Class: SpinelKit::Json::Builder

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

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Builder

Returns a new instance of Builder.



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# File 'lib/spinel_kit/json_builder.rb', line 38

def initialize
  @buf   = "{"
  @first = true
end

Class Method Details

.escape(s) ⇒ Object

Escape a string for inclusion inside a JSON string literal (no surrounding quotes). Handles “, , and the JSON control-char escapes (b f n r t); other control bytes go through u00XX. ASCII-clean input passes through unchanged.



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# File 'lib/spinel_kit/json_builder.rb', line 101

def self.escape(s)
  out = ""
  i = 0
  n = s.length
  while i < n
    c = s[i]
    if c == "\""
      out = out + "\\\""
    elsif c == "\\"
      out = out + "\\\\"
    elsif c == "\n"
      out = out + "\\n"
    elsif c == "\r"
      out = out + "\\r"
    elsif c == "\t"
      out = out + "\\t"
    elsif c == "\b"
      out = out + "\\b"
    elsif c == "\f"
      out = out + "\\f"
    elsif c < " "
      b = c.getbyte(0)
      out = out + "\\u00" + Builder.hex2(b)
    else
      out = out + c
    end
    i += 1
  end
  out
end

.hex2(n) ⇒ Object

Two-digit lowercase hex of a byte (0..255).



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# File 'lib/spinel_kit/json_builder.rb', line 133

def self.hex2(n)
  hex = "0123456789abcdef"
  out = ""
  out = out + hex[(n / 16) % 16, 1]
  out = out + hex[n % 16, 1]
  out
end

.quote(s) ⇒ Object

Wrap a string in JSON quotes, escaping its body.



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# File 'lib/spinel_kit/json_builder.rb', line 93

def self.quote(s)
  "\"" + Builder.escape(s) + "\""
end

Instance Method Details

#add_bool(key, value) ⇒ Object

Append ‘“key”:true|false`.



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# File 'lib/spinel_kit/json_builder.rb', line 57

def add_bool(key, value)
  comma
  @buf = @buf + Builder.quote(key) + ":" + (value ? "true" : "false")
end

#add_num(key, value) ⇒ Object

Append ‘“key”:<number>` – `value.to_s` covers Integer (“5”) and Float (“1.5”). For hardcoded literals prefer add_raw.



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# File 'lib/spinel_kit/json_builder.rb', line 51

def add_num(key, value)
  comma
  @buf = @buf + Builder.quote(key) + ":" + value.to_s
end

#add_obj(key, child) ⇒ Object

Append ‘“key”:<nested object>` from another Builder.



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# File 'lib/spinel_kit/json_builder.rb', line 69

def add_obj(key, child)
  comma
  @buf = @buf + Builder.quote(key) + ":" + child.dump
end

#add_raw(key, raw) ⇒ Object

Append ‘“key”:<already-encoded JSON>` – for arrays / numeric literals.



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# File 'lib/spinel_kit/json_builder.rb', line 63

def add_raw(key, raw)
  comma
  @buf = @buf + Builder.quote(key) + ":" + raw
end

#add_str(key, value) ⇒ Object

Append ‘“key”:“escaped-value”`.



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# File 'lib/spinel_kit/json_builder.rb', line 44

def add_str(key, value)
  comma
  @buf = @buf + Builder.quote(key) + ":" + Builder.quote(value)
end

#comma ⇒ Object

Emit a separator before every entry except the first.



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# File 'lib/spinel_kit/json_builder.rb', line 80

def comma
  if @first
    @first = false
  else
    @buf = @buf + ","
  end
end

#dump ⇒ Object

Close the object and return the JSON string.



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# File 'lib/spinel_kit/json_builder.rb', line 75

def dump
  @buf + "}"
end