Class: PostgresPR::Utils::CustomBuffer

Inherits:
Object
  • Object
show all
Defined in:
lib/postgres-pr/utils/buffer.rb

Defined Under Namespace

Classes: EOF, Error

Constant Summary collapse

NUL = 
"\000"

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(content) ⇒ CustomBuffer

Returns a new instance of CustomBuffer.



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# File 'lib/postgres-pr/utils/buffer.rb', line 116

def initialize(content)
  self.init_buffer content
end

Class Method Details

.from_string(str) ⇒ Object 



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# File 'lib/postgres-pr/utils/buffer.rb', line 107

def self.from_string(str)
  new(str)
end

.of_size(size) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/postgres-pr/utils/buffer.rb', line 111

def self.of_size(size)
  raise ArgumentError if size < 0
  new('#' * size)
end

Instance Method Details

#at_end? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/postgres-pr/utils/buffer.rb', line 142

def at_end?
  @position == @size
end

#close ⇒ Object 



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# File 'lib/postgres-pr/utils/buffer.rb', line 126

def close
end

#content ⇒ Object 



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# File 'lib/postgres-pr/utils/buffer.rb', line 146

def content
  @content
end

#copy_from_stream(stream, n) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/postgres-pr/utils/buffer.rb', line 187

def copy_from_stream(stream, n)
  raise ArgumentError if n < 0
  while n > 0
    str = stream.read(n) 
    write(str)
    n -= str.size
  end
  raise if n < 0 
end

#init_buffer(content) ⇒ Object 



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# File 'lib/postgres-pr/utils/buffer.rb', line 120

def init_buffer(content)
  @size = content.size
  @content = content
  @position = 0
end

#position ⇒ Object 



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# File 'lib/postgres-pr/utils/buffer.rb', line 133

def position
  @position
end

#position=(new_pos) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/postgres-pr/utils/buffer.rb', line 137

def position=(new_pos)
  raise ArgumentError if new_pos < 0 or new_pos > @size
  @position = new_pos
end

#read(n) ⇒ Object

Raises:



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# File 'lib/postgres-pr/utils/buffer.rb', line 150

def read(n)
  raise EOF, 'cannot read beyond the end of buffer' if @position + n > @size
  str = @content[@position, n]
  @position += n
  str
end

#read_cstring ⇒ Object

returns a Ruby string without the trailing NUL character

Raises:



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# File 'lib/postgres-pr/utils/buffer.rb', line 228

def read_cstring
  nul_pos = @content.index(NUL, @position)
  raise Error, "no cstring found!" unless nul_pos

  sz = nul_pos - @position
  str = @content[@position, sz]
  @position += sz + 1
  return str
end

#read_int16_network ⇒ Object

Raises:



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# File 'lib/postgres-pr/utils/buffer.rb', line 173

def read_int16_network
  pos = @position
  raise EOF, 'cannot read beyond the end of buffer' if pos + 2 > @size
  @position += 2
  @content.get_int16_network(pos)
end

#read_int32_network ⇒ Object

Raises:



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# File 'lib/postgres-pr/utils/buffer.rb', line 180

def read_int32_network
  pos = @position
  raise EOF, 'cannot read beyond the end of buffer' if pos + 4 > @size
  @position += 4
  @content.get_int32_network(pos)
end

#read_rest ⇒ Object

read till the end of the buffer



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# File 'lib/postgres-pr/utils/buffer.rb', line 239

def read_rest
  read(self.size-@position)
end

#readbyte ⇒ Object Also known as: read_byte

Raises:



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# File 'lib/postgres-pr/utils/buffer.rb', line 165

def readbyte
  raise EOF, 'cannot read beyond the end of buffer' if @position >= @size
  byte = @content.getbyte(@position)
  @position += 1
  byte
end

#size ⇒ Object 



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# File 'lib/postgres-pr/utils/buffer.rb', line 129

def size
  @size
end

#write(str) ⇒ Object

Raises:



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# File 'lib/postgres-pr/utils/buffer.rb', line 157

def write(str)
  sz = str.size
  raise EOF, 'cannot write beyond the end of buffer' if @position + sz > @size
  @content[@position, sz] = str
  @position += sz
  self
end

#write_cstring(cstr) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/postgres-pr/utils/buffer.rb', line 221

def write_cstring(cstr)
  raise ArgumentError, "Invalid Ruby/cstring" if cstr.include?(NUL)
  write(cstr)
  write(NUL)
end

#write_int16_network(int16) ⇒ Object

Raises:



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# File 'lib/postgres-pr/utils/buffer.rb', line 205

def write_int16_network(int16)
  raise EOF, 'cannot write beyond the end of buffer' if @position + 2 > @size
  @content[@position, 2] = [int16].pack('n')
  @position += 2
  self
end

#write_int32_network(int32) ⇒ Object

Raises:



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# File 'lib/postgres-pr/utils/buffer.rb', line 212

def write_int32_network(int32)
  raise EOF, 'cannot write beyond the end of buffer' if @position + 4 > @size
  @content[@position, 4] = [int32].pack('N')
  @position += 4
  self
end

#writebyte(byte) ⇒ Object Also known as: write_byte

Raises:



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# File 'lib/postgres-pr/utils/buffer.rb', line 197

def writebyte(byte)
  raise EOF, 'cannot write beyond the end of buffer' if @position >= @size
  @content.setbyte(@position, byte)
  @position += 1
  self
end