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EWF/library/kernel/json_string.e
Jocelyn Fiat 82f832a556 Updated license and copyright.
Updated classes with bottom indexing notes related to copyright and license.
2014-09-30 10:46:12 +02:00

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note
description: "[
A JSON_STRING represent a string in JSON.
A string is a collection of zero or more Unicodes characters, wrapped in double
quotes, using blackslash espaces.
]"
author: "$Author$"
date: "$Date$"
revision: "$Revision$"
license: "MIT (see http://www.opensource.org/licenses/mit-license.php)"
class
JSON_STRING
inherit
JSON_VALUE
redefine
is_equal
end
create
make_from_string, make_from_string_32, make_from_string_general,
make_from_escaped_json_string,
make_with_escaped_json, make_json, make_json_from_string_32
convert
make_from_string ({READABLE_STRING_8, STRING_8, IMMUTABLE_STRING_8}),
make_from_string_32 ({READABLE_STRING_32, STRING_32, IMMUTABLE_STRING_32}),
make_from_string_general ({READABLE_STRING_GENERAL, STRING_GENERAL, IMMUTABLE_STRING_GENERAL})
feature {NONE} -- Initialization
make_from_string (s: READABLE_STRING_8)
-- Initialize from ascii string `s'.
require
s_not_void: s /= Void
do
make_from_escaped_json_string (escaped_json_string (s))
end
make_from_string_32 (s: READABLE_STRING_32)
-- Initialize from unicode string `s'.
require
s_not_void: s /= Void
do
make_from_escaped_json_string (escaped_json_string (s))
end
make_from_string_general (s: READABLE_STRING_GENERAL)
-- Initialize from string `s'.
require
s_not_void: s /= Void
do
if attached {READABLE_STRING_8} s as s8 then
make_from_string (s8)
else
make_from_string_32 (s.as_string_32)
end
end
make_from_escaped_json_string (a_escaped_string: READABLE_STRING_8)
-- Initialize with `a_escaped_string' already JSON escaped.
require
a_escaped_string_not_void: a_escaped_string /= Void
do
item := a_escaped_string
end
make_with_escaped_json (a_escaped_string: READABLE_STRING_8)
-- Initialize with `a_escaped_string' already JSON escaped.
obsolete
"Use `make_from_escaped_json_string' Sept/2014"
require
a_escaped_string_not_void: a_escaped_string /= Void
do
make_from_escaped_json_string (a_escaped_string)
end
make_from_json_string (a_json: JSON_STRING)
-- Initialize with `a_json' string value.
do
make_from_escaped_json_string (a_json.item)
end
make_json (s: READABLE_STRING_8)
-- Initialize.
obsolete
"Use `make_from_string' Sept/2014"
require
item_not_void: s /= Void
do
make_with_escaped_json (escaped_json_string (s))
end
make_json_from_string_32 (s: READABLE_STRING_32)
-- Initialize from STRING_32 `s'.
obsolete
"Use `make_from_string_32' Sept/2014"
require
item_not_void: s /= Void
do
make_with_escaped_json (escaped_json_string (s))
end
feature -- Access
item: STRING
-- Contents with escaped entities if any
feature -- Conversion
unescaped_string_8: STRING_8
-- Unescaped ascii string from `item'.
--| note: valid only if `item' does not encode any unicode character.
local
s: like item
do
s := item
create Result.make (s.count)
unescape_to_string_8 (Result)
end
unescaped_string_32: STRING_32
-- Unescaped uncode string from `item'
--| some encoders uses UTF-8 , and not the recommended pure json encoding
--| thus, let's support the UTF-8 encoding during decoding.
local
s: READABLE_STRING_8
do
s := item
create Result.make (s.count)
unescape_to_string_32 (Result)
end
representation: STRING
-- String representation of `item' with escaped entities if any.
do
create Result.make (item.count + 2)
Result.append_character ('%"')
Result.append (item)
Result.append_character ('%"')
end
unescape_to_string_8 (a_output: STRING_8)
-- Unescape string `item' into `a_output'.
--| note: valid only if `item' does not encode any unicode character.
local
s: like item
i, n: INTEGER
c: CHARACTER
do
s := item
n := s.count
from
i := 1
until
i > n
loop
c := s [i]
if c = '\' then
if i < n then
inspect s [i + 1]
when '%"' then
a_output.append_character ('%"')
i := i + 2
when '\' then
a_output.append_character ('\')
i := i + 2
when '/' then
a_output.append_character ('/')
i := i + 2
when 'b' then
a_output.append_character ('%B')
i := i + 2
when 'f' then
a_output.append_character ('%F')
i := i + 2
when 'n' then
a_output.append_character ('%N')
i := i + 2
when 'r' then
a_output.append_character ('%R')
i := i + 2
when 't' then
a_output.append_character ('%T')
i := i + 2
when 'u' then
--| Leave unicode \uXXXX unescaped
a_output.append_character (c) -- '\'
i := i + 1
else
a_output.append_character (c) -- '\'
i := i + 1
end
else
a_output.append_character (c) -- '\'
i := i + 1
end
else
a_output.append_character (c)
i := i + 1
end
end
end
unescape_to_string_32 (a_output: STRING_32)
-- Unescape string `item' into `a_output' string 32.
--| some encoders uses UTF-8 , and not the recommended pure json encoding
--| thus, let's support the UTF-8 encoding during decoding.
local
s: READABLE_STRING_8
i, n: INTEGER
c: NATURAL_32
ch: CHARACTER_8
hex: READABLE_STRING_8
do
s := item
n := s.count
from
i := 1
until
i > n
loop
ch := s.item (i)
if ch = '\' then
if i < n then
inspect s [i + 1]
when '%"' then
a_output.append_character ('%"')
i := i + 2
when '\' then
a_output.append_character ('\')
i := i + 2
when '/' then
a_output.append_character ('/')
i := i + 2
when 'b' then
a_output.append_character ('%B')
i := i + 2
when 'f' then
a_output.append_character ('%F')
i := i + 2
when 'n' then
a_output.append_character ('%N')
i := i + 2
when 'r' then
a_output.append_character ('%R')
i := i + 2
when 't' then
a_output.append_character ('%T')
i := i + 2
when 'u' then
hex := s.substring (i + 2, i + 5) -- i+2 , i+2+4-1
if hex.count = 4 then
a_output.append_code (hexadecimal_to_natural_32 (hex))
end
i := i + 6 -- i+2+4
else
a_output.append_character (ch) -- '\'
i := i + 1
end
else
a_output.append_character (ch) -- '\'
i := i + 1
end
else
c := ch.natural_32_code
if c <= 0x7F then
-- 0xxxxxxx
check
ch = c.to_character_32
end
a_output.append_character (ch)
elseif c <= 0xDF then
-- 110xxxxx 10xxxxxx
i := i + 1
if i <= n then
a_output.append_code (((c & 0x1F) |<< 6) | (s.code (i) & 0x3F))
end
elseif c <= 0xEF then
-- 1110xxxx 10xxxxxx 10xxxxxx
i := i + 2
if i <= n then
a_output.append_code (((c & 0xF) |<< 12) | ((s.code (i - 1) & 0x3F) |<< 6) | (s.code (i) & 0x3F))
end
elseif c <= 0xF7 then
-- 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
i := i + 3
if i <= n then
a_output.append_code (((c & 0x7) |<< 18) | ((s.code (i - 2) & 0x3F) |<< 12) | ((s.code (i - 1) & 0x3F) |<< 6) | (s.code (i) & 0x3F))
end
end
i := i + 1
end
end
end
feature -- Visitor pattern
accept (a_visitor: JSON_VISITOR)
-- Accept `a_visitor'.
-- (Call `visit_json_string' procedure on `a_visitor'.)
do
a_visitor.visit_json_string (Current)
end
feature -- Comparison
is_equal (other: like Current): BOOLEAN
-- Is JSON_STRING made of same character sequence as `other'
-- (possibly with a different capacity)?
do
Result := item.same_string (other.item)
end
feature -- Change Element
append (a_escaped_string: READABLE_STRING_8)
-- Add JSON escaped string `a_escaped_string'
require
a_escaped_string_not_void: a_escaped_string /= Void
do
item.append_string (a_escaped_string)
end
append_json_string (a_json_string: JSON_STRING)
-- Add JSON string `a_json_string'
require
a_json_string_not_void: a_json_string /= Void
do
append (a_json_string.item)
end
append_string (s: READABLE_STRING_8)
-- Add ascii string `s'
require
s_not_void: s /= Void
do
append (escaped_json_string (s))
end
append_string_32 (s: READABLE_STRING_32)
-- Add unicode string `s'
require
s_not_void: s /= Void
do
append (escaped_json_string (s))
end
append_string_general (s: READABLE_STRING_GENERAL)
-- Add unicode string `s'
require
s_not_void: s /= Void
do
if attached {READABLE_STRING_8} s as s8 then
append_string (s.as_string_8)
else
append_string_32 (s.as_string_32)
end
end
feature -- Status report
hash_code: INTEGER
-- Hash code value
do
Result := item.hash_code
end
feature -- Status report
debug_output: STRING
-- String that should be displayed in debugger to represent `Current'.
do
Result := item
end
feature {NONE} -- Implementation
is_hexadecimal (s: READABLE_STRING_8): BOOLEAN
-- Is `s' an hexadecimal value?
local
i: INTEGER
do
from
Result := True
i := 1
until
i > s.count or not Result
loop
Result := s [i].is_hexa_digit
i := i + 1
end
end
hexadecimal_to_natural_32 (s: READABLE_STRING_8): NATURAL_32
-- Hexadecimal string `s' converted to NATURAL_32 value
require
s_not_void: s /= Void
is_hexadecimal: is_hexadecimal (s)
local
i, nb: INTEGER
char: CHARACTER
do
nb := s.count
if nb >= 2 and then s.item (2) = 'x' then
i := 3
else
i := 1
end
from
until
i > nb
loop
Result := Result * 16
char := s.item (i)
if char >= '0' and then char <= '9' then
Result := Result + (char |-| '0').to_natural_32
else
Result := Result + (char.lower |-| 'a' + 10).to_natural_32
end
i := i + 1
end
end
escaped_json_string (s: READABLE_STRING_GENERAL): STRING_8
-- JSON string with '"' and '\' characters and unicode escaped
require
s_not_void: s /= Void
local
i, j, n: INTEGER
uc: CHARACTER_32
c: CHARACTER_8
h: STRING_8
do
n := s.count
create Result.make (n + n // 10)
from
i := 1
until
i > n
loop
uc := s.item (i)
if uc.is_character_8 then
c := uc.to_character_8
inspect c
when '%"' then
Result.append_string ("\%"")
when '\' then
Result.append_string ("\\")
when '/' then
-- To avoid issue with Javascript </script> ...
-- escape only </ to <\/
if s.valid_index (i - 1) and then s.item (i - 1) = '<' then
Result.append_string ("\/")
else
Result.append_string ("/")
end
when '%B' then
Result.append_string ("\b")
when '%F' then
Result.append_string ("\f")
when '%N' then
Result.append_string ("\n")
when '%R' then
Result.append_string ("\r")
when '%T' then
Result.append_string ("\t")
else
Result.extend (c)
end
else
Result.append ("\u")
h := uc.code.to_hex_string
-- Remove first 0 and keep 4 hexa digit
from
j := 1
until
h.count = 4 or (j <= h.count and then h.item (j) /= '0')
loop
j := j + 1
end
h := h.substring (j, h.count)
from
until
h.count >= 4
loop
h.prepend_integer (0)
end
check
hexastring_has_4_chars: h.count = 4
end
Result.append (h)
end
i := i + 1
end
end
invariant
item_not_void: item /= Void
note
copyright: "2010-2014, Javier Velilla and others https://github.com/eiffelhub/json."
license: "https://github.com/eiffelhub/json/blob/master/License.txt"
end