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/***********************************************************************/
/* */
/* Objective Caml */
/* */
/* Manuel Serrano and Xavier Leroy, INRIA Rocquencourt */
/* */
/* Copyright 2000 Institut National de Recherche en Informatique et */
/* en Automatique. All rights reserved. This file is distributed */
/* under the terms of the GNU Library General Public License, with */
/* the special exception on linking described in file ../../LICENSE. */
/* */
/***********************************************************************/
/* $Id: mmap_unix.c 10648 2010-08-18 12:46:09Z doligez $ */
#include <stddef.h>
#include <string.h>
#include "bigarray.h"
#include "custom.h"
#include "fail.h"
#include "io.h"
#include "mlvalues.h"
#include "sys.h"
#include "signals.h"
extern int caml_ba_element_size[]; /* from bigarray_stubs.c */
#ifdef HAS_UNISTD
#include <unistd.h>
#endif
#ifdef HAS_MMAP
#include <sys/types.h>
#include <sys/mman.h>
#endif
#if defined(HAS_MMAP)
#ifndef MAP_FAILED
#define MAP_FAILED ((void *) -1)
#endif
CAMLprim value caml_ba_map_file(value vfd, value vkind, value vlayout,
value vshared, value vdim, value vstart)
{
int fd, flags, major_dim, shared;
intnat num_dims, i;
intnat dim[CAML_BA_MAX_NUM_DIMS];
file_offset currpos, startpos, file_size, data_size;
uintnat array_size, page, delta;
char c;
void * addr;
fd = Int_val(vfd);
flags = Int_val(vkind) | Int_val(vlayout);
startpos = File_offset_val(vstart);
num_dims = Wosize_val(vdim);
major_dim = flags & CAML_BA_FORTRAN_LAYOUT ? num_dims - 1 : 0;
/* Extract dimensions from Caml array */
num_dims = Wosize_val(vdim);
if (num_dims < 1 || num_dims > CAML_BA_MAX_NUM_DIMS)
caml_invalid_argument("Bigarray.mmap: bad number of dimensions");
for (i = 0; i < num_dims; i++) {
dim[i] = Long_val(Field(vdim, i));
if (dim[i] == -1 && i == major_dim) continue;
if (dim[i] < 0)
caml_invalid_argument("Bigarray.create: negative dimension");
}
/* Determine file size */
caml_enter_blocking_section();
currpos = lseek(fd, 0, SEEK_CUR);
if (currpos == -1) {
caml_leave_blocking_section();
caml_sys_error(NO_ARG);
}
file_size = lseek(fd, 0, SEEK_END);
if (file_size == -1) {
caml_leave_blocking_section();
caml_sys_error(NO_ARG);
}
/* Determine array size in bytes (or size of array without the major
dimension if that dimension wasn't specified) */
array_size = caml_ba_element_size[flags & CAML_BA_KIND_MASK];
for (i = 0; i < num_dims; i++)
if (dim[i] != -1) array_size *= dim[i];
/* Check if the major dimension is unknown */
if (dim[major_dim] == -1) {
/* Determine major dimension from file size */
if (file_size < startpos) {
caml_leave_blocking_section();
caml_failwith("Bigarray.mmap: file position exceeds file size");
}
data_size = file_size - startpos;
dim[major_dim] = (uintnat) (data_size / array_size);
array_size = dim[major_dim] * array_size;
if (array_size != data_size) {
caml_leave_blocking_section();
caml_failwith("Bigarray.mmap: file size doesn't match array dimensions");
}
} else {
/* Check that file is large enough, and grow it otherwise */
if (file_size < startpos + array_size) {
if (lseek(fd, startpos + array_size - 1, SEEK_SET) == -1) {
caml_leave_blocking_section();
caml_sys_error(NO_ARG);
}
c = 0;
if (write(fd, &c, 1) != 1) {
caml_leave_blocking_section();
caml_sys_error(NO_ARG);
}
}
}
/* Restore original file position */
lseek(fd, currpos, SEEK_SET);
/* Determine offset so that the mapping starts at the given file pos */
page = getpagesize();
delta = (uintnat) (startpos % page);
/* Do the mmap */
shared = Bool_val(vshared) ? MAP_SHARED : MAP_PRIVATE;
addr = mmap(NULL, array_size + delta, PROT_READ | PROT_WRITE,
shared, fd, startpos - delta);
caml_leave_blocking_section();
if (addr == (void *) MAP_FAILED) caml_sys_error(NO_ARG);
addr = (void *) ((uintnat) addr + delta);
/* Build and return the Caml bigarray */
return caml_ba_alloc(flags | CAML_BA_MAPPED_FILE, num_dims, addr, dim);
}
#else
value caml_ba_map_file(value vfd, value vkind, value vlayout,
value vshared, value vdim, value vpos)
{
caml_invalid_argument("Bigarray.map_file: not supported");
return Val_unit;
}
#endif
CAMLprim value caml_ba_map_file_bytecode(value * argv, int argn)
{
return caml_ba_map_file(argv[0], argv[1], argv[2],
argv[3], argv[4], argv[5]);
}
void caml_ba_unmap_file(void * addr, uintnat len)
{
#if defined(HAS_MMAP)
uintnat page = getpagesize();
uintnat delta = (uintnat) addr % page;
munmap((void *)((uintnat)addr - delta), len + delta);
#endif
}
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