Glacier.Grep is a native, high-performance, zero-allocation C# search engine and index for .NET 10. Built to take on ripgrep within the Glacier ecosystem, it provides aggressive hardware acceleration (SIMD), concurrent work-stealing directory scanning, and built-in support for the Model Context Protocol (MCP).
- 🚀 SIMD-Accelerated Hot Path: Utilizes hardware-accelerated set searching via .NET 10
SearchValues<byte>and auto-vectorized scanning on raw UTF-8 bytes without string conversions. - 📂 Lock-Free Directory Enumeration: Implements custom
FileSystemEnumerablechecking which evaluates file metadata (hidden status, symlinks) and ignore matches entirely on the stack before materializing path strings. - ⚙️ Advanced Ignore File Support: Evaluates rules from
.gitignore,.ignore, and.rgignorehierarchically, matchingripgrep's prioritized exclusion behavior. - ⚡ Hybrid I/O Dispatcher: Automatically routes files based on size (using zero-copy Memory-Mapped Files for >1MB and RandomAccess read into
ArrayPool<byte>for <1MB). - 🔍 Zero-Allocation Regex Matching: Leverages .NET JIT-compiled regex engines with
Regex.EnumerateMatches(ReadOnlySpan<char>)for zero heap allocation searches. - 🤖 MCP Server Support: Built-in support for the Model Context Protocol, allowing seamless integration with AI agents and tools.
To build and run Glacier.Grep, clone this repository and build using .NET 10 CLI:
dotnet build src/Glacier.Grep.Host/Glacier.Grep.Host.csproj -c ReleaseYou can run Glacier.Grep directly from the command line:
# Basic literal search
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "public class"
# Case-sensitive search with 2 lines of context in a specific directory
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "public class" --dir "C:\src\myproject" --sensitive --context 2
# Regex search restricted to C# files
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "void\s+\w+Async" --regex --globs "*.cs"
# Search hidden files, binary files, and invert the match (lines NOT containing "Oranges")
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "Oranges" --hidden --text --invert
# Limit search depth to 2 directories
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "target" --max-depth 2Glacier.Grep includes a built-in MCP (Model Context Protocol) server host, allowing you to use your search engine as a tool for AI agents (like Claude or Antigravity).
Build the host application in Release mode:
dotnet build src/Glacier.Grep.Host/Glacier.Grep.Host.csproj -c ReleaseAdd the following entry to your mcp_config.json:
{
"mcpServers": {
"glacier-grep": {
"command": "dotnet",
"args": [
"ABS_PATH_TO_REPO/src/Glacier.Grep.Host/bin/Release/net10.0/Glacier.Grep.Host.dll"
]
}
}
}search_grep: Performs a high-performance search across files in a directory.query(string, required): The search query (literal or regex).path(string, optional): Base directory to search.isRegex(boolean, optional): Treat query as regular expression.caseSensitive(boolean, optional): Perform case-sensitive match.contextLines(integer, optional): Lines of context to include around matches.fileGlobs(array of strings, optional): Filter files (e.g.["*.cs"]).searchHidden(boolean, optional): Search hidden files and folders.searchBinary(boolean, optional): Search binary files (do not skip).invertMatch(boolean, optional): Invert the match (show lines that do NOT contain the query).maxDepth(integer, optional): Maximum recursion depth for subdirectories.
Glacier.Grep is engineered in pure C# .NET 10 to saturate CPU memory bandwidth. On exact case-sensitive code symbol searches, Glacier.Grep outperforms Rust's Ripgrep by 12%, while maintaining near-parity (within 1.2x–1.5x) on complex case-insensitive searches with zero native DLL dependencies.
- Target Corpus: 590 files, 257.83 MB
- Platform: Windows x64, AMD Ryzen AI 9 HX 370
| Search Query | Match Mode | Ripgrep (Rust) | Glacier.Grep (.NET 10) | Result |
|---|---|---|---|---|
"public class" |
Case-Sensitive | 134.9 ms | 120.4 ms | 🚀 Glacier is 12% FASTER |
"ThreadIndependentReaderWriterLock" |
Case-Insensitive | 115.7 ms | 142.3 ms | ⚡ Near-Parity (within 1.23x of Rust) |
"public class" |
Case-Insensitive | 137.9 ms | 210.4 ms | 🔹 Ripgrep leads (within 1.52x of Rust) |
For files >= 1 MB, HybridIoDispatcher maps files directly from the OS page cache via file-backed MemoryMappedFile.CreateFromFile using 16 MB UTF-8 codepoint-aligned windows, avoiding swap-backed copies and multi-gigabyte regex decode buffers.
- Directory Traverser: Zero-allocation metadata filtration. Prunes ignored folders (like
.git,node_modules,bin/) and applies.gitignore,.ignore, and.rgignorerules. - Hybrid I/O Dispatcher: Chooses the fastest reading technique depending on file size.
- Search Core: Evaluates the bytes using
ReadOnlySpan<byte>and JIT vectorization. - MCP Integration: Integrates the search capabilities over standard stdio JSON-RPC.
- Genuine file-backed memory mapping & UTF-8 codepoint-safe 16 MB chunking — eliminates anonymous swap copies, multi-GB regex char[] allocations, and split UTF-8 codepoints at chunk boundaries.
- 100% Native AOT MCP Server — strongly-typed source-generated McpJsonContext JSON-RPC envelopes for initialize, ools/list, and ools/call with end-to-end tests.
- Accurate directory traversal — removed hardcoded skipping of legitimate elease/ folders and RELEASE files.
Developed by Ian Cowley and Antigravity (Google DeepMind).
This project is licensed under the MIT License - see the LICENSE file for details.
Part of the Glacier Ecosystem — high-performance, zero-allocation developer tooling and data engines natively built for modern C# and .NET 10.
- 🌐 Website & Documentation: glaciersoftware.dev
- ☕ Buy Me a Coffee: buymeacoffee.com/glaciersoftware
- ❤️ GitHub Sponsors: github.com/sponsors/ian-cowley
- 🐙 All Repositories: github.com/ian-cowley