start conversion to Go

vag.go

@@ -0,0 +1,109 @@
+package jakaudiotools
+
+import (
+	"bytes"
+	"fmt"
+)
+
+type VAGEntry struct {
+	Name string
+	Data []byte
+}
+
+func ParseVAG(vagWAD []byte, vagDict []byte, game int8) ([]VAGEntry, error) {
+	entries := []VAGEntry{}
+	separator := "VAGp"
+	dictionaryEntrySize := 12
+
+	if game != 1 {
+		separator = "pGAV"
+		dictionaryEntrySize = 16
+	}
+
+	magic := []byte(separator)
+	stereo := []byte("Stereo")
+	mono := []byte("Mono")
+
+	stereoInterleaveSize := 8192
+
+	fileStart := 0
+	firstTime := true
+	previousFileStart := 0
+	fileCount := 0
+	skipInterleave := false
+
+	vagDictLookup := processVAGDict(vagDict, dictionaryEntrySize)
+
+	for fileStart != -1 {
+		previousFileStart = fileStart
+		if firstTime {
+			location := bytes.Index(vagWAD[fileStart:], magic)
+			if location != -1 {
+				fileStart += location
+			} else {
+				fileStart = -1
+			}
+			firstTime = false
+		} else {
+			//if last time the start of a stereo file was found we can start looking for the next file starting after the interleave
+			if skipInterleave {
+				location := bytes.Index(vagWAD[fileStart+len(magic)+stereoInterleaveSize:], magic)
+				if location != -1 {
+					fileStart += len(magic) + stereoInterleaveSize + location
+				} else {
+					fileStart = -1
+				}
+				skipInterleave = false
+			} else {
+				location := bytes.Index(vagWAD[fileStart+len(magic):], magic)
+				if location != -1 {
+					fileStart += len(magic) + location
+				} else {
+					fileStart = -1
+				}
+			}
+		}
+		stereoLocation := bytes.Index(vagWAD, stereo)
+		monoLocation := bytes.Index(vagWAD, mono)
+
+		audioType := "mono"
+		if stereoLocation != -1 && (monoLocation == -1 || stereoLocation < monoLocation) {
+			audioType = "stereo"
+		}
+
+		if audioType == "stereo" && !skipInterleave {
+			skipInterleave = true
+		}
+
+		if fileStart >= 0 && fileStart != previousFileStart {
+			fileCount += 1
+			outname := fmt.Sprintf("%d", fileCount)
+			if vagDict != nil && game <= 2 {
+				if fileCount-1 >= len(vagDictLookup) {
+					return nil, fmt.Errorf("file count exceeds number of entries in VAG dict")
+				}
+				outname = vagDictLookup[fileCount-1]
+			}
+			fmt.Printf("%s file named %s found\n", audioType, outname)
+			entry := VAGEntry{
+				Name: outname,
+				Data: vagWAD[previousFileStart:fileStart],
+			}
+			entries = append(entries, entry)
+		}
+
+	}
+	return entries, nil
+}
+
+func processVAGDict(vagDict []byte, entrySize int) []string {
+	names := []string{}
+	for i := 0; i < len(vagDict); i += entrySize {
+		if i+entrySize > len(vagDict) {
+			break
+		}
+		name := string(vagDict[i+4 : i+entrySize])
+		names = append(names, name)
+	}
+	return names
+}