/* buffer.c for MudOS 0.9.x by John Garnett, 1993/11/07 */
#include "std.h"
#ifndef NO_BUFFER_TYPE
#include "crctab.h"
#include "lpc_incl.h"
#include "stralloc.h"
buffer_t null_buf =
{
1, /* Ref count, which will ensure that it will
* never be deallocated */
0 /* size */
};
INLINE buffer_t *
null_buffer()
{
null_buf.ref++;
return &null_buf;
} /* null_buffer() */
INLINE void
free_buffer P1(buffer_t *, b)
{
b->ref--;
/* don't try to free the null_buffer (ref count might overflow) */
if ((b->ref > 0) || (b == &null_buf)) {
return;
}
FREE((char *) b);
} /* free_buffer() */
buffer_t *
allocate_buffer P1(int, size)
{
buffer_t *buf;
#ifndef NO_BUFFER_TYPE
if ((size < 0) || (size > max_buffer_size)) {
error("Illegal buffer size.\n");
}
if (size == 0) {
return null_buffer();
}
/* using calloc() so that memory will be zero'd out when allocated */
buf = (buffer_t *) DCALLOC(sizeof(buffer_t) + size - 1, 1,
TAG_BUFFER, "allocate_buffer");
buf->size = size;
buf->ref = 1;
return buf;
#else
return NULL;
#endif
}
int write_buffer P4(buffer_t *, buf, int, start, char *, str, int, theLength)
{
int size;
size = buf->size;
if (start < 0) {
start = size + start;
if (start < 0) {
return 0;
}
}
/*
* can't write past the end of the buffer since we can't reallocate the
* buffer here (no easy way to propagate back the changes to the caller
*/
if ((start + theLength) > size) {
return 0;
}
memcpy(buf->item + start, str, theLength);
return 1;
} /* write_buffer() */
char *
read_buffer P4(buffer_t *, b, int, start, int, len, int *, rlen)
{
char *str;
unsigned int size;
if (len < 0)
return 0;
size = b->size;
if (start < 0) {
start = size + start;
if (start < 0) {
return 0;
}
}
if (len == 0) {
len = size;
}
if (start >= size) {
return 0;
}
if ((start + len) > size) {
len = (size - start);
}
for (str = (char *)b->item + start, size = 0; *str && size < len; str++, size++)
;
str = new_string(size, "read_buffer: str");
memcpy(str, b->item + start, size);
str[*rlen = size] = '\0';
return str;
} /* read_buffer() */
#endif
