blob: ed14abc615f322cdfc8334f1b44bf48d3e8e570a [file] [log] [blame]
/*
** $Id: lzio.c,v 1.23 2002/12/04 17:38:31 roberto Exp roberto $
** a generic input stream interface
** See Copyright Notice in lua.h
*/
#include <string.h>
#define lzio_c
#include "lua.h"
#include "llimits.h"
#include "lmem.h"
#include "lzio.h"
int luaZ_fill (ZIO *z) {
size_t size;
const char *buff = z->reader(NULL, z->data, &size);
if (buff == NULL || size == 0) return EOZ;
z->n = size - 1;
z->p = buff;
return char2int(*(z->p++));
}
int luaZ_lookahead (ZIO *z) {
if (z->n == 0) {
int c = luaZ_fill(z);
if (c == EOZ) return c;
z->n++;
z->p--;
}
return char2int(*z->p);
}
void luaZ_init (ZIO *z, lua_Chunkreader reader, void *data, const char *name) {
z->reader = reader;
z->data = data;
z->name = name;
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) {
if (luaZ_fill(z) == EOZ)
return n; /* return number of missing bytes */
else {
++z->n; /* filbuf removed first byte; put back it */
--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;
}
/* ------------------------------------------------------------------------ */
char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) {
if (n > buff->buffsize) {
if (n < LUA_MINBUFFER) n = LUA_MINBUFFER;
luaM_reallocvector(L, buff->buffer, buff->buffsize, n, char);
buff->buffsize = n;
}
return buff->buffer;
}