lzio.c
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上传日期:2019-04-29
资源大小:56270k
文件大小:2k
- /*
- ** $Id: lzio.c,v 1.13 2000/06/12 13:52:05 roberto Exp $
- ** a generic input stream interface
- ** See Copyright Notice in lua.h
- */
- #include <stdio.h>
- #include <string.h>
- #include "lua.h"
- #include "lzio.h"
- /* ----------------------------------------------------- memory buffers --- */
- static int zmfilbuf (ZIO* z) {
- (void)z; /* to avoid warnings */
- return EOZ;
- }
- ZIO* zmopen (ZIO* z, const char* b, size_t size, const char *name) {
- if (b==NULL) return NULL;
- z->n = size;
- z->p = (const unsigned char *)b;
- z->filbuf = zmfilbuf;
- z->u = NULL;
- z->name = name;
- return z;
- }
- /* ------------------------------------------------------------ strings --- */
- ZIO* zsopen (ZIO* z, const char* s, const char *name) {
- if (s==NULL) return NULL;
- return zmopen(z, s, strlen(s), name);
- }
- /* -------------------------------------------------------------- FILEs --- */
- static int zffilbuf (ZIO* z) {
- size_t n;
- if (feof((FILE *)z->u)) return EOZ;
- n = fread(z->buffer, 1, ZBSIZE, (FILE *)z->u);
- if (n==0) return EOZ;
- z->n = n-1;
- z->p = z->buffer;
- return *(z->p++);
- }
- ZIO* zFopen (ZIO* z, FILE* f, const 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 --- */
- size_t zread (ZIO *z, void *b, size_t n) {
- while (n) {
- size_t 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;
- }