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raku - 包含指针的 N​​ativeCall 结构

转载 作者:行者123 更新时间:2023-12-04 12:18:53 25 4
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我有以下结构:

typedef struct _info{
DWORD myInfo;
BYTE *pInfo;
LPWSTR ExtData;

} Info;

我使用 NativeCall 表示这个结构体因此:
class Info is repr('CStruct') {
has int32 $.myInfo;
has Pointer[int8] $.pInfo ;
has Pointer[int16] $.ExtData;
}

这个代表好吗?如何访问和设置 $.pInfo 指向的数据?

最佳答案

这种表示对我来说似乎没问题……鉴于这个发明的 C 库:
(请不要选择我的 C foo - 它离题了)

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

typedef unsigned long int DWORD;
typedef unsigned char BYTE;
typedef char * LPWSTR;

typedef struct _info{
DWORD myInfo;
BYTE *pInfo;
LPWSTR ExtData;
} Info;


Info* create_info();
void display_info();
void double_info(Info*);

Info*
create_info() {
DWORD init_myinfo = 2016;
BYTE init_pinfo = 37;
char init_ExtData[] = "Hello World";

Info *new_info = malloc(sizeof(Info));
if (new_info == NULL) {
printf( "Memory alloc failed\n" );
exit(1);
}

new_info->myInfo = init_myinfo;

BYTE *pinfo = malloc(sizeof(BYTE));
*pinfo = init_pinfo;
new_info->pInfo = pinfo;

char *ext_data = malloc(sizeof(init_ExtData));
strcpy(ext_data, init_ExtData);
new_info->ExtData = ext_data;

return new_info;
}

void
display_info(Info *inf) {
printf("myInfo: %lu\n", inf->myInfo);
printf("pInfo: %i\n", *inf->pInfo);
printf("ExtData: %s\n", inf->ExtData);
}

void
double_info(Info *inf) {

inf->myInfo *= 2;

if ( *(inf->pInfo) < 128 )
*(inf->pInfo) *= 2;

int extdata_len = strlen(inf->ExtData);
char *tmp_extdata = malloc(extdata_len * 2 + 2);
strncpy(tmp_extdata, inf->ExtData, extdata_len);
tmp_extdata[extdata_len] = '+';
strcpy(&tmp_extdata[extdata_len+1], inf->ExtData);
inf->ExtData = tmp_extdata;
}
那么你使用 NativeCall 的 perl6 结构定义或多或少是有效的:
#!/usr/bin/env perl6
use NativeCall;

class Info is repr('CStruct') {
has int32 $.myInfo;
has Pointer[int8] $.pInfo ;
has Pointer[Str] $.ExtData;

method Str {
qq:to/END HERE/;
myInfo: $!myInfo
pInfo: { $!pInfo.deref }
ExtData: { $!ExtData.deref }
END HERE
}
}

our sub create_info() returns Info is native('pinfo') { * }
our sub display_info(Info) is native('pinfo') { * }
our sub double_info(Info is rw) is native('pinfo') { * }

my Info $inf = create_info();
say 'Displaying $inf after calling create_info()';
display_info $inf;

double_info $inf;
say 'Displaying $inf after calling double_info()';
display_info $inf;

say 'Displaying $inf by calling attribute methods on Perl6 object';
say "myInfo: $inf.myInfo()";
say "pInfo: $inf.pInfo.deref()";
say "ExtData: $inf.ExtData.deref()";

say 'Displaying $inf by stringifying Perl6 object';
say "$inf";
exit 0;
这会产生一系列结果;
Displaying $inf after calling create_info()
myInfo: 2016
pInfo: 37
ExtData: Hello World
Displaying $inf after calling double_info()
myInfo: 4032
pInfo: 74
ExtData: Hello World+Hello World
Displaying $inf by calling attribute methods on Perl6 object
myInfo: 4032
pInfo: 74
ExtData: Hello World+Hello World
Displaying $inf by stringifying Perl6 object
myInfo: 4032
pInfo: 74
ExtData: Hello World+Hello World
或者,可以在 perl6 类中隐藏更多的“胶水”;
#!/usr/bin/env perl6
use NativeCall;

class Info is repr('CStruct') {
has int32 $.myInfo is rw ;
has Pointer[int8] $!pInfo ;
has Pointer[Str] $!ExtData ;

my sub create_info() returns Info is native('pinfo') { * }
my sub display_info(Info) is native('pinfo') { * }
my sub double_info(Info is rw) is native('pinfo') { * }

method new { create_info() }
method display { display_info(self) }
method double { double_info(self) }

method pInfo { $!pInfo.deref }
method ExtData { $!ExtData.deref }

method Str {
qq:to/END HERE/;
myInfo: { self.myInfo }
pInfo: { self.pInfo }
ExtData: { self.ExtData }
END HERE
}
}

my Info $inf .= new;
say 'Displaying $inf after calling .new';
$inf.display ;

$inf.double ;
say 'Displaying $inf after calling .double';
$inf.display ;

say 'Displaying $inf by calling attribute methods on Perl6 object';
say "myInfo: $inf.myInfo()";
say "pInfo: $inf.pInfo()";
say "ExtData: $inf.ExtData()";

$inf.myInfo = 12046 ;
say 'Displaying $inf by stringifying Perl6 object';
say "$inf";
exit 0;
......更干净的外观。它同样产生;
Displaying $inf after calling .new
myInfo: 2016
pInfo: 37
ExtData: Hello World
Displaying $inf after calling .double
myInfo: 4032
pInfo: 74
ExtData: Hello World+Hello World
Displaying $inf by calling attribute methods on Perl6 object
myInfo: 4032
pInfo: 74
ExtData: Hello World+Hello World
Displaying $inf by stringifying Perl6 object
myInfo: 12046
pInfo: 74
ExtData: Hello World+Hello World
笔记:
(1) 您对 Pointer 类型的属性调用 .deref() 方法以获取所指向的实际数据。
(2) NativeCall documentation必须多次阅读;-)
(3) 无论我尝试什么,我都无法修改通过指针引用的数据 - 我不断收到“无法修改不可变数据”。
(4) YMMV

关于raku - 包含指针的 N​​ativeCall 结构,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35246529/

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