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Diffstat (limited to 'gcc-4.7/libgo/go/fmt/scan.go')
| -rw-r--r-- | gcc-4.7/libgo/go/fmt/scan.go | 1164 |
1 files changed, 1164 insertions, 0 deletions
diff --git a/gcc-4.7/libgo/go/fmt/scan.go b/gcc-4.7/libgo/go/fmt/scan.go new file mode 100644 index 000000000..0b3e04069 --- /dev/null +++ b/gcc-4.7/libgo/go/fmt/scan.go @@ -0,0 +1,1164 @@ +// Copyright 2010 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package fmt + +import ( + "errors" + "io" + "math" + "os" + "reflect" + "strconv" + "unicode/utf8" +) + +// runeUnreader is the interface to something that can unread runes. +// If the object provided to Scan does not satisfy this interface, +// a local buffer will be used to back up the input, but its contents +// will be lost when Scan returns. +type runeUnreader interface { + UnreadRune() error +} + +// ScanState represents the scanner state passed to custom scanners. +// Scanners may do rune-at-a-time scanning or ask the ScanState +// to discover the next space-delimited token. +type ScanState interface { + // ReadRune reads the next rune (Unicode code point) from the input. + // If invoked during Scanln, Fscanln, or Sscanln, ReadRune() will + // return EOF after returning the first '\n' or when reading beyond + // the specified width. + ReadRune() (r rune, size int, err error) + // UnreadRune causes the next call to ReadRune to return the same rune. + UnreadRune() error + // SkipSpace skips space in the input. Newlines are treated as space + // unless the scan operation is Scanln, Fscanln or Sscanln, in which case + // a newline is treated as EOF. + SkipSpace() + // Token skips space in the input if skipSpace is true, then returns the + // run of Unicode code points c satisfying f(c). If f is nil, + // !unicode.IsSpace(c) is used; that is, the token will hold non-space + // characters. Newlines are treated as space unless the scan operation + // is Scanln, Fscanln or Sscanln, in which case a newline is treated as + // EOF. The returned slice points to shared data that may be overwritten + // by the next call to Token, a call to a Scan function using the ScanState + // as input, or when the calling Scan method returns. + Token(skipSpace bool, f func(rune) bool) (token []byte, err error) + // Width returns the value of the width option and whether it has been set. + // The unit is Unicode code points. + Width() (wid int, ok bool) + // Because ReadRune is implemented by the interface, Read should never be + // called by the scanning routines and a valid implementation of + // ScanState may choose always to return an error from Read. + Read(buf []byte) (n int, err error) +} + +// Scanner is implemented by any value that has a Scan method, which scans +// the input for the representation of a value and stores the result in the +// receiver, which must be a pointer to be useful. The Scan method is called +// for any argument to Scan, Scanf, or Scanln that implements it. +type Scanner interface { + Scan(state ScanState, verb rune) error +} + +// Scan scans text read from standard input, storing successive +// space-separated values into successive arguments. Newlines count +// as space. It returns the number of items successfully scanned. +// If that is less than the number of arguments, err will report why. +func Scan(a ...interface{}) (n int, err error) { + return Fscan(os.Stdin, a...) +} + +// Scanln is similar to Scan, but stops scanning at a newline and +// after the final item there must be a newline or EOF. +func Scanln(a ...interface{}) (n int, err error) { + return Fscanln(os.Stdin, a...) +} + +// Scanf scans text read from standard input, storing successive +// space-separated values into successive arguments as determined by +// the format. It returns the number of items successfully scanned. +func Scanf(format string, a ...interface{}) (n int, err error) { + return Fscanf(os.Stdin, format, a...) +} + +type stringReader string + +func (r *stringReader) Read(b []byte) (n int, err error) { + n = copy(b, *r) + *r = (*r)[n:] + if n == 0 { + err = io.EOF + } + return +} + +// Sscan scans the argument string, storing successive space-separated +// values into successive arguments. Newlines count as space. It +// returns the number of items successfully scanned. If that is less +// than the number of arguments, err will report why. +func Sscan(str string, a ...interface{}) (n int, err error) { + return Fscan((*stringReader)(&str), a...) +} + +// Sscanln is similar to Sscan, but stops scanning at a newline and +// after the final item there must be a newline or EOF. +func Sscanln(str string, a ...interface{}) (n int, err error) { + return Fscanln((*stringReader)(&str), a...) +} + +// Sscanf scans the argument string, storing successive space-separated +// values into successive arguments as determined by the format. It +// returns the number of items successfully parsed. +func Sscanf(str string, format string, a ...interface{}) (n int, err error) { + return Fscanf((*stringReader)(&str), format, a...) +} + +// Fscan scans text read from r, storing successive space-separated +// values into successive arguments. Newlines count as space. It +// returns the number of items successfully scanned. If that is less +// than the number of arguments, err will report why. +func Fscan(r io.Reader, a ...interface{}) (n int, err error) { + s, old := newScanState(r, true, false) + n, err = s.doScan(a) + s.free(old) + return +} + +// Fscanln is similar to Fscan, but stops scanning at a newline and +// after the final item there must be a newline or EOF. +func Fscanln(r io.Reader, a ...interface{}) (n int, err error) { + s, old := newScanState(r, false, true) + n, err = s.doScan(a) + s.free(old) + return +} + +// Fscanf scans text read from r, storing successive space-separated +// values into successive arguments as determined by the format. It +// returns the number of items successfully parsed. +func Fscanf(r io.Reader, format string, a ...interface{}) (n int, err error) { + s, old := newScanState(r, false, false) + n, err = s.doScanf(format, a) + s.free(old) + return +} + +// scanError represents an error generated by the scanning software. +// It's used as a unique signature to identify such errors when recovering. +type scanError struct { + err error +} + +const eof = -1 + +// ss is the internal implementation of ScanState. +type ss struct { + rr io.RuneReader // where to read input + buf buffer // token accumulator + peekRune rune // one-rune lookahead + prevRune rune // last rune returned by ReadRune + count int // runes consumed so far. + atEOF bool // already read EOF + ssave +} + +// ssave holds the parts of ss that need to be +// saved and restored on recursive scans. +type ssave struct { + validSave bool // is or was a part of an actual ss. + nlIsEnd bool // whether newline terminates scan + nlIsSpace bool // whether newline counts as white space + fieldLimit int // max value of ss.count for this field; fieldLimit <= limit + limit int // max value of ss.count. + maxWid int // width of this field. +} + +// The Read method is only in ScanState so that ScanState +// satisfies io.Reader. It will never be called when used as +// intended, so there is no need to make it actually work. +func (s *ss) Read(buf []byte) (n int, err error) { + return 0, errors.New("ScanState's Read should not be called. Use ReadRune") +} + +func (s *ss) ReadRune() (r rune, size int, err error) { + if s.peekRune >= 0 { + s.count++ + r = s.peekRune + size = utf8.RuneLen(r) + s.prevRune = r + s.peekRune = -1 + return + } + if s.atEOF || s.nlIsEnd && s.prevRune == '\n' || s.count >= s.fieldLimit { + err = io.EOF + return + } + + r, size, err = s.rr.ReadRune() + if err == nil { + s.count++ + s.prevRune = r + } else if err == io.EOF { + s.atEOF = true + } + return +} + +func (s *ss) Width() (wid int, ok bool) { + if s.maxWid == hugeWid { + return 0, false + } + return s.maxWid, true +} + +// The public method returns an error; this private one panics. +// If getRune reaches EOF, the return value is EOF (-1). +func (s *ss) getRune() (r rune) { + r, _, err := s.ReadRune() + if err != nil { + if err == io.EOF { + return eof + } + s.error(err) + } + return +} + +// mustReadRune turns io.EOF into a panic(io.ErrUnexpectedEOF). +// It is called in cases such as string scanning where an EOF is a +// syntax error. +func (s *ss) mustReadRune() (r rune) { + r = s.getRune() + if r == eof { + s.error(io.ErrUnexpectedEOF) + } + return +} + +func (s *ss) UnreadRune() error { + if u, ok := s.rr.(runeUnreader); ok { + u.UnreadRune() + } else { + s.peekRune = s.prevRune + } + s.prevRune = -1 + s.count-- + return nil +} + +func (s *ss) error(err error) { + panic(scanError{err}) +} + +func (s *ss) errorString(err string) { + panic(scanError{errors.New(err)}) +} + +func (s *ss) Token(skipSpace bool, f func(rune) bool) (tok []byte, err error) { + defer func() { + if e := recover(); e != nil { + if se, ok := e.(scanError); ok { + err = se.err + } else { + panic(e) + } + } + }() + if f == nil { + f = notSpace + } + s.buf = s.buf[:0] + tok = s.token(skipSpace, f) + return +} + +// space is a copy of the unicode.White_Space ranges, +// to avoid depending on package unicode. +var space = [][2]uint16{ + {0x0009, 0x000d}, + {0x0020, 0x0020}, + {0x0085, 0x0085}, + {0x00a0, 0x00a0}, + {0x1680, 0x1680}, + {0x180e, 0x180e}, + {0x2000, 0x200a}, + {0x2028, 0x2029}, + {0x202f, 0x202f}, + {0x205f, 0x205f}, + {0x3000, 0x3000}, +} + +func isSpace(r rune) bool { + if r >= 1<<16 { + return false + } + rx := uint16(r) + for _, rng := range space { + if rx < rng[0] { + return false + } + if rx <= rng[1] { + return true + } + } + return false +} + +// notSpace is the default scanning function used in Token. +func notSpace(r rune) bool { + return !isSpace(r) +} + +// skipSpace provides Scan() methods the ability to skip space and newline characters +// in keeping with the current scanning mode set by format strings and Scan()/Scanln(). +func (s *ss) SkipSpace() { + s.skipSpace(false) +} + +// readRune is a structure to enable reading UTF-8 encoded code points +// from an io.Reader. It is used if the Reader given to the scanner does +// not already implement io.RuneReader. +type readRune struct { + reader io.Reader + buf [utf8.UTFMax]byte // used only inside ReadRune + pending int // number of bytes in pendBuf; only >0 for bad UTF-8 + pendBuf [utf8.UTFMax]byte // bytes left over +} + +// readByte returns the next byte from the input, which may be +// left over from a previous read if the UTF-8 was ill-formed. +func (r *readRune) readByte() (b byte, err error) { + if r.pending > 0 { + b = r.pendBuf[0] + copy(r.pendBuf[0:], r.pendBuf[1:]) + r.pending-- + return + } + _, err = r.reader.Read(r.pendBuf[0:1]) + return r.pendBuf[0], err +} + +// unread saves the bytes for the next read. +func (r *readRune) unread(buf []byte) { + copy(r.pendBuf[r.pending:], buf) + r.pending += len(buf) +} + +// ReadRune returns the next UTF-8 encoded code point from the +// io.Reader inside r. +func (r *readRune) ReadRune() (rr rune, size int, err error) { + r.buf[0], err = r.readByte() + if err != nil { + return 0, 0, err + } + if r.buf[0] < utf8.RuneSelf { // fast check for common ASCII case + rr = rune(r.buf[0]) + return + } + var n int + for n = 1; !utf8.FullRune(r.buf[0:n]); n++ { + r.buf[n], err = r.readByte() + if err != nil { + if err == io.EOF { + err = nil + break + } + return + } + } + rr, size = utf8.DecodeRune(r.buf[0:n]) + if size < n { // an error + r.unread(r.buf[size:n]) + } + return +} + +var ssFree = newCache(func() interface{} { return new(ss) }) + +// Allocate a new ss struct or grab a cached one. +func newScanState(r io.Reader, nlIsSpace, nlIsEnd bool) (s *ss, old ssave) { + // If the reader is a *ss, then we've got a recursive + // call to Scan, so re-use the scan state. + s, ok := r.(*ss) + if ok { + old = s.ssave + s.limit = s.fieldLimit + s.nlIsEnd = nlIsEnd || s.nlIsEnd + s.nlIsSpace = nlIsSpace + return + } + + s = ssFree.get().(*ss) + if rr, ok := r.(io.RuneReader); ok { + s.rr = rr + } else { + s.rr = &readRune{reader: r} + } + s.nlIsSpace = nlIsSpace + s.nlIsEnd = nlIsEnd + s.prevRune = -1 + s.peekRune = -1 + s.atEOF = false + s.limit = hugeWid + s.fieldLimit = hugeWid + s.maxWid = hugeWid + s.validSave = true + s.count = 0 + return +} + +// Save used ss structs in ssFree; avoid an allocation per invocation. +func (s *ss) free(old ssave) { + // If it was used recursively, just restore the old state. + if old.validSave { + s.ssave = old + return + } + // Don't hold on to ss structs with large buffers. + if cap(s.buf) > 1024 { + return + } + s.buf = s.buf[:0] + s.rr = nil + ssFree.put(s) +} + +// skipSpace skips spaces and maybe newlines. +func (s *ss) skipSpace(stopAtNewline bool) { + for { + r := s.getRune() + if r == eof { + return + } + if r == '\n' { + if stopAtNewline { + break + } + if s.nlIsSpace { + continue + } + s.errorString("unexpected newline") + return + } + if !isSpace(r) { + s.UnreadRune() + break + } + } +} + +// token returns the next space-delimited string from the input. It +// skips white space. For Scanln, it stops at newlines. For Scan, +// newlines are treated as spaces. +func (s *ss) token(skipSpace bool, f func(rune) bool) []byte { + if skipSpace { + s.skipSpace(false) + } + // read until white space or newline + for { + r := s.getRune() + if r == eof { + break + } + if !f(r) { + s.UnreadRune() + break + } + s.buf.WriteRune(r) + } + return s.buf +} + +// typeError indicates that the type of the operand did not match the format +func (s *ss) typeError(field interface{}, expected string) { + s.errorString("expected field of type pointer to " + expected + "; found " + reflect.TypeOf(field).String()) +} + +var complexError = errors.New("syntax error scanning complex number") +var boolError = errors.New("syntax error scanning boolean") + +func indexRune(s string, r rune) int { + for i, c := range s { + if c == r { + return i + } + } + return -1 +} + +// consume reads the next rune in the input and reports whether it is in the ok string. +// If accept is true, it puts the character into the input token. +func (s *ss) consume(ok string, accept bool) bool { + r := s.getRune() + if r == eof { + return false + } + if indexRune(ok, r) >= 0 { + if accept { + s.buf.WriteRune(r) + } + return true + } + if r != eof && accept { + s.UnreadRune() + } + return false +} + +// peek reports whether the next character is in the ok string, without consuming it. +func (s *ss) peek(ok string) bool { + r := s.getRune() + if r != eof { + s.UnreadRune() + } + return indexRune(ok, r) >= 0 +} + +func (s *ss) notEOF() { + // Guarantee there is data to be read. + if r := s.getRune(); r == eof { + panic(io.EOF) + } + s.UnreadRune() +} + +// accept checks the next rune in the input. If it's a byte (sic) in the string, it puts it in the +// buffer and returns true. Otherwise it return false. +func (s *ss) accept(ok string) bool { + return s.consume(ok, true) +} + +// okVerb verifies that the verb is present in the list, setting s.err appropriately if not. +func (s *ss) okVerb(verb rune, okVerbs, typ string) bool { + for _, v := range okVerbs { + if v == verb { + return true + } + } + s.errorString("bad verb %" + string(verb) + " for " + typ) + return false +} + +// scanBool returns the value of the boolean represented by the next token. +func (s *ss) scanBool(verb rune) bool { + s.skipSpace(false) + s.notEOF() + if !s.okVerb(verb, "tv", "boolean") { + return false + } + // Syntax-checking a boolean is annoying. We're not fastidious about case. + switch s.getRune() { + case '0': + return false + case '1': + return true + case 't', 'T': + if s.accept("rR") && (!s.accept("uU") || !s.accept("eE")) { + s.error(boolError) + } + return true + case 'f', 'F': + if s.accept("aA") && (!s.accept("lL") || !s.accept("sS") || !s.accept("eE")) { + s.error(boolError) + } + return false + } + return false +} + +// Numerical elements +const ( + binaryDigits = "01" + octalDigits = "01234567" + decimalDigits = "0123456789" + hexadecimalDigits = "0123456789aAbBcCdDeEfF" + sign = "+-" + period = "." + exponent = "eEp" +) + +// getBase returns the numeric base represented by the verb and its digit string. +func (s *ss) getBase(verb rune) (base int, digits string) { + s.okVerb(verb, "bdoUxXv", "integer") // sets s.err + base = 10 + digits = decimalDigits + switch verb { + case 'b': + base = 2 + digits = binaryDigits + case 'o': + base = 8 + digits = octalDigits + case 'x', 'X', 'U': + base = 16 + digits = hexadecimalDigits + } + return +} + +// scanNumber returns the numerical string with specified digits starting here. +func (s *ss) scanNumber(digits string, haveDigits bool) string { + if !haveDigits { + s.notEOF() + if !s.accept(digits) { + s.errorString("expected integer") + } + } + for s.accept(digits) { + } + return string(s.buf) +} + +// scanRune returns the next rune value in the input. +func (s *ss) scanRune(bitSize int) int64 { + s.notEOF() + r := int64(s.getRune()) + n := uint(bitSize) + x := (r << (64 - n)) >> (64 - n) + if x != r { + s.errorString("overflow on character value " + string(r)) + } + return r +} + +// scanBasePrefix reports whether the integer begins with a 0 or 0x, +// and returns the base, digit string, and whether a zero was found. +// It is called only if the verb is %v. +func (s *ss) scanBasePrefix() (base int, digits string, found bool) { + if !s.peek("0") { + return 10, decimalDigits, false + } + s.accept("0") + found = true // We've put a digit into the token buffer. + // Special cases for '0' && '0x' + base, digits = 8, octalDigits + if s.peek("xX") { + s.consume("xX", false) + base, digits = 16, hexadecimalDigits + } + return +} + +// scanInt returns the value of the integer represented by the next +// token, checking for overflow. Any error is stored in s.err. +func (s *ss) scanInt(verb rune, bitSize int) int64 { + if verb == 'c' { + return s.scanRune(bitSize) + } + s.skipSpace(false) + s.notEOF() + base, digits := s.getBase(verb) + haveDigits := false + if verb == 'U' { + if !s.consume("U", false) || !s.consume("+", false) { + s.errorString("bad unicode format ") + } + } else { + s.accept(sign) // If there's a sign, it will be left in the token buffer. + if verb == 'v' { + base, digits, haveDigits = s.scanBasePrefix() + } + } + tok := s.scanNumber(digits, haveDigits) + i, err := strconv.ParseInt(tok, base, 64) + if err != nil { + s.error(err) + } + n := uint(bitSize) + x := (i << (64 - n)) >> (64 - n) + if x != i { + s.errorString("integer overflow on token " + tok) + } + return i +} + +// scanUint returns the value of the unsigned integer represented +// by the next token, checking for overflow. Any error is stored in s.err. +func (s *ss) scanUint(verb rune, bitSize int) uint64 { + if verb == 'c' { + return uint64(s.scanRune(bitSize)) + } + s.skipSpace(false) + s.notEOF() + base, digits := s.getBase(verb) + haveDigits := false + if verb == 'U' { + if !s.consume("U", false) || !s.consume("+", false) { + s.errorString("bad unicode format ") + } + } else if verb == 'v' { + base, digits, haveDigits = s.scanBasePrefix() + } + tok := s.scanNumber(digits, haveDigits) + i, err := strconv.ParseUint(tok, base, 64) + if err != nil { + s.error(err) + } + n := uint(bitSize) + x := (i << (64 - n)) >> (64 - n) + if x != i { + s.errorString("unsigned integer overflow on token " + tok) + } + return i +} + +// floatToken returns the floating-point number starting here, no longer than swid +// if the width is specified. It's not rigorous about syntax because it doesn't check that +// we have at least some digits, but Atof will do that. +func (s *ss) floatToken() string { + s.buf = s.buf[:0] + // NaN? + if s.accept("nN") && s.accept("aA") && s.accept("nN") { + return string(s.buf) + } + // leading sign? + s.accept(sign) + // Inf? + if s.accept("iI") && s.accept("nN") && s.accept("fF") { + return string(s.buf) + } + // digits? + for s.accept(decimalDigits) { + } + // decimal point? + if s.accept(period) { + // fraction? + for s.accept(decimalDigits) { + } + } + // exponent? + if s.accept(exponent) { + // leading sign? + s.accept(sign) + // digits? + for s.accept(decimalDigits) { + } + } + return string(s.buf) +} + +// complexTokens returns the real and imaginary parts of the complex number starting here. +// The number might be parenthesized and has the format (N+Ni) where N is a floating-point +// number and there are no spaces within. +func (s *ss) complexTokens() (real, imag string) { + // TODO: accept N and Ni independently? + parens := s.accept("(") + real = s.floatToken() + s.buf = s.buf[:0] + // Must now have a sign. + if !s.accept("+-") { + s.error(complexError) + } + // Sign is now in buffer + imagSign := string(s.buf) + imag = s.floatToken() + if !s.accept("i") { + s.error(complexError) + } + if parens && !s.accept(")") { + s.error(complexError) + } + return real, imagSign + imag +} + +// convertFloat converts the string to a float64value. +func (s *ss) convertFloat(str string, n int) float64 { + if p := indexRune(str, 'p'); p >= 0 { + // Atof doesn't handle power-of-2 exponents, + // but they're easy to evaluate. + f, err := strconv.ParseFloat(str[:p], n) + if err != nil { + // Put full string into error. + if e, ok := err.(*strconv.NumError); ok { + e.Num = str + } + s.error(err) + } + n, err := strconv.Atoi(str[p+1:]) + if err != nil { + // Put full string into error. + if e, ok := err.(*strconv.NumError); ok { + e.Num = str + } + s.error(err) + } + return math.Ldexp(f, n) + } + f, err := strconv.ParseFloat(str, n) + if err != nil { + s.error(err) + } + return f +} + +// convertComplex converts the next token to a complex128 value. +// The atof argument is a type-specific reader for the underlying type. +// If we're reading complex64, atof will parse float32s and convert them +// to float64's to avoid reproducing this code for each complex type. +func (s *ss) scanComplex(verb rune, n int) complex128 { + if !s.okVerb(verb, floatVerbs, "complex") { + return 0 + } + s.skipSpace(false) + s.notEOF() + sreal, simag := s.complexTokens() + real := s.convertFloat(sreal, n/2) + imag := s.convertFloat(simag, n/2) + return complex(real, imag) +} + +// convertString returns the string represented by the next input characters. +// The format of the input is determined by the verb. +func (s *ss) convertString(verb rune) (str string) { + if !s.okVerb(verb, "svqx", "string") { + return "" + } + s.skipSpace(false) + s.notEOF() + switch verb { + case 'q': + str = s.quotedString() + case 'x': + str = s.hexString() + default: + str = string(s.token(true, notSpace)) // %s and %v just return the next word + } + return +} + +// quotedString returns the double- or back-quoted string represented by the next input characters. +func (s *ss) quotedString() string { + s.notEOF() + quote := s.getRune() + switch quote { + case '`': + // Back-quoted: Anything goes until EOF or back quote. + for { + r := s.mustReadRune() + if r == quote { + break + } + s.buf.WriteRune(r) + } + return string(s.buf) + case '"': + // Double-quoted: Include the quotes and let strconv.Unquote do the backslash escapes. + s.buf.WriteRune(quote) + for { + r := s.mustReadRune() + s.buf.WriteRune(r) + if r == '\\' { + // In a legal backslash escape, no matter how long, only the character + // immediately after the escape can itself be a backslash or quote. + // Thus we only need to protect the first character after the backslash. + r := s.mustReadRune() + s.buf.WriteRune(r) + } else if r == '"' { + break + } + } + result, err := strconv.Unquote(string(s.buf)) + if err != nil { + s.error(err) + } + return result + default: + s.errorString("expected quoted string") + } + return "" +} + +// hexDigit returns the value of the hexadecimal digit +func (s *ss) hexDigit(d rune) int { + digit := int(d) + switch digit { + case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9': + return digit - '0' + case 'a', 'b', 'c', 'd', 'e', 'f': + return 10 + digit - 'a' + case 'A', 'B', 'C', 'D', 'E', 'F': + return 10 + digit - 'A' + } + s.errorString("Scan: illegal hex digit") + return 0 +} + +// hexByte returns the next hex-encoded (two-character) byte from the input. +// There must be either two hexadecimal digits or a space character in the input. +func (s *ss) hexByte() (b byte, ok bool) { + rune1 := s.getRune() + if rune1 == eof { + return + } + if isSpace(rune1) { + s.UnreadRune() + return + } + rune2 := s.mustReadRune() + return byte(s.hexDigit(rune1)<<4 | s.hexDigit(rune2)), true +} + +// hexString returns the space-delimited hexpair-encoded string. +func (s *ss) hexString() string { + s.notEOF() + for { + b, ok := s.hexByte() + if !ok { + break + } + s.buf.WriteByte(b) + } + if len(s.buf) == 0 { + s.errorString("Scan: no hex data for %x string") + return "" + } + return string(s.buf) +} + +const floatVerbs = "beEfFgGv" + +const hugeWid = 1 << 30 + +// scanOne scans a single value, deriving the scanner from the type of the argument. +func (s *ss) scanOne(verb rune, field interface{}) { + s.buf = s.buf[:0] + var err error + // If the parameter has its own Scan method, use that. + if v, ok := field.(Scanner); ok { + err = v.Scan(s, verb) + if err != nil { + if err == io.EOF { + err = io.ErrUnexpectedEOF + } + s.error(err) + } + return + } + + switch v := field.(type) { + case *bool: + *v = s.scanBool(verb) + case *complex64: + *v = complex64(s.scanComplex(verb, 64)) + case *complex128: + *v = s.scanComplex(verb, 128) + case *int: + *v = int(s.scanInt(verb, intBits)) + case *int8: + *v = int8(s.scanInt(verb, 8)) + case *int16: + *v = int16(s.scanInt(verb, 16)) + case *int32: + *v = int32(s.scanInt(verb, 32)) + case *int64: + *v = s.scanInt(verb, 64) + case *uint: + *v = uint(s.scanUint(verb, intBits)) + case *uint8: + *v = uint8(s.scanUint(verb, 8)) + case *uint16: + *v = uint16(s.scanUint(verb, 16)) + case *uint32: + *v = uint32(s.scanUint(verb, 32)) + case *uint64: + *v = s.scanUint(verb, 64) + case *uintptr: + *v = uintptr(s.scanUint(verb, uintptrBits)) + // Floats are tricky because you want to scan in the precision of the result, not + // scan in high precision and convert, in order to preserve the correct error condition. + case *float32: + if s.okVerb(verb, floatVerbs, "float32") { + s.skipSpace(false) + s.notEOF() + *v = float32(s.convertFloat(s.floatToken(), 32)) + } + case *float64: + if s.okVerb(verb, floatVerbs, "float64") { + s.skipSpace(false) + s.notEOF() + *v = s.convertFloat(s.floatToken(), 64) + } + case *string: + *v = s.convertString(verb) + case *[]byte: + // We scan to string and convert so we get a copy of the data. + // If we scanned to bytes, the slice would point at the buffer. + *v = []byte(s.convertString(verb)) + default: + val := reflect.ValueOf(v) + ptr := val + if ptr.Kind() != reflect.Ptr { + s.errorString("Scan: type not a pointer: " + val.Type().String()) + return + } + switch v := ptr.Elem(); v.Kind() { + case reflect.Bool: + v.SetBool(s.scanBool(verb)) + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + v.SetInt(s.scanInt(verb, v.Type().Bits())) + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + v.SetUint(s.scanUint(verb, v.Type().Bits())) + case reflect.String: + v.SetString(s.convertString(verb)) + case reflect.Slice: + // For now, can only handle (renamed) []byte. + typ := v.Type() + if typ.Elem().Kind() != reflect.Uint8 { + s.errorString("Scan: can't handle type: " + val.Type().String()) + } + str := s.convertString(verb) + v.Set(reflect.MakeSlice(typ, len(str), len(str))) + for i := 0; i < len(str); i++ { + v.Index(i).SetUint(uint64(str[i])) + } + case reflect.Float32, reflect.Float64: + s.skipSpace(false) + s.notEOF() + v.SetFloat(s.convertFloat(s.floatToken(), v.Type().Bits())) + case reflect.Complex64, reflect.Complex128: + v.SetComplex(s.scanComplex(verb, v.Type().Bits())) + default: + s.errorString("Scan: can't handle type: " + val.Type().String()) + } + } +} + +// errorHandler turns local panics into error returns. +func errorHandler(errp *error) { + if e := recover(); e != nil { + if se, ok := e.(scanError); ok { // catch local error + *errp = se.err + } else if eof, ok := e.(error); ok && eof == io.EOF { // out of input + *errp = eof + } else { + panic(e) + } + } +} + +// doScan does the real work for scanning without a format string. +func (s *ss) doScan(a []interface{}) (numProcessed int, err error) { + defer errorHandler(&err) + for _, field := range a { + s.scanOne('v', field) + numProcessed++ + } + // Check for newline if required. + if !s.nlIsSpace { + for { + r := s.getRune() + if r == '\n' || r == eof { + break + } + if !isSpace(r) { + s.errorString("Scan: expected newline") + break + } + } + } + return +} + +// advance determines whether the next characters in the input match +// those of the format. It returns the number of bytes (sic) consumed +// in the format. Newlines included, all runs of space characters in +// either input or format behave as a single space. This routine also +// handles the %% case. If the return value is zero, either format +// starts with a % (with no following %) or the input is empty. +// If it is negative, the input did not match the string. +func (s *ss) advance(format string) (i int) { + for i < len(format) { + fmtc, w := utf8.DecodeRuneInString(format[i:]) + if fmtc == '%' { + // %% acts like a real percent + nextc, _ := utf8.DecodeRuneInString(format[i+w:]) // will not match % if string is empty + if nextc != '%' { + return + } + i += w // skip the first % + } + sawSpace := false + for isSpace(fmtc) && i < len(format) { + sawSpace = true + i += w + fmtc, w = utf8.DecodeRuneInString(format[i:]) + } + if sawSpace { + // There was space in the format, so there should be space (EOF) + // in the input. + inputc := s.getRune() + if inputc == eof { + return + } + if !isSpace(inputc) { + // Space in format but not in input: error + s.errorString("expected space in input to match format") + } + s.skipSpace(true) + continue + } + inputc := s.mustReadRune() + if fmtc != inputc { + s.UnreadRune() + return -1 + } + i += w + } + return +} + +// doScanf does the real work when scanning with a format string. +// At the moment, it handles only pointers to basic types. +func (s *ss) doScanf(format string, a []interface{}) (numProcessed int, err error) { + defer errorHandler(&err) + end := len(format) - 1 + // We process one item per non-trivial format + for i := 0; i <= end; { + w := s.advance(format[i:]) + if w > 0 { + i += w + continue + } + // Either we failed to advance, we have a percent character, or we ran out of input. + if format[i] != '%' { + // Can't advance format. Why not? + if w < 0 { + s.errorString("input does not match format") + } + // Otherwise at EOF; "too many operands" error handled below + break + } + i++ // % is one byte + + // do we have 20 (width)? + var widPresent bool + s.maxWid, widPresent, i = parsenum(format, i, end) + if !widPresent { + s.maxWid = hugeWid + } + s.fieldLimit = s.limit + if f := s.count + s.maxWid; f < s.fieldLimit { + s.fieldLimit = f + } + + c, w := utf8.DecodeRuneInString(format[i:]) + i += w + + if numProcessed >= len(a) { // out of operands + s.errorString("too few operands for format %" + format[i-w:]) + break + } + field := a[numProcessed] + + s.scanOne(c, field) + numProcessed++ + s.fieldLimit = s.limit + } + if numProcessed < len(a) { + s.errorString("too many operands") + } + return +} |