diff options
| -rw-r--r-- | src/H5FDdirect.c | 112 |
1 files changed, 76 insertions, 36 deletions
diff --git a/src/H5FDdirect.c b/src/H5FDdirect.c index b3b2b0f..0f95f7fb 100644 --- a/src/H5FDdirect.c +++ b/src/H5FDdirect.c @@ -860,11 +860,13 @@ H5FD_direct_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, ha { H5FD_direct_t *file = (H5FD_direct_t*)_file; ssize_t nbytes; - size_t alloc_size; - void *copy_buf, *p1, *p2; + size_t alloc_size, tmp_size; + void *copy_buf, *p1, *p2, *p3; hsize_t _boundary; hsize_t _fbsize; hsize_t _cbsize; + haddr_t copy_addr = addr; + hsize_t copy_size = size; herr_t ret_value=SUCCEED; /* Return value */ FUNC_ENTER_NOAPI(H5FD_direct_read, FAIL) @@ -891,6 +893,11 @@ H5FD_direct_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, ha * and aligned data first, then copy the data into memory buffer. */ if((addr%_fbsize==0) && (size%_fbsize==0) && ((haddr_t)buf%_boundary==0)) { + /* Seek to the correct location */ + if ((addr!=file->pos || OP_READ!=file->op) && + file_seek(file->fd, (file_offset_t)addr, SEEK_SET)<0) + HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position") + while (size>0) { do { nbytes = HDread(file->fd, buf, size); @@ -911,48 +918,76 @@ H5FD_direct_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, ha buf = (char*)buf + nbytes; } } else { - /* allocate memory needed for the Direct IO option. Make a bigger - * buffer for aligned I/O. */ - alloc_size = (size / _fbsize + 1) * _fbsize + _fbsize; + /* allocate memory needed for the Direct IO option up to the maximal + * copy buffer size. Make a bigger buffer for aligned I/O if size is + * smaller than maximal copy buffer. */ + if(size < _cbsize) + alloc_size = (size / _fbsize + 1) * _fbsize + _fbsize; + else + alloc_size = _cbsize; if (posix_memalign(©_buf, _boundary, alloc_size) != 0) HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "posix_memalign failed") - memset(copy_buf, 0, alloc_size); /* look for the aligned position for reading the data */ - if(file_seek(file->fd, (file_offset_t)(addr - addr % _fbsize), SEEK_SET) < 0) + if(file_seek(file->fd, (file_offset_t)(copy_addr - copy_addr % _fbsize), SEEK_SET) < 0) HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position") /* - * Read the aligned data in file first, being careful of interrupted system calls, - * partial results, and the end of the file. + * Read the aligned data in file into aligned buffer first, then copy the data + * into the final buffer. If the data size is bigger than maximal copy buffer + * size, do the reading by segment (the outer while loop). If not, do one step + * reading. */ - p1 = copy_buf; - while(alloc_size > 0) { - do { - nbytes = HDread(file->fd, p1, alloc_size); - } while(-1==nbytes && EINTR==errno); - - if (-1==nbytes) /* error */ - HSYS_GOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "file read failed") - if (0==nbytes) { - /* end of file but not end of format address space */ - break; - } else { - assert(nbytes>0); - assert((size_t)nbytes<=alloc_size); - H5_CHECK_OVERFLOW(nbytes,ssize_t,size_t); - H5_CHECK_OVERFLOW(nbytes,ssize_t,haddr_t); - alloc_size -= (size_t)nbytes; - p1 = (unsigned char*)p1 + nbytes; - } - } - - /*look for the right position to copy the data and copy the data - *to the original buffer.*/ - p2 = (unsigned char*)copy_buf + addr % _fbsize; - memcpy(buf, p2, size); - - /*update address and buffer*/ + p3 = buf; + do { + /* Read the aligned data in file first, being careful of interrupted system calls, + * partial results, and the end of the file. */ + memset(copy_buf, 0, alloc_size); + p1 = copy_buf; + tmp_size = alloc_size; + while(tmp_size > 0) { + do { + nbytes = HDread(file->fd, p1, tmp_size); + } while(-1==nbytes && EINTR==errno); + + if (-1==nbytes) /* error */ + HSYS_GOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "file read failed") + if (0==nbytes) { + /* end of file but not end of format address space */ + break; + } else { + assert(nbytes>0); + assert((size_t)nbytes<=tmp_size); + H5_CHECK_OVERFLOW(nbytes,ssize_t,size_t); + H5_CHECK_OVERFLOW(nbytes,ssize_t,haddr_t); + tmp_size -= (size_t)nbytes; + p1 = (unsigned char*)p1 + nbytes; + } + } + + /* look for the right position and copy the data to the original buffer. + * Consider all possible situations here: file address is not aligned on + * file block size; the end of data address is not aligned; the end of data + * address is aligned; data size is smaller or bigger than maximal copy size.*/ + p2 = (unsigned char*)copy_buf + copy_addr % _fbsize; + if(size < _cbsize) + memcpy(p3, p2, size); + else if(size >= _cbsize && copy_size <= alloc_size) + memcpy(p3, p2, copy_size); + else if(size >= _cbsize && copy_size > alloc_size) { + memcpy(p3, p2, (alloc_size - copy_addr % _fbsize)); + p3 = (unsigned char*)p3 + (alloc_size - copy_addr % _fbsize); + } + + /* update the size and address of data being read. */ + if(copy_size > (alloc_size - copy_addr % _fbsize)) + copy_size -= (alloc_size - copy_addr % _fbsize); + else + copy_size = 0; + copy_addr += (alloc_size - copy_addr % _fbsize); + } while (copy_size > 0); + + /*Final step: update address and buffer*/ addr += (haddr_t)size; buf = (unsigned char*)buf + size; @@ -1030,6 +1065,11 @@ H5FD_direct_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, h * data out. */ if((addr%_fbsize==0) && (size%_fbsize==0) && ((haddr_t)buf%_boundary==0)) { + /* Seek to the correct location */ + if ((addr!=file->pos || OP_WRITE!=file->op) && + file_seek(file->fd, (file_offset_t)addr, SEEK_SET)<0) + HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position") + while (size>0) { do { nbytes = HDwrite(file->fd, buf, size); |