100 lines
1.8 KiB
C
100 lines
1.8 KiB
C
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#include "stdio_impl.h"
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#include <errno.h>
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#include <limits.h>
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#include <string.h>
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#include <stdlib.h>
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#include "libc.h"
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struct cookie {
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char **bufp;
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size_t *sizep;
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size_t pos;
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char *buf;
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size_t len;
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size_t space;
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};
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struct ms_FILE {
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FILE f;
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struct cookie c;
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unsigned char buf[BUFSIZ];
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};
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static off_t ms_seek(FILE *f, off_t off, int whence)
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{
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ssize_t base;
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struct cookie *c = f->cookie;
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if (whence>2U) {
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fail:
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errno = EINVAL;
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return -1;
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}
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base = (size_t [3]){0, c->pos, c->len}[whence];
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if (off < -base || off > SSIZE_MAX-base) goto fail;
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return c->pos = base+off;
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}
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static size_t ms_write(FILE *f, const unsigned char *buf, size_t len)
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{
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struct cookie *c = f->cookie;
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size_t len2 = f->wpos - f->wbase;
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char *newbuf;
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if (len2) {
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f->wpos = f->wbase;
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if (ms_write(f, f->wbase, len2) < len2) return 0;
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}
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if (len + c->pos >= c->space) {
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len2 = 2*c->space+1 | c->pos+len+1;
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newbuf = realloc(c->buf, len2);
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if (!newbuf) return 0;
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*c->bufp = c->buf = newbuf;
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memset(c->buf + c->space, 0, len2 - c->space);
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c->space = len2;
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}
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memcpy(c->buf+c->pos, buf, len);
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c->pos += len;
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if (c->pos >= c->len) c->len = c->pos;
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*c->sizep = c->pos;
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return len;
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}
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static int ms_close(FILE *f)
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{
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return 0;
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}
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FILE *open_memstream(char **bufp, size_t *sizep)
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{
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struct ms_FILE *f;
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char *buf;
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if (!(f=malloc(sizeof *f))) return 0;
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if (!(buf=malloc(sizeof *buf))) {
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free(f);
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return 0;
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}
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memset(&f->f, 0, sizeof f->f);
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memset(&f->c, 0, sizeof f->c);
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f->f.cookie = &f->c;
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f->c.bufp = bufp;
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f->c.sizep = sizep;
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f->c.pos = f->c.len = f->c.space = *sizep = 0;
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f->c.buf = *bufp = buf;
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*buf = 0;
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f->f.flags = F_NORD;
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f->f.fd = -1;
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f->f.buf = f->buf;
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f->f.buf_size = sizeof f->buf;
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f->f.lbf = EOF;
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f->f.write = ms_write;
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f->f.seek = ms_seek;
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f->f.close = ms_close;
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f->f.mode = -1;
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if (!libc.threaded) f->f.lock = -1;
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return __ofl_add(&f->f);
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}
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