Class: AssertSame::TextDiff

Inherits:
Object
  • Object
show all
Defined in:
lib/text_diff.rb

Class Method Summary collapse

Class Method Details

.array_diff(a, b) ⇒ Object 



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# File 'lib/text_diff.rb', line 37

def self.array_diff(a, b)
    diff = ArrayDiff.new(a, b)

    return nil if diff.diffs.empty?

    result = []

    from = to = nextfrom = 0
    offset = 0
    diff.diffs.each do |tuple|
        first = tuple[0][1]
        length = tuple.length
        action = tuple[0][0]
        addcount = 0
        remcount = 0
        tuple.each do |l| 
            if l[0] == "+"
                addcount += 1
            elsif l[0] == "-"
                remcount += 1
            end
        end
        if remcount == 0
            to = first-offset-1
            nextfrom = to+1
        else
            to = first-1
            nextfrom = to+remcount+1
        end
        result += self.chunk(a, from, to)
        from = nextfrom
        lastdel = (tuple[0][0] == "-")
        tuple.each do |l|
            if l[0] == "-"
                offset -= 1
            else
                offset += 1
            end
            result << [l[0], l[2]]
        end
    end
    if (a.length - from) > 2
        result += self.chunk(a, from, from+2)
    elsif a.length > 0
        result += self.chunk(a, from, a.length-1)
    end
    linecount = addcount = remcount = offset = current_offset = 0
    info_index = nil
    result.each_with_index do |l, i|
        if l[0] == '@'
            result[info_index] = self.record_stat(result, info_index, remcount, addcount, 
                linecount, offset) if info_index
            info_index = i
            offset += addcount - remcount
            linecount = 0
            addcount = remcount = 0
        elsif l[0] == '-'
            remcount += 1
            linecount += 1
        elsif l[0] == '+'
            addcount += 1
            linecount += 1
        else
            linecount += 1
        end
    end
    result[info_index] = self.record_stat(result, info_index, remcount, addcount, linecount, offset) if info_index
    return result.map{|x| x.join('')}.join("\n")
end

.chunk(arr, from, to) ⇒ Object 



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# File 'lib/text_diff.rb', line 14

def self.chunk(arr, from, to)
    result = []
    if to - from > 2
        result += self.mapped_chunk(arr, from, from+2) if from > 0
        result << ['@', to-2]
        result += self.mapped_chunk(arr, to-2, to)
    else 
        result << ['@', from] if from == 0
        result += self.mapped_chunk(arr, from, to)
    end
end

.diff(a_text, b_text) ⇒ Object 



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# File 'lib/text_diff.rb', line 31

def self.diff(a_text, b_text)
    a = a_text.split("\n")
    b = b_text.split("\n")
    self.array_diff(a, b)
end

.mapped_chunk(arr, from, to) ⇒ Object 



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# File 'lib/text_diff.rb', line 9

def self.mapped_chunk(arr, from, to)
    return [] if to < from
    arr[from, to-from+1].map{|x| [' ', x]}
end

.record_stat(arr, at, remcount, addcount, linecount, offset) ⇒ Object 



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# File 'lib/text_diff.rb', line 26

def self.record_stat(arr, at, remcount, addcount, linecount, offset)
    index = arr[at][1]+1
    ['', "@@ -#{index},#{linecount-addcount}, +#{index+offset},#{linecount-remcount} @@"]
end