alpar@9: /* zio.c (simulation of non-standard low-level i/o functions) */
alpar@9: 
alpar@9: /* Written by Andrew Makhorin <mao@gnu.org>, April 2011
alpar@9:  * For conditions of distribution and use, see copyright notice in
alpar@9:  * zlib.h */
alpar@9: 
alpar@9: /* (reserved for copyright notice) */
alpar@9: 
alpar@9: #include <assert.h>
alpar@9: #include <stdio.h>
alpar@9: #include "zio.h"
alpar@9: 
alpar@9: static FILE *file[FOPEN_MAX];
alpar@9: static int initialized = 0;
alpar@9: 
alpar@9: static void initialize(void)
alpar@9: {     int fd;
alpar@9:       assert(!initialized);
alpar@9:       file[0] = stdin;
alpar@9:       file[1] = stdout;
alpar@9:       file[2] = stderr;
alpar@9:       for (fd = 3; fd < FOPEN_MAX; fd++)
alpar@9:          file[fd] = NULL;
alpar@9:       initialized = 1;
alpar@9:       return;
alpar@9: }
alpar@9: 
alpar@9: int open(const char *path, int oflag, ...)
alpar@9: {     FILE *fp;
alpar@9:       int fd;
alpar@9:       if (!initialized) initialize();
alpar@9:       /* see file gzlib.c, function gz_open */
alpar@9:       if (oflag == O_RDONLY)
alpar@9:          fp = fopen(path, "rb");
alpar@9:       else if (oflag == (O_WRONLY | O_CREAT | O_TRUNC))
alpar@9:          fp = fopen(path, "wb");
alpar@9:       else if (oflag == (O_WRONLY | O_CREAT | O_APPEND))
alpar@9:          fp = fopen(path, "ab");
alpar@9:       else
alpar@9:          assert(oflag != oflag);
alpar@9:       if (fp == NULL)
alpar@9:          return -1;
alpar@9:       for (fd = 0; fd < FOPEN_MAX; fd++)
alpar@9:          if (file[fd] == NULL) break;
alpar@9:       assert(fd < FOPEN_MAX);
alpar@9:       file[fd] = fp;
alpar@9:       return fd;
alpar@9: }
alpar@9: 
alpar@9: long read(int fd, void *buf, unsigned long nbyte)
alpar@9: {     unsigned long count;
alpar@9:       if (!initialized) initialize();
alpar@9:       assert(0 <= fd && fd < FOPEN_MAX);
alpar@9:       assert(file[fd] != NULL);
alpar@9:       count = fread(buf, 1, nbyte, file[fd]);
alpar@9:       if (ferror(file[fd]))
alpar@9:          return -1;
alpar@9:       return count;
alpar@9: }
alpar@9: 
alpar@9: long write(int fd, const void *buf, unsigned long nbyte)
alpar@9: {     unsigned long count;
alpar@9:       if (!initialized) initialize();
alpar@9:       assert(0 <= fd && fd < FOPEN_MAX);
alpar@9:       assert(file[fd] != NULL);
alpar@9:       count = fwrite(buf, 1, nbyte, file[fd]);
alpar@9:       if (count != nbyte)
alpar@9:          return -1;
alpar@9:       if (fflush(file[fd]) != 0)
alpar@9:          return -1;
alpar@9:       return count;
alpar@9: }
alpar@9: 
alpar@9: long lseek(int fd, long offset, int whence)
alpar@9: {     if (!initialized) initialize();
alpar@9:       assert(0 <= fd && fd < FOPEN_MAX);
alpar@9:       assert(file[fd] != NULL);
alpar@9:       if (fseek(file[fd], offset, whence) != 0)
alpar@9:          return -1;
alpar@9:       return ftell(file[fd]);
alpar@9: }
alpar@9: 
alpar@9: int close(int fd)
alpar@9: {     if (!initialized) initialize();
alpar@9:       assert(0 <= fd && fd < FOPEN_MAX);
alpar@9:       assert(file[fd] != NULL);
alpar@9:       fclose(file[fd]);
alpar@9:       file[fd] = NULL;
alpar@9:       return 0;
alpar@9: }
alpar@9: 
alpar@9: /* eof */