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Annotation of embedaddon/libpdel/io/count_fp.c, revision 1.1.1.1

1.1       misho       1: 
                      2: /*
                      3:  * Copyright (c) 2001-2002 Packet Design, LLC.
                      4:  * All rights reserved.
                      5:  * 
                      6:  * Subject to the following obligations and disclaimer of warranty,
                      7:  * use and redistribution of this software, in source or object code
                      8:  * forms, with or without modifications are expressly permitted by
                      9:  * Packet Design; provided, however, that:
                     10:  * 
                     11:  *    (i)  Any and all reproductions of the source or object code
                     12:  *         must include the copyright notice above and the following
                     13:  *         disclaimer of warranties; and
                     14:  *    (ii) No rights are granted, in any manner or form, to use
                     15:  *         Packet Design trademarks, including the mark "PACKET DESIGN"
                     16:  *         on advertising, endorsements, or otherwise except as such
                     17:  *         appears in the above copyright notice or in the software.
                     18:  * 
                     19:  * THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
                     20:  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
                     21:  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
                     22:  * THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
                     23:  * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
                     24:  * OR NON-INFRINGEMENT.  PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
                     25:  * OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
                     26:  * OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
                     27:  * RELIABILITY OR OTHERWISE.  IN NO EVENT SHALL PACKET DESIGN BE
                     28:  * LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
                     29:  * OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
                     30:  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
                     31:  * DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
                     32:  * USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
                     33:  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
                     34:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
                     35:  * THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
                     36:  * THE POSSIBILITY OF SUCH DAMAGE.
                     37:  *
                     38:  * Author: Archie Cobbs <archie@freebsd.org>
                     39:  */
                     40: 
                     41: #include <sys/types.h>
                     42: 
                     43: #include <stdio.h>
                     44: #include <stdlib.h>
                     45: #include <stdarg.h>
                     46: #include <string.h>
                     47: 
                     48: #include "structs/structs.h"
                     49: #include "structs/type/array.h"
                     50: 
                     51: #include "util/typed_mem.h"
                     52: #include "io/count_fp.h"
                     53: 
                     54: #define MEM_TYPE               "count_fp"
                     55: 
                     56: /* Our state */
                     57: struct count_info {
                     58:        FILE            *fp;
                     59:        off_t           remain;
                     60:        int             closeit;
                     61: };
                     62: 
                     63: /*
                     64:  * Internal functions
                     65:  */
                     66: static int     count_read(void *cookie, char *buf, int len);
                     67: static int     count_close(void *cookie);
                     68: 
                     69: /*
                     70:  * Create a FILE * that reads a limited amount from another FILE *.
                     71:  */
                     72: FILE *
                     73: count_fopen(FILE *fp, off_t count, int closeit)
                     74: {
                     75:        struct count_info *c;
                     76: 
                     77:        /* Create info */
                     78:        if ((c = MALLOC(MEM_TYPE, sizeof(*c))) == NULL)
                     79:                return (NULL);
                     80:        memset(c, 0, sizeof(*c));
                     81:        c->fp = fp;
                     82:        c->remain = count;
                     83:        c->closeit = closeit;
                     84: 
                     85:        /* Create new FILE * */
                     86:        if ((fp = funopen(c, count_read, NULL, NULL, count_close)) == NULL) {
                     87:                FREE(MEM_TYPE, c);
                     88:                return (NULL);
                     89:        }
                     90: 
                     91:        /* Set to non-buffered so we don't read to much from underlying fp */
                     92:        setbuf(fp, NULL);
                     93: 
                     94:        /* Done */
                     95:        return (fp);
                     96: }
                     97: 
                     98: /*
                     99:  * Read from a count_fp.
                    100:  */
                    101: static int
                    102: count_read(void *cookie, char *buf, int len)
                    103: {
                    104:        struct count_info *const c = cookie;
                    105:        int ret;
                    106: 
                    107:        if (c->remain == 0)
                    108:                return (0);
                    109:        if (len > c->remain)
                    110:                len = c->remain;
                    111:        if ((ret = fread(buf, 1, len, c->fp)) != len) {
                    112:                if (ferror(c->fp))
                    113:                        return (-1);
                    114:        }
                    115:        c->remain -= ret;
                    116:        return (ret);
                    117: }
                    118: 
                    119: /*
                    120:  * Close a count_fp.
                    121:  */
                    122: static int
                    123: count_close(void *cookie)
                    124: {
                    125:        struct count_info *const c = cookie;
                    126: 
                    127:        if (c->closeit)
                    128:                fclose(c->fp);
                    129:        FREE(MEM_TYPE, c);
                    130:        return (0);
                    131: }
                    132: