| #include "stdio_impl.h" |
| #include <errno.h> |
| #include <string.h> |
| #include <inttypes.h> |
| |
| struct cookie { |
| size_t pos, len, size; |
| unsigned char *buf; |
| int mode; |
| }; |
| |
| struct mem_FILE { |
| FILE f; |
| struct cookie c; |
| unsigned char buf[UNGET+BUFSIZ], buf2[]; |
| }; |
| |
| static off_t mseek(FILE *f, off_t off, int whence) |
| { |
| ssize_t base; |
| struct cookie *c = f->cookie; |
| if (whence>2U) { |
| fail: |
| errno = EINVAL; |
| return -1; |
| } |
| base = (size_t [3]){0, c->pos, c->len}[whence]; |
| if (off < -base || off > (ssize_t)c->size-base) goto fail; |
| return c->pos = base+off; |
| } |
| |
| static size_t mread(FILE *f, unsigned char *buf, size_t len) |
| { |
| struct cookie *c = f->cookie; |
| size_t rem = c->len - c->pos; |
| if (c->pos > c->len) rem = 0; |
| if (len > rem) { |
| len = rem; |
| f->flags |= F_EOF; |
| } |
| memcpy(buf, c->buf+c->pos, len); |
| c->pos += len; |
| rem -= len; |
| if (rem > f->buf_size) rem = f->buf_size; |
| f->rpos = f->buf; |
| f->rend = f->buf + rem; |
| memcpy(f->rpos, c->buf+c->pos, rem); |
| c->pos += rem; |
| return len; |
| } |
| |
| static size_t mwrite(FILE *f, const unsigned char *buf, size_t len) |
| { |
| struct cookie *c = f->cookie; |
| size_t rem; |
| size_t len2 = f->wpos - f->wbase; |
| if (len2) { |
| f->wpos = f->wbase; |
| if (mwrite(f, f->wpos, len2) < len2) return 0; |
| } |
| if (c->mode == 'a') c->pos = c->len; |
| rem = c->size - c->pos; |
| if (len > rem) len = rem; |
| memcpy(c->buf+c->pos, buf, len); |
| c->pos += len; |
| if (c->pos > c->len) { |
| c->len = c->pos; |
| if (c->len < c->size) c->buf[c->len] = 0; |
| else if ((f->flags&F_NORD) && c->size) c->buf[c->size-1] = 0; |
| } |
| return len; |
| } |
| |
| static int mclose(FILE *m) |
| { |
| return 0; |
| } |
| |
| FILE *fmemopen(void *restrict buf, size_t size, const char *restrict mode) |
| { |
| struct mem_FILE *f; |
| int plus = !!strchr(mode, '+'); |
| |
| if (!size || !strchr("rwa", *mode)) { |
| errno = EINVAL; |
| return 0; |
| } |
| |
| if (!buf && size > PTRDIFF_MAX) { |
| errno = ENOMEM; |
| return 0; |
| } |
| |
| f = malloc(sizeof *f + (buf?0:size)); |
| if (!f) return 0; |
| memset(&f->f, 0, sizeof f->f); |
| f->f.cookie = &f->c; |
| f->f.fd = -1; |
| f->f.lbf = EOF; |
| f->f.buf = f->buf + UNGET; |
| f->f.buf_size = sizeof f->buf - UNGET; |
| if (!buf) { |
| buf = f->buf2;; |
| memset(buf, 0, size); |
| } |
| |
| memset(&f->c, 0, sizeof f->c); |
| f->c.buf = buf; |
| f->c.size = size; |
| f->c.mode = *mode; |
| |
| if (!plus) f->f.flags = (*mode == 'r') ? F_NOWR : F_NORD; |
| if (*mode == 'r') f->c.len = size; |
| else if (*mode == 'a') f->c.len = f->c.pos = strnlen(buf, size); |
| |
| f->f.read = mread; |
| f->f.write = mwrite; |
| f->f.seek = mseek; |
| f->f.close = mclose; |
| |
| if (!libc.threaded) f->f.lock = -1; |
| |
| return __ofl_add(&f->f); |
| } |