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/*
** $Id: lzio.c $
** Buffered streams
** See Copyright Notice in lua.h
*/
#define lzio_c
#define LUA_CORE
#include "lprefix.h"
#include <string.h>
#include "lua.h"
#include "llimits.h"
#include "lmem.h"
#include "lstate.h"
#include "lzio.h"
int luaZ_fill
(ZIO
*z
) {
size_t size
;
lua_State
*L
= z
->L
;
const char *buff
;
lua_unlock
(L
);
buff
= z
->reader
(L
, z
->data
, &size
);
lua_lock
(L
);
if (buff
== NULL
|| size
== 0)
return EOZ
;
z
->n
= size
- 1; /* discount char being returned */
z
->p
= buff
;
return cast_uchar
(*(z
->p
++));
}
void luaZ_init
(lua_State
*L
, ZIO
*z
, lua_Reader reader
, void *data
) {
z
->L
= L
;
z
->reader
= reader
;
z
->data
= data
;
z
->n
= 0;
z
->p
= NULL
;
}
/* --------------------------------------------------------------- read --- */
size_t luaZ_read
(ZIO
*z
, void *b
, size_t n
) {
while (n
) {
size_t m
;
if (z
->n
== 0) { /* no bytes in buffer? */
if (luaZ_fill
(z
) == EOZ
) /* try to read more */
return n
; /* no more input; return number of missing bytes */
else {
z
->n
++; /* luaZ_fill consumed first byte; put it back */
z
->p
--;
}
}
m
= (n
<= z
->n
) ? n
: z
->n
; /* min. between n and z->n */
memcpy(b
, z
->p
, m
);
z
->n
-= m
;
z
->p
+= m
;
b
= (char *)b
+ m
;
n
-= m
;
}
return 0;
}