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# coding: utf-8
# typed: strict
# frozen_string_literal: true
################################################################################
#
# Copyright (C) 2008 James Healy (jimmy@deefa.com)
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
################################################################################
class PDF::Reader
# wraps a string containing a PDF CMap and provides convenience methods for
# extracting various useful information.
#
class CMap # :nodoc:
CMAP_KEYWORDS = {
"begincodespacerange" => :noop,
"endcodespacerange" => :noop,
"beginbfchar" => :noop,
"endbfchar" => :noop,
"beginbfrange" => :noop,
"endbfrange" => :noop,
"begin" => :noop,
"begincmap" => :noop,
"def" => :noop
} #: Hash[String, Symbol]
#: Hash[Integer, Array[Integer]]
attr_reader :map
#: (String) -> void
def initialize(data)
@map = {} #: Hash[Integer, Array[Integer]]
process_data(data)
end
#: () -> Integer
def size
@map.size
end
# Convert a glyph code into one or more Codepoints.
#
# Returns an array of Integers.
#
#: (Integer) -> Array[Integer]
def decode(c)
@map.fetch(c, [])
end
private
#: (String, ?Symbol) -> void
def process_data(data, initial_mode = :none)
parser = build_parser(data)
mode = initial_mode
instructions = []
while token = parser.parse_token(CMAP_KEYWORDS)
if token.is_a?(String) || token.is_a?(Array)
if token == "beginbfchar"
mode = :char
elsif token == "endbfchar"
process_bfchar_instructions(instructions)
instructions = []
mode = :none
elsif token == "beginbfrange"
mode = :range
elsif token == "endbfrange"
process_bfrange_instructions(instructions)
instructions = []
mode = :none
elsif mode == :char
instructions << token.to_s
elsif mode == :range
instructions << token
end
end
end
end
#: (String) -> PDF::Reader::Parser
def build_parser(instructions)
buffer = Buffer.new(StringIO.new(instructions))
Parser.new(buffer)
end
# The following includes some manual decoding of UTF-16BE strings into unicode codepoints. In
# theory we could replace all the UTF-16 code with something based on Ruby's encoding support:
#
# str.dup.force_encoding("utf-16be").encode!("utf-8").unpack("U*")
#
# However, some cmaps contain broken surrogate pairs and the ruby encoding support raises an
# exception when we try converting broken UTF-16 to UTF-8
#
#: (String) -> Array[Integer]
def str_to_int(str)
unpacked_string = if str.bytesize == 1 # UTF-8
str.unpack("C*")
else # UTF-16
str.unpack("n*")
end
result = []
while unpacked_string.any? do
if unpacked_string.size >= 2 &&
unpacked_string.first.to_i >= 0xD800 &&
unpacked_string.first.to_i <= 0xDBFF
# this is a Unicode UTF-16 "Surrogate Pair" see Unicode Spec. Chapter 3.7
# lets convert to a UTF-32. (the high bit is between 0xD800-0xDBFF, the
# low bit is between 0xDC00-0xDFFF) for example: U+1D44E (U+D835 U+DC4E)
point_one = unpacked_string.shift.to_i
point_two = unpacked_string.shift.to_i
result << (point_one - 0xD800) * 0x400 + (point_two - 0xDC00) + 0x10000
else
result << unpacked_string.shift
end
end
result
end
#: (Array[String]) -> void
def process_bfchar_instructions(instructions)
instructions.each_slice(2) do |one, two|
find = str_to_int(one.to_s)
replace = str_to_int(two.to_s)
if find.any? && replace.any?
@map[find.first.to_i] = replace
end
end
end
#: (Array[Array[String] | String]) -> void
def process_bfrange_instructions(instructions)
instructions.each_slice(3) do |start, finish, to|
if start.kind_of?(String) && finish.kind_of?(String) && to.kind_of?(String)
bfrange_type_one(start, finish, to)
elsif start.kind_of?(String) && finish.kind_of?(String) && to.kind_of?(Array)
bfrange_type_two(start, finish, to)
else
raise MalformedPDFError, "invalid bfrange section"
end
end
end
#: (String, String, String) -> void
def bfrange_type_one(start_code, end_code, dst)
start_code = str_to_int(start_code).first
end_code = str_to_int(end_code).first
dst = str_to_int(dst)
return if start_code.nil? || end_code.nil?
# add all values in the range to our mapping
(start_code..end_code).each_with_index do |val, idx|
@map[val] = dst.length == 1 ? [dst[0].to_i + idx] : [dst[0].to_i, dst[1].to_i + 1]
end
end
#: (String, String, Array[String]) -> void
def bfrange_type_two(start_code, end_code, dst)
start_code = str_to_int(start_code).first
end_code = str_to_int(end_code).first
return if start_code.nil? || end_code.nil?
from_range = (start_code..end_code)
# add all values in the range to our mapping
from_range.each_with_index do |val, idx|
dst_char = dst[idx]
@map[val.to_i] = str_to_int(dst_char) if dst_char
end
end
end
end
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