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