssemblyRef: External assembly dependencies
• ModuleRef: Multi-module assembly references

Relationship Tables (Type System Structure)

• InterfaceImpl: Interface implementation relationships
• NestedClass: Nested type parent-child relationships
• GenericParam: Generic type and method parameters
• GenericParamConstraint: Generic parameter constraints

Attribute and Metadata Tables

• CustomAttribute: Custom attribute applications
• Constant: Compile-time constant values
• DeclSecurity: Declarative security permissions
• FieldMarshal: Native interop marshalling specifications

Thread Safety and Concurrency

crate::metadata::streams::tablesheader::TablesHeader provides comprehensive thread safety for concurrent metadata access:

• Immutable data: All table data read-only after construction
• Independent access: Multiple threads can access different tables safely
• Parallel iteration: Safe concurrent processing of table rows
• No synchronization: Zero contention between concurrent operations

Examples

Basic Table Access and Type Analysis

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, TypeDefRaw, MethodDefRaw}};

let tables = TablesHeader::from(tables_data)?;

// Safe table presence checking
if tables.has_table(TableId::TypeDef) {
    let typedef_table = tables.table::<TypeDefRaw>().unwrap();
     
    println!("Assembly defines {} types", typedef_table.row_count);
     
    // Analyze type characteristics
    for (index, type_def) in typedef_table.iter().enumerate().take(10) {
        let is_public = type_def.flags & 0x00000007 == 0x00000001;
        let is_sealed = type_def.flags & 0x00000100 != 0;
        let is_abstract = type_def.flags & 0x00000080 != 0;
         
        println!("Type {}: public={}, sealed={}, abstract={}",
                 index, is_public, is_sealed, is_abstract);
    }
}

Cross-Table Relationship Analysis

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, TypeDefRaw, FieldRaw, MethodDefRaw}};

let tables = TablesHeader::from(tables_data)?;

// Analyze complete type structure with members
if let (Some(typedef_table), Some(field_table), Some(method_table)) = (
    tables.table::<TypeDefRaw>(),
    tables.table::<FieldRaw>(),
    tables.table::<MethodDefRaw>()
) {
    for (type_idx, type_def) in typedef_table.iter().enumerate().take(5) {
        // Calculate member ranges for this type
        let next_type = typedef_table.get((type_idx + 1) as u32);
         
        let field_start = type_def.field_list.saturating_sub(1);
        let field_end = next_type.as_ref()
            .map(|t| t.field_list.saturating_sub(1))
            .unwrap_or(field_table.row_count);
         
        let method_start = type_def.method_list.saturating_sub(1);
        let method_end = next_type.as_ref()
            .map(|t| t.method_list.saturating_sub(1))
            .unwrap_or(method_table.row_count);
         
        println!("Type {}: {} fields, {} methods",
                 type_idx,
                 field_end.saturating_sub(field_start),
                 method_end.saturating_sub(method_start));
    }
}

High-Performance Parallel Processing

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, CustomAttributeRaw}};
use rayon::prelude::*;
use std::collections::HashMap;

let tables = TablesHeader::from(tables_data)?;

// Parallel analysis of custom attributes
if let Some(ca_table) = tables.table::<CustomAttributeRaw>() {
    // Process attributes in parallel for large assemblies
    let attribute_analysis: HashMap<u32, u32> = ca_table.par_iter()
        .map(|attr| {
            // Extract parent table type from coded index
            let parent_table = 1u32; // Simplified for documentation
            (parent_table, 1u32)
        })
        .collect::<Vec<_>>()
        .into_iter()
        .fold(HashMap::new(), |mut acc, (table, count)| {
            *acc.entry(table).or_insert(0) += count;
            acc
        });
     
    println!("Custom attribute distribution:");
    for (table_id, count) in attribute_analysis {
        println!("  Table {}: {} attributes", table_id, count);
    }
}

Memory-Efficient Large Table Processing

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, MemberRefRaw}};

let tables = TablesHeader::from(tables_data)?;

// Process large tables without loading all data into memory
if let Some(memberref_table) = tables.table::<MemberRefRaw>() {
    const CHUNK_SIZE: u32 = 1000;
    let total_rows = memberref_table.row_count;
     
    println!("Processing {} member references in {} chunks",
             total_rows, (total_rows + CHUNK_SIZE - 1) / CHUNK_SIZE);
     
    let mut external_method_refs = 0;
    let mut external_field_refs = 0;
     
    // Process in chunks to manage memory usage
    for chunk_start in (0..total_rows).step_by(CHUNK_SIZE as usize) {
        let chunk_end = (chunk_start + CHUNK_SIZE).min(total_rows);
         
        for i in chunk_start..chunk_end {
            if let Some(member_ref) = memberref_table.get(i) {
                // Analyze member reference type and parent
                let is_method = true; // Simplified: check signature
                let is_external = true; // Simplified: check class reference
                 
                if is_external {
                    if is_method {
                        external_method_refs += 1;
                    } else {
                        external_field_refs += 1;
                    }
                }
            }
        }
    }
     
    println!("External references: {} methods, {} fields",
             external_method_refs, external_field_refs);
}

Complete Assembly Introspection

use dotscope::metadata::{streams::TablesHeader, tables::TableId};

let tables = TablesHeader::from(tables_data)?;

println!("Assembly Metadata Analysis");
println!("=========================");
println!("Total tables: {}", tables.table_count());
println!();

// Analyze present tables and their characteristics
let summaries = tables.table_summary();
for summary in summaries {
    match summary.table_id {
        TableId::TypeDef => println!("✓ {} type definitions", summary.row_count),
        TableId::MethodDef => println!("✓ {} method definitions", summary.row_count),
        TableId::Field => println!("✓ {} field definitions", summary.row_count),
        TableId::Assembly => println!("✓ Assembly metadata present"),
        TableId::AssemblyRef => println!("✓ {} assembly references", summary.row_count),
        TableId::CustomAttribute => println!("✓ {} custom attributes", summary.row_count),
        TableId::GenericParam => println!("✓ {} generic parameters (generics used)", summary.row_count),
        TableId::DeclSecurity => println!("✓ {} security declarations", summary.row_count),
        TableId::ManifestResource => println!("✓ {} embedded resources", summary.row_count),
        _ => println!("✓ {:?}: {} rows", summary.table_id, summary.row_count),
    }
}

// Feature detection
println!();
println!("Assembly Features:");
if tables.has_table(TableId::GenericParam) {
    println!("  ✓ Uses generic types/methods");
}
if tables.has_table(TableId::Event) {
    println!("  ✓ Defines events");
}
if tables.has_table(TableId::Property) {
    println!("  ✓ Defines properties");
}
if tables.has_table(TableId::DeclSecurity) {
    println!("  ✓ Has security declarations");
}
if tables.has_table(TableId::ImplMap) {
    println!("  ✓ Uses P/Invoke");
}

Security Considerations

Input Validation

• ECMA-335 compliance: Strict adherence to specification format requirements
• Bounds checking: All table and row access validated against buffer boundaries
• Index validation: Cross-table references verified for correctness
• Size limits: Reasonable limits prevent resource exhaustion attacks

Memory Safety

• Lifetime enforcement: Rust borrow checker prevents use-after-free vulnerabilities
• Type safety: Generic parameters prevent incorrect table type access
• Bounds verification: All array and slice access is bounds-checked
• Controlled unsafe: Minimal unsafe code with careful pointer management

ECMA-335 Compliance

This implementation fully complies with ECMA-335 Partition II specifications:

• Section II.24.2.6: Metadata tables stream format and binary layout
• Section II.22: Complete metadata table definitions and relationships
• Compression format: Proper variable-width encoding for table indices
• Heap integration: Correct interpretation of string, blob, and GUID heap references

See Also

• crate::metadata::tables::MetadataTable: Individual table access and iteration
• crate::metadata::tables::TableId: Enumeration of all supported table types
• crate::metadata::streams: Overview of all metadata stream types
• ECMA-335 II.24.2.6: Tables header specification

Efficient Table Access Examples

Basic Table Access

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, TypeDefRaw, MethodDefRaw, FieldRaw}};

// Check if a table is present before accessing it
if tables_header.has_table(TableId::TypeDef) {
    // Get efficient access to the TypeDef table
    if let Some(typedef_table) = tables_header.table::<TypeDefRaw>() {
        println!("TypeDef table has {} rows", typedef_table.row_count);
         
        // Access individual rows by index (0-based)
        if let Some(first_type) = typedef_table.get(0) {
            println!("First type: flags={}, name_idx={}, namespace_idx={}",
                    first_type.flags, first_type.type_name, first_type.type_namespace);
        }
    }
}

Iterating Over Table Rows

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, MethodDefRaw}};

// Iterate over all methods in the assembly
if let Some(method_table) = tables_header.table::<MethodDefRaw>() {
    for (index, method) in method_table.iter().enumerate() {
        println!("Method {}: RVA={:#x}, impl_flags={}, flags={}, name_idx={}",
                index, method.rva, method.impl_flags, method.flags, method.name);
         
        // Break after first 10 for demonstration
        if index >= 9 { break; }
    }
}

Parallel Processing with Rayon

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, FieldRaw}};
use rayon::prelude::*;

// Process field metadata in parallel
if let Some(field_table) = tables_header.table::<FieldRaw>() {
    let field_count = field_table.par_iter()
        .filter(|field| field.flags & 0x0010 != 0) // FieldAttributes.Static
        .count();
     
    println!("Found {} static fields", field_count);
}

Cross-Table Analysis

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, TypeDefRaw, MethodDefRaw}};

// Analyze types and their methods together
if let (Some(typedef_table), Some(method_table)) = (
    tables_header.table::<TypeDefRaw>(),
    tables_header.table::<MethodDefRaw>()
) {
    for (type_idx, type_def) in typedef_table.iter().enumerate().take(5) {
        println!("Type {}: methods {}-{}",
                type_idx, type_def.method_list,
                type_def.method_list.saturating_add(10)); // Simplified example
         
        // In real usage, you'd calculate the actual method range
        // by looking at the next type's method_list or using table bounds
    }
}

Working with Table Summaries

use dotscope::metadata::streams::TablesHeader;

// Get overview of all present tables
let summaries = tables_header.table_summary();

for summary in summaries {
    println!("Table {:?}: {} rows", summary.table_id, summary.row_count);
}

// Check for specific tables by ID
if tables_header.has_table_by_id(0x02) { // TypeDef table ID
    println!("TypeDef table is present");
}

println!("Total metadata tables: {}", tables_header.table_count());

Memory-Efficient Pattern

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, CustomAttributeRaw}};

// Process large tables without loading all data at once
if let Some(ca_table) = tables_header.table::<CustomAttributeRaw>() {
    println!("Processing {} custom attributes", ca_table.row_count);
     
    // Process in chunks to manage memory usage
    const CHUNK_SIZE: u32 = 100;
    let total_rows = ca_table.row_count;
     
    for chunk_start in (0..total_rows).step_by(CHUNK_SIZE as usize) {
        let chunk_end = (chunk_start + CHUNK_SIZE).min(total_rows);
         
        for i in chunk_start..chunk_end {
            if let Some(attr) = ca_table.get(i) {
                // Process individual custom attribute
                // attr.parent, attr.type_def, attr.value are available
                // without copying the entire table into memory
            }
        }
         
        // Optional: yield control or log progress
        println!("Processed chunk {}-{}", chunk_start, chunk_end);
    }
}

Reference

• ‘https://ecma-international.org/wp-content/uploads/ECMA-335_6th_edition_june_2012.pdf’ - II.24.2.6 && II.22

Fields

major_version: u8

Major version of the metadata table schema, must be 2 per ECMA-335.

This field indicates the major version of the metadata table format. According to ECMA-335 Section II.24.2.6, this value must be 2 for all compliant .NET assemblies. Different major versions would indicate incompatible changes to the table format.

minor_version: u8

Minor version of the metadata table schema, must be 0 per ECMA-335.

This field indicates the minor version of the metadata table format. The ECMA-335 specification requires this value to be 0. Minor version changes would indicate backward-compatible additions to the table format.

valid: u64

Bit vector indicating which of the 64 possible metadata tables are present.

Each bit corresponds to a specific table ID (0-63) as defined in ECMA-335. A set bit (1) indicates the corresponding table is present and contains data. The number of set bits determines how many row count entries follow in the header.

Table ID Mapping

• Bit 0: Module table
• Bit 1: TypeRef table
• Bit 2: TypeDef table
• Bit 4: Field table
• Bit 6: MethodDef table
• … (see ECMA-335 II.22 for complete mapping)

sorted: u64

Bit vector indicating which metadata tables are sorted.

For each present table (indicated by valid), the corresponding bit in sorted indicates whether that table’s rows are sorted according to ECMA-335 requirements. Some tables must be sorted for binary search operations, while others may be unsorted for faster insertion during metadata generation.

info: TableInfoRef

Shared table information containing row counts and heap index sizes.

This reference-counted structure provides efficient access to table metadata including row counts for each present table and the size encoding for heap indices (strings, blobs, GUIDs). The Arc allows multiple table instances to share this information without duplication.

Implementations

impl<'a> TablesHeader<'a>

pub fn from(data: &'a [u8]) -> Result<TablesHeader<'a>>

Parse and construct a metadata tables header from binary data.

Creates a crate::metadata::streams::tablesheader::TablesHeader by parsing the compressed metadata tables stream (#~) according to ECMA-335 Section II.24.2.6. This method performs comprehensive validation of the stream format and constructs efficient access structures for all present metadata tables.

Binary Format Parsed

The method parses the following header structure:

Offset | Size | Field              | Description
-------|------|--------------------|-----------------------------------------
0      | 4    | Reserved           | Must be 0x00000000
4      | 1    | MajorVersion       | Schema major version (must be 2)
5      | 1    | MinorVersion       | Schema minor version (must be 0)
6      | 1    | HeapSizes          | String/Blob/GUID heap index sizes
7      | 1    | Reserved           | Must be 0x01
8      | 8    | Valid              | Bit vector of present tables
16     | 8    | Sorted             | Bit vector of sorted tables
24     | 4*N  | Rows[]             | Row counts for each present table
24+4*N | Var  | TableData[]        | Binary table data

Validation Performed

The method enforces ECMA-335 compliance through comprehensive validation:

• Minimum size: Data must contain complete header (≥24 bytes)
• Version checking: Major version must be 2, minor version must be 0
• Table presence: At least one table must be present (valid ≠ 0)
• Format integrity: Row count array and table data must be accessible
• Table structure: Each present table validated for proper format

Construction Process

1. Header parsing: Extract version, heap sizes, and table bit vectors
2. Row count extraction: Read row counts for all present tables
3. Table initialization: Parse each present table’s binary data
4. Reference setup: Establish efficient access structures
5. Validation: Verify all tables conform to ECMA-335 format

Arguments

• data - Complete binary data of the compressed metadata tables stream

Returns

• Ok(TablesHeader) - Successfully parsed and validated tables header
• Err(Error) - Parsing failed due to format violations or insufficient data

Errors

Returns crate::Error in the following cases:

• crate::Error::OutOfBounds: Data too short for complete header (< 24 bytes)
• Malformed data: No valid tables present (all bits in valid are 0)
• Version error: Unsupported major/minor version combination
• Format error: Invalid table data or corrupted stream structure
• Table error: Individual table parsing failures due to malformed data

Examples

Basic Tables Header Construction

use dotscope::metadata::streams::TablesHeader;

// Read compressed metadata tables stream from assembly
let tables_stream_data = &[/* binary data from #~ stream */];

let tables = TablesHeader::from(tables_stream_data)?;

// Verify successful construction
println!("Parsed metadata with {} tables", tables.table_count());
println!("Schema version: {}.{}", tables.major_version, tables.minor_version);

// Check for common tables
use dotscope::metadata::tables::TableId;
if tables.has_table(TableId::TypeDef) {
    println!("Assembly defines {} types", tables.table_row_count(TableId::TypeDef));
}
if tables.has_table(TableId::MethodDef) {
    println!("Assembly defines {} methods", tables.table_row_count(TableId::MethodDef));
}

Error Handling and Validation

use dotscope::metadata::streams::TablesHeader;

// Error: Data too short
let too_short = [0u8; 20]; // Only 20 bytes, need at least 24
assert!(TablesHeader::from(&too_short).is_err());

// Error: No valid tables
let no_tables = [
    0x00, 0x00, 0x00, 0x00, // Reserved
    0x02, 0x00,             // Version 2.0
    0x01, 0x01,             // HeapSizes, Reserved
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // Valid = 0 (no tables)
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // Sorted
];
assert!(TablesHeader::from(&no_tables).is_err());

Large Assembly Processing

use dotscope::metadata::streams::TablesHeader;

// Process large assembly with many tables
let large_assembly_data = &[/* large assembly #~ stream data */];

let start_time = std::time::Instant::now();
let tables = TablesHeader::from(large_assembly_data)?;
let parse_time = start_time.elapsed();

println!("Parsed {} tables in {:?}", tables.table_count(), parse_time);

// Analyze assembly size and complexity
let summaries = tables.table_summary();
let total_rows: u32 = summaries.iter().map(|s| s.row_count).sum();

println!("Assembly complexity:");
println!("  Total metadata rows: {}", total_rows);
println!("  Average rows per table: {:.1}",
         total_rows as f64 / tables.table_count() as f64);

// Identify the most complex tables
let mut large_tables: Vec<_> = summaries.iter()
    .filter(|s| s.row_count > 1000)
    .collect();
large_tables.sort_by_key(|s| std::cmp::Reverse(s.row_count));

println!("Largest tables:");
for summary in large_tables.iter().take(3) {
    println!("  {:?}: {} rows", summary.table_id, summary.row_count);
}

Assembly Feature Detection

use dotscope::metadata::{streams::TablesHeader, tables::TableId};

let assembly_data = &[/* assembly #~ stream data */];
let tables = TablesHeader::from(assembly_data)?;

println!("Assembly Feature Analysis:");
println!("=========================");

// Detect .NET framework features
if tables.has_table(TableId::GenericParam) {
    let generic_count = tables.table_row_count(TableId::GenericParam);
    println!("✓ Uses generics ({} parameters)", generic_count);
}

if tables.has_table(TableId::Event) {
    let event_count = tables.table_row_count(TableId::Event);
    println!("✓ Defines events ({} events)", event_count);
}

if tables.has_table(TableId::Property) {
    let prop_count = tables.table_row_count(TableId::Property);
    println!("✓ Defines properties ({} properties)", prop_count);
}

if tables.has_table(TableId::DeclSecurity) {
    let security_count = tables.table_row_count(TableId::DeclSecurity);
    println!("✓ Has security declarations ({} declarations)", security_count);
}

if tables.has_table(TableId::ImplMap) {
    let pinvoke_count = tables.table_row_count(TableId::ImplMap);
    println!("✓ Uses P/Invoke ({} mappings)", pinvoke_count);
}

if tables.has_table(TableId::ManifestResource) {
    let resource_count = tables.table_row_count(TableId::ManifestResource);
    println!("✓ Embeds resources ({} resources)", resource_count);
}

Thread Safety

Construction is thread-safe when called with different data sources. The resulting crate::metadata::streams::tablesheader::TablesHeader instance is immutable and safe for concurrent access across multiple threads.

ECMA-335 Compliance

This method implements full ECMA-335 Partition II compliance:

• Section II.24.2.6: Metadata tables stream header format
• Section II.22: Individual table format specifications
• Compression format: Variable-width index encoding based on heap sizes
• Table relationships: Proper handling of cross-table references

See Also

• TablesHeader::table: Access individual metadata tables after construction
• TablesHeader::table_summary: Get overview of all present tables
• crate::metadata::tables::TableInfo: Table metadata and row count information
• ECMA-335 II.24.2.6: Tables header specification

pub fn table_count(&self) -> u32

Get the total number of metadata tables present in this assembly.

Returns the count of tables that are actually present and contain data. This is equivalent to the number of set bits in the valid field.

Examples

use dotscope::metadata::streams::TablesHeader;

println!("Assembly contains {} metadata tables", tables.table_count());

Thread Safety

This method is thread-safe and can be called concurrently from multiple threads.

pub fn table<T: RowReadable>(&'a self) -> Option<&'a MetadataTable<'a, T>>

where Self: TableAccess<'a, T>,

Get a specific table for efficient access to metadata table rows.

This method provides safe, type-driven access to metadata tables without copying data. The returned table reference allows efficient iteration and random access to rows. The table type is automatically determined from the generic parameter, eliminating the need to specify table IDs and preventing type mismatches.

Type Parameter

• T - The table row type (e.g., crate::metadata::tables::TypeDefRaw) The table ID is automatically inferred from the type parameter.

Returns

• Some(&MetadataTable<T>) - Reference to the crate::metadata::tables::MetadataTable if present
• None - If the table is not present in this assembly

Examples

use dotscope::metadata::{streams::TablesHeader, tables::TypeDefRaw};

// Safe, ergonomic access with automatic type inference
if let Some(typedef_table) = tables.table::<TypeDefRaw>() {
    // Efficient access to all type definitions
    for type_def in typedef_table.iter().take(5) {
        println!("Type: flags={:#x}, name_idx={}, namespace_idx={}",
                type_def.flags, type_def.type_name, type_def.type_namespace);
    }
     
    // Random access to specific rows
    if let Some(first_type) = typedef_table.get(0) {
        println!("First type name index: {}", first_type.type_name);
    }
}

Thread Safety

This method is thread-safe and can be called concurrently from multiple threads. The returned table reference is also safe for concurrent read access.

Implementation Details

This method uses a trait to provide safe, compile-time verified table access. The trait implementation automatically maps each table type to its corresponding table ID, ensuring type safety without runtime overhead. No unsafe code is required.

pub fn has_table(&self, table_id: TableId) -> bool

Check if a specific metadata table is present in this assembly.

Use this method to safely check for table presence before accessing it. This avoids potential panics when working with assemblies that may not contain all possible metadata tables.

Arguments

• table_id - The crate::metadata::tables::TableId to check for presence

Examples

use dotscope::metadata::{streams::TablesHeader, tables::{TableId, EventRaw}};

/// Safe pattern: check before access
if tables.has_table(TableId::Event) {
    if let Some(event_table) = tables.table::<EventRaw>() {
        println!("Assembly has {} events", event_table.row_count);
    }
} else {
    println!("No events defined in this assembly");
}

Thread Safety

This method is thread-safe and can be called concurrently from multiple threads.

pub fn has_table_by_id(&self, table_id: u8) -> bool

Check if a metadata table is present by its numeric ID.

This method provides a way to check for table presence using the raw numeric table identifiers (0-63) as defined in the ECMA-335 specification.

Arguments

• table_id - The numeric table ID (0-63) to check for presence

Returns

• true - If the table is present
• false - If the table is not present or table_id > 63

Examples

use dotscope::metadata::streams::TablesHeader;

// Check for specific tables by their numeric IDs
if tables.has_table_by_id(0x02) { // TypeDef
    println!("TypeDef table present");
}
if tables.has_table_by_id(0x06) { // MethodDef  
    println!("MethodDef table present");
}
if tables.has_table_by_id(0x04) { // Field
    println!("Field table present");
}

Thread Safety

This method is thread-safe and can be called concurrently from multiple threads.

pub fn present_tables(&self) -> impl Iterator<Item = TableId> + '_

Get an iterator over all present metadata tables.

This method returns an iterator that yields crate::metadata::tables::TableId values for all tables that are present in this assembly’s metadata. Useful for discovering what metadata is available without having to check each table individually.

Examples

use dotscope::metadata::streams::TablesHeader;

println!("Present metadata tables:");
for table_id in tables.present_tables() {
    let row_count = tables.table_row_count(table_id);
    println!("  {:?}: {} rows", table_id, row_count);
}

Thread Safety

This method is thread-safe and can be called concurrently from multiple threads.

pub fn table_row_count(&self, table_id: TableId) -> u32

Get the row count for a specific metadata table.

Returns the number of rows in the specified table. This information is available even if you don’t access the table data itself.

Arguments

• table_id - The crate::metadata::tables::TableId to get the row count for

Returns

Row count (0 if table is not present)

Examples

use dotscope::metadata::{streams::TablesHeader, tables::TableId};

let type_count = tables.table_row_count(TableId::TypeDef);
let method_count = tables.table_row_count(TableId::MethodDef);
let field_count = tables.table_row_count(TableId::Field);

println!("Assembly contains:");
println!("  {} types", type_count);
println!("  {} methods", method_count);
println!("  {} fields", field_count);

Thread Safety

This method is thread-safe and can be called concurrently from multiple threads.

pub fn table_summary(&self) -> Vec<TableSummary>

Get a summary of all present metadata tables with their row counts.

Returns a vector of summary structs containing the table ID and row count for each table present in this assembly. This provides an efficient way to get an overview of the assembly’s metadata structure without accessing individual tables.

Examples

use dotscope::metadata::streams::TablesHeader;

let summaries = tables.table_summary();
for summary in summaries {
    println!("Table {:?}: {} rows", summary.table_id, summary.row_count);
}

Thread Safety

This method is thread-safe and can be called concurrently from multiple threads.

pub fn write_header_to<W: Write>(&self, writer: &mut W) -> Result<()>

Writes the tables stream header to a writer in ECMA-335 binary format.

Serializes the tables stream header including version info, heap sizes, valid/sorted table bitmasks, and row counts for present tables according to ECMA-335 Section II.24.2.6.

Note: This method writes only the header, not the actual table row data. Table row data should be written separately using the RowWritable implementations.

Binary Format Written

Offset | Size | Field        | Description
-------|------|--------------|----------------------------------
0      | 4    | Reserved     | Must be 0x00000000
4      | 1    | MajorVersion | Schema major version (2)
5      | 1    | MinorVersion | Schema minor version (0)
6      | 1    | HeapSizes    | Heap index size flags
7      | 1    | Reserved     | Must be 0x01
8      | 8    | Valid        | Bit vector of present tables
16     | 8    | Sorted       | Bit vector of sorted tables
24     | 4*N  | Rows[]       | Row counts for each present table

Arguments

• writer - Any type implementing std::io::Write

Returns

• Ok(()) - Header written successfully
• Err(Error) - Write operation failed

Errors

Returns an error if writing to the writer fails.

Examples

use dotscope::metadata::streams::TablesHeader;

let mut buffer = Vec::new();
tables.write_header_to(&mut buffer)?;

// Buffer now contains the serialized tables stream header
println!("Header size: {} bytes", buffer.len());

pub fn header_size(&self) -> usize

Returns the serialized size of the tables stream header in bytes.

The size includes the fixed header fields (24 bytes) plus 4 bytes for each present table’s row count.

Returns

The total size in bytes when written with write_header_to.

Examples

use dotscope::metadata::streams::TablesHeader;

let header_size = tables.header_size();
println!("Tables stream header: {} bytes", header_size);