From 77e4b066cb8d506b4bc944ab4eb2d6e4679e2202 Mon Sep 17 00:00:00 2001
From: Arda Serdar Pektezol <1669855+pektezol@users.noreply.github.com>
Date: Sat, 15 Jun 2024 13:58:30 +0300
Subject: enable multithreading with goroutines (#20)

---
 cmd/parser.go | 79 ++++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 46 insertions(+), 33 deletions(-)

(limited to 'cmd/parser.go')

diff --git a/cmd/parser.go b/cmd/parser.go
index f21d91f..06ebbfe 100644
--- a/cmd/parser.go
+++ b/cmd/parser.go
@@ -4,21 +4,17 @@ import (
 	"errors"
 	"fmt"
 	"os"
-	"strings"
+	"path/filepath"
+	"sync"
 
 	"github.com/pektezol/bitreader"
 	"github.com/pektezol/sdp.go/pkg/packets"
+	"github.com/pektezol/sdp.go/pkg/types"
 	"github.com/pektezol/sdp.go/pkg/writer"
 )
 
-type Demo struct {
-	Headers  packets.Headers   `json:"headers"`
-	Messages []packets.Message `json:"messages"`
-}
-
 type Parser struct {
 	DemoPath string
-	writer   strings.Builder
 }
 
 func NewParser(demoPath string) *Parser {
@@ -35,48 +31,61 @@ func main() {
 		os.Exit(1)
 	}
 	parser := NewParser(os.Args[1])
-	_, err := parser.ParseDemos()
+	demos, err := parser.ParseDemos()
 	if err != nil {
 		fmt.Println(err.Error())
 		os.Exit(1)
 	}
-	fmt.Println(parser.GetOutput())
-}
-
-func (p *Parser) GetOutput() string {
-	return p.writer.String()
+	for _, d := range demos {
+		fmt.Println(d.Writer.GetOutputString())
+		// You can also marshal structs into JSON and print them:
+		// out, _ := json.Marshal(d)
+		// fmt.Println(string(out))
+	}
 }
 
-func (p *Parser) ParseDemos() ([]Demo, error) {
-	writer.AppendLine("Generated By: github.com/pektezol/sdp.go")
+func (p *Parser) ParseDemos() ([]*types.Demo, error) {
 	files, err := os.ReadDir(p.DemoPath)
 	if err != nil {
 		// not a directory
 		file, err := os.Open(p.DemoPath)
 		if err != nil {
-			return []Demo{}, err
+			return []*types.Demo{}, err
 		}
 		defer file.Close()
+		demo := &types.Demo{}
+		demo.Writer = writer.NewWriter()
+		demo.Writer.AppendLine("Generated By: github.com/pektezol/sdp.go")
 		reader := bitreader.NewReader(file, littleEndian)
-		demo := demoParserHandler(reader, file.Name())
-		p.writer = writer.GetWriter()
-		return []Demo{demo}, nil
+		p.demoParserHandler(reader, file.Name(), demo, nil)
+		return []*types.Demo{demo}, nil
 	} else {
-		demos := []Demo{}
 		// directory
+		demoCount := 0
 		for _, fileinfo := range files {
 			if len(fileinfo.Name()) > 4 && fileinfo.Name()[len(fileinfo.Name())-4:] == ".dem" {
-				file, err := os.Open(p.DemoPath + fileinfo.Name())
+				demoCount++
+			}
+		}
+		wg := new(sync.WaitGroup)
+		wg.Add(demoCount)
+		demos := make([]*types.Demo, demoCount)
+		for i := 0; i < len(demos); i++ {
+			demos[i] = &types.Demo{}
+			demos[i].Writer = writer.NewWriter()
+			demos[i].Writer.AppendLine("Generated By: github.com/pektezol/sdp.go")
+		}
+		for i, fileinfo := range files {
+			if len(fileinfo.Name()) > 4 && fileinfo.Name()[len(fileinfo.Name())-4:] == ".dem" {
+				file, err := os.Open(filepath.Join(p.DemoPath, fileinfo.Name()))
 				if err != nil {
-					return []Demo{}, err
+					return []*types.Demo{}, err
 				}
 				defer file.Close()
-				reader := bitreader.NewReader(file, littleEndian)
-				demo := demoParserHandler(reader, file.Name())
-				demos = append(demos, demo)
+				go p.demoParserHandler(bitreader.NewReader(file, littleEndian), file.Name(), demos[i], wg)
 			}
 		}
-		p.writer = writer.GetWriter()
+		wg.Wait()
 		if len(demos) == 0 {
 			return demos, errors.New("no demo found in given directory")
 		}
@@ -84,23 +93,27 @@ func (p *Parser) ParseDemos() ([]Demo, error) {
 	}
 }
 
-func demoParserHandler(reader *bitreader.Reader, filename string) Demo {
-	demo := Demo{}
-	writer.AppendLine("\nFile Name: %s", filename)
+func (p *Parser) demoParserHandler(reader *bitreader.Reader, filename string, demo *types.Demo, wg *sync.WaitGroup) {
+	demo.Writer.AppendLine("\nFile Name: %s", filename)
 	// this is for recovering after a panic inside parse headers and packet.
 	// this approach was taken since error handling bitreader functions would take a long time.
 	defer func() {
 		if err := recover(); err != nil {
-			writer.AppendLine("failed to parse demo: %v", err)
+			if wg != nil {
+				wg.Done()
+			}
+			demo.Writer.AppendLine("failed to parse demo: %v", err)
 		}
 	}()
-	demo.Headers = packets.ParseHeaders(reader)
+	demo.Headers = packets.ParseHeaders(reader, demo)
 	for {
-		message := packets.ParseMessage(reader)
+		message := packets.ParseMessage(reader, demo)
 		demo.Messages = append(demo.Messages, message)
 		if message.PacketType == 7 {
+			if wg != nil {
+				wg.Done()
+			}
 			break
 		}
 	}
-	return demo
 }
-- 
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