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Annotation of embedaddon/pimd/libite/fsendfile.c, revision 1.1

1.1     ! misho       1: /* Copy data between file streams
        !             2:  *
        !             3:  * Copyright (c) 2013  Tobias Waldekranz <tobias@waldekranz.com>
        !             4:  *
        !             5:  * Permission is hereby granted, free of charge, to any person obtaining a copy
        !             6:  * of this software and associated documentation files (the "Software"), to deal
        !             7:  * in the Software without restriction, including without limitation the rights
        !             8:  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
        !             9:  * copies of the Software, and to permit persons to whom the Software is
        !            10:  * furnished to do so, subject to the following conditions:
        !            11:  *
        !            12:  * The above copyright notice and this permission notice shall be included in
        !            13:  * all copies or substantial portions of the Software.
        !            14:  *
        !            15:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        !            16:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        !            17:  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
        !            18:  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
        !            19:  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
        !            20:  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
        !            21:  * THE SOFTWARE.
        !            22:  */
        !            23: 
        !            24: #include <errno.h>
        !            25: #include <stdio.h>
        !            26: #include <stdlib.h>
        !            27: 
        !            28: 
        !            29: /**
        !            30:  * fsendfile - copy data between file streams
        !            31:  * @src: Source stream
        !            32:  * @dst: Destination stream
        !            33:  * @len: Number of bytes to copy
        !            34:  *
        !            35:  * @dst may be %NULL, in which case @len bytes are read and discarded
        !            36:  * from @src.  This can be useful for streams where seeking is not
        !            37:  * permitted.  Additionally, @len may be the special value zero (0), in
        !            38:  * which case fsendfile() will copy until %EOF is seen on @src.
        !            39:  *
        !            40:  * Returns:
        !            41:  * The number of bytes copied.  If an error is detected -1 is returned
        !            42:  * and @errno will be set accordingly.
        !            43:  */
        !            44: size_t fsendfile(FILE *src, FILE *dst, size_t len)
        !            45: {
        !            46:        char *buf;
        !            47:        size_t blk = BUFSIZ, num = 0, tot = 0;
        !            48: 
        !            49:         if (!src) {
        !            50:                 errno = EINVAL;
        !            51:                 return -1;
        !            52:         }
        !            53:                 
        !            54:        buf = (char *)malloc(BUFSIZ);
        !            55:        if (!buf)
        !            56:                return -1;
        !            57: 
        !            58:        while (!len || tot < len) {
        !            59:                if (len && ((len - tot) < BUFSIZ))
        !            60:                        blk = len - tot;
        !            61: 
        !            62:                num = fread(buf, 1, blk, src);
        !            63:                if (num == 0)
        !            64:                        break;
        !            65: 
        !            66:                if (dst && (fwrite(buf, num, 1, dst) != 1)) {
        !            67:                        num = -1;
        !            68:                        break;
        !            69:                }
        !            70: 
        !            71:                tot += num;
        !            72:        }
        !            73: 
        !            74:        free(buf);
        !            75: 
        !            76:        return (num == (size_t)-1) ? (size_t)-1 : tot;
        !            77: }
        !            78: 
        !            79: #ifdef UNITTEST
        !            80: #include <err.h>
        !            81: #include <unistd.h>
        !            82: 
        !            83: int main(void)
        !            84: {
        !            85:        int i = 0;
        !            86:        char *files[] = {
        !            87:                "/etc/passwd", "/tmp/tok",
        !            88:                "/etc/passwd", "/tmp/passwd",
        !            89:                "/etc/passwd", "/tmp/passwd",
        !            90:                NULL
        !            91:        };
        !            92:        FILE *src, *dst;
        !            93: 
        !            94:        while (files[i]) {
        !            95:                 src = fopen(files[i], "r");
        !            96:                 dst = fopen(files[i + 1], "w");
        !            97:                printf("fsendfile(%s, %s, 512)\t", files[i], files[i + 1]);
        !            98:                if (-1 == fsendfile(src, dst, 512))
        !            99:                        err(1, "Failed fsendfile(%s, %s)", files[i], files[i + 1]);
        !           100: 
        !           101:                if (!access(files[i + 1], F_OK))
        !           102:                        printf("OK => %s\n", files[i + 1]);
        !           103: 
        !           104:                remove(files[i + 1]);
        !           105:                i += 2;
        !           106:        }
        !           107: 
        !           108:        return 0;
        !           109: }
        !           110: #endif /* UNITTEST */
        !           111: 
        !           112: /**
        !           113:  * Local Variables:
        !           114:  *  compile-command: "make V=1 -f fsendfile.mk"
        !           115:  *  version-control: t
        !           116:  *  indent-tabs-mode: t
        !           117:  *  c-file-style: "linux"
        !           118:  * End:
        !           119:  */