package gapstring import ( "bytes" "fmt" "encoding/binary" "strings" "unicode/utf16" ) // XXX: I think there's a clever way to do this with interfaces // XXX: But I'm too exhausted to figure it out. // XXX: I'll have to fix it later; it doesn't matter much for performance type chunk struct { gap int // This takes precedence over data data []byte } func (c chunk) length() int { if c.gap > 0 { return c.gap } else { return len(c.data) } } func (c chunk) missing() int { return c.gap } func (c chunk) slice(a, b int) chunk { if b > c.length() { panic("runtime error: index out of range") } if c.gap > 0 { return chunk{gap: b - a} } else { return chunk{data: c.data[a:b]} } } type GapString struct { chunks []chunk } func New() GapString { return GapString{ chunks: []chunk{}, } } func OfGap(gap int) GapString { return GapString{ chunks: []chunk{{gap: gap}}, } } func OfBytes(b []byte) GapString { return GapString{ chunks: []chunk{{data: b}}, } } func OfString(s string) GapString { return OfBytes([]byte(s)) } func (g GapString) Length() int { n := 0 for _, c := range g.chunks { n += c.length() } return n } func (g GapString) Missing() int { n := 0 for _, c := range g.chunks { n += c.missing() } return n } func (g GapString) Append(h GapString) GapString { if h.Length() > 0 { return GapString{ chunks: append(g.chunks, h.chunks...), } } else { return g } } func (g GapString) AppendGap(gap int) GapString { return g.Append(OfGap(gap)) } func (g GapString) AppendBytes(b []byte) GapString { return g.Append(OfBytes(b)) } func (g GapString) AppendString(s string) GapString { return g.Append(OfString(s)) } func (g GapString) Slice(start, end int) GapString { outchunks := make([]chunk, 0, len(g.chunks)) if end > g.Length() { panic("runtime error: slice bounds out of range") } for _, c := range g.chunks { chunklen := c.length() // Discard chunks that appear before the first if start > chunklen { start -= chunklen end -= chunklen continue } // Append chunks until we're done cend := chunklen if cend > end { cend = end } if start != cend { outchunks = append(outchunks, c.slice(start, cend)) } start = 0 end -= cend if end == 0 { break } } return GapString{chunks: outchunks} } func (g GapString) Xor(mask ...byte) GapString { ret := GapString{} pos := 0 for _, c := range g.chunks { ret = ret.AppendGap(c.gap) out := make([]byte, len(c.data)) for i, b := range c.data { m := mask[(pos+i)%len(mask)] out[i] = b ^ m } ret = ret.AppendBytes(out) pos += c.length() } return ret } func (g GapString) Bytes(fill ...byte) []byte { ret := make([]byte, g.Length()) pos := 0 for _, c := range g.chunks { // Fill in gap if len(fill) > 0 { for i := 0; i < c.gap; i += 1 { ret[pos] = fill[pos % len(fill)] pos += 1 } } // Fill in bytes for _, b := range c.data { ret[pos] = b pos += 1 } } ret = ret[0:pos] return ret } // Returns -1 if it's a gap func (g GapString) ValueAt(pos int) int { v := g.Slice(pos, pos+1) if v.chunks[0].gap > 0 { return -1 } else { return int(v.chunks[0].data[0]) } } func (g GapString) String(fill string) string { return string(g.Bytes([]byte(fill)...)) } func (g GapString) HexString() string { out := new(strings.Builder) glen := g.Length() for i := 0; i < glen; i += 1 { c := g.ValueAt(i) if c == -1 { out.WriteString("--") } else { // There's probably a faster way to do this. Do we care? fmt.Fprintf(out, "%02x", c) } if i + 1 < glen { out.WriteRune(' ') if i % 8 == 7 { out.WriteRune(' ') } } } return out.String() } var fluffych = []rune{ '·', '☺', '☻', '♥', '♦', '♣', '♠', '•', '◘', '○', '◙', '♂', '♀', '♪', '♫', '☼', '►', '◄', '↕', '‼', '¶', '§', '▬', '↨', '↑', '↓', '→', '←', '∟', '↔', '▲', '▼', ' ', '!', '"', '#', '$', '%', '&', '\'', '(', ')', '*', '+', ',', '-', '.', '/', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', ':', ';', '<', '=', '>', '?', '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '[', '\\', ']', '^', '_', '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '{', '|', '}', '~', '⌂', 'Ç', 'ü', 'é', 'â', 'ä', 'à', 'å', 'ç', 'ê', 'ë', 'è', 'ï', 'î', 'ì', 'Ä', 'Å', 'É', 'æ', 'Æ', 'ô', 'ö', 'ò', 'û', 'ù', 'ÿ', 'Ö', 'Ü', '¢', '£', '¥', '₧', 'ƒ', 'á', 'í', 'ó', 'ú', 'ñ', 'Ñ', 'ª', 'º', '¿', '⌐', '¬', '½', '¼', '¡', '«', '»', '░', '▒', '▓', '│', '┤', '╡', '╢', '╖', '╕', '╣', '║', '╗', '╝', '╜', '╛', '┐', '└', '┴', '┬', '├', '─', '┼', '╞', '╟', '╚', '╔', '╩', '╦', '╠', '═', '╬', '╧', '╨', '╤', '╥', '╙', '╘', '╒', '╓', '╫', '╪', '┘', '┌', '█', '▄', '▌', '▐', '▀', 'α', 'ß', 'Γ', 'π', 'Σ', 'σ', 'µ', 'τ', 'Φ', 'Θ', 'Ω', 'δ', '∞', 'φ', 'ε', '∩', '≡', '±', '≥', '≤', '⌠', '⌡', '÷', '≈', '°', '∀', '∃', '√', 'ⁿ', '²', '■', '¤', } func (g GapString) Runes() string { out := new(strings.Builder) glen := g.Length() for i := 0; i < glen; i += 1 { c := g.ValueAt(i) if c == -1 { out.WriteRune('�') } else { out.WriteRune(fluffych[c]) } } return out.String() } func (g GapString) Hexdump() string { out := new(strings.Builder) skipping := false glen := g.Length() pos := 0 prev := []byte{} for ; pos < glen; { // Check for repeats end := pos + 16 if end > glen { end = glen } cur := g.Slice(pos, end) curBytes := cur.Bytes() if 0 == bytes.Compare(prev, curBytes) { if ! skipping { fmt.Fprintln(out, "*") skipping = true } continue } fmt.Fprintf(out, "%08x ", pos) fmt.Fprintf(out, "%-50s", cur.HexString()) fmt.Fprintln(out, cur.Runes()) pos += cur.Length() } fmt.Fprintf(out, "%08x\n", pos) return out.String() } func (g GapString) Uint32LE() (uint32, GapString) { return binary.LittleEndian.Uint32(g.Slice(0, 4).Bytes()), g.Slice(4, g.Length()) } func (g GapString) Uint16LE() (uint16, GapString) { return binary.LittleEndian.Uint16(g.Slice(0, 2).Bytes()), g.Slice(2, g.Length()) } func (g GapString) Utf16(o binary.ByteOrder, fill string) string { in := g.Bytes([]byte(fill)...) ints := make([]uint16, len(in)/2) for i := 0; i < len(in); i += 2 { ints[i/2] = o.Uint16(in[i:]) } return string(utf16.Decode(ints)) } func (g GapString) Utf16LE(gap string) string { return g.Utf16(binary.LittleEndian, gap) } func (g GapString) Utf16BE(gap string) string { return g.Utf16(binary.BigEndian, gap) }