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# coding: utf-8
# 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" => 1,
"endcodespacerange" => 1,
"beginbfchar" => 1,
"endbfchar" => 1,
"beginbfrange" => 1,
"endbfrange" => 1,
"begin" => 1,
"begincmap" => 1,
"def" => 1
}
attr_reader :map
def initialize(data)
@map = {}
process_data(data)
end
def process_data(data)
parser = build_parser(data)
mode = nil
instructions = []
while token = parser.parse_token(CMAP_KEYWORDS)
if token == "beginbfchar"
mode = :char
elsif token == "endbfchar"
process_bfchar_instructions(instructions)
instructions = []
mode = nil
elsif token == "beginbfrange"
mode = :range
elsif token == "endbfrange"
process_bfrange_instructions(instructions)
instructions = []
mode = nil
elsif mode == :char || mode == :range
instructions << token
end
end
end
def size
@map.size
end
# Convert a glyph code into one or more Codepoints.
#
# Returns an array of Integers.
#
def decode(c)
# TODO: implement the conversion
return c unless Integer === c
@map[c]
end
private
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
#
def str_to_int(str)
return nil if str.nil? || str.size == 0
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[0] > 0xD800 && unpacked_string[0] < 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)
points = [unpacked_string.shift, unpacked_string.shift]
result << (points[0] - 0xD800) * 0x400 + (points[1] - 0xDC00) + 0x10000
else
result << unpacked_string.shift
end
end
result
end
def process_bfchar_instructions(instructions)
instructions.each_slice(2) do |one, two|
find = str_to_int(one)
replace = str_to_int(two)
@map[find.first] = replace
end
end
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 "invalid bfrange section"
end
end
end
def bfrange_type_one(start_code, end_code, dst)
start_code = str_to_int(start_code)[0]
end_code = str_to_int(end_code)[0]
dst = str_to_int(dst)
# 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] + idx] : [dst[0], dst[1] + 1]
end
end
def bfrange_type_two(start_code, end_code, dst)
start_code = str_to_int(start_code)[0]
end_code = str_to_int(end_code)[0]
from_range = (start_code..end_code)
# add all values in the range to our mapping
from_range.each_with_index do |val, idx|
@map[val] = str_to_int(dst[idx])
end
end
end
end
|
