update readme md

Author: spacemagneto

README.md

@@ -1 +1,71 @@
-# compressjson
+# compressjson: High-Performance JSON Transcoder (Zstd + Base64)
+
+## Overview
+
+The compressjson library provides a high-throughput, type-safe solution for converting Go structs to a compact, text-safe string representation and vice-versa.
+This tool is designed for low-latency, high-throughput scenarios and is ideal for:
+1. High-Speed Caching (e.g., Redis, Memcached) where decompression speed is critical for read latency. 
+2. Storage Optimization for large JSON objects in databases.
+3. Efficient Data Transfer in high-load, distributed systems.
+
+
+## Operating Pipeline
+### The encode/decode process is an optimized three-stage chain:
+
+| Step | Operation        | Library / Settings                     | Purpose                                           |
+|------|------------------|----------------------------------------|---------------------------------------------------|
+| 1    | Serialization    | `goccy/go-json`                        | Ultra-fast conversion of Go structs ↔ bytes       |
+| 2    | Compression      | `klauspost/compress/zstd` <br> `SpeedFastest` | Maximum compression/decompression speed           |
+| 3    | Encoding         | `encoding/base64` (std lib)            | Convert binary data to transport-safe ASCII string |
+
+
+# Usage
+### Installation
+```bash
+    go get github.com/spacemagneto/compressjson
+```
+
+## Example Code
+
+```go
+package main
+
+import (
+	"log"
+
+	"github.com/spacemagneto/compressjson"
+)
+
+type User struct {
+	ID   int    `json:"id"`
+	Name string `json:"name"`
+	Role string `json:"role"`
+}
+
+func main() {
+	transcoder := compressjson.NewTranscoder[[]User]()
+
+	users := []User{
+		{ID: 1, Name: "Alice", Role: "admin"},
+		{ID: 2, Name: "Bob", Role: "user"},
+		{ID: 3, Name: "Charlie", Role: "moderator"},
+	}
+
+	encoded, err := transcoder.Encode(users)
+	if err != nil {
+		log.Fatalf("encode failed: %v", err)
+	}
+
+	var decoded []User
+	decoded, err = transcoder.Decode(encoded)
+	if err != nil {
+		log.Fatalf("decode failed: %v", err)
+	}
+
+	...
+}
+```
+
+### Testing Support
+
+For users integrating and testing compressjson in various scenarios (e.g., handling specific errors, simulating compression/decompression outcomes), the repository includes a dedicated transcoder mock pkg that provides the MockTranscoder implementation. This facilitates robust unit testing and integration testing without requiring actual Zstd operations.

transcoder.go

@@ -6,7 +6,7 @@ import (
 	"github.com/spacemagneto/compressjson/lib"
 )
 
-// transcoder is a concrete, high-performance implementation of transcoder[T]
+// Transcoder is a concrete, high-performance implementation of transcoder[T]
 // designed for low-latency, high-throughput scenarios. It is safe for concurrent use
 // by multiple goroutines and reuses internal buffers and native resources across calls.
 // Call Close when the transcoder is no longer needed to free memory.