diff --git a/core/strings/reader.odin b/core/strings/reader.odin new file mode 100644 index 000000000..1dbfe9451 --- /dev/null +++ b/core/strings/reader.odin @@ -0,0 +1,143 @@ +package strings + +import "core:io" +import "core:unicode/utf8" + +Reader :: struct { + using stream: io.Stream, + s: string, + i: i64, // current reading index + prev_rune: int, // previous reading index of rune or < 0 +} + +reader_reset :: proc(r: ^Reader, s: string) { + r.data = r; + r.s = s; + r.i = 0; + r.prev_rune = -1; +} + +new_reader :: proc(s: string, allocator := context.allocator) -> ^Reader { + r := new(Reader, allocator); + reader_reset(r, s); + r.vtable = _reader_vtable; + return r; +} + +@(private) +_reader_vtable := &io.Stream_VTable{ + impl_size = proc(s: io.Stream) -> i64 { + r := (^Reader)(s.data); + return i64(len(r.s)); + }, + impl_read = proc(s: io.Stream, p: []byte) -> (n: int, err: io.Error) { + r := (^Reader)(s.data); + if r.i >= i64(len(r.s)) { + return 0, .EOF; + } + r.prev_rune = -1; + n = copy(p, r.s[r.i:]); + r.i += i64(n); + return; + }, + impl_read_at = proc(s: io.Stream, p: []byte, off: i64) -> (n: int, err: io.Error) { + r := (^Reader)(s.data); + if off < 0 { + return 0, .Invalid_Offset; + } + if off >= i64(len(r.s)) { + return 0, .EOF; + } + n = copy(p, r.s[off:]); + if n < len(p) { + err = .EOF; + } + return; + }, + impl_read_byte = proc(s: io.Stream) -> (byte, io.Error) { + r := (^Reader)(s.data); + r.prev_rune = -1; + if r.i >= i64(len(r.s)) { + return 0, .EOF; + } + b := r.s[r.i]; + r.i += 1; + return b, nil; + }, + impl_unread_byte = proc(s: io.Stream) -> io.Error { + r := (^Reader)(s.data); + if r.i <= 0 { + return .Invalid_Unread; + } + r.prev_rune = -1; + r.i -= 1; + return nil; + }, + impl_read_rune = proc(s: io.Stream) -> (ch: rune, size: int, err: io.Error) { + r := (^Reader)(s.data); + if r.i >= i64(len(r.s)) { + r.prev_rune = -1; + return 0, 0, .EOF; + } + r.prev_rune = int(r.i); + if c := r.s[r.i]; c < utf8.RUNE_SELF { + r.i += 1; + return rune(c), 1, nil; + } + ch, size = utf8.decode_rune_in_string(r.s[r.i:]); + r.i += i64(size); + return; + }, + impl_unread_rune = proc(s: io.Stream) -> io.Error { + r := (^Reader)(s.data); + if r.i <= 0 { + return .Invalid_Unread; + } + if r.prev_rune < 0 { + return .Invalid_Unread; + } + r.i = i64(r.prev_rune); + r.prev_rune = -1; + return nil; + }, + impl_seek = proc(s: io.Stream, offset: i64, whence: io.Seek_From) -> (i64, io.Error) { + r := (^Reader)(s.data); + r.prev_rune = -1; + abs: i64; + switch whence { + case .Start: + abs = offset; + case .Current: + abs = r.i + offset; + case .End: + abs = i64(len(r.s)) + offset; + case: + return 0, .Invalid_Whence; + } + + if abs < 0 { + return 0, .Invalid_Offset; + } + r.i = abs; + return abs, nil; + }, + impl_write_to = proc(s: io.Stream, w: io.Writer) -> (n: i64, err: io.Error) { + r := (^Reader)(s.data); + r.prev_rune = -1; + if r.i >= i64(len(r.s)) { + return 0, nil; + } + s := r.s[r.i:]; + m: int; + m, err = io.write_string(w, s); + if m > len(s) { + panic("strings.Reader.write_to: invalid io.write_string count"); + } + r.i += i64(m); + n = i64(m); + if m != len(s) && err == nil { + err = .Short_Write; + } + return; + }, +};