The html data tag table uses five quad words of 64 bits per table entry. The first quad word spacifies the length of the html tag in characters. The second and third quad words specify the mask to be used to clear unwanted bits from the two registers used to compare the tag with the table. Finally, the fourth and fifth quad words specify the actual tag in string format (notice the strings are reversed due to being held in little endian format). Using this approach a nice tight tidy loop can be used to get the tag identifer (the row in the table).
html_tags dq 1, 000000000000000FFH, 00000000000000000H, "a", 0
dq 1, 000000000000000FFH, 00000000000000000H, "b", 0
dq 1, 000000000000000FFH, 00000000000000000H, "i", 0
dq 1, 000000000000000FFH, 00000000000000000H, "p", 0
dq 1, 000000000000000FFH, 00000000000000000H, "q", 0
dq 1, 000000000000000FFH, 00000000000000000H, "s", 0
dq 1, 000000000000000FFH, 00000000000000000H, "u", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "rb", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "dd", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "ld", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "td", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "me", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "1h", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "2h", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "3h", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "4h", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "5h", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "6h", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "rh", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "il", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "lo", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "br", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "pr", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "tr", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "dt", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "ht", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "rt", 0
dq 2, 0000000000000FFFFH, 00000000000000000H, "lu", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "idb", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "odb", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "loc", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "led", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "nfd", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "vid", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "gmi", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "sni", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "dbk", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "pam", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "van", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "erp", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "ctr", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "bus", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "pus", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "rav", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "rbw", 0
dq 3, 00000000000FFFFFFH, 00000000000000000H, "gvs", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "rbba", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "aera", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "esab", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "ydob", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "etic", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "edoc", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "atad", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "mrof", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "daeh", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "lmth", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "knil", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "niam", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "kram", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "unem", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "atem", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "ybur", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "pmas", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "naps", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "emit", 0
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "htap", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "edisa", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "oidua", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "debme", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "tupni", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "lebal", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "retem", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "marap", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "llams", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "elyts", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "elbat", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "ydobt", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "tooft", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "daeht", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "eltit", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "kcart", 0
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "oediv", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "retnec", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "nottub", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "savnac", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "golaid", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "erugif", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "retoof", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "redaeh", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "puorgh", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "emarfi", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "negyek", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "dnegel", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "tcejbo", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "noitpo", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "tuptuo", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "tpircs", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "tceles", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "ecruos", 0
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "gnorts", 0
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "sserdda", 0
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "elcitra", 0
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "noitpac", 0
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "sliated", 0
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "noitces", 0
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "yrammus", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "epytcod!", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "puorgloc", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "tsilatad", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "tesdleif", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "metiunem", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "tpircson", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "puorgtpo", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "ssergorp", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "etalpmet", 0
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "aeratxet", 0
dq 10, 0FFFFFFFFFFFFFFFFH, 0000000000000FFFFH, "ouqkcolb", "et"
dq 10, 0FFFFFFFFFFFFFFFFH, 0000000000000FFFFH, "itpacgif", "no"
db 0
Refinements to the pseudo code described in Part II of this tutorial
As with all things, even pseudo code can be optimised when it actually comes to the coding aspect. In writing the code, I attempted to follow the pseudo code as written, but realised that there were a few things missing. I will not bore you with the details, but simply present the final parse code to you.
title Parse_Html
option casemap:none
node struct
next_node dq ?
previous_node dq ?
parent_node dq ?
first_child dq ?
last_child dq ?
html_tag dq ?
html_attribute_string dq ?
html_text_string dq ?
node ends
.data
html_tags dq 1, 000000000000000FFH, 00000000000000000H, "a", 0 ; 0
dq 1, 000000000000000FFH, 00000000000000000H, "b", 0 ; 1
dq 1, 000000000000000FFH, 00000000000000000H, "i", 0 ; 2
dq 1, 000000000000000FFH, 00000000000000000H, "p", 0 ; 3
dq 1, 000000000000000FFH, 00000000000000000H, "q", 0 ; 4
dq 1, 000000000000000FFH, 00000000000000000H, "s", 0 ; 5
dq 1, 000000000000000FFH, 00000000000000000H, "u", 0 ; 6
dq 2, 0000000000000FFFFH, 00000000000000000H, "rb", 0 ; 7
dq 2, 0000000000000FFFFH, 00000000000000000H, "dd", 0 ; 8
dq 2, 0000000000000FFFFH, 00000000000000000H, "ld", 0 ; 9
dq 2, 0000000000000FFFFH, 00000000000000000H, "td", 0 ; 10
dq 2, 0000000000000FFFFH, 00000000000000000H, "me", 0 ; 11
dq 2, 0000000000000FFFFH, 00000000000000000H, "1h", 0 ; 12
dq 2, 0000000000000FFFFH, 00000000000000000H, "2h", 0 ; 13
dq 2, 0000000000000FFFFH, 00000000000000000H, "3h", 0 ; 14
dq 2, 0000000000000FFFFH, 00000000000000000H, "4h", 0 ; 15
dq 2, 0000000000000FFFFH, 00000000000000000H, "5h", 0 ; 16
dq 2, 0000000000000FFFFH, 00000000000000000H, "6h", 0 ; 17
dq 2, 0000000000000FFFFH, 00000000000000000H, "rh", 0 ; 18
dq 2, 0000000000000FFFFH, 00000000000000000H, "il", 0 ; 19
dq 2, 0000000000000FFFFH, 00000000000000000H, "lo", 0 ; 20
dq 2, 0000000000000FFFFH, 00000000000000000H, "br", 0 ; 21
dq 2, 0000000000000FFFFH, 00000000000000000H, "pr", 0 ; 22
dq 2, 0000000000000FFFFH, 00000000000000000H, "tr", 0 ; 23
dq 2, 0000000000000FFFFH, 00000000000000000H, "dt", 0 ; 24
dq 2, 0000000000000FFFFH, 00000000000000000H, "ht", 0 ; 25
dq 2, 0000000000000FFFFH, 00000000000000000H, "rt", 0 ; 26
dq 2, 0000000000000FFFFH, 00000000000000000H, "lu", 0 ; 27
dq 3, 00000000000FFFFFFH, 00000000000000000H, "idb", 0 ; 28
dq 3, 00000000000FFFFFFH, 00000000000000000H, "odb", 0 ; 29
dq 3, 00000000000FFFFFFH, 00000000000000000H, "loc", 0 ; 30
dq 3, 00000000000FFFFFFH, 00000000000000000H, "led", 0 ; 31
dq 3, 00000000000FFFFFFH, 00000000000000000H, "nfd", 0 ; 32
dq 3, 00000000000FFFFFFH, 00000000000000000H, "vid", 0 ; 33
dq 3, 00000000000FFFFFFH, 00000000000000000H, "gmi", 0 ; 34
dq 3, 00000000000FFFFFFH, 00000000000000000H, "sni", 0 ; 35
dq 3, 00000000000FFFFFFH, 00000000000000000H, "dbk", 0 ; 36
dq 3, 00000000000FFFFFFH, 00000000000000000H, "pam", 0 ; 37
dq 3, 00000000000FFFFFFH, 00000000000000000H, "van", 0 ; 38
dq 3, 00000000000FFFFFFH, 00000000000000000H, "erp", 0 ; 39
dq 3, 00000000000FFFFFFH, 00000000000000000H, "ctr", 0 ; 40
dq 3, 00000000000FFFFFFH, 00000000000000000H, "bus", 0 ; 41
dq 3, 00000000000FFFFFFH, 00000000000000000H, "pus", 0 ; 42
dq 3, 00000000000FFFFFFH, 00000000000000000H, "rav", 0 ; 43
dq 3, 00000000000FFFFFFH, 00000000000000000H, "rbw", 0 ; 44
dq 3, 00000000000FFFFFFH, 00000000000000000H, "gvs", 0 ; 45
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "rbba", 0 ; 46
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "aera", 0 ; 47
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "esab", 0 ; 48
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "ydob", 0 ; 49
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "etic", 0 ; 50
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "edoc", 0 ; 51
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "atad", 0 ; 52
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "mrof", 0 ; 53
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "daeh", 0 ; 54
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "lmth", 0 ; 55
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "knil", 0 ; 56
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "niam", 0 ; 57
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "kram", 0 ; 58
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "unem", 0 ; 59
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "atem", 0 ; 60
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "ybur", 0 ; 61
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "pmas", 0 ; 62
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "naps", 0 ; 63
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "emit", 0 ; 64
dq 4, 000000000FFFFFFFFH, 00000000000000000H, "htap", 0 ; 65
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "edisa", 0 ; 66
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "oidua", 0 ; 67
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "debme", 0 ; 68
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "tupni", 0 ; 69
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "lebal", 0 ; 70
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "retem", 0 ; 71
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "marap", 0 ; 72
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "llams", 0 ; 73
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "elyts", 0 ; 74
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "elbat", 0 ; 75
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "ydobt", 0 ; 76
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "tooft", 0 ; 77
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "daeht", 0 ; 78
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "eltit", 0 ; 79
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "kcart", 0 ; 80
dq 5, 0000000FFFFFFFFFFH, 00000000000000000H, "oediv", 0 ; 81
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "retnec", 0 ; 82
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "nottub", 0 ; 83
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "savnac", 0 ; 84
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "golaid", 0 ; 85
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "erugif", 0 ; 86
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "retoof", 0 ; 87
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "redaeh", 0 ; 88
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "puorgh", 0 ; 89
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "emarfi", 0 ; 90
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "negyek", 0 ; 91
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "dnegel", 0 ; 92
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "tcejbo", 0 ; 93
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "noitpo", 0 ; 94
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "tuptuo", 0 ; 95
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "tpircs", 0 ; 96
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "tceles", 0 ; 97
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "ecruos", 0 ; 98
dq 6, 00000FFFFFFFFFFFFH, 00000000000000000H, "gnorts", 0 ; 99
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "sserdda", 0 ; 100
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "elcitra", 0 ; 101
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "noitpac", 0 ; 102
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "sliated", 0 ; 103
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "noitces", 0 ; 104
dq 7, 000FFFFFFFFFFFFFFH, 00000000000000000H, "yrammus", 0 ; 105
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "epytcod!", 0 ; 106
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "puorgloc", 0 ; 107
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "tsilatad", 0 ; 108
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "tesdleif", 0 ; 109
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "metiunem", 0 ; 110
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "tpircson", 0 ; 111
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "puorgtpo", 0 ; 112
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "ssergorp", 0 ; 113
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "etalpmet", 0 ; 114
dq 8, 0FFFFFFFFFFFFFFFFH, 00000000000000000H, "aeratxet", 0 ; 115
dq 10, 0FFFFFFFFFFFFFFFFH, 0000000000000FFFFH, "ouqkcolb", "et" ; 116
dq 10, 0FFFFFFFFFFFFFFFFH, 0000000000000FFFFH, "itpacgif", "no" ; 117
start_comment dd '--!<'
end_comment dd '>--'
end_script_tag dq 'tpircs/<'
end_style_tag dq '>elyts/<'
.code
;
; r15 points to the source
; r14 points to the free workspace
;
Parse_Html proc first_node: qword, last_node: qword
mov first_node, rcx
mov last_node, rdx
create_node: mov rdi, r14
add r14, sizeof node
hunt_for_tag: mov eax, dword ptr [rsi]
cmp al, 21
je end_of_parse
cmp al, '<'
je found_start_tag
add rsi, 1
jmp hunt_for_tag
found_start_tag: cmp eax, start_comment
jne not_start_comment
;
; Process the comment
;
hunt_for_end_comment: add rsi, 1
mov eax, dword ptr [rsi]
and eax, 0FFFFFFH
cmp eax, end_comment
jne hunt_for_end_comment
add rsi, 3
jmp hunt_for_tag
not_start_comment: cmp ah, '/'
je start_end_tag
xor r10, r10
process_tag: mov r13, r14
add rsi, 1
mov al, byte ptr [rsi]
copy_html_tag: add rsi, 1
add r14, 1
mov byte ptr [r14], al
inc byte ptr [r13]
mov al, byte ptr [rsi]
cmp al, '0'
jb tag_no_number
cmp al, '9'
jbe copy_html_tag
tag_no_number: or al, 020H
cmp al, 'a'
jb end_start_html_tag
cmp al, 'z'
ja end_start_html_tag
jmp copy_html_tag
end_start_html_tag: add r14, 1
;
; Find the tag in the table
;
lea r12, html_tags
xor rdx, rdx
xor rcx, rcx
mov bl, byte ptr [r13]
find_html_tag_length_loop: mov rdx, qword ptr [r12]
or rdx, rdx
je tag_not_found
cmp bl, dl
je identify_html_tag
lea r12, 40[r12]
add rcx, 1
jmp find_html_tag_length_loop
identify_html_tag: mov r8, qword ptr 1[r13]
mov r9, qword ptr 9[r13]
and r8, qword ptr 8[r12]
and r9, qword ptr 16[r12]
cmp r8, qword ptr 24[r12]
jne next_tag_in_table
cmp r9, qword ptr 32[r12]
jne next_tag_in_table
mov node.html_tag[rdi], rcx
jmp tag_found
next_tag_in_table: lea r12, 40[r12]
add rcx, 1
mov rdx, qword ptr [r12]
or rdx, rdx
je tag_not_found
jmp identify_html_tag
;
; Find the start of the attributes or end of tag
;
tag_found: mov al, byte ptr [rsi]
cmp al, ' '
je find_non_space
cmp al, 009H
je find_non_space
cmp al, 00DH
je find_non_space
cmp al, 00AH
jne found_non_space
find_non_space: add rsi, 1
jmp tag_found
found_non_space: cmp al, '>'
je found_end_attributes
cmp al, '/'
je nearly_found_end_attributes
;
; We have found the start of the attributes
;
mov node.html_attribute_string[rdi], r14
find_end_of_attributes: mov byte ptr [r14], al
add rsi, 1
add r14, 1
mov al, byte ptr [rsi]
cmp al, '"'
je skip_to_end_double_quotes
cmp al, "'"
je skip_to_end_single_quotes
cmp al, '>'
je found_end_attributes
cmp al, '/'
je nearly_found_end_attributes
jmp find_end_of_attributes
skip_to_end_double_quotes: mov byte ptr [r14], al
add rsi, 1
add r14, 1
mov al, byte ptr [rsi]
cmp al, '"'
je find_end_of_attributes
jmp skip_to_end_double_quotes
skip_to_end_single_quotes: mov byte ptr [r14], al
add rsi, 1
add r14, 1
mov al, byte ptr [rsi]
cmp al, '"'
je find_end_of_attributes
jmp skip_to_end_single_quotes
nearly_found_end_attributes: add rsi, 1
mov al, byte ptr [rsi]
cmp al, '>'
jne nearly_found_end_attributes
found_end_attributes: xor al, al
mov byte ptr [r14], al
add r14, 1
add rsi, 1
or r10, r10
je next_sub_section
mov rax, node.html_tag[rdi]
ret
;
; Need to know if this is a self terminating tag
;
next_sub_section: mov rbx, node.html_tag[rdi]
;
; Special case for <script>
;
cmp rbx, 96
je process_script
;
; Special case for <style>
;
cmp rbx, 74
je process_style
cmp rbx, 7
je self_terminating
cmp rbx, 18
je self_terminating
cmp rbx, 30
je self_terminating
cmp rbx, 34
je self_terminating
cmp rbx, 44
je self_terminating
cmp rbx, 47
je self_terminating
cmp rbx, 48
je self_terminating
cmp rbx, 56
je self_terminating
cmp rbx, 60
je self_terminating
cmp rbx, 68
je self_terminating
cmp rbx, 69
je self_terminating
cmp rbx, 72
je self_terminating
cmp rbx, 80
je self_terminating
cmp rbx, 91
je self_terminating
cmp rbx, 98
je self_terminating
cmp rbx, 106
je self_terminating
;
; Skip spaces etc
;
find_next_non_space: mov al, byte ptr [rsi]
cmp al, ' '
je skip_space
cmp al, 009H
je skip_space
cmp al, 00DH
je skip_space
cmp al, 00AH
jne check_for_text
skip_space: add rsi, 1
jmp find_next_non_space
check_for_text: cmp al, '<'
je recursive_call
;
; Non space characters after the start tag need to be remembered
;
mov node.html_text_string[rdi], r14
copy_text_string: mov byte ptr [r14], al
add r14, 1
add rsi, 1
mov al, byte ptr [rsi]
cmp al, '<'
jne copy_text_string
add r14, 1
;
; Apply recursive call to Parse_Html
;
recursive_call: add r14, 1
push rdi
lea rdx, node.last_child[rdi]
lea rcx, node.first_child[rdi]
sub rsp, 16
call Parse_Html
add rsp, 16
pop rdi
cmp node.html_tag[rdi], rax
je self_terminating
int 3
;
; Process self terminating tags
;
self_terminating: mov rcx, first_node
mov rdx, last_node
mov rax, qword ptr [rcx]
or rax, rax
jne not_first_node
mov qword ptr [rcx], rdi
jmp chain_to_end
not_first_node: mov rax, qword ptr [rdx]
mov node.next_node[rax], rdi
chain_to_end: mov rax, qword ptr [rdx]
mov node.previous_node[rdi], rax
mov qword ptr [rdx], rdi
jmp create_node
tag_not_found: int 3
start_end_tag: add rsi, 1
xor r10, r10
inc r10
jmp process_tag
;
; Search for </script> end tag
;
process_script: mov node.html_text_string[rdi], r14
process_script_loop: mov rax, qword ptr [rsi]
mov rbx, end_script_tag
cmp rax, rbx
je recursive_call
mov byte ptr [r14], al
add rsi, 1
add r14, 1
jmp process_script_loop
;
; Search for </style> end tag
;
process_style: mov node.html_text_string[rdi], r14
process_style_loop: mov rax, qword ptr [rsi]
mov rbx, end_style_tag
cmp rax, rbx
je recursive_call
mov byte ptr [r14], al
add rsi, 1
add r14, 1
jmp process_style_loop
end_of_parse: ret
Parse_Html endp
end
Testing
The 'harness' code you will need is:-
title HTMLParse
option casemap:none
FILE_ATTRIBUTE_NORMAL = 080H
OPEN_EXISTING = 3
GENERIC_READ = 080000000H
MEM_COMMIT = 01000H
PAGE_READWRITE = 040H
CreateFileA proto :qword, :qword, :qword, :qword, :qword, :qword, :qword
GetFileSize proto :qword, :qword
ReadFile proto :qword, :qword, :qword, :qword, :qword
CloseHandle proto :qword
VirtualAlloc proto :qword, :qword, :qword, :qword
Parse_Html proto :qword, :qword, :qword
node struct
next_node dq ?
previous_node dq ?
parent_node dq ?
first_child dq ?
last_child dq ?
node_tag dq ?
node_attribute_string dq ?
node_text_string dq ?
node_text_length dq ?
node ends
.data
filename db 'index.html', 0
bytes_read dq 0
node_base dq 0
first_node dq 0
last_node dq 0
.code
MainStartup proc
;
; Read the file into a buffer
;
xor rax, rax
push rax
push FILE_ATTRIBUTE_NORMAL
push OPEN_EXISTING
sub rsp, 32
mov r9, rax
mov r8, rax
mov rdx, GENERIC_READ
lea rcx, filename
call CreateFileA
add rsp, 56
mov r15, rax
xor rdx, rdx
mov rcx, r15
sub rsp, 16
call GetFileSize
add rsp, 16
mov r14, rax
mov r9, PAGE_READWRITE
mov r8, MEM_COMMIT
mov rdx, r14
inc rdx
xor rcx, rcx
sub rsp, 32
call VirtualAlloc
add rsp, 32
mov r13, rax
mov al, 21
mov byte ptr [r13+r14], al
xor rax, rax
push rax
sub rsp, 32
lea r9, bytes_read
mov r8, r14
mov rdx, r13
mov rcx, r15
call ReadFile
add rsp, 40
sub rsp, 8
mov rcx, r15
call CloseHandle
add rsp, 8
mov rax, r14
mov rbx, sizeof node
imul rbx
;
; Compute memory for the number of nodes required to parse
; I have done this by saying that there cannot be more than
; the number of bytes in the html file. For example, a 100
; byte file would allocate 100 nodes - an overkill but it
; will speed things up considerably as we do not have to use
; the heap!
;
mov r14, rax
mov r9, PAGE_READWRITE
mov r8, MEM_COMMIT
mov rdx, r14
inc rdx
xor rcx, rcx
sub rsp, 32
call VirtualAlloc
add rsp, 32
mov r15, rax
mov rsi, r13
;
; Get memory for the string area
;
mov r9, PAGE_READWRITE
mov r8, MEM_COMMIT
mov rdx, 10000000
xor rcx, rcx
sub rsp, 32
call VirtualAlloc
add rsp, 32
mov r14, rax
;
; Now begin the parse of the HTML. RSI contains the source
; base and R15 contains the address for the current node
; and R14 contains the string area address
;
mov eax, dword ptr [rsi]
and eax, 0FFFFFFH
cmp eax, 0BFBBEFH
jne parse_file
add rsi, 3
parse_file: lea rcx, first_node
lea rdx, last_node
sub rsp, 16
call Parse_Html
add rsp, 16
xor rax, rax
ret
MainStartup endp
end
Remember to set the 'linker->advanced->Entry Point' option to MainStartup and include an 'index.html' file to parse in the source directory.
If you have any questions about this set of tutorials, please leave a reply and I will get back to you as soon as I can.
This post has been edited by Martyn.Rae: 07 July 2017 - 05:52 AM
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