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Annotation of 43BSD/contrib/cpm/src/copen.c, revision 1.1.1.1

1.1       root        1: /*     copen.c 1.8     85/03/24        */
                      2: 
                      3: #include <stdio.h>
                      4: #include "cpmio.h"
                      5: #include "cpmfio.h"
                      6: 
                      7: /*
                      8:  * Open cp/m file with the given file name and extension, return
                      9:  * file pointer. A null pointer is returned if the file could not
                     10:  * be opened. mode tells whether the file is to be read, written
                     11:  * or both.
                     12:  */
                     13: 
                     14: C_FILE *
                     15: c_open(name, ext, mode)
                     16:        char *name, *ext;
                     17: {
                     18: 
                     19:        register int    i, index, scnt;
                     20:        register C_FILE *fptr;
                     21:        char *malloc(), *fixname();
                     22: 
                     23:        if ((index = searchdir(name, ext)) == -1) {
                     24:                fprintf(stderr, "file not found: %s\n", fixname(name, ext));
                     25:                return (NULL);
                     26:        }
                     27:        /* test for legal mode */
                     28:        if (!(mode & RW)) {
                     29:                fprintf(stderr, "open: illegal mode - %d\n", mode);
                     30:                return (NULL);
                     31:        }
                     32: #ifdef DEBUG
                     33:        printf("directory index: %d\n", index); 
                     34: #endif
                     35:        for ((i = 0, fptr=c_iob); i < C_NFILE; i++,fptr++)
                     36:                if (!(fptr->c_flag)) 
                     37:                        break;
                     38:        if (i == C_NFILE) {
                     39:                fprintf(stderr, "too many open files\n");
                     40:                return (NULL);
                     41:        }
                     42: 
                     43: /*
                     44:  * Free file descriptor slot found, initialize field, allocate
                     45:  * memory and read first block.
                     46:  */
                     47:        if ((fptr->c_buf = malloc(blksiz)) == NULL) {
                     48:                printf("c_open: no memory!\n");
                     49:                return (NULL);
                     50:        }
                     51:        fptr->c_extno = 0;
                     52:        fptr->c_base = fptr->c_buf;
                     53:        fptr->c_flag = mode;
                     54:        fptr->c_blk = 0;
                     55:        fptr->c_ext = index;
                     56:        fptr->c_dirp = dirbuf+index;
                     57:        fptr->c_seccnt = 0xff &(dirbuf+index)->blkcnt;
                     58:        scnt = (fptr->c_seccnt > blksiz/seclth) ? blksiz/seclth:fptr->c_seccnt;
                     59: #ifdef DEBUG
                     60:        printf("c_open: scnt=%d\n",scnt); 
                     61: #endif
                     62:        if (getblock(0xff &(int)fptr->c_dirp->pointers[0], fptr->c_buf, scnt)
                     63:                                                                == EOF)
                     64:                return (NULL);
                     65:        fptr->c_cnt = seclth*scnt;
                     66:        fptr->c_seccnt -= scnt;
                     67:        return (fptr);
                     68: }

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