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Diffstat (limited to 'vendor/modernc.org/token/position.go')
-rw-r--r-- | vendor/modernc.org/token/position.go | 359 |
1 files changed, 0 insertions, 359 deletions
diff --git a/vendor/modernc.org/token/position.go b/vendor/modernc.org/token/position.go deleted file mode 100644 index 57895ad6e..000000000 --- a/vendor/modernc.org/token/position.go +++ /dev/null @@ -1,359 +0,0 @@ -// 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 token is variant of the stdlib package token with types FileSet and -// Token removed. -package token // import "modernc.org/token" - -import ( - "fmt" - "sort" -) - -// ----------------------------------------------------------------------------- -// Positions - -// Position describes an arbitrary source position -// including the file, line, and column location. -// A Position is valid if the line number is > 0. -type Position struct { - Filename string // filename, if any - Offset int // offset, starting at 0 - Line int // line number, starting at 1 - Column int // column number, starting at 1 (byte count) -} - -// IsValid reports whether the position is valid. -func (pos *Position) IsValid() bool { return pos.Line > 0 } - -// String returns a string in one of several forms: -// -// file:line:column valid position with file name -// file:line valid position with file name but no column (column == 0) -// line:column valid position without file name -// line valid position without file name and no column (column == 0) -// file invalid position with file name -// - invalid position without file name -func (pos Position) String() string { - s := pos.Filename - if pos.IsValid() { - if s != "" { - s += ":" - } - s += fmt.Sprintf("%d", pos.Line) - if pos.Column != 0 { - s += fmt.Sprintf(":%d", pos.Column) - } - } - if s == "" { - s = "-" - } - return s -} - -// Pos is a compact encoding of a source position within a file set. -// It can be converted into a Position for a more convenient, but much -// larger, representation. -// -// The Pos value for a given file is a number in the range [base, base+size], -// where base and size are specified when a file is added to the file set. -// The difference between a Pos value and the corresponding file base -// corresponds to the byte offset of that position (represented by the Pos value) -// from the beginning of the file. Thus, the file base offset is the Pos value -// representing the first byte in the file. -// -// To create the Pos value for a specific source offset (measured in bytes), -// first add the respective file to the current file set using FileSet.AddFile -// and then call File.Pos(offset) for that file. Given a Pos value p -// for a specific file set fset, the corresponding Position value is -// obtained by calling fset.Position(p). -// -// Pos values can be compared directly with the usual comparison operators: -// If two Pos values p and q are in the same file, comparing p and q is -// equivalent to comparing the respective source file offsets. If p and q -// are in different files, p < q is true if the file implied by p was added -// to the respective file set before the file implied by q. -type Pos int - -// The zero value for Pos is NoPos; there is no file and line information -// associated with it, and NoPos.IsValid() is false. NoPos is always -// smaller than any other Pos value. The corresponding Position value -// for NoPos is the zero value for Position. -const NoPos Pos = 0 - -// IsValid reports whether the position is valid. -func (p Pos) IsValid() bool { - return p != NoPos -} - -// ----------------------------------------------------------------------------- -// File - -// A File is a handle for a file belonging to a FileSet. -// A File has a name, size, and line offset table. -type File struct { - name string // file name as provided to AddFile - base int // Pos value range for this file is [base...base+size] - size int // file size as provided to AddFile - - lines []int // lines contains the offset of the first character for each line (the first entry is always 0) - infos []lineInfo -} - -// NewFile returns a new file with a given filename and file size. -// -func NewFile(filename string, size int) *File { - return &File{name: filename, base: 1, size: size, lines: []int{0}} -} - -// Name returns the file name of file f as registered with AddFile. -func (f *File) Name() string { - return f.name -} - -// Base returns the base offset of file f as registered with AddFile. -func (f *File) Base() int { - return f.base -} - -// Size returns the size of file f as registered with AddFile. -func (f *File) Size() int { - return f.size -} - -// LineCount returns the number of lines in file f. -func (f *File) LineCount() int { - n := len(f.lines) - return n -} - -// AddLine adds the line offset for a new line. -// The line offset must be larger than the offset for the previous line -// and smaller than the file size; otherwise the line offset is ignored. -func (f *File) AddLine(offset int) { - if i := len(f.lines); (i == 0 || f.lines[i-1] < offset) && offset < f.size { - f.lines = append(f.lines, offset) - } -} - -// MergeLine merges a line with the following line. It is akin to replacing -// the newline character at the end of the line with a space (to not change the -// remaining offsets). To obtain the line number, consult e.g. Position.Line. -// MergeLine will panic if given an invalid line number. -func (f *File) MergeLine(line int) { - if line < 1 { - panic(fmt.Sprintf("invalid line number %d (should be >= 1)", line)) - } - if line >= len(f.lines) { - panic(fmt.Sprintf("invalid line number %d (should be < %d)", line, len(f.lines))) - } - // To merge the line numbered <line> with the line numbered <line+1>, - // we need to remove the entry in lines corresponding to the line - // numbered <line+1>. The entry in lines corresponding to the line - // numbered <line+1> is located at index <line>, since indices in lines - // are 0-based and line numbers are 1-based. - copy(f.lines[line:], f.lines[line+1:]) - f.lines = f.lines[:len(f.lines)-1] -} - -// SetLines sets the line offsets for a file and reports whether it succeeded. -// The line offsets are the offsets of the first character of each line; -// for instance for the content "ab\nc\n" the line offsets are {0, 3}. -// An empty file has an empty line offset table. -// Each line offset must be larger than the offset for the previous line -// and smaller than the file size; otherwise SetLines fails and returns -// false. -// Callers must not mutate the provided slice after SetLines returns. -func (f *File) SetLines(lines []int) bool { - // verify validity of lines table - size := f.size - for i, offset := range lines { - if i > 0 && offset <= lines[i-1] || size <= offset { - return false - } - } - - // set lines table - f.lines = lines - return true -} - -// SetLinesForContent sets the line offsets for the given file content. -// It ignores position-altering //line comments. -func (f *File) SetLinesForContent(content []byte) { - var lines []int - line := 0 - for offset, b := range content { - if line >= 0 { - lines = append(lines, line) - } - line = -1 - if b == '\n' { - line = offset + 1 - } - } - - // set lines table - f.lines = lines -} - -// LineStart returns the Pos value of the start of the specified line. -// It ignores any alternative positions set using AddLineColumnInfo. -// LineStart panics if the 1-based line number is invalid. -func (f *File) LineStart(line int) Pos { - if line < 1 { - panic(fmt.Sprintf("invalid line number %d (should be >= 1)", line)) - } - if line > len(f.lines) { - panic(fmt.Sprintf("invalid line number %d (should be < %d)", line, len(f.lines))) - } - return Pos(f.base + f.lines[line-1]) -} - -// A lineInfo object describes alternative file, line, and column -// number information (such as provided via a //line directive) -// for a given file offset. -type lineInfo struct { - // fields are exported to make them accessible to gob - Offset int - Filename string - Line, Column int -} - -// AddLineInfo is like AddLineColumnInfo with a column = 1 argument. -// It is here for backward-compatibility for code prior to Go 1.11. -func (f *File) AddLineInfo(offset int, filename string, line int) { - f.AddLineColumnInfo(offset, filename, line, 1) -} - -// AddLineColumnInfo adds alternative file, line, and column number -// information for a given file offset. The offset must be larger -// than the offset for the previously added alternative line info -// and smaller than the file size; otherwise the information is -// ignored. -// -// AddLineColumnInfo is typically used to register alternative position -// information for line directives such as //line filename:line:column. -func (f *File) AddLineColumnInfo(offset int, filename string, line, column int) { - if i := len(f.infos); i == 0 || f.infos[i-1].Offset < offset && offset < f.size { - f.infos = append(f.infos, lineInfo{offset, filename, line, column}) - } -} - -// Pos returns the Pos value for the given file offset; -// the offset must be <= f.Size(). -// f.Pos(f.Offset(p)) == p. -func (f *File) Pos(offset int) Pos { - if offset > f.size { - panic(fmt.Sprintf("invalid file offset %d (should be <= %d)", offset, f.size)) - } - return Pos(f.base + offset) -} - -// Offset returns the offset for the given file position p; -// p must be a valid Pos value in that file. -// f.Offset(f.Pos(offset)) == offset. -func (f *File) Offset(p Pos) int { - if int(p) < f.base || int(p) > f.base+f.size { - panic(fmt.Sprintf("invalid Pos value %d (should be in [%d, %d])", p, f.base, f.base+f.size)) - } - return int(p) - f.base -} - -// Line returns the line number for the given file position p; -// p must be a Pos value in that file or NoPos. -func (f *File) Line(p Pos) int { - return f.Position(p).Line -} - -func searchLineInfos(a []lineInfo, x int) int { - return sort.Search(len(a), func(i int) bool { return a[i].Offset > x }) - 1 -} - -// unpack returns the filename and line and column number for a file offset. -// If adjusted is set, unpack will return the filename and line information -// possibly adjusted by //line comments; otherwise those comments are ignored. -func (f *File) unpack(offset int, adjusted bool) (filename string, line, column int) { - filename = f.name - if i := searchInts(f.lines, offset); i >= 0 { - line, column = i+1, offset-f.lines[i]+1 - } - if adjusted && len(f.infos) > 0 { - // few files have extra line infos - if i := searchLineInfos(f.infos, offset); i >= 0 { - alt := &f.infos[i] - filename = alt.Filename - if i := searchInts(f.lines, alt.Offset); i >= 0 { - // i+1 is the line at which the alternative position was recorded - d := line - (i + 1) // line distance from alternative position base - line = alt.Line + d - if alt.Column == 0 { - // alternative column is unknown => relative column is unknown - // (the current specification for line directives requires - // this to apply until the next PosBase/line directive, - // not just until the new newline) - column = 0 - } else if d == 0 { - // the alternative position base is on the current line - // => column is relative to alternative column - column = alt.Column + (offset - alt.Offset) - } - } - } - } - return -} - -func (f *File) position(p Pos, adjusted bool) (pos Position) { - offset := int(p) - f.base - pos.Offset = offset - pos.Filename, pos.Line, pos.Column = f.unpack(offset, adjusted) - return -} - -// PositionFor returns the Position value for the given file position p. -// If adjusted is set, the position may be adjusted by position-altering -// //line comments; otherwise those comments are ignored. -// p must be a Pos value in f or NoPos. -func (f *File) PositionFor(p Pos, adjusted bool) (pos Position) { - if p != NoPos { - if int(p) < f.base || int(p) > f.base+f.size { - panic(fmt.Sprintf("invalid Pos value %d (should be in [%d, %d])", p, f.base, f.base+f.size)) - } - pos = f.position(p, adjusted) - } - return -} - -// Position returns the Position value for the given file position p. -// Calling f.Position(p) is equivalent to calling f.PositionFor(p, true). -func (f *File) Position(p Pos) (pos Position) { - return f.PositionFor(p, true) -} - -// ----------------------------------------------------------------------------- -// Helper functions - -func searchInts(a []int, x int) int { - // This function body is a manually inlined version of: - // - // return sort.Search(len(a), func(i int) bool { return a[i] > x }) - 1 - // - // With better compiler optimizations, this may not be needed in the - // future, but at the moment this change improves the go/printer - // benchmark performance by ~30%. This has a direct impact on the - // speed of gofmt and thus seems worthwhile (2011-04-29). - // TODO(gri): Remove this when compilers have caught up. - i, j := 0, len(a) - for i < j { - h := int(uint(i+j) >> 1) // avoid overflow when computing h - // i ≤ h < j - if a[h] <= x { - i = h + 1 - } else { - j = h - } - } - return i - 1 -} |