-/* PSPP - computes sample statistics.
- Copyright (C) 2007 Free Software Foundation, Inc.
+/* PSPP - a program for statistical analysis.
+ Copyright (C) 2007, 2009 Free Software Foundation, Inc.
- This program 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 2 of the
- License, or (at your option) any later version.
+ This program 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.
- This program 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.
+ This program 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.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include "xalloc.h"
/* A casereader. */
-struct casereader
+struct casereader
{
struct taint *taint; /* Corrupted? */
- size_t value_cnt; /* Values per case. */
+ struct caseproto *proto; /* Format of contained cases. */
casenumber case_cnt; /* Number of cases,
CASENUMBER_MAX if unknown. */
const struct casereader_class *class; /* Class. */
static void insert_shim (struct casereader *);
-/* Creates a new case in C and reads the next case from READER
- into it. The caller owns C and must destroy C when its data
- is no longer needed. Return true if successful, false when
- cases have been exhausted or upon detection of an I/O error.
- In the latter case, C is set to the null case.
+/* Reads and returns the next case from READER. The caller owns
+ the returned case and must call case_unref on it when its data
+ is no longer needed. Returns a null pointer if cases have
+ been exhausted or upon detection of an I/O error.
The case returned is effectively consumed: it can never be
read again through READER. If this is inconvenient, READER
may be cloned in advance with casereader_clone, or
casereader_peek may be used instead. */
-bool
-casereader_read (struct casereader *reader, struct ccase *c)
+struct ccase *
+casereader_read (struct casereader *reader)
{
- if (reader->case_cnt != 0 && reader->class->read (reader, reader->aux, c))
+ if (reader->case_cnt != 0)
{
- assert (case_get_value_cnt (c) == reader->value_cnt);
+ /* ->read may use casereader_swap to replace itself by
+ another reader and then delegate to that reader by
+ recursively calling casereader_read. Currently only
+ lazy_casereader does this and, with luck, nothing else
+ ever will.
+
+ To allow this to work, however, we must decrement
+ case_cnt before calling ->read. If we decremented
+ case_cnt after calling ->read, then this would actually
+ drop two cases from case_cnt instead of one, and we'd
+ lose the last case in the casereader. */
+ struct ccase *c;
if (reader->case_cnt != CASENUMBER_MAX)
reader->case_cnt--;
- return true;
- }
- else
- {
- reader->case_cnt = 0;
- case_nullify (c);
- return false;
+ c = reader->class->read (reader, reader->aux);
+ if (c != NULL)
+ {
+ size_t n_widths UNUSED = caseproto_get_n_widths (reader->proto);
+ assert (case_get_value_cnt (c) >= n_widths);
+ expensive_assert (caseproto_equal (case_get_proto (c), 0,
+ reader->proto, 0, n_widths));
+ return c;
+ }
}
+ reader->case_cnt = 0;
+ return NULL;
}
/* Destroys READER.
Returns false if an I/O error was detected on READER, true
otherwise. */
bool
-casereader_destroy (struct casereader *reader)
+casereader_destroy (struct casereader *reader)
{
bool ok = true;
- if (reader != NULL)
+ if (reader != NULL)
{
reader->class->destroy (reader, reader->aux);
ok = taint_destroy (reader->taint);
+ caseproto_unref (reader->proto);
free (reader);
}
return ok;
to read the same sequence of cases in the same order, barring
I/O errors. */
struct casereader *
-casereader_clone (const struct casereader *reader_)
+casereader_clone (const struct casereader *reader_)
{
struct casereader *reader = (struct casereader *) reader_;
struct casereader *clone;
+ if ( reader == NULL )
+ return NULL;
if (reader->class->clone == NULL)
insert_shim (reader);
*NEW2 (if NEW2 is non-null), then destroys ORIGINAL. */
void
casereader_split (struct casereader *original,
- struct casereader **new1, struct casereader **new2)
+ struct casereader **new1, struct casereader **new2)
{
- if (new1 != NULL && new2 != NULL)
+ if (new1 != NULL && new2 != NULL)
{
*new1 = casereader_rename (original);
*new2 = casereader_clone (*new1);
preventing the original owner from accessing the casereader
again. */
struct casereader *
-casereader_rename (struct casereader *reader)
+casereader_rename (struct casereader *reader)
{
struct casereader *new = xmemdup (reader, sizeof *reader);
free (reader);
/* Exchanges the casereaders referred to by A and B. */
void
-casereader_swap (struct casereader *a, struct casereader *b)
+casereader_swap (struct casereader *a, struct casereader *b)
{
- if (a != b)
+ if (a != b)
{
struct casereader tmp = *a;
*a = *b;
}
}
-/* Creates a new case in C and reads the (IDX + 1)'th case from
- READER into it. The caller owns C and must destroy C when its
- data is no longer needed. Return true if successful, false
- when cases have been exhausted or upon detection of an I/O
- error. In the latter case, C is set to the null case. */
-bool
-casereader_peek (struct casereader *reader, casenumber idx, struct ccase *c)
+/* Reads and returns the (IDX + 1)'th case from READER. The
+ caller owns the returned case and must call case_unref on it
+ when it is no longer needed. Returns a null pointer if cases
+ have been exhausted or upon detection of an I/O error. */
+struct ccase *
+casereader_peek (struct casereader *reader, casenumber idx)
{
if (idx < reader->case_cnt)
{
+ struct ccase *c;
if (reader->class->peek == NULL)
insert_shim (reader);
- if (reader->class->peek (reader, reader->aux, idx, c))
- return true;
- else if (casereader_error (reader))
+ c = reader->class->peek (reader, reader->aux, idx);
+ if (c != NULL)
+ return c;
+ else if (casereader_error (reader))
reader->case_cnt = 0;
}
if (reader->case_cnt > idx)
reader->case_cnt = idx;
- case_nullify (c);
- return false;
+ return NULL;
+}
+
+/* Returns true if no cases remain to be read from READER, or if
+ an error has occurred on READER. (A return value of false
+ does *not* mean that the next call to casereader_peek or
+ casereader_read will return true, because an error can occur
+ in the meantime.) */
+bool
+casereader_is_empty (struct casereader *reader)
+{
+ if (reader->case_cnt == 0)
+ return true;
+ else
+ {
+ struct ccase *c = casereader_peek (reader, 0);
+ if (c == NULL)
+ return true;
+ else
+ {
+ case_unref (c);
+ return false;
+ }
+ }
}
/* Returns true if an I/O error or another hard error has
occurred on READER, a clone of READER, or on some object on
which READER's data has a dependency, false otherwise. */
bool
-casereader_error (const struct casereader *reader)
+casereader_error (const struct casereader *reader)
{
return taint_is_tainted (reader->taint);
}
taint_propagate to propagate to the casereader's taint
structure, which may be obtained via casereader_get_taint. */
void
-casereader_force_error (struct casereader *reader)
+casereader_force_error (struct casereader *reader)
{
taint_set_taint (reader->taint);
}
/* Returns READER's associate taint object, for use with
taint_propagate and other taint functions. */
const struct taint *
-casereader_get_taint (const struct casereader *reader)
+casereader_get_taint (const struct casereader *reader)
{
return reader->taint;
}
actual number of cases in such a casereader, use
casereader_count_cases. */
casenumber
-casereader_get_case_cnt (struct casereader *reader)
+casereader_get_case_cnt (struct casereader *reader)
{
return reader->case_cnt;
}
if (reader->case_cnt == CASENUMBER_MAX)
{
casenumber n_cases = 0;
- struct ccase c;
+ struct ccase *c;
struct casereader *clone = casereader_clone (reader);
- for (; casereader_read (clone, &c); case_destroy (&c))
+ for (; (c = casereader_read (clone)) != NULL; case_unref (c))
n_cases++;
casereader_destroy (clone);
return reader->case_cnt;
}
-/* Returns the number of struct values in each case in READER. */
-size_t
-casereader_get_value_cnt (struct casereader *reader)
+/* Returns the prototype for the cases in READER. The caller
+ must not unref the returned prototype. */
+const struct caseproto *
+casereader_get_proto (const struct casereader *reader)
{
- return reader->value_cnt;
+ return reader->proto;
}
/* Copies all the cases in READER to WRITER, propagating errors
void
casereader_transfer (struct casereader *reader, struct casewriter *writer)
{
- struct ccase c;
+ struct ccase *c;
taint_propagate (casereader_get_taint (reader),
casewriter_get_taint (writer));
- while (casereader_read (reader, &c))
- casewriter_write (writer, &c);
+ while ((c = casereader_read (reader)) != NULL)
+ casewriter_write (writer, c);
casereader_destroy (reader);
}
function, in which case the cloned casereader should have the
same taint object as the original casereader.)
- VALUE_CNT must be the number of struct values per case read
- from the casereader.
+ PROTO must be the prototype for the cases that may be read
+ from the casereader. The caller retains its reference to
+ PROTO.
CASE_CNT is an upper limit on the number of cases that
casereader_read will return from the casereader in successive
functions, respectively. */
struct casereader *
casereader_create_sequential (const struct taint *taint,
- size_t value_cnt, casenumber case_cnt,
- const struct casereader_class *class, void *aux)
+ const struct caseproto *proto,
+ casenumber case_cnt,
+ const struct casereader_class *class, void *aux)
{
struct casereader *reader = xmalloc (sizeof *reader);
reader->taint = taint != NULL ? taint_clone (taint) : taint_create ();
- reader->value_cnt = value_cnt;
+ reader->proto = caseproto_ref (proto);
reader->case_cnt = case_cnt;
reader->class = class;
reader->aux = aux;
return reader;
}
+
+/* If READER is a casereader of the given CLASS, returns its
+ associated auxiliary data; otherwise, returns a null pointer.
+
+ This function is intended for use from casereader
+ implementations, not by casereader users. Even within
+ casereader implementations, its usefulness is quite limited,
+ for at least two reasons. First, every casereader member
+ function already receives a pointer to the casereader's
+ auxiliary data. Second, a casereader's class can change
+ (through a call to casereader_swap) and this is in practice
+ quite common (e.g. any call to casereader_clone on a
+ casereader that does not directly support clone will cause the
+ casereader to be replaced by a shim caseader). */
+void *
+casereader_dynamic_cast (struct casereader *reader,
+ const struct casereader_class *class)
+{
+ return reader->class == class ? reader->aux : NULL;
+}
\f
/* Random-access casereader implementation.
/* Returns the random_reader in which the given heap_node is
embedded. */
static struct random_reader *
-random_reader_from_heap_node (const struct heap_node *node)
+random_reader_from_heap_node (const struct heap_node *node)
{
return heap_data (node, struct random_reader, heap_node);
}
/* Data shared among clones of a random reader. */
-struct random_reader_shared
+struct random_reader_shared
{
struct heap *readers; /* Heap of struct random_readers. */
casenumber min_offset; /* Smallest offset of any random_reader. */
void *aux;
};
-static struct casereader_class random_reader_casereader_class;
+static const struct casereader_class random_reader_casereader_class;
/* Creates and returns a new random_reader with the given SHARED
data and OFFSET. Inserts the new random reader into the
static int
compare_random_readers_by_offset (const struct heap_node *a_,
const struct heap_node *b_,
- const void *aux UNUSED)
+ const void *aux UNUSED)
{
const struct random_reader *a = random_reader_from_heap_node (a_);
const struct random_reader *b = random_reader_from_heap_node (b_);
casereader_create_sequential is more appropriate for a data
source that is naturally sequential.
- VALUE_CNT must be the number of struct values per case read
- from the casereader.
+ PROTO must be the prototype for the cases that may be read
+ from the casereader. The caller retains its reference to
+ PROTO.
CASE_CNT is an upper limit on the number of cases that
casereader_read will return from the casereader in successive
member functions and auxiliary data to pass to those member
functions, respectively. */
struct casereader *
-casereader_create_random (size_t value_cnt, casenumber case_cnt,
+casereader_create_random (const struct caseproto *proto, casenumber case_cnt,
const struct casereader_random_class *class,
- void *aux)
+ void *aux)
{
struct random_reader_shared *shared = xmalloc (sizeof *shared);
shared->readers = heap_create (compare_random_readers_by_offset, NULL);
shared->class = class;
shared->aux = aux;
shared->min_offset = 0;
- return casereader_create_sequential (NULL, value_cnt, case_cnt,
+ return casereader_create_sequential (NULL, proto, case_cnt,
&random_reader_casereader_class,
make_random_reader (shared, 0));
}
offset in the heap. */
static void
advance_random_reader (struct casereader *reader,
- struct random_reader_shared *shared)
+ struct random_reader_shared *shared)
{
casenumber old, new;
}
/* struct casereader_class "read" function for random reader. */
-static bool
-random_reader_read (struct casereader *reader, void *br_, struct ccase *c)
+static struct ccase *
+random_reader_read (struct casereader *reader, void *br_)
{
struct random_reader *br = br_;
struct random_reader_shared *shared = br->shared;
-
- if (shared->class->read (reader, shared->aux,
- br->offset - shared->min_offset, c))
+ struct ccase *c = shared->class->read (reader, shared->aux,
+ br->offset - shared->min_offset);
+ if (c != NULL)
{
br->offset++;
heap_changed (shared->readers, &br->heap_node);
- advance_random_reader (reader, shared);
- return true;
+ advance_random_reader (reader, shared);
}
- else
- return false;
+ return c;
}
/* struct casereader_class "destroy" function for random
reader. */
static void
-random_reader_destroy (struct casereader *reader, void *br_)
+random_reader_destroy (struct casereader *reader, void *br_)
{
struct random_reader *br = br_;
struct random_reader_shared *shared = br->shared;
heap_delete (shared->readers, &br->heap_node);
- if (heap_is_empty (shared->readers))
+ if (heap_is_empty (shared->readers))
{
heap_destroy (shared->readers);
shared->class->destroy (reader, shared->aux);
/* struct casereader_class "clone" function for random reader. */
static struct casereader *
-random_reader_clone (struct casereader *reader, void *br_)
+random_reader_clone (struct casereader *reader, void *br_)
{
struct random_reader *br = br_;
struct random_reader_shared *shared = br->shared;
return casereader_create_sequential (casereader_get_taint (reader),
- casereader_get_value_cnt (reader),
+ reader->proto,
casereader_get_case_cnt (reader),
&random_reader_casereader_class,
make_random_reader (shared,
}
/* struct casereader_class "peek" function for random reader. */
-static bool
-random_reader_peek (struct casereader *reader, void *br_,
- casenumber idx, struct ccase *c)
+static struct ccase *
+random_reader_peek (struct casereader *reader, void *br_, casenumber idx)
{
struct random_reader *br = br_;
struct random_reader_shared *shared = br->shared;
return shared->class->read (reader, shared->aux,
- br->offset - shared->min_offset + idx, c);
+ br->offset - shared->min_offset + idx);
}
/* Casereader class for random reader. */
-static struct casereader_class random_reader_casereader_class =
+static const struct casereader_class random_reader_casereader_class =
{
random_reader_read,
random_reader_destroy,
window of cases that spans the positions of the original
casereader and all of its clones (the "clone set"), from the
position of the casereader that has read the fewest cases to
- the position of the casereader that has read the most.
+ the position of the casereader that has read the most.
Thus, if all of the casereaders in the clone set are at
approximately the same position, only a few cases are buffered
/* A buffering shim for a non-clonable or non-peekable
casereader. */
-struct shim
+struct shim
{
struct casewindow *window; /* Window of buffered cases. */
struct casereader *subreader; /* Subordinate casereader. */
};
-static struct casereader_random_class shim_class;
+static const struct casereader_random_class shim_class;
/* Interposes a buffering shim atop READER. */
static void
-insert_shim (struct casereader *reader)
+insert_shim (struct casereader *reader)
{
- size_t value_cnt = casereader_get_value_cnt (reader);
+ const struct caseproto *proto = casereader_get_proto (reader);
casenumber case_cnt = casereader_get_case_cnt (reader);
struct shim *b = xmalloc (sizeof *b);
- b->window = casewindow_create (value_cnt, get_workspace_cases (value_cnt));
- b->subreader = casereader_create_random (value_cnt, case_cnt,
- &shim_class, b);
+ b->window = casewindow_create (proto, settings_get_workspace_cases (proto));
+ b->subreader = casereader_create_random (proto, case_cnt, &shim_class, b);
casereader_swap (reader, b->subreader);
taint_propagate (casewindow_get_taint (b->window),
casereader_get_taint (reader));
Return true if successful, false upon reaching the end of B's
subreader or an I/O error. */
static bool
-prime_buffer (struct shim *b, casenumber case_cnt)
+prime_buffer (struct shim *b, casenumber case_cnt)
{
- while (casewindow_get_case_cnt (b->window) < case_cnt)
+ while (casewindow_get_case_cnt (b->window) < case_cnt)
{
- struct ccase tmp;
- if (!casereader_read (b->subreader, &tmp))
+ struct ccase *tmp = casereader_read (b->subreader);
+ if (tmp == NULL)
return false;
- casewindow_push_head (b->window, &tmp);
+ casewindow_push_head (b->window, tmp);
}
return true;
}
/* Reads the case at the given 0-based OFFSET from the front of
- the window into C. Returns true if successful, false if
- OFFSET is beyond the end of file or upon I/O error. */
-static bool
+ the window into C. Returns the case if successful, or a null
+ pointer if OFFSET is beyond the end of file or upon I/O error.
+ The caller must call case_unref() on the returned case when it
+ is no longer needed. */
+static struct ccase *
shim_read (struct casereader *reader UNUSED, void *b_,
- casenumber offset, struct ccase *c)
+ casenumber offset)
{
struct shim *b = b_;
- return (prime_buffer (b, offset + 1)
- && casewindow_get_case (b->window, offset, c));
+ if (!prime_buffer (b, offset + 1))
+ return NULL;
+ return casewindow_get_case (b->window, offset);
}
/* Destroys B. */
static void
-shim_destroy (struct casereader *reader UNUSED, void *b_)
+shim_destroy (struct casereader *reader UNUSED, void *b_)
{
struct shim *b = b_;
casewindow_destroy (b->window);
}
/* Class for the buffered reader. */
-static struct casereader_random_class shim_class =
+static const struct casereader_random_class shim_class =
{
shim_read,
shim_destroy,
projects / pspp-builds.git / blobdiff