library for uniform buffered input.

This commit is contained in:
Roberto Ierusalimschy 1997-06-16 13:50:22 -03:00
parent 611680af08
commit 9fe5be3acf
2 changed files with 164 additions and 0 deletions

117
zio.c Normal file
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/*
* zio.c
* a generic input stream interface
* $Id: zio.c,v 1.5 1997/06/13 13:49:16 lhf Exp $
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "zio.h"
#ifdef POPEN
FILE *popen();
int pclose();
#else
#define popen(x,y) NULL /* that is, popen always fails */
#define pclose(x) (-1)
#endif
/* ----------------------------------------------------- memory buffers --- */
static int zmfilbuf(ZIO* z)
{
return EOZ;
}
static int zmclose(ZIO* z)
{
return 1;
}
ZIO* zmopen(ZIO* z, char* b, int size)
{
if (b==NULL) return NULL;
z->n=size;
z->p= (unsigned char *)b;
z->filbuf=zmfilbuf;
z->close=zmclose;
z->u=NULL;
return z;
}
/* ------------------------------------------------------------ strings --- */
ZIO* zsopen(ZIO* z, char* s)
{
if (s==NULL) return NULL;
return zmopen(z,s,strlen(s));
}
/* -------------------------------------------------------------- FILEs --- */
static int zffilbuf(ZIO* z)
{
int n=fread(z->buffer,1,ZBSIZE,z->u);
if (n==0) return EOZ;
z->n=n-1;
z->p=z->buffer;
return *(z->p++);
}
static int zfclose(ZIO* z)
{
if (z->u==stdin) return 0;
return fclose(z->u);
}
ZIO* zFopen(ZIO* z, FILE* f)
{
if (f==NULL) return NULL;
z->n=0;
z->p=z->buffer;
z->filbuf=zffilbuf;
z->close=zfclose;
z->u=f;
return z;
}
ZIO* zfopen(ZIO* z, char* s, char* m)
{
return zFopen(z,fopen(s,m));
}
/* -------------------------------------------------------------- pipes --- */
static int zpclose(ZIO* z)
{
return pclose(z->u);
}
ZIO* zpopen(ZIO* z, char* s, char* m)
{
z=zFopen(z,popen(s,m));
if (z==NULL) return NULL;
z->close=zpclose;
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; /* retorna quantos faltaram ler */
zungetc(z); /* poe o resultado de filbuf no buffer */
}
m = (n <= z->n) ? n : z->n; /* minimo de n e z->n */
memcpy(b, z->p, m);
z->n -= m;
z->p += m;
b = (char *)b + m;
n -= m;
}
return 0;
}

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zio.h Normal file
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/*
* zio.h
* a generic input stream interface
* $Id: zio.h,v 1.4 1997/06/13 13:49:16 lhf Exp $
*/
#ifndef zio_h
#define zio_h
#include <stdio.h>
#define EOZ (-1) /* end of stream */
typedef struct zio ZIO;
int zgetc(ZIO* z); /* get next byte */
int zungetc(ZIO* z); /* put back last byte read */
int zread(ZIO* z, void* b, int n); /* read next n bytes */
int zclose(ZIO* z); /* close stream */
ZIO* zFopen(ZIO* z, FILE* f); /* open FILEs */
ZIO* zfopen(ZIO* z, char* s, char* m); /* file by name */
ZIO* zpopen(ZIO* z, char* s, char* m); /* pipe */
ZIO* zsopen(ZIO* z, char* s); /* string */
ZIO* zmopen(ZIO* z, char* b, int size); /* memory */
#define zgetc(z) (--(z)->n>=0 ? ((int)*(z)->p++): (z)->filbuf(z))
#define zungetc(z) (++(z)->n,--(z)->p)
#define zclose(z) (*(z)->close)(z)
/* --------- Private Part ------------------ */
#define ZBSIZE 256 /* buffer size */
struct zio {
int n; /* bytes still unread */
unsigned char* p; /* current position in buffer */
int (*filbuf)(ZIO* z);
int (*close)(ZIO* z);
void* u; /* additional data */
unsigned char buffer[ZBSIZE]; /* buffer */
};
#endif