hakurei/internal/pkg/asm.go

package pkg

import (
	"encoding/binary"
	"fmt"
	"io"
	"strconv"
	"strings"
)

func Disassemble(r io.Reader, real bool, showHeader bool, force bool) (s string, err error) {
	var values [][2]string
	sb := new(strings.Builder)
	header := true
	for err == nil {
		if header {
			var kind uint64
			var size uint64
			hsb := new(strings.Builder)

			if kind, err = nextUint64(r); err != nil {
				break
			}
			if size, err = nextUint64(r); err != nil {
				break
			}
			for i := 0; uint64(i) < size; i++ {
				var did Checksum
				var dkind uint64
				if dkind, err = nextUint64(r); err != nil {
					break
				}
				if did, err = nextIdent(r); err != nil {
					break
				}

				hsb.WriteString(fmt.Sprintf("\t\t\t%s\t%s\n", intToKind(dkind), Encode(did)))
			}
			header = false
			if showHeader {
				values = append(values, [2]string{"head", fmt.Sprintf("%s [\n%s]", intToKind(kind), hsb.String())})
			}
		}
		var k uint32
		if k, err = nextUint32(r); err != nil {
			break
		}
		kind := IRValueKind(k)
		switch kind {
		case IRKindEnd:
			var a uint32
			if a, err = nextUint32(r); err != nil {
				break
			}
			if a&1 != 0 {
				var sum Checksum
				if sum, err = nextIdent(r); err != nil {
					break
				}
				values = append(values, [2]string{"end", Encode(sum)})
			} else {
				values = append(values, [2]string{"end", ""})
			}
			header = true
			continue

		case IRKindIdent:
			// discard ancillary
			if _, err = nextUint32(r); err != nil {
				break
			}
			var sum Checksum
			if sum, err = nextIdent(r); err != nil {
				break
			}

			values = append(values, [2]string{"id", Encode(sum)})
			continue
		case IRKindUint32:
			var i uint32
			if i, err = nextUint32(r); err != nil {
				break
			}
			values = append(values, [2]string{"int", strconv.FormatUint(uint64(i), 10)})
		case IRKindString:
			var l uint32
			if l, err = nextUint32(r); err != nil {
				break
			}
			s := make([]byte, l+(wordSize-(l)%wordSize)%wordSize)
			if _, err = r.Read(s); err != nil {
				break
			}
			values = append(values, [2]string{"str", fmt.Sprintf("\"%s\"", string(s[:l]))})
			continue
		default:
			var i uint32
			if i, err = nextUint32(r); err != nil {
				break
			}
			values = append(values, [2]string{fmt.Sprintf("$%x", uint32(kind)), strconv.FormatUint(uint64(i), 10)})
		}
	}
	if err != io.EOF {
		return
	}
	err = nil
	for i := 0; i < len(values); i++ {
		sb.WriteString(fmt.Sprintf("%s\t\t%s\n", values[i][0], values[i][1]))
	}
	return sb.String(), err
}
func nextUint32(r io.Reader) (uint32, error) {
	i := make([]byte, 4)
	_, err := r.Read(i)
	if err != nil {
		return 0, err
	}
	return binary.LittleEndian.Uint32(i), nil
}
func nextUint64(r io.Reader) (uint64, error) {
	i := make([]byte, 8)
	_, err := r.Read(i)
	if err != nil {
		return 0, err
	}
	return binary.LittleEndian.Uint64(i), nil
}
func nextIdent(r io.Reader) (Checksum, error) {
	i := make([]byte, 48)
	if _, err := r.Read(i); err != nil {
		return Checksum{}, err
	}
	return Checksum(i), nil
}
func intToKind(i uint64) string {
	switch Kind(i) {
	case KindHTTPGet:
		return "http_get"
	case KindTar:
		return "tar"
	case KindExec:
		return "exec"
	case KindExecNet:
		return "exec_net"
	case KindFile:
		return "file"
	default:
		return fmt.Sprintf("$%d", i-KindCustomOffset)
	}
}