lua/lzio.c
Roberto Ierusalimschy 063d4e4543 Lua 5.3.5 ported to git
This is the first commit for the branch Lua 5.3. All source files
were copied from the official distribution of 5.3.5 in the Lua site.
The test files are the same of 5.3.4. The manual came from the
previous RCS repository, revision 1.167.1.2.
2018-12-17 14:46:37 -02:00

69 lines
1.3 KiB
C

/*
** $Id: lzio.c,v 1.37.1.1 2017/04/19 17:20:42 roberto Exp $
** 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;
}