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buffer.c
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buffer.c
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#include "buffer.h"
#include "xwrap.h"
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
void binit(struct buffer *b, size_t size)
{
char *p;
p = (char *) xmalloc(size);
b->addr = b->begin = b->end = p;
b->size = size;
}
void bfree(struct buffer *b)
{
if (b->addr != NULL) {
free(b->addr);
b->addr = b->begin = b->end = NULL;
b->size = 0;
}
}
static inline int bavail_write(struct buffer *b)
{
return b->end - b->begin;
}
static inline int bavail_read(struct buffer *b)
{
return b->addr + b->size - b->end;
}
static inline void bcheck_empty(struct buffer *b)
{
if (b->begin == b->end)
b->begin = b->end = b->addr;
}
int bread(struct buffer *b, int fd)
{
int size;
int n;
size = bavail_read(b);
if (size == 0)
return 0;
n = read(fd, b->end, size);
if (n < 1)
return -1;
b->end += n;
return n;
}
int bwrite(struct buffer *b, int fd)
{
int size;
int n;
size = bavail_write(b);
if (size == 0)
return 0;
n = write(fd, b->begin, size);
if (n < 1)
return -1;
b->begin += n;
bcheck_empty(b);
return n;
}
int bgets(struct buffer *b, char *s, size_t len)
{
int size;
char *p;
int n;
if (len == 0)
return 0;
size = bavail_write(b);
if (size == 0)
return 0;
if ((p = memchr(b->begin, '\n', size)) == NULL)
return 0;
n = p - b->begin + 1;
if (len > n)
len = n;
memcpy(s, b->begin, len);
b->begin += len;
bcheck_empty(b);
return len;
}
int bputs(struct buffer *b, char *s, size_t len)
{
int size;
if (len == 0)
return 0;
size = bavail_read(b);
if (size == 0)
return 0;
if (len > size)
len = size;
memcpy(b->end, s, len);
b->end += len;
return len;
}
int bcanfill(struct buffer *b)
{
return bavail_read(b) > 0;
}
int bhasdata(struct buffer *b)
{
return bavail_write(b) > 0;
}