string_spec.rb

#
# This file is part of ruby-ffi.
# For licensing, see LICENSE.SPECS
#

require File.expand_path(File.join(File.dirname(__FILE__), "spec_helper"))
describe "String tests" do
  include FFI
  module StrLibTest
    extend FFI::Library
    ffi_lib TestLibrary::PATH
    attach_function :ptr_ret_pointer, [ :pointer, :int], :string
    attach_function :string_equals, [ :string, :string ], :int
    attach_function :pointer_string_equals, :string_equals, [ :pointer, :string ], :int
    attach_function :string_dummy, [ :string ], :void
    attach_function :string_null, [ ], :string
  end

  it "A String can be passed to a :pointer argument" do
    str = "string buffer"
    expect(StrLibTest.pointer_string_equals(str, str)).to eq(1)
    expect(StrLibTest.pointer_string_equals(str + "a", str)).to eq(0)
  end

  it "Poison null byte raises error" do
    s = "123\0abc"
    expect { StrLibTest.string_equals(s, s) }.to raise_error(ArgumentError)
  end

  it "casts nil as NULL pointer" do
    expect(StrLibTest.string_dummy(nil)).to be_nil
  end

  it "return nil for NULL char*" do
    expect(StrLibTest.string_null).to be_nil
  end

  it "reads an array of strings until encountering a NULL pointer" do
    strings = ["foo", "bar", "baz", "testing", "ffi"]
    ptrary = FFI::MemoryPointer.new(:pointer, 6)
    ary = strings.inject([]) do |a, str|
      f = FFI::MemoryPointer.new(1024)
      f.put_string(0, str)
      a << f
    end
    ary.insert(3, nil)
    ptrary.write_array_of_pointer(ary)
    expect(ptrary.get_array_of_string(0)).to eq(["foo", "bar", "baz"])
  end

  it "reads an array of strings of the size specified, substituting nil when a pointer is NULL" do
    strings = ["foo", "bar", "baz", "testing", "ffi"]
    ptrary = FFI::MemoryPointer.new(:pointer, 6)
    ary = strings.inject([]) do |a, str|
      f = FFI::MemoryPointer.new(1024)
      f.put_string(0, str)
      a << f
    end
    ary.insert(2, nil)
    ptrary.write_array_of_pointer(ary)
    expect(ptrary.get_array_of_string(0, 4)).to eq(["foo", "bar", nil, "baz"])
  end

  it "reads an array of strings, taking a memory offset parameter" do
    strings = ["foo", "bar", "baz", "testing", "ffi"]
    ptrary = FFI::MemoryPointer.new(:pointer, 5)
    ary = strings.inject([]) do |a, str|
      f = FFI::MemoryPointer.new(1024)
      f.put_string(0, str)
      a << f
    end
    ptrary.write_array_of_pointer(ary)
    expect(ptrary.get_array_of_string(2 * FFI.type_size(:pointer), 3)).to eq(["baz", "testing", "ffi"])
  end

  it "raises an IndexError when trying to read an array of strings out of bounds" do
    strings = ["foo", "bar", "baz", "testing", "ffi"]
    ptrary = FFI::MemoryPointer.new(:pointer, 5)
    ary = strings.inject([]) do |a, str|
      f = FFI::MemoryPointer.new(1024)
      f.put_string(0, str)
      a << f
    end
    ptrary.write_array_of_pointer(ary)
    expect { ptrary.get_array_of_string(0, 6) }.to raise_error(IndexError)
  end

  it "raises an IndexError when trying to read an array of strings using a negative offset" do
    strings = ["foo", "bar", "baz", "testing", "ffi"]
    ptrary = FFI::MemoryPointer.new(:pointer, 5)
    ary = strings.inject([]) do |a, str|
      f = FFI::MemoryPointer.new(1024)
      f.put_string(0, str)
      a << f
    end
    ptrary.write_array_of_pointer(ary)
    expect { ptrary.get_array_of_string(-1) }.to raise_error(IndexError)
  end
end