Struct MessageCompressor 

pub struct MessageCompressor;

Message compressor for reducing context size while preserving important content.

Implementations

impl MessageCompressor

pub fn compress_code_block(code: &str, max_lines: usize) -> String

Compress a code block by keeping head and tail lines.

When a code block exceeds max_lines, this function keeps approximately 60% of lines from the head and 40% from the tail, with an omission marker in between.

Arguments

• code - The code content to compress
• max_lines - Maximum number of lines to keep (excluding omission marker)

Returns

The compressed code string. If the code is already within limits, returns the original code unchanged.

Example

let code = (0..100).map(|i| format!("line {}", i)).collect::<Vec<_>>().join("\n");
let compressed = MessageCompressor::compress_code_block(&code, 50);
// Result: first 30 lines + omission marker + last 20 lines

pub fn extract_code_blocks(text: &str) -> Vec<CodeBlock>

Extract code blocks from markdown text.

Detects fenced code blocks (language ... ) and returns information about each block including position and language.

Arguments

• text - The markdown text to search

Returns

A vector of CodeBlock structs containing the code, language, and position information.

pub fn compress_code_blocks_in_text(text: &str, max_lines: usize) -> String

Compress all code blocks in markdown text.

Finds all code blocks and compresses those exceeding the max lines limit.

Arguments

• text - The markdown text containing code blocks
• max_lines - Maximum lines per code block

Returns

The text with compressed code blocks.

pub fn compress_tool_output(content: &str, max_chars: usize) -> String

Compress tool output by truncating with head/tail preservation.

When tool output exceeds max_chars, keeps approximately 70% from the head and 30% from the tail, with an omission marker in between.

Arguments

• content - The tool output content to compress
• max_chars - Maximum characters to keep (excluding omission marker)

Returns

The compressed content string.

pub fn extract_file_references(text: &str) -> Vec<String>

Extract file path references from text.

Detects file paths in various formats (relative, absolute, home-relative).

Arguments

• text - The text to search for file references

Returns

A vector of file path strings found in the text.

pub fn compress_message( message: &Message, config: &CompressionConfig, ) -> Message

Compress a message’s content based on configuration.

Applies compression to text content, code blocks, and tool outputs according to the provided configuration.

Arguments

• message - The message to compress
• config - Compression configuration

Returns

A new message with compressed content.

pub fn batch_compress_tool_results( messages: &[Message], max_chars: usize, ) -> Vec<Message>

Batch compress tool results in a message array.

Arguments

• messages - The messages to process
• max_chars - Maximum characters for tool output

Returns

A new vector of messages with compressed tool results.

pub fn truncate_messages( messages: &[Message], max_tokens: usize, keep_first: usize, keep_last: usize, ) -> Vec<Message>

Intelligently truncate a message array to fit within token limits.

Keeps the first N and last M messages, removing middle messages to fit within the token budget.

Arguments

• messages - The messages to truncate
• max_tokens - Maximum total tokens allowed
• keep_first - Number of messages to keep from the start
• keep_last - Number of messages to keep from the end

Returns

A truncated vector of messages fitting within the token limit.

pub fn calculate_compression_result( original: &Message, compressed: &Message, ) -> CompressionResult

Calculate compression result for a message.

pub fn compress_with_pruning( messages: &[Message], usage_ratio: f64, compression_config: &CompressionConfig, pruning_config: &PruningConfig, ) -> Vec<Message>

Apply progressive pruning to messages based on context usage.

This method combines standard compression with progressive pruning to manage context size more effectively.

Arguments

• messages - The messages to process
• usage_ratio - Current context usage ratio (0.0-1.0)
• compression_config - Configuration for standard compression
• pruning_config - Configuration for progressive pruning

Returns

A new vector of messages with both compression and pruning applied.

Example

let messages = vec![...];
let compressed = MessageCompressor::compress_with_pruning(
    &messages,
    0.4, // 40% context usage
    &CompressionConfig::default(),
    &PruningConfig::default(),
);

pub fn compress_tool_output_with_pruning( content: &str, max_chars: usize, usage_ratio: f64, pruning_config: &PruningConfig, ) -> String

Compress tool output with progressive pruning support.

This method extends the standard tool output compression with progressive pruning based on context usage.

Arguments

• content - The tool output content to compress
• max_chars - Maximum characters for standard compression
• usage_ratio - Current context usage ratio (0.0-1.0)
• pruning_config - Configuration for progressive pruning

Returns

The compressed/pruned content string.