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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
enum {
Block_Free;
Block_Busy;
Block_Full;
Block_Done;
};
typedef struct
{
int state;
int capacity;
int size;
char *data;
} Block;
Block *Block_new(int size)
{
size &= ~(4 * sizeof(double) - 1);
Block *b= (Block *)calloc(1, sizeof(Block));
if (b)
{
b->state= Block_Free;
b->capacity= size;
if ((b->data= (char *)calloc(1, size)))
return b;
free(b);
}
return 0;
}
void Block_delete(Block *b)
{
free(b->data);
free(b);
}
void Block_reset(Block *b)
{
b->state= Block_Free;
b->size= 0;
}
typedef struct
{
Block *input;
Block *output;
} Buffer;
Buffer *Buffer_new(int size)
{
Buffer *b= (Buffer *)calloc(1, sizeof(Buffer));
if (b)
{
if ((b->input= Block_new(size)))
{
if ((b->output= Block_new(size)))
return b;
Buffer_delete(b->input);
}
free(b);
}
return 0;
}
void Buffer_delete(Buffer *b)
{
Block_delete(b->input);
Block_delete(b->output);
delete(b);
}
int Buffer_swap(Buffer *b)
{
if (input->state == Block_Full)
{
Block *b= input;
Block_reset(b->output);
b->input= b->output;
b->output= b->input;
return 1;
}
output->state= Block_done;
return 0;
}
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