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Annotation of embedaddon/pimd/libite/fsendfile.c, revision 1.1.1.1

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:  */