glib 数组
原文地址： http://hi.baidu.com/study_together/blog/item/7440fe81f66265af0df4d23f.html
编译：gcc -g -Wall -O0 fuck.c -o fuck `pkg-config --libs --cflags glib-2.0`
1
基本操作
这里是向数组添加和删除数据的一些主要方法：
#include < glib.h >
#include < stdio.h >
int main( int argc, char ** argv) {
GArray * a = g_array_new(FALSE, FALSE, sizeof ( char * ));
char * first = " hello " , * second = " there " , * third = " world " ;
g_array_append_val(a, first);
g_array_append_val(a, second);
g_array_append_val(a, third);
printf( " There are now %d items in the array\n " , a -> len);
printf( " The first item is '%s'\n " , g_array_index(a, char * , 0 ));
printf( " The third item is '%s'\n " , g_array_index(a, char * , 2 ));
g_array_remove_index(a, 1 );
printf( " There are now %d items in the array\n " , a -> len);
g_array_free(a, FALSE);
return 0 ;
}
***** Output *****
There are now 3 items in the array
The first item is 'hello'
The third item is 'world'
There are now 2 items in the array
2
更多 new/free 选项
本示例中包含创建和销毁 GArray 的一些不同方法：
#include < glib.h >
#include < stdio.h >
int main( int argc, char ** argv) {
GArray * a = g_array_sized_new(TRUE, TRUE, sizeof ( int ), 16 );
printf( " Array preallocation is hidden, so array size == %d\n " , a -> len);
printf( " Array was init'd to zeros, so 3rd item is = %d\n " , g_array_index(a, int , 2 ));
g_array_free(a, FALSE);
// this creates an empty array, then resizes it to 16 elements
a = g_array_new(FALSE, FALSE, sizeof ( char ));
g_array_set_size(a, 16 );
g_array_free(a, FALSE);
a = g_array_new(FALSE, FALSE, sizeof ( char ));
char * x = g_strdup( " hello world " );
g_array_append_val(a, x);
g_array_free(a, TRUE);
return 0 ;
}
***** Output *****
Array preallocation is hidden, so array size == 0
Array was init'd to zeros, so 3rd item is = 0
3
添加数据的更多方法
到目前为止您已经看到如何使用 g_array_append_val 将数据添加到数组。不过，有其他的方式可以将数据置入数组，如下所示：
#include < glib.h >
#include < stdio.h >
void prt(GArray * a) {
printf( " Array holds: " );
int i;
for (i = 0 ; i < a -> len; i ++ )
printf( " %d " , g_array_index(a, int , i));
printf( " \n " );
}
int main( int argc, char ** argv) {
GArray * a = g_array_new(FALSE, FALSE, sizeof ( int ));
printf( " Array is empty, so appending some values\n " );
int x[ 2 ] = { 4 , 5 };
g_array_append_vals(a, & x, 2 );
prt(a);
printf( " Now to prepend some values\n " );
int y[ 2 ] = { 2 , 3 };
g_array_prepend_vals(a, & y, 2 );
prt(a);
printf( " And one more prepend\n " );
int z = 1 ;
g_array_prepend_val(a, z);
prt(a);
g_array_free(a, FALSE);
return 0 ;
}
***** Output *****
Array is empty, so appending some values
Array holds: 4 5
Now to prepend some values
Array holds: 2 3 4 5
And one more prepend
Array holds: 1 2 3 4 5
4
插入数据
也可以向数组中各个不同的位置插入数据；不是限于只能附加或者向最前添加条目。这里是其工作方式：
#include < glib.h >
#include < stdio.h >
void prt(GArray * a) {
printf( " Array holds: " );
int i;
for (i = 0 ; i < a -> len; i ++ )
printf( " %d " , g_array_index(a, int , i));
printf( " \n " );
}
int main( int argc, char ** argv) {
GArray * a = g_array_new(FALSE, FALSE, sizeof ( int ));
int x[ 2 ] = { 1 , 5 };
g_array_append_vals(a, & x, 2 );
prt(a);
printf( " Inserting a '2'\n " );
int b = 2 ;
g_array_insert_val(a, 1 , b);
prt(a);
printf( " Inserting multiple values\n " );
int y[ 2 ] = { 3 , 4 };
g_array_insert_vals(a, 2 , y, 2 );
prt(a);
g_array_free(a, FALSE);
return 0 ;
}
***** Output *****
Array holds: 1 5
Inserting a '2'
Array holds: 1 2 5
Inserting multiple values
Array holds: 1 2 3 4 5
5
删除数据
有三种方法可以从 GArray 删除数据：
* g_array_remove_index 和 g_array_remove_range，这两个函数会保持现有顺序
* g_array_remove_index_fast，不保持现有顺序
这里是所有三种方法的示例：
#include < glib.h >
#include < stdio.h >
void prt(GArray * a) {
int i;
printf( " Array holds: " );
for (i = 0 ; i < a -> len; i ++ )
printf( " %d " , g_array_index(a, int , i));
printf( " \n " );
}
int main( int argc, char ** argv) {
GArray * a = g_array_new(FALSE, FALSE, sizeof ( int ));
int x[ 6 ] = { 1 , 2 , 3 , 4 , 5 , 6 };
g_array_append_vals(a, & x, 6 );
prt(a);
printf( " Removing the first item\n " );
g_array_remove_index(a, 0 );
prt(a);
printf( " Removing the first two items\n " );
g_array_remove_range(a, 0 , 2 );
prt(a);
printf( " Removing the first item very quickly\n " );
g_array_remove_index_fast(a, 0 );
prt(a);
g_array_free(a, FALSE);
return 0 ;
}
***** Output *****
Array holds: 1 2 3 4 5 6
Removing the first item
Array holds: 2 3 4 5 6
Removing the first two items
Array holds: 4 5 6
Removing the first item very quickly
Array holds: 6 5
6
排序
对 GArray 排序很直观；它使用的是在 GList 和 GSList 部分已经出现过的 GCompareFunc：
#include < glib.h >
#include < stdio.h >
void prt(GArray * a) {
int i;
printf( " Array holds: " );
for (i = 0 ; i < a -> len; i ++ )
printf( " %d " , g_array_index(a, int , i));
printf( " \n " );
}
int compare_ints(gpointer a, gpointer b) {
int * x = ( int * )a;
int * y = ( int * )b;
return * x - * y;
}
int main( int argc, char ** argv) {
GArray * a = g_array_new(FALSE, FALSE, sizeof ( int ));
int x[ 6 ] = { 2 , 1 , 6 , 5 , 4 , 3 };
g_array_append_vals(a, & x, 6 );
prt(a);
printf( " Sorting\n " );
g_array_sort(a, (GCompareFunc)compare_ints);
prt(a);
g_array_free(a, FALSE);
return 0 ;
}
***** Output *****
Array holds: 2 1 6 5 4 3
Sorting
Array holds: 1 2 3 4 5 6
7
指针数组 有错误需要调试
GLib 还提供了 GPtrArray，这是一个为保存指针专门设计的数组。使用它比使用基本的 GArray 更简单，因为在创建或者添加、
索引元素时不需要指定具体类型。它与 GArray 非常类似，所以我们将只是回顾基本操作的一些示例：
#include < glib.h >
#include < stdio.h >
int main( int argc, char ** argv) {
GPtrArray * a = g_ptr_array_new();
g_ptr_array_add(a, g_strdup( " hello " ));
g_ptr_array_add(a, g_strdup( " again " ));
g_ptr_array_add(a, g_strdup( " there " ));
g_ptr_array_add(a, g_strdup( " world " ));
g_ptr_array_add(a, g_strdup( " \n " ));
printf( " >Here are the GPtrArray contents\n " );
g_ptr_array_foreach(a, (GFunc)printf, NULL);
printf( " >Removing the third item\n " );
g_ptr_array_remove_index(a, 2 );
g_ptr_array_foreach(a, (GFunc)printf, NULL);
printf( " >Removing the second and third item\n " );
g_ptr_array_remove_range(a, 1 , 2 );
g_ptr_array_foreach(a, (GFunc)printf, NULL);
printf( " The first item is '%s'\n " , g_ptr_array_index(a, 0 ));
g_ptr_array_free(a, TRUE);
return 0 ;
}
***** Output *****
>Here are the GPtrArray contents
hello again there world
>Removing the third item
hello again world
>Removing the second and third item
hello
The first item is 'hello '
8
字节数组
GLib 提供了另一个特定类型的数组是 GByteArray。它与您已经了解的类型非常类似，不过有一些区别，因为它是为存储二进制数据而设计的。
它非常便于在循环中读取二进制数据，因为它隐藏了“read into a buffer-resize buffer-read some more”的周期。这里是一些示例代码：
#include < glib.h >
#include < stdio.h >
int main( int argc, char ** argv) {
GByteArray * a = g_byte_array_new();
guint8 x = 0xFF ;
g_byte_array_append(a, & x, sizeof (x));
printf( " The first byte value (in decimal) is %d\n " , a -> data[ 0 ]);
x = 0x01 ;
g_byte_array_prepend(a, & x, sizeof (x));
printf( " After prepending, the first value is %d\n " , a -> data[ 0 ]);
g_byte_array_remove_index(a, 0 );
printf( " After removal, the first value is again %d\n " , a -> data[ 0 ]);
g_byte_array_append(g_byte_array_append(a, & x, sizeof (x)), & x, sizeof (x));
printf( " After two appends, array length is %d\n " , a -> len);
g_byte_array_free(a, TRUE);
return 0 ;
}
***** Output *****
The first byte value (in decimal) is 255
After prepending, the first value is 1
After removal, the first value is again 255
After two appends, array length is 3
完