diff options
Diffstat (limited to 'vendor/github.com/pmezard/go-difflib/difflib/difflib.go')
| -rw-r--r-- | vendor/github.com/pmezard/go-difflib/difflib/difflib.go | 772 |
1 files changed, 0 insertions, 772 deletions
diff --git a/vendor/github.com/pmezard/go-difflib/difflib/difflib.go b/vendor/github.com/pmezard/go-difflib/difflib/difflib.go deleted file mode 100644 index 003e99f..0000000 --- a/vendor/github.com/pmezard/go-difflib/difflib/difflib.go +++ /dev/null @@ -1,772 +0,0 @@ -// Package difflib is a partial port of Python difflib module. -// -// It provides tools to compare sequences of strings and generate textual diffs. -// -// The following class and functions have been ported: -// -// - SequenceMatcher -// -// - unified_diff -// -// - context_diff -// -// Getting unified diffs was the main goal of the port. Keep in mind this code -// is mostly suitable to output text differences in a human friendly way, there -// are no guarantees generated diffs are consumable by patch(1). -package difflib - -import ( - "bufio" - "bytes" - "fmt" - "io" - "strings" -) - -func min(a, b int) int { - if a < b { - return a - } - return b -} - -func max(a, b int) int { - if a > b { - return a - } - return b -} - -func calculateRatio(matches, length int) float64 { - if length > 0 { - return 2.0 * float64(matches) / float64(length) - } - return 1.0 -} - -type Match struct { - A int - B int - Size int -} - -type OpCode struct { - Tag byte - I1 int - I2 int - J1 int - J2 int -} - -// SequenceMatcher compares sequence of strings. The basic -// algorithm predates, and is a little fancier than, an algorithm -// published in the late 1980's by Ratcliff and Obershelp under the -// hyperbolic name "gestalt pattern matching". The basic idea is to find -// the longest contiguous matching subsequence that contains no "junk" -// elements (R-O doesn't address junk). The same idea is then applied -// recursively to the pieces of the sequences to the left and to the right -// of the matching subsequence. This does not yield minimal edit -// sequences, but does tend to yield matches that "look right" to people. -// -// SequenceMatcher tries to compute a "human-friendly diff" between two -// sequences. Unlike e.g. UNIX(tm) diff, the fundamental notion is the -// longest *contiguous* & junk-free matching subsequence. That's what -// catches peoples' eyes. The Windows(tm) windiff has another interesting -// notion, pairing up elements that appear uniquely in each sequence. -// That, and the method here, appear to yield more intuitive difference -// reports than does diff. This method appears to be the least vulnerable -// to synching up on blocks of "junk lines", though (like blank lines in -// ordinary text files, or maybe "<P>" lines in HTML files). That may be -// because this is the only method of the 3 that has a *concept* of -// "junk" <wink>. -// -// Timing: Basic R-O is cubic time worst case and quadratic time expected -// case. SequenceMatcher is quadratic time for the worst case and has -// expected-case behavior dependent in a complicated way on how many -// elements the sequences have in common; best case time is linear. -type SequenceMatcher struct { - a []string - b []string - b2j map[string][]int - IsJunk func(string) bool - autoJunk bool - bJunk map[string]struct{} - matchingBlocks []Match - fullBCount map[string]int - bPopular map[string]struct{} - opCodes []OpCode -} - -func NewMatcher(a, b []string) *SequenceMatcher { - m := SequenceMatcher{autoJunk: true} - m.SetSeqs(a, b) - return &m -} - -func NewMatcherWithJunk(a, b []string, autoJunk bool, - isJunk func(string) bool) *SequenceMatcher { - - m := SequenceMatcher{IsJunk: isJunk, autoJunk: autoJunk} - m.SetSeqs(a, b) - return &m -} - -// Set two sequences to be compared. -func (m *SequenceMatcher) SetSeqs(a, b []string) { - m.SetSeq1(a) - m.SetSeq2(b) -} - -// Set the first sequence to be compared. The second sequence to be compared is -// not changed. -// -// SequenceMatcher computes and caches detailed information about the second -// sequence, so if you want to compare one sequence S against many sequences, -// use .SetSeq2(s) once and call .SetSeq1(x) repeatedly for each of the other -// sequences. -// -// See also SetSeqs() and SetSeq2(). -func (m *SequenceMatcher) SetSeq1(a []string) { - if &a == &m.a { - return - } - m.a = a - m.matchingBlocks = nil - m.opCodes = nil -} - -// Set the second sequence to be compared. The first sequence to be compared is -// not changed. -func (m *SequenceMatcher) SetSeq2(b []string) { - if &b == &m.b { - return - } - m.b = b - m.matchingBlocks = nil - m.opCodes = nil - m.fullBCount = nil - m.chainB() -} - -func (m *SequenceMatcher) chainB() { - // Populate line -> index mapping - b2j := map[string][]int{} - for i, s := range m.b { - indices := b2j[s] - indices = append(indices, i) - b2j[s] = indices - } - - // Purge junk elements - m.bJunk = map[string]struct{}{} - if m.IsJunk != nil { - junk := m.bJunk - for s, _ := range b2j { - if m.IsJunk(s) { - junk[s] = struct{}{} - } - } - for s, _ := range junk { - delete(b2j, s) - } - } - - // Purge remaining popular elements - popular := map[string]struct{}{} - n := len(m.b) - if m.autoJunk && n >= 200 { - ntest := n/100 + 1 - for s, indices := range b2j { - if len(indices) > ntest { - popular[s] = struct{}{} - } - } - for s, _ := range popular { - delete(b2j, s) - } - } - m.bPopular = popular - m.b2j = b2j -} - -func (m *SequenceMatcher) isBJunk(s string) bool { - _, ok := m.bJunk[s] - return ok -} - -// Find longest matching block in a[alo:ahi] and b[blo:bhi]. -// -// If IsJunk is not defined: -// -// Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where -// alo <= i <= i+k <= ahi -// blo <= j <= j+k <= bhi -// and for all (i',j',k') meeting those conditions, -// k >= k' -// i <= i' -// and if i == i', j <= j' -// -// In other words, of all maximal matching blocks, return one that -// starts earliest in a, and of all those maximal matching blocks that -// start earliest in a, return the one that starts earliest in b. -// -// If IsJunk is defined, first the longest matching block is -// determined as above, but with the additional restriction that no -// junk element appears in the block. Then that block is extended as -// far as possible by matching (only) junk elements on both sides. So -// the resulting block never matches on junk except as identical junk -// happens to be adjacent to an "interesting" match. -// -// If no blocks match, return (alo, blo, 0). -func (m *SequenceMatcher) findLongestMatch(alo, ahi, blo, bhi int) Match { - // CAUTION: stripping common prefix or suffix would be incorrect. - // E.g., - // ab - // acab - // Longest matching block is "ab", but if common prefix is - // stripped, it's "a" (tied with "b"). UNIX(tm) diff does so - // strip, so ends up claiming that ab is changed to acab by - // inserting "ca" in the middle. That's minimal but unintuitive: - // "it's obvious" that someone inserted "ac" at the front. - // Windiff ends up at the same place as diff, but by pairing up - // the unique 'b's and then matching the first two 'a's. - besti, bestj, bestsize := alo, blo, 0 - - // find longest junk-free match - // during an iteration of the loop, j2len[j] = length of longest - // junk-free match ending with a[i-1] and b[j] - j2len := map[int]int{} - for i := alo; i != ahi; i++ { - // look at all instances of a[i] in b; note that because - // b2j has no junk keys, the loop is skipped if a[i] is junk - newj2len := map[int]int{} - for _, j := range m.b2j[m.a[i]] { - // a[i] matches b[j] - if j < blo { - continue - } - if j >= bhi { - break - } - k := j2len[j-1] + 1 - newj2len[j] = k - if k > bestsize { - besti, bestj, bestsize = i-k+1, j-k+1, k - } - } - j2len = newj2len - } - - // Extend the best by non-junk elements on each end. In particular, - // "popular" non-junk elements aren't in b2j, which greatly speeds - // the inner loop above, but also means "the best" match so far - // doesn't contain any junk *or* popular non-junk elements. - for besti > alo && bestj > blo && !m.isBJunk(m.b[bestj-1]) && - m.a[besti-1] == m.b[bestj-1] { - besti, bestj, bestsize = besti-1, bestj-1, bestsize+1 - } - for besti+bestsize < ahi && bestj+bestsize < bhi && - !m.isBJunk(m.b[bestj+bestsize]) && - m.a[besti+bestsize] == m.b[bestj+bestsize] { - bestsize += 1 - } - - // Now that we have a wholly interesting match (albeit possibly - // empty!), we may as well suck up the matching junk on each - // side of it too. Can't think of a good reason not to, and it - // saves post-processing the (possibly considerable) expense of - // figuring out what to do with it. In the case of an empty - // interesting match, this is clearly the right thing to do, - // because no other kind of match is possible in the regions. - for besti > alo && bestj > blo && m.isBJunk(m.b[bestj-1]) && - m.a[besti-1] == m.b[bestj-1] { - besti, bestj, bestsize = besti-1, bestj-1, bestsize+1 - } - for besti+bestsize < ahi && bestj+bestsize < bhi && - m.isBJunk(m.b[bestj+bestsize]) && - m.a[besti+bestsize] == m.b[bestj+bestsize] { - bestsize += 1 - } - - return Match{A: besti, B: bestj, Size: bestsize} -} - -// Return list of triples describing matching subsequences. -// -// Each triple is of the form (i, j, n), and means that -// a[i:i+n] == b[j:j+n]. The triples are monotonically increasing in -// i and in j. It's also guaranteed that if (i, j, n) and (i', j', n') are -// adjacent triples in the list, and the second is not the last triple in the -// list, then i+n != i' or j+n != j'. IOW, adjacent triples never describe -// adjacent equal blocks. -// -// The last triple is a dummy, (len(a), len(b), 0), and is the only -// triple with n==0. -func (m *SequenceMatcher) GetMatchingBlocks() []Match { - if m.matchingBlocks != nil { - return m.matchingBlocks - } - - var matchBlocks func(alo, ahi, blo, bhi int, matched []Match) []Match - matchBlocks = func(alo, ahi, blo, bhi int, matched []Match) []Match { - match := m.findLongestMatch(alo, ahi, blo, bhi) - i, j, k := match.A, match.B, match.Size - if match.Size > 0 { - if alo < i && blo < j { - matched = matchBlocks(alo, i, blo, j, matched) - } - matched = append(matched, match) - if i+k < ahi && j+k < bhi { - matched = matchBlocks(i+k, ahi, j+k, bhi, matched) - } - } - return matched - } - matched := matchBlocks(0, len(m.a), 0, len(m.b), nil) - - // It's possible that we have adjacent equal blocks in the - // matching_blocks list now. - nonAdjacent := []Match{} - i1, j1, k1 := 0, 0, 0 - for _, b := range matched { - // Is this block adjacent to i1, j1, k1? - i2, j2, k2 := b.A, b.B, b.Size - if i1+k1 == i2 && j1+k1 == j2 { - // Yes, so collapse them -- this just increases the length of - // the first block by the length of the second, and the first - // block so lengthened remains the block to compare against. - k1 += k2 - } else { - // Not adjacent. Remember the first block (k1==0 means it's - // the dummy we started with), and make the second block the - // new block to compare against. - if k1 > 0 { - nonAdjacent = append(nonAdjacent, Match{i1, j1, k1}) - } - i1, j1, k1 = i2, j2, k2 - } - } - if k1 > 0 { - nonAdjacent = append(nonAdjacent, Match{i1, j1, k1}) - } - - nonAdjacent = append(nonAdjacent, Match{len(m.a), len(m.b), 0}) - m.matchingBlocks = nonAdjacent - return m.matchingBlocks -} - -// Return list of 5-tuples describing how to turn a into b. -// -// Each tuple is of the form (tag, i1, i2, j1, j2). The first tuple -// has i1 == j1 == 0, and remaining tuples have i1 == the i2 from the -// tuple preceding it, and likewise for j1 == the previous j2. -// -// The tags are characters, with these meanings: -// -// 'r' (replace): a[i1:i2] should be replaced by b[j1:j2] -// -// 'd' (delete): a[i1:i2] should be deleted, j1==j2 in this case. -// -// 'i' (insert): b[j1:j2] should be inserted at a[i1:i1], i1==i2 in this case. -// -// 'e' (equal): a[i1:i2] == b[j1:j2] -func (m *SequenceMatcher) GetOpCodes() []OpCode { - if m.opCodes != nil { - return m.opCodes - } - i, j := 0, 0 - matching := m.GetMatchingBlocks() - opCodes := make([]OpCode, 0, len(matching)) - for _, m := range matching { - // invariant: we've pumped out correct diffs to change - // a[:i] into b[:j], and the next matching block is - // a[ai:ai+size] == b[bj:bj+size]. So we need to pump - // out a diff to change a[i:ai] into b[j:bj], pump out - // the matching block, and move (i,j) beyond the match - ai, bj, size := m.A, m.B, m.Size - tag := byte(0) - if i < ai && j < bj { - tag = 'r' - } else if i < ai { - tag = 'd' - } else if j < bj { - tag = 'i' - } - if tag > 0 { - opCodes = append(opCodes, OpCode{tag, i, ai, j, bj}) - } - i, j = ai+size, bj+size - // the list of matching blocks is terminated by a - // sentinel with size 0 - if size > 0 { - opCodes = append(opCodes, OpCode{'e', ai, i, bj, j}) - } - } - m.opCodes = opCodes - return m.opCodes -} - -// Isolate change clusters by eliminating ranges with no changes. -// -// Return a generator of groups with up to n lines of context. -// Each group is in the same format as returned by GetOpCodes(). -func (m *SequenceMatcher) GetGroupedOpCodes(n int) [][]OpCode { - if n < 0 { - n = 3 - } - codes := m.GetOpCodes() - if len(codes) == 0 { - codes = []OpCode{OpCode{'e', 0, 1, 0, 1}} - } - // Fixup leading and trailing groups if they show no changes. - if codes[0].Tag == 'e' { - c := codes[0] - i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2 - codes[0] = OpCode{c.Tag, max(i1, i2-n), i2, max(j1, j2-n), j2} - } - if codes[len(codes)-1].Tag == 'e' { - c := codes[len(codes)-1] - i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2 - codes[len(codes)-1] = OpCode{c.Tag, i1, min(i2, i1+n), j1, min(j2, j1+n)} - } - nn := n + n - groups := [][]OpCode{} - group := []OpCode{} - for _, c := range codes { - i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2 - // End the current group and start a new one whenever - // there is a large range with no changes. - if c.Tag == 'e' && i2-i1 > nn { - group = append(group, OpCode{c.Tag, i1, min(i2, i1+n), - j1, min(j2, j1+n)}) - groups = append(groups, group) - group = []OpCode{} - i1, j1 = max(i1, i2-n), max(j1, j2-n) - } - group = append(group, OpCode{c.Tag, i1, i2, j1, j2}) - } - if len(group) > 0 && !(len(group) == 1 && group[0].Tag == 'e') { - groups = append(groups, group) - } - return groups -} - -// Return a measure of the sequences' similarity (float in [0,1]). -// -// Where T is the total number of elements in both sequences, and -// M is the number of matches, this is 2.0*M / T. -// Note that this is 1 if the sequences are identical, and 0 if -// they have nothing in common. -// -// .Ratio() is expensive to compute if you haven't already computed -// .GetMatchingBlocks() or .GetOpCodes(), in which case you may -// want to try .QuickRatio() or .RealQuickRation() first to get an -// upper bound. -func (m *SequenceMatcher) Ratio() float64 { - matches := 0 - for _, m := range m.GetMatchingBlocks() { - matches += m.Size - } - return calculateRatio(matches, len(m.a)+len(m.b)) -} - -// Return an upper bound on ratio() relatively quickly. -// -// This isn't defined beyond that it is an upper bound on .Ratio(), and -// is faster to compute. -func (m *SequenceMatcher) QuickRatio() float64 { - // viewing a and b as multisets, set matches to the cardinality - // of their intersection; this counts the number of matches - // without regard to order, so is clearly an upper bound - if m.fullBCount == nil { - m.fullBCount = map[string]int{} - for _, s := range m.b { - m.fullBCount[s] = m.fullBCount[s] + 1 - } - } - - // avail[x] is the number of times x appears in 'b' less the - // number of times we've seen it in 'a' so far ... kinda - avail := map[string]int{} - matches := 0 - for _, s := range m.a { - n, ok := avail[s] - if !ok { - n = m.fullBCount[s] - } - avail[s] = n - 1 - if n > 0 { - matches += 1 - } - } - return calculateRatio(matches, len(m.a)+len(m.b)) -} - -// Return an upper bound on ratio() very quickly. -// -// This isn't defined beyond that it is an upper bound on .Ratio(), and -// is faster to compute than either .Ratio() or .QuickRatio(). -func (m *SequenceMatcher) RealQuickRatio() float64 { - la, lb := len(m.a), len(m.b) - return calculateRatio(min(la, lb), la+lb) -} - -// Convert range to the "ed" format -func formatRangeUnified(start, stop int) string { - // Per the diff spec at http://www.unix.org/single_unix_specification/ - beginning := start + 1 // lines start numbering with one - length := stop - start - if length == 1 { - return fmt.Sprintf("%d", beginning) - } - if length == 0 { - beginning -= 1 // empty ranges begin at line just before the range - } - return fmt.Sprintf("%d,%d", beginning, length) -} - -// Unified diff parameters -type UnifiedDiff struct { - A []string // First sequence lines - FromFile string // First file name - FromDate string // First file time - B []string // Second sequence lines - ToFile string // Second file name - ToDate string // Second file time - Eol string // Headers end of line, defaults to LF - Context int // Number of context lines -} - -// Compare two sequences of lines; generate the delta as a unified diff. -// -// Unified diffs are a compact way of showing line changes and a few -// lines of context. The number of context lines is set by 'n' which -// defaults to three. -// -// By default, the diff control lines (those with ---, +++, or @@) are -// created with a trailing newline. This is helpful so that inputs -// created from file.readlines() result in diffs that are suitable for -// file.writelines() since both the inputs and outputs have trailing -// newlines. -// -// For inputs that do not have trailing newlines, set the lineterm -// argument to "" so that the output will be uniformly newline free. -// -// The unidiff format normally has a header for filenames and modification -// times. Any or all of these may be specified using strings for -// 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'. -// The modification times are normally expressed in the ISO 8601 format. -func WriteUnifiedDiff(writer io.Writer, diff UnifiedDiff) error { - buf := bufio.NewWriter(writer) - defer buf.Flush() - wf := func(format string, args ...interface{}) error { - _, err := buf.WriteString(fmt.Sprintf(format, args...)) - return err - } - ws := func(s string) error { - _, err := buf.WriteString(s) - return err - } - - if len(diff.Eol) == 0 { - diff.Eol = "\n" - } - - started := false - m := NewMatcher(diff.A, diff.B) - for _, g := range m.GetGroupedOpCodes(diff.Context) { - if !started { - started = true - fromDate := "" - if len(diff.FromDate) > 0 { - fromDate = "\t" + diff.FromDate - } - toDate := "" - if len(diff.ToDate) > 0 { - toDate = "\t" + diff.ToDate - } - if diff.FromFile != "" || diff.ToFile != "" { - err := wf("--- %s%s%s", diff.FromFile, fromDate, diff.Eol) - if err != nil { - return err - } - err = wf("+++ %s%s%s", diff.ToFile, toDate, diff.Eol) - if err != nil { - return err - } - } - } - first, last := g[0], g[len(g)-1] - range1 := formatRangeUnified(first.I1, last.I2) - range2 := formatRangeUnified(first.J1, last.J2) - if err := wf("@@ -%s +%s @@%s", range1, range2, diff.Eol); err != nil { - return err - } - for _, c := range g { - i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2 - if c.Tag == 'e' { - for _, line := range diff.A[i1:i2] { - if err := ws(" " + line); err != nil { - return err - } - } - continue - } - if c.Tag == 'r' || c.Tag == 'd' { - for _, line := range diff.A[i1:i2] { - if err := ws("-" + line); err != nil { - return err - } - } - } - if c.Tag == 'r' || c.Tag == 'i' { - for _, line := range diff.B[j1:j2] { - if err := ws("+" + line); err != nil { - return err - } - } - } - } - } - return nil -} - -// Like WriteUnifiedDiff but returns the diff a string. -func GetUnifiedDiffString(diff UnifiedDiff) (string, error) { - w := &bytes.Buffer{} - err := WriteUnifiedDiff(w, diff) - return string(w.Bytes()), err -} - -// Convert range to the "ed" format. -func formatRangeContext(start, stop int) string { - // Per the diff spec at http://www.unix.org/single_unix_specification/ - beginning := start + 1 // lines start numbering with one - length := stop - start - if length == 0 { - beginning -= 1 // empty ranges begin at line just before the range - } - if length <= 1 { - return fmt.Sprintf("%d", beginning) - } - return fmt.Sprintf("%d,%d", beginning, beginning+length-1) -} - -type ContextDiff UnifiedDiff - -// Compare two sequences of lines; generate the delta as a context diff. -// -// Context diffs are a compact way of showing line changes and a few -// lines of context. The number of context lines is set by diff.Context -// which defaults to three. -// -// By default, the diff control lines (those with *** or ---) are -// created with a trailing newline. -// -// For inputs that do not have trailing newlines, set the diff.Eol -// argument to "" so that the output will be uniformly newline free. -// -// The context diff format normally has a header for filenames and -// modification times. Any or all of these may be specified using -// strings for diff.FromFile, diff.ToFile, diff.FromDate, diff.ToDate. -// The modification times are normally expressed in the ISO 8601 format. -// If not specified, the strings default to blanks. -func WriteContextDiff(writer io.Writer, diff ContextDiff) error { - buf := bufio.NewWriter(writer) - defer buf.Flush() - var diffErr error - wf := func(format string, args ...interface{}) { - _, err := buf.WriteString(fmt.Sprintf(format, args...)) - if diffErr == nil && err != nil { - diffErr = err - } - } - ws := func(s string) { - _, err := buf.WriteString(s) - if diffErr == nil && err != nil { - diffErr = err - } - } - - if len(diff.Eol) == 0 { - diff.Eol = "\n" - } - - prefix := map[byte]string{ - 'i': "+ ", - 'd': "- ", - 'r': "! ", - 'e': " ", - } - - started := false - m := NewMatcher(diff.A, diff.B) - for _, g := range m.GetGroupedOpCodes(diff.Context) { - if !started { - started = true - fromDate := "" - if len(diff.FromDate) > 0 { - fromDate = "\t" + diff.FromDate - } - toDate := "" - if len(diff.ToDate) > 0 { - toDate = "\t" + diff.ToDate - } - if diff.FromFile != "" || diff.ToFile != "" { - wf("*** %s%s%s", diff.FromFile, fromDate, diff.Eol) - wf("--- %s%s%s", diff.ToFile, toDate, diff.Eol) - } - } - - first, last := g[0], g[len(g)-1] - ws("***************" + diff.Eol) - - range1 := formatRangeContext(first.I1, last.I2) - wf("*** %s ****%s", range1, diff.Eol) - for _, c := range g { - if c.Tag == 'r' || c.Tag == 'd' { - for _, cc := range g { - if cc.Tag == 'i' { - continue - } - for _, line := range diff.A[cc.I1:cc.I2] { - ws(prefix[cc.Tag] + line) - } - } - break - } - } - - range2 := formatRangeContext(first.J1, last.J2) - wf("--- %s ----%s", range2, diff.Eol) - for _, c := range g { - if c.Tag == 'r' || c.Tag == 'i' { - for _, cc := range g { - if cc.Tag == 'd' { - continue - } - for _, line := range diff.B[cc.J1:cc.J2] { - ws(prefix[cc.Tag] + line) - } - } - break - } - } - } - return diffErr -} - -// Like WriteContextDiff but returns the diff a string. -func GetContextDiffString(diff ContextDiff) (string, error) { - w := &bytes.Buffer{} - err := WriteContextDiff(w, diff) - return string(w.Bytes()), err -} - -// Split a string on "\n" while preserving them. The output can be used -// as input for UnifiedDiff and ContextDiff structures. -func SplitLines(s string) []string { - lines := strings.SplitAfter(s, "\n") - lines[len(lines)-1] += "\n" - return lines -} |