;
; String helpers
;
; (C) KolibriOS team (parts from another project)
; (C) 2022 Coldy (str_buld function)
; Thank's you for use this code and software based on it!
; I will glad if it's will be helpful.
;
; Distributed under terms of GPL
;
;****************************************
;* input: esi = pointer to string *
;* output: ecx = length of the string *
;****************************************
strlen:
push eax esi
xor ecx, ecx
@@:
lodsb
or al, al
jz @f
inc ecx
jmp @b
@@:
pop esi eax
ret
;*************************************************
;* input: esi = pointer to the src string *
;* edi = pointer to the dest string *
;* ecx = number of bytes to copy *
;*************************************************
strncpy:
push eax ecx esi edi
@@:
lodsb
stosb
or al, al
jz @f
dec ecx
jz @f
jmp @b
@@:
pop edi esi ecx eax
ret
if 0 ; { Not used
;*************************************************
;* input: esi = pointer to the src string *
;* edi = pointer to the dest string *
;*************************************************
strcpy:
push esi edi
; ecx = ???
; ZF = 0
rep movsb
pop edi esi
ret
;*************************************************
;* input: esi = pointer to the src string *
;* edi = pointer to the dest string *
;* ecx = number of bytes to copy *
;*************************************************
strncat:
push edi
push ecx esi
mov esi, edi
call strlen
add edi, ecx
pop esi ecx
call strncpy
pop edi
ret
;*************************************************
;* (c) Coldy 2022 *
;* input: edi = pointer to the dest string *
;* ecx = number of bytes to zero *
;*************************************************
;memnz:
; push eax ecx edi
; xor eax, eax
; rep stosb
; pop edi ecx eax
; ret
end if ; }
;
; str_build
;
; Purose: Build output string by template. Allocate necessary output
; buffer, copy parts from template and insert strings instead
; of $ wildcard.
;
; SPECIAL CASE:
; For use dollar sing ($) in text, just mark this plase(s) in
; template and provide pointer(s) on string with this sign in args)
;
; PRECAUTION:
; 1. Not safe, caller must provide args count >= $ wildcard count
; 2. If used dynamic memory allocator then caller must free output
; buffer
; 3. Looks like cdecl, but she is not. For cdecl need compat wrapper
; 4. Dirties all registers, incl. ebp
;
; Input:
; esp+4 = pointer to template string
; esp+8 = wildcard strings pointers in reverse order
;
; Options:
if ~STR_BUILD_OFFSET
STR_BUILD_OFFSET = 0
; Optional, specify STR_BUILD_OFFSET value for offset from start
; of output buffer (this useful for postinsert initial characters
; before output sting). By default - no offset (0)
end if
if ~STR_BUILD_EXTRA
STR_BUILD_EXTRA = 0
; Optional, specify STR_BUILD_EXTRA value for extra length of
; output bufer (this useful for postadding characters after
; output string). By default - no extra length (0)
end if
;
; { STR_BUILD_NO_DOLLAR_SIGN - should be removed, see cpecial case above }
;
; Next two options below can reduse total code size by exclude
; corresponding parts if they are not used
;
if ~STR_BUILD_NO_STARTING_TEXT
STR_BUILD_NO_STARTING_TEXT = 0
; Specify STR_BUILD_NO_STARTING_TEXT if you do not used templates
; starting with text, e.g."Some text first $, $"
; By default is disabled (0)
end if
;
if ~STR_BUILD_NO_DOUBLE_WILDCARD
STR_BUILD_NO_DOUBLE_WILDCARD = 0
; Specify STR_BUILD_NO_DOUBLE_WILDCARD if you not used templates
; with double wildcards, e.g. "$$ some text" or "Some text $$"
; By default is disabled (0)
end if
;
; mem_alloc(size)
; external memory allocator, stdcall. Must return pointer (in eax)
; to base of memory block by size length. By defauld used internal
;
; Output:
; eax = Pointer to output string (see PRECAUTION #2) or 0 if error
; edi = Cursor of output string. No mean inf if eax = 0
;
; Stack struct
; ------
; | ArgN |
; -------
; | ... |
; -------
; ebp+4 | Arg1 |
; ------ -------
; ebp | TplS | Template string
; ------ -------
; | ret | Caller return address (not used), esp when entry
; -------
; | $off1 | 1st offset in template string
; -------
; | ... |
; -------
; | $offN | N-offset in template string
; -------
; | EOTpl | End of template string, esp after phase 1.1
; -------
; | Len1 | Length of 1st wildcard string
; -------
; | ... |
; -------
; | LenN | Length of N wildcard string, esp after phase 1.2
; -------
;
str_build:
mov ebp, esp ; Store caller esp...
add ebp, 8 ; ... and shift return address and tamplate string
mov esi, [ebp-4]
xor edx, edx ; Offsets, length...
xor edi, edi ; Found count...
; Phase 1.1. Scan to find positions $ and store to stack offsets $+1
; and end of template string. Break scan if zero byte appear
.scan:
lodsb
inc edx
or al, al
jz .end_scan
cmp al, '$'
je .found
jmp .scan
.found:
push edx ; Store offset
inc edi
jmp .scan
.end_scan:
or edi, edi
jz .error ; Not found
push edx ; Store last offset (end of template string)
sub edx, edi
dec edx ; Total length + zero string
; Phase 1.2. Store to stack lengths of wildcard strings
mov eax, edi
@@:
mov esi,[ebp+4*(eax-1)]
call strlen
add edx, ecx
push ecx
dec eax
inc edi ; once edi*2 instead
test eax,eax
jnz @b
add edx, STR_BUILD_OFFSET + STR_BUILD_EXTRA
; Phase 1.3. Allocate buffer for output string
if defined mem_alloc
stdcall mem_alloc, edx
else
mov eax, 68
mov ebx, 12
mov ecx, edx
int 0x40
end if
test eax,eax
jz .exit
mov byte[eax+edx],0 ; Mark end of output string
; Phase 2. Build output string
; eax = base of output string
xor ebx, ebx ; ebx = index of args data
; ecx = free, but used below
mov edx, edi ; edx = index of stored data
; esi = free, but used below
mov edi, eax ; edi = cursor of output string
add edi, STR_BUILD_OFFSET
if ~STR_BUILD_NO_STARTING_TEXT ; {
mov ecx, [esp+4*edx] ; Offset
cmp ecx,1 ; Wildcard first?
je .build
mov esi, -2 ; One or double wildcard at the end
neg ecx
add ecx, [esp+4*edx-4] ; Next offset
cmp ecx, 1 ; More one wildcard at the end?
je @f
dec esi
@@:
mov ecx,esi
add ecx,[esp+4*edx-4] ; Next offset
mov esi,[ebp-4] ; Template string
call strncpy
add edi, ecx ; Advance cursor
end if; } STR_BUILD_NO_STARTING_TEXT
.build:
mov esi, [ebp+4*ebx] ; Wildcard string
mov ecx,[esp+4*ebx] ; Length
call strncpy
add edi, ecx ; Advance cursor
mov ecx, [esp+4*edx] ; Offset
mov esi,[ebp-4] ; Template string
add esi, ecx
cmp byte [esi], 0 ; End of string?
je .exit
if ~STR_BUILD_NO_DOUBLE_WILDCARD ; {
cmp byte [esi], '$'
je @f
end if; } STR_BUILD_NO_DOUBLE_WILDCARD
neg ecx
add ecx,[esp+4*edx-4] ; Next offset
dec ecx
call strncpy
add edi, ecx ; Advance cursor
@@: ; { STR_BUILD_NO_DOUBLE_WILDCARD }
inc ebx
dec edx
cmp ebx, edx
jne .build
.exit:
; Restore stack
sub ebp, 8
mov esp,ebp
ret
.error:
xor eax, eax
ret