| /* |
| * zio.c |
| * a generic input stream interface |
| * $Id: zio.c,v 1.1 1997/06/16 16:50:22 roberto Exp roberto $ |
| */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include "zio.h" |
| |
| |
| /* ----------------------------------------------------- memory buffers --- */ |
| |
| static int zmfilbuf(ZIO* z) |
| { |
| return EOZ; |
| } |
| |
| 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->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++); |
| } |
| |
| |
| ZIO* zFopen(ZIO* z, FILE* f) |
| { |
| if (f==NULL) return NULL; |
| z->n=0; |
| z->p=z->buffer; |
| z->filbuf=zffilbuf; |
| z->u=f; |
| 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; |
| } |