diff options
| -rw-r--r-- | lib/lib.c | 36 |
1 files changed, 18 insertions, 18 deletions
@@ -277,42 +277,42 @@ int stridx(char *haystack, char needle) // Return how long the file at fd is, if there's any way to determine it. off_t fdlength(int fd) { - off_t bottom = 0, top = 0, pos, old; - int size; + struct stat st; + off_t base = 0, range = 1, expand = 1, old; - // If the ioctl works for this, return it. + if (!fstat(fd, &st) && S_ISREG(st.st_mode)) return st.st_size; - if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512L; + // If the ioctl works for this, return it. + // TODO: is blocksize still always 512, or do we stat for it? + // unsigned int size; + // if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512L; // If not, do a binary search for the last location we can read. (Some // block devices don't do BLKGETSIZE right.) This should probably have // a CONFIG option... + // If not, do a binary search for the last location we can read. + old = lseek(fd, 0, SEEK_CUR); do { char temp; - - pos = bottom + (top - bottom) / 2; - - // If we can read from the current location, it's bigger. + off_t pos = base + range / 2; if (lseek(fd, pos, 0)>=0 && read(fd, &temp, 1)==1) { - if (bottom == top) bottom = top = (top+1) * 2; - else bottom = pos; - - // If we can't, it's smaller. + off_t delta = (pos + 1) - base; + base += delta; + if (expand) range = (expand <<= 1) - base; + else range -= delta; } else { - if (bottom == top) { - if (!top) return 0; - bottom = top/2; - } else top = pos; + expand = 0; + range = pos - base; } - } while (bottom + 1 != top); + } while (range > 0); lseek(fd, old, SEEK_SET); - return pos + 1; + return base; } // Read contents of file as a single freshly allocated nul-terminated string. |