我正在使用 Visual c++。
我正在尝试实现一个循环缓冲区，这个 CB 必须处理特定类型的数据......事实上，它是一个结构数据，其中我们有某种原始数据要存储在 char 类型和与之关联的日期数据...这已使用结构实现。
这是更多详细信息的代码：
#include <stdio.h>
#include <time.h>
#include <windows.h>
//data=date_label+raw_data
typedef struct DataFragment
{
char data[4];
clock_t date;
}DataFragment;
typedef struct CircularBuffer
{
DataFragment *buffer; // data buffer
DataFragment *buffer_end; // end of data buffer
size_t capacity; // maximum number of items in the buffer
size_t count; // number of items in the buffer
size_t sz; // size of each item in the buffer
DataFragment *head; // pointer to head
DataFragment *tail; // pointer to tail
} CircularBuffer;
void cb_init(struct CircularBuffer *cb, size_t capacity, size_t sz)
{
if((cb->buffer = (DataFragment*) malloc(capacity * sz))!=NULL)
puts("success alocation");
//if(cb->buffer == NULL)
//handle error
cb->buffer_end = (DataFragment *)cb->buffer + (capacity-1)*sz;
cb->capacity = capacity;
cb->count = 0;
cb->sz = sz;
cb->head = cb->buffer;
cb->tail = cb->buffer;
}
void cb_free(struct CircularBuffer *cb)
{
free(cb->buffer);
// clear out other fields too, just to be safe
}
void cb_push_back(struct CircularBuffer *cb, const DataFragment *item)
{
//if(cb->count == cb->capacity)
//handle error when it's full
memcpy(cb->head->data, item->data,4);
cb->head->date=item->date;
cb->head = (DataFragment*)cb->head + cb->sz;
if(cb->head == cb->buffer_end)
cb->head = cb->buffer;
cb->count++;
}
void cb_pop_front(struct CircularBuffer *cb, DataFragment *item)
{
//if(cb->count == 0)
//handle error
memcpy(item->data, cb->tail->data,4);
item->date=cb->tail->date;
cb->tail = (DataFragment*)cb->tail + cb->sz;
if(cb->tail == cb->buffer_end)
cb->tail = cb->buffer;
cb->count--;
}
int main(int argc, char *argv[])
{
struct CircularBuffer pbuf;
pbuf.buffer=NULL;
pbuf.buffer_end=NULL;
pbuf.capacity=0;
pbuf.count=0;
pbuf.head=NULL;
pbuf.sz=0;
pbuf.tail=NULL;
struct CircularBuffer *buf= &pbuf;
size_t sizz = sizeof(DataFragment);
//initialisation of the circlar buffer to a total bytes
//of capacity*sizz=100*sizeof(struct DataFragment)
cb_init(buf,100,sizz);
//temporary container of data
DataFragment temp,temp2;
for(int i=0;i<4;i++)
temp.data[i]='k';
for(int i=0;i<4;i++)
temp2.data[i]='o';
//pushing temporary buffer to the CB...40*2=80<capacity of the CB
for(int i=0;i<40;i++)
{
Sleep(20);
temp.date=clock();
cb_push_back(buf,&temp);
Sleep(10);
temp2.date=clock();
cb_push_back(buf,&temp2);
}
DataFragment temp3;
for(int i=0;i<20;i++)
{
cb_pop_front(buf,&temp3);
printf("%d\n", temp3.data); //print integers....no need of end caracter
}
cb_free(buf);
return 0;
}
当我编译代码时，一切都很好，但是当我调试时，我注意到 buffer_end 指针有问题，它说 bad_pointer ......如果容量大于 56 就会发生这种情况......我不知道为什么指针不能指向缓冲区的末尾。但是如果容量小于 56，则指针正好指向缓冲区的末尾
如果有人知道为什么会这样，以及如何解决它，请帮助我..
提前致谢