git.ozlabs.org Git - ccan/blob - ccan/rbuf/rbuf.c

   1 /* Licensed under BSD-MIT - see LICENSE file for details */
   2 #include <ccan/rbuf/rbuf.h>
   3 #include <sys/types.h>
   4 #include <sys/stat.h>
   5 #include <unistd.h>
   6 #include <errno.h>
   7 #include <string.h>
   8 #include <fcntl.h>
   9
  10 bool rbuf_open(struct rbuf *rbuf, const char *name, char *buf, size_t buf_max,
  11                void *(*expandfn)(struct membuf *, void *, size_t))
  12 {
  13         int fd = open(name, O_RDONLY);
  14         if (fd >= 0) {
  15                 rbuf_init(rbuf, fd, buf, buf_max, expandfn);
  16                 return true;
  17         }
  18         return false;
  19 }
  20
  21 size_t rbuf_good_size(int fd)
  22 {
  23         struct stat st;
  24
  25         if (fstat(fd, &st) == 0 && st.st_blksize >= 4096)
  26                 return st.st_blksize;
  27         return 4096;
  28 }
  29
  30 static ssize_t get_more(struct rbuf *rbuf)
  31 {
  32         ssize_t r;
  33
  34         /* This is so we only call rbuf_good_size once. */
  35         if (tcon_unwrap(&rbuf->m)->max_elems == 0)
  36                 membuf_prepare_space(&rbuf->m, rbuf_good_size(rbuf->fd));
  37         else /* membuf doubles internally, so just ask for anything. */
  38                 membuf_prepare_space(&rbuf->m, 1);
  39
  40         /* This happens if realloc fails (errno already ENOMEM) */
  41         if (!membuf_num_space(&rbuf->m))
  42                 return -1;
  43
  44         r = read(rbuf->fd, membuf_space(&rbuf->m), membuf_num_space(&rbuf->m));
  45         if (r <= 0)
  46                 return r;
  47
  48         membuf_add(&rbuf->m, r);
  49         return r;
  50 }
  51
  52 void *rbuf_fill_all(struct rbuf *rbuf)
  53 {
  54         ssize_t r;
  55
  56         while ((r = get_more(rbuf)) != 0)
  57                 if (r < 0)
  58                         return NULL;
  59         return rbuf_start(rbuf);
  60 }
  61
  62 void *rbuf_fill(struct rbuf *rbuf)
  63 {
  64         if (!rbuf_len(rbuf)) {
  65                 if (get_more(rbuf) < 0)
  66                         return NULL;
  67         }
  68         return rbuf_start(rbuf);
  69 }
  70
  71 char *rbuf_read_str(struct rbuf *rbuf, char term)
  72 {
  73         char *p;
  74         ssize_t r = 0;
  75         size_t prev = 0;
  76
  77         while (!(p = memchr(membuf_elems(&rbuf->m) + prev,
  78                             term,
  79                             membuf_num_elems(&rbuf->m) - prev))) {
  80                 prev += r;
  81                 r = get_more(rbuf);
  82                 if (r < 0)
  83                         return NULL;
  84                 /* EOF with no term. */
  85                 if (r == 0) {
  86                         char *ret;
  87                         size_t len = rbuf_len(rbuf);
  88
  89                         /* Nothing read at all? */
  90                         if (!len && term) {
  91                                 errno = 0;
  92                                 return NULL;
  93                         }
  94
  95                         /* Put term after input (get_more made room). */
  96                         assert(membuf_num_space(&rbuf->m) > 0);
  97                         ret = membuf_consume(&rbuf->m, len);
  98                         ret[len] = '\0';
  99                         return ret;
 100                 }
 101         }
 102         *p = '\0';
 103         return membuf_consume(&rbuf->m, p + 1 - (char *)rbuf_start(rbuf));
 104 }