lua/lzio.c

85 lines
1.6 KiB
C

/*
** $Id: lzio.c,v 1.6 1999/03/04 14:49:18 roberto Exp roberto $
** a generic input stream interface
** See Copyright Notice in lua.h
*/
#include <stdio.h>
#include <string.h>
#include "lzio.h"
/* ----------------------------------------------------- memory buffers --- */
static int zmfilbuf (ZIO* z) {
return EOZ;
}
ZIO* zmopen (ZIO* z, char* b, int size, char *name)
{
if (b==NULL) return NULL;
z->n=size;
z->p= (unsigned char *)b;
z->filbuf=zmfilbuf;
z->u=NULL;
z->name=name;
return z;
}
/* ------------------------------------------------------------ strings --- */
ZIO* zsopen (ZIO* z, char* s, char *name)
{
if (s==NULL) return NULL;
return zmopen(z,s,strlen(s),name);
}
/* -------------------------------------------------------------- FILEs --- */
static int zffilbuf (ZIO* z) {
int n;
if (feof((FILE *)z->u)) return EOZ;
n=fread(z->buffer,1,ZBSIZE,z->u);
if (n==0) return EOZ;
z->n=n-1;
z->p=z->buffer;
return *(z->p++);
}
ZIO* zFopen (ZIO* z, FILE* f, char *name)
{
if (f==NULL) return NULL;
z->n=0;
z->p=z->buffer;
z->filbuf=zffilbuf;
z->u=f;
z->name=name;
return z;
}
/* --------------------------------------------------------------- read --- */
int zread (ZIO *z, void *b, int n) {
while (n) {
int m;
if (z->n == 0) {
if (z->filbuf(z) == EOZ)
return n; /* return number of missing bytes */
zungetc(z); /* put result from 'filbuf' in the buffer */
}
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;
}