diff options
Diffstat (limited to 'libc-top-half/musl/src/stdio/open_memstream.c')
-rw-r--r-- | libc-top-half/musl/src/stdio/open_memstream.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/libc-top-half/musl/src/stdio/open_memstream.c b/libc-top-half/musl/src/stdio/open_memstream.c new file mode 100644 index 0000000..aa50220 --- /dev/null +++ b/libc-top-half/musl/src/stdio/open_memstream.c @@ -0,0 +1,109 @@ +#include "stdio_impl.h" +#include <errno.h> +#include <limits.h> +#include <string.h> +#include <stdlib.h> +#include "libc.h" + +struct cookie { + char **bufp; + size_t *sizep; + size_t pos; + char *buf; + size_t len; + size_t space; +}; + +struct ms_FILE { + FILE f; + struct cookie c; + unsigned char buf[BUFSIZ]; +}; + +static off_t ms_seek(FILE *f, off_t off, int whence) +{ + ssize_t base; + struct cookie *c = f->cookie; + if (whence>2U) { +fail: + errno = EINVAL; + return -1; + } +#ifdef __wasilibc_unmodified_upstream // WASI's SEEK_* constants have different values. + base = (size_t [3]){0, c->pos, c->len}[whence]; +#else + base = (size_t [3]) { + [SEEK_SET] = 0, + [SEEK_CUR] = c->pos, + [SEEK_END] = c->len + }[whence]; +#endif + if (off < -base || off > SSIZE_MAX-base) goto fail; + return c->pos = base+off; +} + +static size_t ms_write(FILE *f, const unsigned char *buf, size_t len) +{ + struct cookie *c = f->cookie; + size_t len2 = f->wpos - f->wbase; + char *newbuf; + if (len2) { + f->wpos = f->wbase; + if (ms_write(f, f->wbase, len2) < len2) return 0; + } + if (len + c->pos >= c->space) { + len2 = 2*c->space+1 | c->pos+len+1; + newbuf = realloc(c->buf, len2); + if (!newbuf) return 0; + *c->bufp = c->buf = newbuf; + memset(c->buf + c->space, 0, len2 - c->space); + c->space = len2; + } + memcpy(c->buf+c->pos, buf, len); + c->pos += len; + if (c->pos >= c->len) c->len = c->pos; + *c->sizep = c->pos; + return len; +} + +static int ms_close(FILE *f) +{ + return 0; +} + +FILE *open_memstream(char **bufp, size_t *sizep) +{ + struct ms_FILE *f; + char *buf; + + if (!(f=malloc(sizeof *f))) return 0; + if (!(buf=malloc(sizeof *buf))) { + free(f); + return 0; + } + memset(&f->f, 0, sizeof f->f); + memset(&f->c, 0, sizeof f->c); + f->f.cookie = &f->c; + + f->c.bufp = bufp; + f->c.sizep = sizep; + f->c.pos = f->c.len = f->c.space = *sizep = 0; + f->c.buf = *bufp = buf; + *buf = 0; + + f->f.flags = F_NORD; + f->f.fd = -1; + f->f.buf = f->buf; + f->f.buf_size = sizeof f->buf; + f->f.lbf = EOF; + f->f.write = ms_write; + f->f.seek = ms_seek; + f->f.close = ms_close; + f->f.mode = -1; + +#if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT) + if (!libc.threaded) f->f.lock = -1; +#endif + + return __ofl_add(&f->f); +} |