[444] | 1 | #include "stdio_impl.h"
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| 2 | #include <errno.h>
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| 3 | #include <limits.h>
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| 4 | #include <string.h>
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| 5 |
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| 6 | struct cookie {
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| 7 | char **bufp;
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| 8 | size_t *sizep;
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| 9 | size_t pos;
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| 10 | char *buf;
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| 11 | size_t len;
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| 12 | size_t space;
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| 13 | };
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| 14 |
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| 15 | static off_t ms_seek(FILE *f, off_t off, int whence)
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| 16 | {
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| 17 | ssize_t base;
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| 18 | struct cookie *c = f->cookie;
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| 19 | if (whence>2U) {
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| 20 | fail:
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| 21 | errno = EINVAL;
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| 22 | return -1;
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| 23 | }
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| 24 | base = (size_t [3]){0, c->pos, c->len}[whence];
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| 25 | if (off < -base || off > SSIZE_MAX-base) goto fail;
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| 26 | return c->pos = base+off;
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| 27 | }
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| 28 |
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| 29 | static size_t ms_write(FILE *f, const unsigned char *buf, size_t len)
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| 30 | {
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| 31 | struct cookie *c = f->cookie;
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| 32 | size_t len2 = f->wpos - f->wbase;
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| 33 | char *newbuf;
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| 34 | if (len2) {
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| 35 | f->wpos = f->wbase;
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| 36 | if (ms_write(f, f->wbase, len2) < len2) return 0;
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| 37 | }
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| 38 | if (len + c->pos >= c->space) {
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| 39 | len2 = 2*c->space+1 | c->pos+len+1;
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| 40 | newbuf = realloc(c->buf, len2);
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| 41 | if (!newbuf) return 0;
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| 42 | *c->bufp = c->buf = newbuf;
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| 43 | memset(c->buf + c->space, 0, len2 - c->space);
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| 44 | c->space = len2;
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| 45 | }
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| 46 | memcpy(c->buf+c->pos, buf, len);
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| 47 | c->pos += len;
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| 48 | if (c->pos >= c->len) c->len = c->pos;
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| 49 | *c->sizep = c->pos;
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| 50 | return len;
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| 51 | }
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| 52 |
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| 53 | static int ms_close(FILE *f)
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| 54 | {
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| 55 | return 0;
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| 56 | }
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| 57 |
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| 58 | FILE *open_memstream(char **bufp, size_t *sizep)
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| 59 | {
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| 60 | FILE *f;
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| 61 | struct cookie *c;
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| 62 | char *buf;
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| 63 |
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| 64 | if (!(f=malloc(sizeof *f + sizeof *c + BUFSIZ))) return 0;
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| 65 | if (!(buf=malloc(sizeof *buf))) {
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| 66 | free(f);
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| 67 | return 0;
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| 68 | }
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| 69 | memset(f, 0, sizeof *f + sizeof *c);
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| 70 | f->cookie = c = (void *)(f+1);
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| 71 |
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| 72 | c->bufp = bufp;
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| 73 | c->sizep = sizep;
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| 74 | c->pos = c->len = c->space = *sizep = 0;
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| 75 | c->buf = *bufp = buf;
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| 76 | *buf = 0;
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| 77 |
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| 78 | f->flags = F_NORD;
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| 79 | f->fd = -1;
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| 80 | f->buf = (void *)(c+1);
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| 81 | f->buf_size = BUFSIZ;
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| 82 | f->lbf = EOF;
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| 83 | f->write = ms_write;
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| 84 | f->seek = ms_seek;
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| 85 | f->close = ms_close;
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| 86 |
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| 87 | if (!libc.threaded) f->lock = -1;
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| 88 |
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| 89 | return __ofl_add(f);
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| 90 | }
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