/
fbblock.go
124 lines (108 loc) · 3.11 KB
/
fbblock.go
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// Copyright (c) 2022 Adrian Siekierka
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
package internal
import (
"encoding/binary"
"fmt"
"math/bits"
"strings"
)
type RawBlockType uint8
type FBFileType uint8
const (
RawBlockUnknown RawBlockType = iota
RawBlockInfo
RawBlockData
FileTypeBasic FBFileType = 2
FileTypeBgGraphics FBFileType = 3
)
type FBFileInfo struct {
Type FBFileType
Name [16]byte
Reserved1 byte
Length uint16
LoadAddress uint16
ExecutionAddress uint16
Pad [104]byte
}
type FBFile struct {
Info FBFileInfo
Data []byte
}
func (tp FBFileType) String() string {
if tp == FileTypeBasic {
return "BASIC"
} else if tp == FileTypeBgGraphics {
return "BG-GRAPHICS"
} else {
return "Unknown"
}
}
func CalcDataChecksum(data []byte) uint16 {
ck := 0
for _, v := range data {
ck += bits.OnesCount8(v)
}
return uint16(ck)
}
func (i FBFileInfo) NameStr() string {
s := ""
for _, c := range i.Name {
if c == 0x00 {
return s
} else {
s += FBByteToString(c)
}
}
return s
}
func (i *FBFileInfo) SetName(s string) {
v, _ := FBStringToBytes(strings.ToUpper(s))
copy(i.Name[:], v)
if len(v) < 16 {
i.Name[len(v)] = 0
}
}
func (i FBFileInfo) MarshalBinary() ([]byte, error) {
buf := make([]byte, 128)
buf[0] = byte(i.Type)
copy(buf[1:17], i.Name[:])
buf[17] = byte(i.Reserved1)
binary.LittleEndian.PutUint16(buf[18:], i.Length)
binary.LittleEndian.PutUint16(buf[20:], i.LoadAddress)
binary.LittleEndian.PutUint16(buf[22:], i.ExecutionAddress)
copy(buf[24:128], i.Pad[:])
return buf, nil
}
func (i *FBFileInfo) UnmarshalBinary(buf []byte) error {
if len(buf) < 128 {
return fmt.Errorf("buffer too small: %d < 128", len(buf))
}
if buf[0] != byte(FileTypeBasic) && buf[0] != byte(FileTypeBgGraphics) {
return fmt.Errorf("unknown file type: %d", buf[0])
}
i.Type = FBFileType(buf[0])
copy(i.Name[:], buf[1:17])
i.Length = binary.LittleEndian.Uint16(buf[18:])
i.LoadAddress = binary.LittleEndian.Uint16(buf[20:])
i.ExecutionAddress = binary.LittleEndian.Uint16(buf[22:])
copy(i.Pad[:], buf[24:128])
return nil
}