Add code comments, rename tail var to b

This commit is contained in:
lash 2023-04-04 07:42:15 +01:00
parent 83fe049b15
commit 684de95198
Signed by untrusted user who does not match committer: lash
GPG Key ID: 21D2E7BB88C2A746
2 changed files with 177 additions and 152 deletions

View File

@ -196,14 +196,14 @@ func RunHalt(b []byte, st *state.State, rs resource.Resource, ctx context.Contex
return b, err
}
// RunMSize
// RunMSize executes the HALT opcode
func RunMSize(b []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
log.Printf("WARNING MSIZE not yet implemented")
_, _, b, err := ParseMSize(b)
return b, err
}
// RunMSize
// RunMNext executes the MNEXT opcode
func RunMNext(b []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
selector, display, b, err := ParseMNext(b)
if err != nil {
@ -213,7 +213,7 @@ func RunMNext(b []byte, st *state.State, rs resource.Resource, ctx context.Conte
return b, err
}
// RunMSize
// RunMPrev executes the MPREV opcode
func RunMPrev(b []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
selector, display, b, err := ParseMPrev(b)
if err != nil {
@ -223,6 +223,7 @@ func RunMPrev(b []byte, st *state.State, rs resource.Resource, ctx context.Conte
return b, err
}
// RunMOut executes the MOUT opcode
func RunMOut(b []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
choice, title, b, err := ParseMOut(b)
if err != nil {

View File

@ -7,151 +7,6 @@ import (
"git.defalsify.org/festive/state"
)
func ParseOp(b []byte) (Opcode, []byte, error) {
op, b, err := opSplit(b)
if err != nil {
return NOOP, b, err
}
return op, b, nil
}
func ParseLoad(b []byte) (string, uint32, []byte, error) {
return parseSymLen(b)
}
func ParseReload(b []byte) (string, []byte, error) {
return parseSym(b)
}
func ParseMap(b []byte) (string, []byte, error) {
return parseSym(b)
}
func ParseMove(b []byte) (string, []byte, error) {
return parseSym(b)
}
func ParseHalt(b []byte) ([]byte, error) {
return parseNoArg(b)
}
func ParseCatch(b []byte) (string, uint32, bool, []byte, error) {
return parseSymSig(b)
}
func ParseCroak(b []byte) (uint32, bool, []byte, error) {
return parseSig(b)
}
func ParseInCmp(b []byte) (string, string, []byte, error) {
return parseTwoSym(b)
}
func ParseMPrev(b []byte) (string, string, []byte, error) {
return parseTwoSym(b)
}
func ParseMNext(b []byte) (string, string, []byte, error) {
return parseTwoSym(b)
}
func ParseMSize(b []byte) (uint32, uint32, []byte, error) {
if len(b) < 2 {
return 0, 0, b, fmt.Errorf("argument too short")
}
r := uint32(b[0])
rr := uint32(b[1])
b = b[2:]
return r, rr, b, nil
}
func ParseMOut(b []byte) (string, string, []byte, error) {
return parseTwoSym(b)
}
func parseNoArg(b []byte) ([]byte, error) {
return b, nil
}
func parseSym(b []byte) (string, []byte, error) {
sym, tail, err := instructionSplit(b)
if err != nil {
return "", b, err
}
return sym, tail, nil
}
func parseTwoSym(b []byte) (string, string, []byte, error) {
symOne, tail, err := instructionSplit(b)
if err != nil {
return "", "", b, err
}
symTwo, tail, err := instructionSplit(tail)
if err != nil {
return "", "", tail, err
}
return symOne, symTwo, tail, nil
}
func parseSymLen(b []byte) (string, uint32, []byte, error) {
sym, tail, err := instructionSplit(b)
if err != nil {
return "", 0, b, err
}
sz, tail, err := intSplit(tail)
if err != nil {
return "", 0, b, err
}
return sym, sz, tail, nil
}
func parseSymSig(b []byte) (string, uint32, bool, []byte, error) {
sym, tail, err := instructionSplit(b)
if err != nil {
return "", 0, false, b, err
}
sig, tail, err := intSplit(tail)
if err != nil {
return "", 0, false, b, err
}
if len(tail) == 0 {
return "", 0, false, b, fmt.Errorf("instruction too short")
}
matchmode := tail[0] > 0
tail = tail[1:]
return sym, sig, matchmode, tail, nil
}
func parseSig(b []byte) (uint32, bool, []byte, error) {
sig, b, err := intSplit(b)
if err != nil {
return 0, false, b, err
}
if len(b) == 0 {
return 0, false, b, fmt.Errorf("instruction too short")
}
matchmode := b[0] > 0
b = b[1:]
return sig, matchmode, b, nil
}
func matchFlag(st *state.State, sig uint32, invertMatch bool) (bool, error) {
r, err := st.GetFlag(sig)
if err != nil {
return false, err
}
if invertMatch {
if !r {
return true, nil
}
} else if r {
return true, nil
}
return false, nil
}
// NewLine creates a new instruction line for the VM.
func NewLine(instructionList []byte, instruction uint16, strargs []string, byteargs []byte, numargs []uint8) []byte {
if instructionList == nil {
@ -173,6 +28,172 @@ func NewLine(instructionList []byte, instruction uint16, strargs []string, bytea
return append(instructionList, b...)
}
// ParseOp verifies and extracts the expected opcode portion of an instruction
func ParseOp(b []byte) (Opcode, []byte, error) {
op, b, err := opSplit(b)
if err != nil {
return NOOP, b, err
}
return op, b, nil
}
// ParseLoad parses and extracts the expected argument portion of a LOAD instruction
func ParseLoad(b []byte) (string, uint32, []byte, error) {
return parseSymLen(b)
}
// ParseReload parses and extracts the expected argument portion of a RELOAD instruction
func ParseReload(b []byte) (string, []byte, error) {
return parseSym(b)
}
// ParseMap parses and extracts the expected argument portion of a MAP instruction
func ParseMap(b []byte) (string, []byte, error) {
return parseSym(b)
}
// ParseMove parses and extracts the expected argument portion of a MOVE instruction
func ParseMove(b []byte) (string, []byte, error) {
return parseSym(b)
}
// ParseHalt parses and extracts the expected argument portion of a HALT instruction
func ParseHalt(b []byte) ([]byte, error) {
return parseNoArg(b)
}
// ParseCatch parses and extracts the expected argument portion of a CATCH instruction
func ParseCatch(b []byte) (string, uint32, bool, []byte, error) {
return parseSymSig(b)
}
// ParseCroak parses and extracts the expected argument portion of a CROAK instruction
func ParseCroak(b []byte) (uint32, bool, []byte, error) {
return parseSig(b)
}
// ParseInCmp parses and extracts the expected argument portion of a INCMP instruction
func ParseInCmp(b []byte) (string, string, []byte, error) {
return parseTwoSym(b)
}
// ParseMPrev parses and extracts the expected argument portion of a MPREV instruction
func ParseMPrev(b []byte) (string, string, []byte, error) {
return parseTwoSym(b)
}
// ParseMNext parses and extracts the expected argument portion of a MNEXT instruction
func ParseMNext(b []byte) (string, string, []byte, error) {
return parseTwoSym(b)
}
// ParseMSize parses and extracts the expected argument portion of a MSIZE instruction
func ParseMSize(b []byte) (uint32, uint32, []byte, error) {
if len(b) < 2 {
return 0, 0, b, fmt.Errorf("argument too short")
}
r := uint32(b[0])
rr := uint32(b[1])
b = b[2:]
return r, rr, b, nil
}
// ParseMOut parses and extracts the expected argument portion of a MOUT instruction
func ParseMOut(b []byte) (string, string, []byte, error) {
return parseTwoSym(b)
}
// noop
func parseNoArg(b []byte) ([]byte, error) {
return b, nil
}
// parse and extract two length-prefixed string values
func parseSym(b []byte) (string, []byte, error) {
sym, b, err := instructionSplit(b)
if err != nil {
return "", b, err
}
return sym, b, nil
}
// parse and extract two length-prefixed string values
func parseTwoSym(b []byte) (string, string, []byte, error) {
symOne, b, err := instructionSplit(b)
if err != nil {
return "", "", b, err
}
symTwo, b, err := instructionSplit(b)
if err != nil {
return "", "", b, err
}
return symOne, symTwo, b, nil
}
// parse and extract one length-prefixed string value, and one length-prefixed integer value
func parseSymLen(b []byte) (string, uint32, []byte, error) {
sym, b, err := instructionSplit(b)
if err != nil {
return "", 0, b, err
}
sz, b, err := intSplit(b)
if err != nil {
return "", 0, b, err
}
return sym, sz, b, nil
}
// parse and extract one length-prefixed string value, and one single byte of integer
func parseSymSig(b []byte) (string, uint32, bool, []byte, error) {
sym, b, err := instructionSplit(b)
if err != nil {
return "", 0, false, b, err
}
sig, b, err := intSplit(b)
if err != nil {
return "", 0, false, b, err
}
if len(b) == 0 {
return "", 0, false, b, fmt.Errorf("instruction too short")
}
matchmode := b[0] > 0
b = b[1:]
return sym, sig, matchmode, b, nil
}
// parse and extract one single byte of integer
func parseSig(b []byte) (uint32, bool, []byte, error) {
sig, b, err := intSplit(b)
if err != nil {
return 0, false, b, err
}
if len(b) == 0 {
return 0, false, b, fmt.Errorf("instruction too short")
}
matchmode := b[0] > 0
b = b[1:]
return sig, matchmode, b, nil
}
// TODO: move to state
func matchFlag(st *state.State, sig uint32, invertMatch bool) (bool, error) {
r, err := st.GetFlag(sig)
if err != nil {
return false, err
}
if invertMatch {
if !r {
return true, nil
}
} else if r {
return true, nil
}
return false, nil
}
// split bytecode into head and b using length-prefixed bitfield
func byteSplit(b []byte) ([]byte, []byte, error) {
bitFieldSize := b[0]
bitField := b[1:1+bitFieldSize]
@ -180,6 +201,7 @@ func byteSplit(b []byte) ([]byte, []byte, error) {
return bitField, b, nil
}
// split bytecode into head and b using length-prefixed integer
func intSplit(b []byte) (uint32, []byte, error) {
l := uint8(b[0])
sz := uint32(l)
@ -201,7 +223,7 @@ func intSplit(b []byte) (uint32, []byte, error) {
return sz, b, nil
}
// split instruction into symbol and arguments
// split bytecode into head and b using length-prefixed string
func instructionSplit(b []byte) (string, []byte, error) {
if len(b) == 0 {
return "", nil, fmt.Errorf("argument is empty")
@ -210,14 +232,15 @@ func instructionSplit(b []byte) (string, []byte, error) {
if sz == 0 {
return "", nil, fmt.Errorf("zero-length argument")
}
tailSz := uint8(len(b))
if tailSz < sz {
return "", nil, fmt.Errorf("corrupt instruction, len %v less than symbol length: %v", tailSz, sz)
bSz := uint8(len(b))
if bSz < sz {
return "", nil, fmt.Errorf("corrupt instruction, len %v less than symbol length: %v", bSz, sz)
}
r := string(b[1:1+sz])
return r, b[1+sz:], nil
}
// check if the start of the given bytecode contains a valid opcode, extract and return it
func opCheck(b []byte, opIn Opcode) ([]byte, error) {
var bb []byte
op, bb, err := opSplit(b)
@ -231,6 +254,7 @@ func opCheck(b []byte, opIn Opcode) ([]byte, error) {
return b, nil
}
// split bytecode into head and b using opcode
func opSplit(b []byte) (Opcode, []byte, error) {
l := len(b)
if l < 2 {