从乱码短信谈短信解码

从乱码短信谈短信解码

 

从乱码短信谈短信解码

 

某项目接收到乱码短信：

Ω f T K p ! C ù

 

从底层读出其内容数据为:0x15,0x33,0x75,0x0d,到第80个byte数据都是0x0d,最后一个byte是0x07。

 

由此为例，分析7bit解码过程： 

 

方法1：

Hex	0x15	0x33	0x75	0x0d
Dec	0001 0101	00110011	01110101	00001101
截取	0001 0101	00110011	01110101	00001101
补位	001 0101	110011 0	10101 00	1101 011
查表	Ω	f	T	K

 

方法2：

Hex	0x15	0x33	0x75	0x0d
倒排	0x0d	0x75	0x33	0x15
Dec	00001101	01110101	00110011	0001 0101
截取	0000 1101	011 10101	00 110011	0 001 0101
补位	1101 011	10101 00	110011 0	0010101
查表	K	T	f	Ω
倒排	Ω	f	T	K

 

 

附编码（选自7bit_default_table pud格式7bit编码对应表）：

                           

注意事项:空位使用0填充(图中6字节的情况)，当编码后最后一个字节空位刚好为7位时(图中7字节的情况)，改为使用字符CR(0x0d)填充, 避免填充后多余字节0x00与c语言字符串结尾符号0x00的冲突

编码过程示例

附7bit default table：

Character		GSM 7-bit default alphabet (Decimal)	GSM 7-bit default alphabet (Hexadecimal)	ISO 8859 Latin 1 (Decimal)	ISO 8859 Latin 1 (Hexadecimal)
@	At sign	0	00	64	40
£	Pound sign	1	01	163	A3
$	Dollar sign	2	02	36	24
¥	Yuan/Yen sign	3	03	165	A5
è	Small letter e with grave accent	4	04	232	E8
é	Small letter e with acute accent	5	05	233	E9
ù	Small letter u with grave accent	6	06	249	F9
ì	Small letter i with grave accent	7	07	236	EC
ò	Small letter o with grave accent	8	08	242	F2
Ç	Capital letter C with cedilla	9	09	199	C7
	Linefeed	10	0A	10	0A
Ø	Capital letter O with stroke	11	0B	216	D8
ø	Small letter o with stroke	12	0C	248	F8
	Carriage return	13	0D	13	0D
Å	Capital letter A with ring	14	0E	197	C5
å	Small letter a with ring	15	0F	229	E5
Δ	Capital letter Greek delta	16	10
_	Underscore	17	11	95	5F
Φ	Capital letter Greek phi	18	12
Γ	Capital letter Greek gamma	19	13
Λ	Capital letter Greek lambda	20	14
Ω	Capital letter Greek omega	21	15
Π	Capital letter Greek pi	22	16
Ψ	Capital letter Greek psi	23	17
Σ	Capital letter Greek sigma	24	18
Θ	Capital letter Greek theta	25	19
Ξ	Capital letter Greek xi	26	1A
	Escape	27	1B
	Form feed	27 10	1B0A	12	0C
^	Caret / Circumflex	27 20	1B14	94	5E
{	Left curly bracket	27 40	1B28	123	7B
}	Right curly bracket	27 41	1B29	125	7D
\	Backslash	27 47	1B2F	92	5C
[	Left square bracket	27 60	1B3C	91	5B
~	Tilde	27 61	1B3D	126	7E
]	Right square bracket	27 62	1B3E	93	5D
|	Vertical bar	27 64	1B40	124	7C
€	Euro sign	27 101	1B65
Æ	Capital letter AE	28	1C	198	C6
æ	Small letter ae	29	1D	230	E6
ß	Small letter German Eszett	30	1E	223	DF
É	Capital letter E with acute accent	31	1F	201	C9
	Space	32	20	32	20
!	Exclamation mark	33	21	33	21
"	Quotation mark	34	22	34	22
#	Number sign	35	23	35	23
¤	Currency sign	36	24	164	A4
%	Percent sign	37	25	37	25
&	Ampersand	38	26	38	26
'	Apostrophe	39	27	39	27
(	Left parenthesis	40	28	40	28
)	Right parenthesis	41	29	41	29
*	Asterisk	42	2A	42	2A
+	Plus sign	43	2B	43	2B
,	Comma	44	2C	44	2C
-	Minus sign / Hyphen	45	2D	45	2D
.	Full stop / Period	46	2E	46	2E
/	Slash	47	2F	47	2F
0	Digit zero	48	30	48	30
1	Digit one	49	31	49	31
2	Digit two	50	32	50	32
3	Digit three	51	33	51	33
4	Digit four	52	34	52	34
5	Digit five	53	35	53	35
6	Digit six	54	36	54	36
7	Digit seven	55	37	55	37
8	Digit eight	56	38	56	38
9	Digit nine	57	39	57	39
:	Colon	58	3A	58	3A
;	Semicolon	59	3B	59	3B
<	Less-than sign	60	3C	60	3C
=	Equals sign	61	3D	61	3D
>	Greater-than sign	62	3E	62	3E
?	Question mark	63	3F	63	3F
¡	Inverted exclamation mark	64	40	161	A1
A	Capital letter A	65	41	65	41
B	Capital letter B	66	42	66	42
C	Capital letter C	67	43	67	43
D	Capital letter D	68	44	68	44
E	Capital letter E	69	45	69	45
F	Capital letter F	70	46	70	46
G	Capital letter G	71	47	71	47
H	Capital letter H	72	48	72	48
I	Capital letter I	73	49	73	49
J	Capital letter J	74	4A	74	4A
K	Capital letter K	75	4B	75	4B
L	Capital letter L	76	4C	76	4C
M	Capital letter M	77	4D	77	4D
N	Capital letter N	78	4E	78	4E
O	Capital letter O	79	4F	79	4F
P	Capital letter P	80	50	80	50
Q	Capital letter Q	81	51	81	51
R	Capital letter R	82	52	82	52
S	Capital letter S	83	53	83	53
T	Capital letter T	84	54	84	54
U	Capital letter U	85	55	85	55
V	Capital letter V	86	56	86	56
W	Capital letter W	87	57	87	57
X	Capital letter X	88	58	88	58
Y	Capital letter Y	89	59	89	59
Z	Capital letter Z	90	5A	90	5A
Ä	Capital letter A with diaeresis	91	5B	196	C4
Ö	Capital letter O with diaeresis	92	5C	214	D6
Ñ	Capital letter N with tilde	93	5D	209	D1
Ü	Capital letter U with diaeresis	94	5E	220	DC
§	Section sign	95	5F	167	A7
¿	Inverted question mark	96	60	191	BF
a	Small letter a	97	61	97	61
b	Small letter b	98	62	98	62
c	Small letter c	99	63	99	63
d	Small letter d	100	64	100	64
e	Small letter e	101	65	101	65
f	Small letter f	102	66	102	66
g	Small letter g	103	67	103	67
h	Small letter h	104	68	104	68
i	Small letter i	105	69	105	69
j	Small letter j	106	6A	106	6A
k	Small letter k	107	6B	107	6B
l	Small letter l	108	6C	108	6C
m	Small letter m	109	6D	109	6D
n	Small letter n	110	6E	110	6E
o	Small letter o	111	6F	111	6F
p	Small letter p	112	70	112	70
q	Small letter q	113	71	113	71
r	Small letter r	114	72	114	72
s	Small letter s	115	73	115	73
t	Small letter t	116	74	116	74
u	Small letter u	117	75	117	75
v	Small letter v	118	76	118	76
w	Small letter w	119	77	119	77
x	Small letter x	120	78	120	78
y	Small letter y	121	79	121	79
z	Small letter z	122	7A	122	7A
ä	Small letter a with diaeresis	123	7B	228	E4
ö	Small letter o with diaeresis	124	7C	246	F6
ñ	Small letter n with tilde	125	7D	241	F1
ü	Small letter u with diaeresis	126	7E	252	FC
à	Small letter a with grave accent	127	7F	224	E0