class Prism::Source

# File lib/prism/parse_result.rb, line 12
def self.for(source, start_line = 1, offsets = [])
  if source.ascii_only?
    ASCIISource.new(source, start_line, offsets)
  elsif source.encoding == Encoding::BINARY
    source.force_encoding(Encoding::UTF_8)

    if source.valid_encoding?
      new(source, start_line, offsets)
    else
      # This is an extremely niche use case where the file is marked as
      # binary, contains multi-byte characters, and those characters are not
      # valid UTF-8. In this case we'll mark it as binary and fall back to
      # treating everything as a single-byte character. This _may_ cause
      # problems when asking for code units, but it appears to be the
      # cleanest solution at the moment.
      source.force_encoding(Encoding::BINARY)
      ASCIISource.new(source, start_line, offsets)
    end
  else
    new(source, start_line, offsets)
  end
end

# File lib/prism/parse_result.rb, line 45
def initialize(source, start_line = 1, offsets = [])
  @source = source
  @start_line = start_line # set after parsing is done
  @offsets = offsets # set after parsing is done
end

# File lib/prism/parse_result.rb, line 97
def character_column(byte_offset)
  character_offset(byte_offset) - character_offset(line_start(byte_offset))
end

# File lib/prism/parse_result.rb, line 92
def character_offset(byte_offset)
  (source.byteslice(0, byte_offset) or raise).length
end

# File lib/prism/parse_result.rb, line 125
def code_units_cache(encoding)
  CodeUnitsCache.new(source, encoding)
end

# File lib/prism/parse_result.rb, line 131
def code_units_column(byte_offset, encoding)
  code_units_offset(byte_offset, encoding) - code_units_offset(line_start(byte_offset), encoding)
end

# File lib/prism/parse_result.rb, line 113
def code_units_offset(byte_offset, encoding)
  byteslice = (source.byteslice(0, byte_offset) or raise).encode(encoding, invalid: :replace, undef: :replace)

  if encoding == Encoding::UTF_16LE || encoding == Encoding::UTF_16BE
    byteslice.bytesize / 2
  else
    byteslice.length
  end
end

# File lib/prism/parse_result.rb, line 87
def column(byte_offset)
  byte_offset - line_start(byte_offset)
end

# File lib/prism/parse_result.rb, line 53
def encoding
  source.encoding
end

# File lib/prism/parse_result.rb, line 70
def line(byte_offset)
  start_line + find_line(byte_offset)
end

# File lib/prism/parse_result.rb, line 82
def line_end(byte_offset)
  offsets[find_line(byte_offset) + 1] || source.bytesize
end

# File lib/prism/parse_result.rb, line 76
def line_start(byte_offset)
  offsets[find_line(byte_offset)]
end

# File lib/prism/parse_result.rb, line 58
def lines
  source.lines
end

# File lib/prism/parse_result.rb, line 64
def slice(byte_offset, length)
  source.byteslice(byte_offset, length) or raise
end

# File lib/prism/parse_result.rb, line 139
def find_line(byte_offset)
  left = 0
  right = offsets.length - 1

  while left <= right
    mid = left + (right - left) / 2
    return mid if (offset = offsets[mid]) == byte_offset

    if offset < byte_offset
      left = mid + 1
    else
      right = mid - 1
    end
  end

  left - 1
end