/* PSPP - a program for statistical analysis.
- Copyright (C) 2004, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2004, 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
#include <assert.h>
#include <limits.h>
+#include <stddef.h>
#include <stdlib.h>
#include <data/value.h>
#include "minmax.h"
#include "xalloc.h"
-/* Reference-counted case implementation. */
-struct case_data
- {
- size_t value_cnt; /* Number of values. */
- unsigned ref_cnt; /* Reference count. */
- union value values[1]; /* Values. */
- };
-
-/* Ensures that C does not share data with any other case. */
-static void
-case_unshare (struct ccase *c)
-{
- if (c->case_data->ref_cnt > 1)
- {
- struct case_data *cd = c->case_data;
- cd->ref_cnt--;
- case_create (c, cd->value_cnt);
- memcpy (c->case_data->values, cd->values,
- sizeof *cd->values * cd->value_cnt);
- }
-}
-
-/* Returns the number of bytes needed by a case with VALUE_CNT
+/* Returns the number of bytes needed by a case with N_VALUES
values. */
static size_t
-case_size (size_t value_cnt)
+case_size (size_t n_values)
{
- return (offsetof (struct case_data, values)
- + value_cnt * sizeof (union value));
+ return offsetof (struct ccase, values) + n_values * sizeof (union value);
}
-/* Initializes C as a null case. */
-void
-case_nullify (struct ccase *c)
+/* Returns true if case C contains COUNT cases starting at index
+ OFS, false if any of those values are out of range for case
+ C. */
+static inline bool UNUSED
+range_is_valid (const struct ccase *c, size_t ofs, size_t count)
{
- c->case_data = NULL;
+ return (count <= c->n_values
+ && ofs <= c->n_values
+ && ofs + count <= c->n_values);
}
-/* Returns true iff C is a null case. */
-bool
-case_is_null (const struct ccase *c)
-{
- return c->case_data == NULL;
-}
-
-/* Initializes C as a new case that can store VALUE_CNT values.
+/* Creates and returns a new case that can store N_VALUES values.
The values have indeterminate contents until explicitly
written. */
-void
-case_create (struct ccase *c, size_t value_cnt)
+struct ccase *
+case_create (size_t n_values)
{
- if (!case_try_create (c, value_cnt))
+ struct ccase *c = case_try_create (n_values);
+ if (c == NULL)
xalloc_die ();
+ return c;
}
-/* Initializes CLONE as a copy of ORIG. */
-void
-case_clone (struct ccase *clone, const struct ccase *orig)
+/* Like case_create, but returns a null pointer if not enough
+ memory is available. */
+struct ccase *
+case_try_create (size_t n_values)
{
- assert (orig->case_data->ref_cnt > 0);
-
- if (clone != orig)
- *clone = *orig;
- orig->case_data->ref_cnt++;
-#ifdef DEBUGGING
- case_unshare (clone);
-#endif
-}
-
-/* Replaces DST by SRC and nullifies SRC.
- DST and SRC must be initialized cases at entry. */
-void
-case_move (struct ccase *dst, struct ccase *src)
-{
- assert (src->case_data->ref_cnt > 0);
-
- if (dst != src)
+ struct ccase *c = malloc (case_size (n_values));
+ if (c)
{
- *dst = *src;
- case_nullify (src);
+ c->n_values = n_values;
+ c->ref_cnt = 1;
}
+ return c;
}
-/* Destroys case C. */
-void
-case_destroy (struct ccase *c)
+/* Resizes case C, which must not be shared, to N_VALUES union
+ values. If N_VALUES is greater than the current size of case
+ C, then the newly added values have indeterminate content that
+ the caller is responsible for initializing. Returns the new
+ case. */
+struct ccase *
+case_resize (struct ccase *c, size_t n_values)
{
- struct case_data *cd;
-
- cd = c->case_data;
- if (cd != NULL && --cd->ref_cnt == 0)
+ assert (!case_is_shared (c));
+ if (n_values != c->n_values)
{
- memset (cd->values, 0xcc, sizeof *cd->values * cd->value_cnt);
- cd->value_cnt = 0xdeadbeef;
- free (cd);
+ c->n_values = n_values;
+ return xrealloc (c, case_size (n_values));
}
+ else
+ return c;
}
-/* Returns the number of union values in C. */
-size_t
-case_get_value_cnt (const struct ccase *c)
-{
- return c->case_data->value_cnt;
-}
+/* case_unshare_and_resize(C, N) is equivalent to
+ case_resize(case_unshare(C), N), but it is faster if case C is
+ shared.
-/* Resizes case C to NEW_CNT union values. */
-void
-case_resize (struct ccase *c, size_t new_cnt)
+ Returns the new case.*/
+struct ccase *
+case_unshare_and_resize (struct ccase *c, size_t n_values)
{
- size_t old_cnt = case_get_value_cnt (c);
- if (old_cnt != new_cnt)
+ if (!case_is_shared (c))
+ return case_resize (c, n_values);
+ else
{
- struct ccase new;
-
- case_create (&new, new_cnt);
- case_copy (&new, 0, c, 0, MIN (old_cnt, new_cnt));
- case_swap (&new, c);
- case_destroy (&new);
+ struct ccase *new = case_create (n_values);
+ case_copy (new, 0, c, 0, MIN (n_values, c->n_values));
+ c->ref_cnt--;
+ return new;
}
}
-/* Swaps cases A and B. */
-void
-case_swap (struct ccase *a, struct ccase *b)
-{
- struct case_data *t = a->case_data;
- a->case_data = b->case_data;
- b->case_data = t;
-}
+/* Copies N_VALUES values from SRC (starting at SRC_IDX) to DST
+ (starting at DST_IDX).
-/* Attempts to create C as a new case that holds VALUE_CNT
- values. Returns true if successful, false if memory
- allocation failed. */
-bool
-case_try_create (struct ccase *c, size_t value_cnt)
-{
- c->case_data = malloc (case_size (value_cnt));
- if (c->case_data != NULL)
- {
- c->case_data->value_cnt = value_cnt;
- c->case_data->ref_cnt = 1;
- return true;
- }
-
- return false;
-}
-
-/* Tries to initialize CLONE as a copy of ORIG.
- Returns true if successful, false if memory allocation
- failed. */
-bool
-case_try_clone (struct ccase *clone, const struct ccase *orig)
-{
- case_clone (clone, orig);
- return true;
-}
-
-/* Copies VALUE_CNT values from SRC (starting at SRC_IDX) to DST
- (starting at DST_IDX). */
+ DST must not be shared. */
void
case_copy (struct ccase *dst, size_t dst_idx,
const struct ccase *src, size_t src_idx,
- size_t value_cnt)
+ size_t n_values)
{
- assert (dst->case_data->ref_cnt > 0);
- assert (dst_idx + value_cnt <= dst->case_data->value_cnt);
+ assert (!case_is_shared (dst));
+ assert (range_is_valid (dst, dst_idx, n_values));
+ assert (range_is_valid (src, dst_idx, n_values));
- assert (src->case_data->ref_cnt > 0);
- assert (src_idx + value_cnt <= src->case_data->value_cnt);
-
- if (dst->case_data != src->case_data || dst_idx != src_idx)
- {
- case_unshare (dst);
- memmove (dst->case_data->values + dst_idx,
- src->case_data->values + src_idx,
- sizeof *dst->case_data->values * value_cnt);
- }
+ if (dst != src || dst_idx != src_idx)
+ memmove (dst->values + dst_idx, src->values + src_idx,
+ sizeof *dst->values * n_values);
}
-/* Copies VALUE_CNT values out of case C to VALUES, starting at
+/* Copies N_VALUES values out of case C to VALUES, starting at
the given START_IDX. */
void
case_copy_out (const struct ccase *c,
- size_t start_idx, union value *values, size_t value_cnt)
+ size_t start_idx, union value *values, size_t n_values)
{
- assert (c->case_data->ref_cnt > 0);
- assert (value_cnt <= c->case_data->value_cnt);
- assert (start_idx + value_cnt <= c->case_data->value_cnt);
-
- memcpy (values, c->case_data->values + start_idx,
- value_cnt * sizeof *values);
+ assert (range_is_valid (c, start_idx, n_values));
+ memcpy (values, c->values + start_idx, n_values * sizeof *values);
}
-/* Copies VALUE_CNT values from VALUES into case C, staring at
- the given START_IDX. */
+/* Copies N_VALUES values from VALUES into case C, starting at
+ the given START_IDX.
+
+ C must not be shared. */
void
case_copy_in (struct ccase *c,
- size_t start_idx, const union value *values, size_t value_cnt)
+ size_t start_idx, const union value *values, size_t n_values)
{
- assert (c->case_data->ref_cnt > 0);
- assert (value_cnt <= c->case_data->value_cnt);
- assert (start_idx + value_cnt <= c->case_data->value_cnt);
-
- case_unshare (c);
- memcpy (c->case_data->values + start_idx, values,
- value_cnt * sizeof *values);
+ assert (!case_is_shared (c));
+ assert (range_is_valid (c, start_idx, n_values));
+ memcpy (c->values + start_idx, values, n_values * sizeof *values);
}
/* Returns a pointer to the `union value' used for the
return case_data_idx (c, var_get_case_index (v));
}
-/* Returns the numeric value of the `union value' in C for
- variable V.
- Case C must be drawn from V's dictionary. */
-double
-case_num (const struct ccase *c, const struct variable *v)
+/* Returns a pointer to the `union value' used for the element of
+ C numbered IDX. The caller must not modify the returned
+ data. */
+const union value *
+case_data_idx (const struct ccase *c, size_t idx)
{
- return case_num_idx (c, var_get_case_index (v));
+ assert (idx < c->n_values);
+ return &c->values[idx];
}
-/* Returns the string value of the `union value' in C for
- variable V.
- Case C must be drawn from V's dictionary.
- (Note that the value is not null-terminated.)
- The caller must not modify the return value. */
-const char *
-case_str (const struct ccase *c, const struct variable *v)
-{
- return case_str_idx (c, var_get_case_index (v));
-}
+/* Returns a pointer to the `union value' used for the element of
+ C for variable V. Case C must be drawn from V's dictionary.
+ The caller is allowed to modify the returned data.
-/* Returns a pointer to the `union value' used for the
- element of C for variable V.
- Case C must be drawn from V's dictionary.
- The caller is allowed to modify the returned data. */
+ Case C must not be shared. */
union value *
case_data_rw (struct ccase *c, const struct variable *v)
{
/* Returns a pointer to the `union value' used for the
element of C numbered IDX.
- The caller must not modify the returned data. */
-const union value *
-case_data_idx (const struct ccase *c, size_t idx)
+ The caller is allowed to modify the returned data.
+
+ Case C must not be shared. */
+union value *
+case_data_rw_idx (struct ccase *c, size_t idx)
{
- assert (c->case_data->ref_cnt > 0);
- assert (idx < c->case_data->value_cnt);
+ assert (!case_is_shared (c));
+ assert (idx < c->n_values);
+ return &c->values[idx];
+}
- return &c->case_data->values[idx];
+/* Returns the numeric value of the `union value' in C for
+ variable V.
+ Case C must be drawn from V's dictionary. */
+double
+case_num (const struct ccase *c, const struct variable *v)
+{
+ return case_num_idx (c, var_get_case_index (v));
}
/* Returns the numeric value of the `union value' in C numbered
double
case_num_idx (const struct ccase *c, size_t idx)
{
- assert (c->case_data->ref_cnt > 0);
- assert (idx < c->case_data->value_cnt);
-
- return c->case_data->values[idx].f;
+ assert (idx < c->n_values);
+ return c->values[idx].f;
}
-/* Returns the string value of the `union value' in C numbered
- IDX.
- (Note that the value is not null-terminated.)
- The caller must not modify the return value. */
+/* Returns the string value of the `union value' in C for
+ variable V. Case C must be drawn from V's dictionary. The
+ caller must not modify the return value.
+
+ Like all "union value"s, the return value is not
+ null-terminated. */
const char *
-case_str_idx (const struct ccase *c, size_t idx)
+case_str (const struct ccase *c, const struct variable *v)
{
- assert (c->case_data->ref_cnt > 0);
- assert (idx < c->case_data->value_cnt);
-
- return c->case_data->values[idx].s;
+ return case_str_idx (c, var_get_case_index (v));
}
-/* Returns a pointer to the `union value' used for the
- element of C numbered IDX.
- The caller is allowed to modify the returned data. */
-union value *
-case_data_rw_idx (struct ccase *c, size_t idx)
-{
- assert (c->case_data->ref_cnt > 0);
- assert (idx < c->case_data->value_cnt);
+/* Returns the string value of the `union value' in C numbered
+ IDX. The caller must not modify the return value.
- case_unshare (c);
- return &c->case_data->values[idx];
+ Like all "union value"s, the return value is not
+ null-terminated. */
+const char *
+case_str_idx (const struct ccase *c, size_t idx)
+{
+ assert (idx < c->n_values);
+ return c->values[idx].s;
}
-/* Compares the values of the VAR_CNT variables in VP
+/* Compares the values of the N_VARS variables in VP
in cases A and B and returns a strcmp()-type result. */
int
case_compare (const struct ccase *a, const struct ccase *b,
- const struct variable *const *vp, size_t var_cnt)
+ const struct variable *const *vp, size_t n_vars)
{
- return case_compare_2dict (a, b, vp, vp, var_cnt);
+ return case_compare_2dict (a, b, vp, vp, n_vars);
}
-/* Compares the values of the VAR_CNT variables in VAP in case CA
- to the values of the VAR_CNT variables in VBP in CB
+/* Compares the values of the N_VARS variables in VAP in case CA
+ to the values of the N_VARS variables in VBP in CB
and returns a strcmp()-type result. */
int
case_compare_2dict (const struct ccase *ca, const struct ccase *cb,
const struct variable *const *vap,
- const struct variable *const *vbp,
- size_t var_cnt)
+ const struct variable *const *vbp,
+ size_t n_vars)
{
- for (; var_cnt-- > 0; vap++, vbp++)
+ for (; n_vars-- > 0; vap++, vbp++)
{
const struct variable *va = *vap;
const struct variable *vb = *vbp;
/* Returns a pointer to the array of `union value's used for C.
The caller must *not* modify the returned data.
- NOTE: This function breaks the case abstraction. It should
- *not* be used often. Prefer the other case functions. */
+ This function breaks the case abstraction. It should *not* be
+ commonly used. Prefer the other case functions. */
const union value *
case_data_all (const struct ccase *c)
{
- assert (c->case_data->ref_cnt > 0);
-
- return c->case_data->values;
+ return c->values;
}
/* Returns a pointer to the array of `union value's used for C.
The caller is allowed to modify the returned data.
- NOTE: This function breaks the case abstraction. It should
- *not* be used often. Prefer the other case functions. */
+ Case C must not be shared.
+
+ This function breaks the case abstraction. It should *not* be
+ commonly used. Prefer the other case functions. */
union value *
case_data_all_rw (struct ccase *c)
{
- assert (c->case_data->ref_cnt > 0);
+ assert (!case_is_shared (c));
+ return c->values;
+}
- case_unshare (c);
- return c->case_data->values;
+/* Internal helper function for case_unshare. */
+struct ccase *
+case_unshare__ (struct ccase *old)
+{
+ struct ccase *new = case_create (old->n_values);
+ memcpy (new->values, old->values, old->n_values * sizeof old->values[0]);
+ --old->ref_cnt;
+ return new;
}
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