ucharcopy(t, s, i) — ActiveSupport::OkJson

ucharcopy(t, s, i)

Copies the valid UTF-8 bytes of a single character from string s at position i to I/O object t, and returns the number of bytes copied. If no valid UTF-8 char exists at position i, ucharcopy writes Ustrerr and returns 1.

Parameters

t req
s req
i req

Source

# File activesupport/lib/active_support/json/backends/okjson.rb, line 505
    def ucharcopy(t, s, i)
      n = s.length - i
      raise Utf8Error if n < 1

      c0 = s[i].ord

      # 1-byte, 7-bit sequence?
      if c0 < Utagx
        t.putc(c0)
        return 1
      end

      raise Utf8Error if c0 < Utag2 # unexpected continuation byte?

      raise Utf8Error if n < 2 # need continuation byte
      c1 = s[i+1].ord
      raise Utf8Error if c1 < Utagx || Utag2 <= c1

      # 2-byte, 11-bit sequence?
      if c0 < Utag3
        raise Utf8Error if ((c0&Umask2)<<6 | (c1&Umaskx)) <= Uchar1max
        t.putc(c0)
        t.putc(c1)
        return 2
      end

      # need second continuation byte
      raise Utf8Error if n < 3

      c2 = s[i+2].ord
      raise Utf8Error if c2 < Utagx || Utag2 <= c2

      # 3-byte, 16-bit sequence?
      if c0 < Utag4
        u = (c0&Umask3)<<12 | (c1&Umaskx)<<6 | (c2&Umaskx)
        raise Utf8Error if u <= Uchar2max
        t.putc(c0)
        t.putc(c1)
        t.putc(c2)
        return 3
      end

      # need third continuation byte
      raise Utf8Error if n < 4
      c3 = s[i+3].ord
      raise Utf8Error if c3 < Utagx || Utag2 <= c3

      # 4-byte, 21-bit sequence?
      if c0 < Utag5
        u = (c0&Umask4)<<18 | (c1&Umaskx)<<12 | (c2&Umaskx)<<6 | (c3&Umaskx)
        raise Utf8Error if u <= Uchar3max
        t.putc(c0)
        t.putc(c1)
        t.putc(c2)
        t.putc(c3)
        return 4
      end

      raise Utf8Error
    rescue Utf8Error
      t.write(Ustrerr)
      return 1
    end

Defined in activesupport/lib/active_support/json/backends/okjson.rb line 505 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveSupport::OkJson

Signature

Parameters