1、协程局部存储键值
需要一种数据结构来存储key值（用来判断协程局部存储空间的使用情况，used或者unsed）：
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| typedef struct co_specific {
uint32_t used;
void (*destructor)(void*);
} specific_t;
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有一个全局的指针co_specific指向一个specific_t数组。
graph LR
key1[key1] --- key2[key2]
key2[key2] --- key3[key3]
key3[key3] --- key4[key4]
co_specific_num变量用来记录specific_t数组的长度。
2、协程自身有一块内存用来存放data
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| typedef struct co_struct {
void **specific;
int spec_num;
} co_t;
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specific数组里面存放了一些指针，这些指针指向协程私有的数据。
specific_t和specific数组是有所对应的：
graph LR
key1[key1] -.-> data1_ptr[data1_ptr]
key2[key2] -.-> data2_ptr[data2_ptr]
key3[key3] -.-> data3_ptr[data3_ptr]
key4[key4] -.-> data4_ptr[data4_ptr]
key1[key1] --- key2[key2]
key2[key2] --- key3[key3]
key3[key3] --- key4[key4]
data1_ptr[data1_ptr] --- data2_ptr[data2_ptr]
data2_ptr[data2_ptr] --- data3_ptr[data3_ptr]
data3_ptr[data3_ptr] --- data4_ptr[data4_ptr]
data1_ptr[data1_ptr] --> data1[data1]
data2_ptr[data2_ptr] --> data2[data2]
data3_ptr[data3_ptr] --> data3[data3]
data4_ptr[data4_ptr] --> data4[data4]
3、算法
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| int co_key_create(void (*destructor)(void*))
{
specific_t *specific = co_specific;
specific_t *specific_end = specific + co_specific_num;
int old_num = co_specific_num;
while(specific < specific_end) {
if(!specific->used) {
specific->used = 1;
specific->destructor = destructor;
return specific - co_specific;
}
specific++;
}
co_specific_num += 16;
co_specific = realloc(co_specific, co_specific_num * sizeof(specific_t));
memset(co_specific + old_num, 0, 16 * sizeof(specific_t));
co_specific[old_num].used = 1;
co_specific[old_num].destructor = destructor;
return old_num;
}
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| int co_key_delete(int key)
{
if(unlikely(key < 0) ||
co_specific_num <= key ||
!co_specific[key].used) {
return EINVAL;
}
co_specific[key].used = 0;
co_specific[key].destructor = NULL;
return 0;
}
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| int co_setspecific(int key, const void *value)
{
if(unlikely(key < 0) ||
co_specific_num <= key ||
!co_specific[key].used) {
return EINVAL;
}
if(current->spec_num <= key) {
current->specific = realloc(current->specific, co_specific_num*sizeof(void *));
memset(current->specific + current->spec_num, 0, (co_specific_num-current->spec_num)*sizeof(void *));
current->spec_num = co_specific_num;
}
current->specific[key] = (void *)value;
return 0;
}
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| void *co_getspecific(int key)
{
if(unlikely(key < 0) ||
co_specific_num <= key ||
!co_specific[key].used) {
return NULL;
}
if(current->spec_num <= key)
return NULL;
else
return current->specific[key];
}
|
代码来自这里。
