/* Specific implementation of the PACK intrinsic | |

Copyright (C) 2002, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. | |

Contributed by Paul Brook <paul@nowt.org> | |

This file is part of the GNU Fortran 95 runtime library (libgfortran). | |

Libgfortran is free software; you can redistribute it and/or | |

modify it under the terms of the GNU General Public | |

License as published by the Free Software Foundation; either | |

version 3 of the License, or (at your option) any later version. | |

Ligbfortran is distributed in the hope that it will be useful, | |

but WITHOUT ANY WARRANTY; without even the implied warranty of | |

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |

GNU General Public License for more details. | |

Under Section 7 of GPL version 3, you are granted additional | |

permissions described in the GCC Runtime Library Exception, version | |

3.1, as published by the Free Software Foundation. | |

You should have received a copy of the GNU General Public License and | |

a copy of the GCC Runtime Library Exception along with this program; | |

see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |

<http://www.gnu.org/licenses/>. */ | |

#include "libgfortran.h" | |

#include <stdlib.h> | |

#include <assert.h> | |

#include <string.h> | |

#if defined (HAVE_GFC_REAL_4) | |

/* PACK is specified as follows: | |

13.14.80 PACK (ARRAY, MASK, [VECTOR]) | |

Description: Pack an array into an array of rank one under the | |

control of a mask. | |

Class: Transformational function. | |

Arguments: | |

ARRAY may be of any type. It shall not be scalar. | |

MASK shall be of type LOGICAL. It shall be conformable with ARRAY. | |

VECTOR (optional) shall be of the same type and type parameters | |

as ARRAY. VECTOR shall have at least as many elements as | |

there are true elements in MASK. If MASK is a scalar | |

with the value true, VECTOR shall have at least as many | |

elements as there are in ARRAY. | |

Result Characteristics: The result is an array of rank one with the | |

same type and type parameters as ARRAY. If VECTOR is present, the | |

result size is that of VECTOR; otherwise, the result size is the | |

number /t/ of true elements in MASK unless MASK is scalar with the | |

value true, in which case the result size is the size of ARRAY. | |

Result Value: Element /i/ of the result is the element of ARRAY | |

that corresponds to the /i/th true element of MASK, taking elements | |

in array element order, for /i/ = 1, 2, ..., /t/. If VECTOR is | |

present and has size /n/ > /t/, element /i/ of the result has the | |

value VECTOR(/i/), for /i/ = /t/ + 1, ..., /n/. | |

Examples: The nonzero elements of an array M with the value | |

| 0 0 0 | | |

| 9 0 0 | may be "gathered" by the function PACK. The result of | |

| 0 0 7 | | |

PACK (M, MASK = M.NE.0) is [9,7] and the result of PACK (M, M.NE.0, | |

VECTOR = (/ 2,4,6,8,10,12 /)) is [9,7,6,8,10,12]. | |

There are two variants of the PACK intrinsic: one, where MASK is | |

array valued, and the other one where MASK is scalar. */ | |

void | |

pack_r4 (gfc_array_r4 *ret, const gfc_array_r4 *array, | |

const gfc_array_l1 *mask, const gfc_array_r4 *vector) | |

{ | |

/* r.* indicates the return array. */ | |

index_type rstride0; | |

GFC_REAL_4 * restrict rptr; | |

/* s.* indicates the source array. */ | |

index_type sstride[GFC_MAX_DIMENSIONS]; | |

index_type sstride0; | |

const GFC_REAL_4 *sptr; | |

/* m.* indicates the mask array. */ | |

index_type mstride[GFC_MAX_DIMENSIONS]; | |

index_type mstride0; | |

const GFC_LOGICAL_1 *mptr; | |

index_type count[GFC_MAX_DIMENSIONS]; | |

index_type extent[GFC_MAX_DIMENSIONS]; | |

int zero_sized; | |

index_type n; | |

index_type dim; | |

index_type nelem; | |

index_type total; | |

int mask_kind; | |

dim = GFC_DESCRIPTOR_RANK (array); | |

mptr = mask->data; | |

/* Use the same loop for all logical types, by using GFC_LOGICAL_1 | |

and using shifting to address size and endian issues. */ | |

mask_kind = GFC_DESCRIPTOR_SIZE (mask); | |

if (mask_kind == 1 || mask_kind == 2 || mask_kind == 4 || mask_kind == 8 | |

#ifdef HAVE_GFC_LOGICAL_16 | |

|| mask_kind == 16 | |

#endif | |

) | |

{ | |

/* Do not convert a NULL pointer as we use test for NULL below. */ | |

if (mptr) | |

mptr = GFOR_POINTER_TO_L1 (mptr, mask_kind); | |

} | |

else | |

runtime_error ("Funny sized logical array"); | |

zero_sized = 0; | |

for (n = 0; n < dim; n++) | |

{ | |

count[n] = 0; | |

extent[n] = array->dim[n].ubound + 1 - array->dim[n].lbound; | |

if (extent[n] <= 0) | |

zero_sized = 1; | |

sstride[n] = array->dim[n].stride; | |

mstride[n] = mask->dim[n].stride * mask_kind; | |

} | |

if (sstride[0] == 0) | |

sstride[0] = 1; | |

if (mstride[0] == 0) | |

mstride[0] = mask_kind; | |

if (zero_sized) | |

sptr = NULL; | |

else | |

sptr = array->data; | |

if (ret->data == NULL || compile_options.bounds_check) | |

{ | |

/* Count the elements, either for allocating memory or | |

for bounds checking. */ | |

if (vector != NULL) | |

{ | |

/* The return array will have as many | |

elements as there are in VECTOR. */ | |

total = vector->dim[0].ubound + 1 - vector->dim[0].lbound; | |

if (total < 0) | |

{ | |

total = 0; | |

vector = NULL; | |

} | |

} | |

else | |

{ | |

/* We have to count the true elements in MASK. */ | |

/* TODO: We could speed up pack easily in the case of only | |

few .TRUE. entries in MASK, by keeping track of where we | |

would be in the source array during the initial traversal | |

of MASK, and caching the pointers to those elements. Then, | |

supposed the number of elements is small enough, we would | |

only have to traverse the list, and copy those elements | |

into the result array. In the case of datatypes which fit | |

in one of the integer types we could also cache the | |

value instead of a pointer to it. | |

This approach might be bad from the point of view of | |

cache behavior in the case where our cache is not big | |

enough to hold all elements that have to be copied. */ | |

const GFC_LOGICAL_1 *m = mptr; | |

total = 0; | |

if (zero_sized) | |

m = NULL; | |

while (m) | |

{ | |

/* Test this element. */ | |

if (*m) | |

total++; | |

/* Advance to the next element. */ | |

m += mstride[0]; | |

count[0]++; | |

n = 0; | |

while (count[n] == extent[n]) | |

{ | |

/* When we get to the end of a dimension, reset it | |

and increment the next dimension. */ | |

count[n] = 0; | |

/* We could precalculate this product, but this is a | |

less frequently used path so probably not worth | |

it. */ | |

m -= mstride[n] * extent[n]; | |

n++; | |

if (n >= dim) | |

{ | |

/* Break out of the loop. */ | |

m = NULL; | |

break; | |

} | |

else | |

{ | |

count[n]++; | |

m += mstride[n]; | |

} | |

} | |

} | |

} | |

if (ret->data == NULL) | |

{ | |

/* Setup the array descriptor. */ | |

ret->dim[0].lbound = 0; | |

ret->dim[0].ubound = total - 1; | |

ret->dim[0].stride = 1; | |

ret->offset = 0; | |

if (total == 0) | |

{ | |

/* In this case, nothing remains to be done. */ | |

ret->data = internal_malloc_size (1); | |

return; | |

} | |

else | |

ret->data = internal_malloc_size (sizeof (GFC_REAL_4) * total); | |

} | |

else | |

{ | |

/* We come here because of range checking. */ | |

index_type ret_extent; | |

ret_extent = ret->dim[0].ubound + 1 - ret->dim[0].lbound; | |

if (total != ret_extent) | |

runtime_error ("Incorrect extent in return value of PACK intrinsic;" | |

" is %ld, should be %ld", (long int) total, | |

(long int) ret_extent); | |

} | |

} | |

rstride0 = ret->dim[0].stride; | |

if (rstride0 == 0) | |

rstride0 = 1; | |

sstride0 = sstride[0]; | |

mstride0 = mstride[0]; | |

rptr = ret->data; | |

while (sptr && mptr) | |

{ | |

/* Test this element. */ | |

if (*mptr) | |

{ | |

/* Add it. */ | |

*rptr = *sptr; | |

rptr += rstride0; | |

} | |

/* Advance to the next element. */ | |

sptr += sstride0; | |

mptr += mstride0; | |

count[0]++; | |

n = 0; | |

while (count[n] == extent[n]) | |

{ | |

/* When we get to the end of a dimension, reset it and increment | |

the next dimension. */ | |

count[n] = 0; | |

/* We could precalculate these products, but this is a less | |

frequently used path so probably not worth it. */ | |

sptr -= sstride[n] * extent[n]; | |

mptr -= mstride[n] * extent[n]; | |

n++; | |

if (n >= dim) | |

{ | |

/* Break out of the loop. */ | |

sptr = NULL; | |

break; | |

} | |

else | |

{ | |

count[n]++; | |

sptr += sstride[n]; | |

mptr += mstride[n]; | |

} | |

} | |

} | |

/* Add any remaining elements from VECTOR. */ | |

if (vector) | |

{ | |

n = vector->dim[0].ubound + 1 - vector->dim[0].lbound; | |

nelem = ((rptr - ret->data) / rstride0); | |

if (n > nelem) | |

{ | |

sstride0 = vector->dim[0].stride; | |

if (sstride0 == 0) | |

sstride0 = 1; | |

sptr = vector->data + sstride0 * nelem; | |

n -= nelem; | |

while (n--) | |

{ | |

*rptr = *sptr; | |

rptr += rstride0; | |

sptr += sstride0; | |

} | |

} | |

} | |

} | |

#endif | |