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page ,132
title strdup - duplicate string in malloc'd memory
;***
;strdup.asm - duplicate a string in malloc'd memory
;
; Copyright (c) 1985-1991, Microsoft Corporation. All rights reserved.
;
;Purpose:
; defines _strdup() - grab new memory, and duplicate the string into it.
;
;Revision History:
; 10-27-83 RN initial version
; 05-18-88 SJM Add model-independent (large model) ifdef
; 08-04-88 SJM convert to cruntime/ add 32-bit support
; 08-23-88 JCR Minor 386 cleanup
; 10-25-88 JCR General cleanup for 386-only code
; 03-23-90 GJF Changed to _stdcall. Also, fixed the copyright.
; 01-18-91 GJF ANSI naming.
; 05-10-91 GJF Back to _cdecl, sigh...
;
;*******************************************************************************
.xlist
include cruntime.inc
.list
extrn strlen:proc
extrn strcpy:proc
extrn malloc:proc
page
;***
;char *_strdup(string) - duplicate string into malloc'd memory
;
;Purpose:
; Allocates enough storage via malloc() for a copy of the
; string, copies the string into the new memory, and returns
; a pointer to it.
;
; Algorithm:
; char *
; _strdup (string)
; char *string;
; {
; char *memory;
;
; if (!string)
; return(NULL);
; if (memory = malloc(strlen(string) + 1))
; return(strcpy(memory,string));
; return(NULL);
; }
;
;Entry:
; char *string - string to copy into new memory
;
;Exit:
; returns a pointer to the newly allocated storage with the
; string in it.
; returns NULL if enough memory could not be allocated, or
; string was NULL.
;
;Uses:
; eax, edx
;
;Exceptions:
;
;*******************************************************************************
CODESEG
% public _strdup
_strdup proc \
uses edi, \
string:ptr byte
mov edi,[string] ; edi=pointer to string
push edi ; stack parameter: string pointer
call strlen ; eax = string length
ifndef _STDCALL_
pop edx ; caller cleans stack (_cdecl)
;else
; callee cleaned stack (_stdcall)
endif
inc eax ; need space for null byte too
push eax ; stack parameter: string length (with null)
call malloc ; eax = pointer to space
ifndef _STDCALL_
pop edx ; caller cleans stack (_cdecl)
;else
; callee cleaned stack (_stdcall)
endif
or eax,eax ; offset == NULL ??
jz short toend ; error -- couldn't malloc space
okay:
push edi ; push address of original string
push eax ; push address of dest string
; source string addr is still on stack
call strcpy ; duplicate the string
ifndef _STDCALL_
pop edx ; caller cleans stack (_cdecl)
pop edx
;else
; callee cleaned stack (_stdcall)
endif
; pointer to duplicate is in eax
toend: ; eax = return value
ifdef _STDCALL_
ret DPSIZE ; _stdcall return
else
ret ; _cdecl return
endif
_strdup endp
end
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