[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/libc/glibc/glibc-2.22/misc/hsearch_r.c b/ap/libc/glibc/glibc-2.22/misc/hsearch_r.c
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+/* Copyright (C) 1993-2015 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1993.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <malloc.h>
+#include <string.h>
+
+#include <search.h>
+
+/* [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
+ [Knuth] The Art of Computer Programming, part 3 (6.4) */
+
+
+/* The reentrant version has no static variables to maintain the state.
+ Instead the interface of all functions is extended to take an argument
+ which describes the current status. */
+typedef struct _ENTRY
+{
+ unsigned int used;
+ ENTRY entry;
+}
+_ENTRY;
+
+
+/* For the used double hash method the table size has to be a prime. To
+ correct the user given table size we need a prime test. This trivial
+ algorithm is adequate because
+ a) the code is (most probably) called a few times per program run and
+ b) the number is small because the table must fit in the core */
+static int
+isprime (unsigned int number)
+{
+ /* no even number will be passed */
+ unsigned int div = 3;
+
+ while (div * div < number && number % div != 0)
+ div += 2;
+
+ return number % div != 0;
+}
+
+
+/* Before using the hash table we must allocate memory for it.
+ Test for an existing table are done. We allocate one element
+ more as the found prime number says. This is done for more effective
+ indexing as explained in the comment for the hsearch function.
+ The contents of the table is zeroed, especially the field used
+ becomes zero. */
+int
+__hcreate_r (nel, htab)
+ size_t nel;
+ struct hsearch_data *htab;
+{
+ /* Test for correct arguments. */
+ if (htab == NULL)
+ {
+ __set_errno (EINVAL);
+ return 0;
+ }
+
+ /* There is still another table active. Return with error. */
+ if (htab->table != NULL)
+ return 0;
+
+ /* We need a size of at least 3. Otherwise the hash functions we
+ use will not work. */
+ if (nel < 3)
+ nel = 3;
+ /* Change nel to the first prime number not smaller as nel. */
+ nel |= 1; /* make odd */
+ while (!isprime (nel))
+ nel += 2;
+
+ htab->size = nel;
+ htab->filled = 0;
+
+ /* allocate memory and zero out */
+ htab->table = (_ENTRY *) calloc (htab->size + 1, sizeof (_ENTRY));
+ if (htab->table == NULL)
+ return 0;
+
+ /* everything went alright */
+ return 1;
+}
+libc_hidden_def (__hcreate_r)
+weak_alias (__hcreate_r, hcreate_r)
+
+
+/* After using the hash table it has to be destroyed. The used memory can
+ be freed and the local static variable can be marked as not used. */
+void
+__hdestroy_r (htab)
+ struct hsearch_data *htab;
+{
+ /* Test for correct arguments. */
+ if (htab == NULL)
+ {
+ __set_errno (EINVAL);
+ return;
+ }
+
+ /* Free used memory. */
+ free (htab->table);
+
+ /* the sign for an existing table is an value != NULL in htable */
+ htab->table = NULL;
+}
+libc_hidden_def (__hdestroy_r)
+weak_alias (__hdestroy_r, hdestroy_r)
+
+
+/* This is the search function. It uses double hashing with open addressing.
+ The argument item.key has to be a pointer to an zero terminated, most
+ probably strings of chars. The function for generating a number of the
+ strings is simple but fast. It can be replaced by a more complex function
+ like ajw (see [Aho,Sethi,Ullman]) if the needs are shown.
+
+ We use an trick to speed up the lookup. The table is created by hcreate
+ with one more element available. This enables us to use the index zero
+ special. This index will never be used because we store the first hash
+ index in the field used where zero means not used. Every other value
+ means used. The used field can be used as a first fast comparison for
+ equality of the stored and the parameter value. This helps to prevent
+ unnecessary expensive calls of strcmp. */
+int
+__hsearch_r (item, action, retval, htab)
+ ENTRY item;
+ ACTION action;
+ ENTRY **retval;
+ struct hsearch_data *htab;
+{
+ unsigned int hval;
+ unsigned int count;
+ unsigned int len = strlen (item.key);
+ unsigned int idx;
+
+ /* Compute an value for the given string. Perhaps use a better method. */
+ hval = len;
+ count = len;
+ while (count-- > 0)
+ {
+ hval <<= 4;
+ hval += item.key[count];
+ }
+ if (hval == 0)
+ ++hval;
+
+ /* First hash function: simply take the modul but prevent zero. */
+ idx = hval % htab->size + 1;
+
+ if (htab->table[idx].used)
+ {
+ /* Further action might be required according to the action value. */
+ if (htab->table[idx].used == hval
+ && strcmp (item.key, htab->table[idx].entry.key) == 0)
+ {
+ *retval = &htab->table[idx].entry;
+ return 1;
+ }
+
+ /* Second hash function, as suggested in [Knuth] */
+ unsigned int hval2 = 1 + hval % (htab->size - 2);
+ unsigned int first_idx = idx;
+
+ do
+ {
+ /* Because SIZE is prime this guarantees to step through all
+ available indeces. */
+ if (idx <= hval2)
+ idx = htab->size + idx - hval2;
+ else
+ idx -= hval2;
+
+ /* If we visited all entries leave the loop unsuccessfully. */
+ if (idx == first_idx)
+ break;
+
+ /* If entry is found use it. */
+ if (htab->table[idx].used == hval
+ && strcmp (item.key, htab->table[idx].entry.key) == 0)
+ {
+ *retval = &htab->table[idx].entry;
+ return 1;
+ }
+ }
+ while (htab->table[idx].used);
+ }
+
+ /* An empty bucket has been found. */
+ if (action == ENTER)
+ {
+ /* If table is full and another entry should be entered return
+ with error. */
+ if (htab->filled == htab->size)
+ {
+ __set_errno (ENOMEM);
+ *retval = NULL;
+ return 0;
+ }
+
+ htab->table[idx].used = hval;
+ htab->table[idx].entry = item;
+
+ ++htab->filled;
+
+ *retval = &htab->table[idx].entry;
+ return 1;
+ }
+
+ __set_errno (ESRCH);
+ *retval = NULL;
+ return 0;
+}
+libc_hidden_def (__hsearch_r)
+weak_alias (__hsearch_r, hsearch_r)