#include <data/value.h>
#include <data/val-type.h>
+#include <data/variable.h>
#include <libpspp/hash.h>
+#include <libpspp/pool.h>
#include <libpspp/str.h>
-#include "variable.h"
+#include "minmax.h"
#include "xalloc.h"
-/* Duplicate a value.
- The caller is responsible for freeing the returned value. */
-union value *
-value_dup (const union value *val, int width)
-{
- return xmemdup (val, MAX (width, sizeof *val));
-}
+/* Copies the contents of string value SRC with width SRC_WIDTH
+ to string value DST with width DST_WIDTH. If SRC_WIDTH is
+ greater than DST_WIDTH, then only the first DST_WIDTH bytes
+ are copied; if DST_WIDTH is greater than SRC_WIDTH, then DST
+ is padded on the right with PAD bytes.
+ SRC and DST must be string values; that is, SRC_WIDTH and
+ DST_WIDTH must both be positive.
-/* Create a value of specified width.
- The caller is responsible for freeing the returned value. */
-union value *
-value_create (int width)
+ It is important that SRC_WIDTH and DST_WIDTH be the actual
+ widths with which SRC and DST were initialized. Passing,
+ e.g., smaller values in order to copy only a prefix of SRC or
+ modify only a prefix of DST will not work in every case. */
+void
+value_copy_rpad (union value *dst, int dst_width,
+ const union value *src, int src_width,
+ char pad)
{
- return xnmalloc (value_cnt_from_width (width), sizeof (union value));
+ buf_copy_rpad (value_str_rw (dst, dst_width), dst_width,
+ value_str (src, src_width), src_width,
+ pad);
}
+/* Copies the contents of null-terminated string SRC to string
+ value DST with width DST_WIDTH. If SRC is more than DST_WIDTH
+ bytes long, then only the first DST_WIDTH bytes are copied; if
+ DST_WIDTH is greater than the length of SRC, then DST is
+ padded on the right with PAD bytes.
-/* Compares A and B, which both have the given WIDTH, and returns
- a strcmp()-type result.
- Only the short string portion of longer strings are
- compared. */
-int
-compare_values_short (const void *a_, const void *b_, const void *var_)
-{
- const union value *a = a_;
- const union value *b = b_;
- const struct variable *var = var_;
- int width = var_get_width (var);
- return value_compare_3way (a, b, MIN (width, MAX_SHORT_STRING));
-}
-
+ DST must be a string value; that is, DST_WIDTH must be
+ positive.
-/* Create a hash of V, which has the given WIDTH.
- Only the short string portion of a longer string is hashed. */
-unsigned
-hash_value_short (const void *v_, const void *var_)
+ It is important that DST_WIDTH be the actual width with which
+ DST was initialized. Passing, e.g., a smaller value in order
+ to modify only a prefix of DST will not work in every case. */
+void
+value_copy_str_rpad (union value *dst, int dst_width, const char *src,
+ char pad)
{
- const union value *v = v_;
- const struct variable *var = var_;
- int width = var_get_width (var);
- return width == 0 ? hash_double (v->f, 0) : hash_bytes (v->s, width, 0);
+ value_copy_buf_rpad (dst, dst_width, src, strlen (src), pad);
}
+/* Copies the SRC_LEN bytes at SRC to string value DST with width
+ DST_WIDTH. If SRC_LEN is greater than DST_WIDTH, then only
+ the first DST_WIDTH bytes are copied; if DST_WIDTH is greater
+ than SRC_LEN, then DST is padded on the right with PAD bytes.
-/* Copies SRC to DST, given that they both contain data of the
- given WIDTH. */
+ DST must be a string value; that is, DST_WIDTH must be
+ positive.
+
+ It is important that DST_WIDTH be the actual width with which
+ DST was initialized. Passing, e.g., a smaller value in order
+ to modify only a prefix of DST will not work in every case. */
void
-value_copy (union value *dst, const union value *src, int width)
+value_copy_buf_rpad (union value *dst, int dst_width,
+ const char *src, size_t src_len, char pad)
{
- if (width == 0)
- dst->f = src->f;
- else
- memcpy (dst->s, src->s, width);
+ buf_copy_rpad (value_str_rw (dst, dst_width), dst_width, src, src_len, pad);
}
/* Sets V to the system-missing value for data of the given
if (width == 0)
v->f = SYSMIS;
else
- memset (v->s, ' ', width);
+ memset (value_str_rw (v, width), ' ', width);
+}
+
+/* Compares A and B, which both have the given WIDTH, and returns
+ a strcmp()-type result. */
+int
+value_compare_3way (const union value *a, const union value *b, int width)
+{
+ return (width == 0
+ ? (a->f < b->f ? -1 : a->f > b->f)
+ : memcmp (value_str (a, width), value_str (b, width), width));
+}
+
+/* Returns true if A and B, which must both have the given WIDTH,
+ have equal contents, false if their contents differ. */
+bool
+value_equal (const union value *a, const union value *b, int width)
+{
+ return (width == 0
+ ? a->f == b->f
+ : !memcmp (value_str (a, width), value_str (b, width), width));
+}
+
+/* Returns a hash of the data in VALUE, which must have the given
+ WIDTH, folding BASIS into the hash value calculation. */
+unsigned int
+value_hash (const union value *value, int width, unsigned int basis)
+{
+ return (width == 0
+ ? hash_double (value->f, basis)
+ : hash_bytes (value_str (value, width), width, basis));
}
/* Tests whether VALUE may be resized from OLD_WIDTH to
bool
value_is_resizable (const union value *value, int old_width, int new_width)
{
- int i;
-
- if (val_type_from_width (old_width) != val_type_from_width (new_width))
+ if (old_width == new_width)
+ return true;
+ else if (val_type_from_width (old_width) != val_type_from_width (new_width))
return false;
- for (i = new_width; i < old_width; i++)
- if (value->s[i] != ' ')
- return false;
- return true;
+ else
+ {
+ const char *str = value_str (value, old_width);
+ int i;
+
+ for (i = new_width; i < old_width; i++)
+ if (str[i] != ' ')
+ return false;
+ return true;
+ }
}
/* Resizes VALUE from OLD_WIDTH to NEW_WIDTH. The arguments must
value_resize (union value *value, int old_width, int new_width)
{
assert (value_is_resizable (value, old_width, new_width));
- if (new_width > old_width)
- memset (&value->s[old_width], ' ', new_width - old_width);
+ if (new_width != old_width)
+ {
+ union value tmp;
+ value_init (&tmp, new_width);
+ value_copy_rpad (&tmp, new_width, value, old_width, ' ');
+ value_destroy (value, old_width);
+ *value = tmp;
+ }
}
-/* Compares A and B, which both have the given WIDTH, and returns
- a strcmp()-type result. */
-int
-value_compare_3way (const union value *a, const union value *b, int width)
+/* Returns true if resizing a value from OLD_WIDTH to NEW_WIDTH
+ actually changes anything, false otherwise. If false is
+ returned, calls to value_resize() with the specified
+ parameters may be omitted without any ill effects.
+
+ This is generally useful only if many values can skip being
+ resized from OLD_WIDTH to NEW_WIDTH. Otherwise you might as
+ well just call value_resize directly. */
+bool
+value_needs_resize (int old_width, int new_width)
{
- return (width == 0
- ? (a->f < b->f ? -1 : a->f > b->f)
- : memcmp (a->s, b->s, width));
+ assert (val_type_from_width (old_width) == val_type_from_width (new_width));
+
+ /* We need to call value_resize if either the new width is
+ longer than the old width (in which case the new characters
+ must be set to spaces) or if either width is a long string.
+ (We could omit resizing if both the old and new widths were
+ long and the new width was shorter, but we choose to do so
+ anyway in hopes of saving memory.) */
+ return (old_width != new_width
+ && (new_width > old_width
+ || old_width >= MIN_LONG_STRING
+ || new_width >= MIN_LONG_STRING));
+}
+
+/* Same as value_init, except that memory for VALUE (if
+ necessary) is allocated from POOL and will be freed
+ automatically when POOL is destroyed.
+
+ VALUE must not be freed manually by calling value_destroy. If
+ it needs to be resized, it must be done using
+ value_resize_pool instead of value_resize. */
+void
+value_init_pool (struct pool *pool, union value *value, int width)
+{
+ if (width > MAX_SHORT_STRING)
+ value->long_string = pool_alloc_unaligned (pool, width);
+}
+
+/* Same as value_resize, except that VALUE must have been
+ allocated from POOL using value_init_pool.
+
+ This function causes some memory in POOL to be wasted in some
+ cases (until the pool is freed), so it should only be done if
+ this is acceptable. */
+void
+value_resize_pool (struct pool *pool, union value *value,
+ int old_width, int new_width)
+{
+ assert (value_is_resizable (value, old_width, new_width));
+ if (new_width > old_width)
+ {
+ if (new_width > MAX_SHORT_STRING)
+ {
+ char *new_long_string = pool_alloc_unaligned (pool, new_width);
+ memcpy (new_long_string, value_str (value, old_width), old_width);
+ value->long_string = new_long_string;
+ }
+ memset (value_str_rw (value, new_width) + old_width, ' ',
+ new_width - old_width);
+ }
}
projects / pspp-builds.git / blobdiff