common: Add simple dynamic array function.

* common/ccparray.c: New.
* common/ccparray.h: New.
* common/t-ccparray.c: New.
* common/Makefile.am (common_sources): Add files.
(module_tests): Add test file.
(t_ccparray_LDADD): New.

Signed-off-by: Werner Koch <wk@gnupg.org>

common/Makefile.am

@@ -72,6 +72,7 @@ common_sources = \
 	xasprintf.c \
 	xreadline.c \
 	membuf.c membuf.h \
+	ccparray.c ccparray.h \
 	iobuf.c iobuf.h \
 	ttyio.c ttyio.h \
 	asshelp.c asshelp2.c asshelp.h \
@@ -156,7 +157,7 @@ module_tests = t-stringhelp t-timestuff \
                t-convert t-percent t-gettime t-sysutils t-sexputil \
 	       t-session-env t-openpgp-oid t-ssh-utils \
 	       t-mapstrings t-zb32 t-mbox-util t-iobuf t-strlist \
-	       t-private-keys
+	       t-private-keys t-ccparray
 if !HAVE_W32CE_SYSTEM
 module_tests += t-exechelp
 endif
@@ -206,6 +207,7 @@ t_mbox_util_LDADD = $(t_common_ldadd)
 t_iobuf_LDADD = $(t_common_ldadd)
 t_strlist_LDADD = $(t_common_ldadd)
 t_private_keys_LDADD = $(t_common_ldadd)
+t_ccparray_LDADD = $(t_common_ldadd)
 
 # System specific test
 if HAVE_W32_SYSTEM

common/ccparray.c

@@ -0,0 +1,147 @@
+/* ccparray.c - A simple dynamic array for character pointer.
+ * Copyright (C) 2016 g10 Code GmbH
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either
+ *
+ *   - the GNU Lesser General Public License as published by the Free
+ *     Software Foundation; either version 3 of the License, or (at
+ *     your option) any later version.
+ *
+ * or
+ *
+ *   - 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.
+ *
+ * or both in parallel, as here.
+ *
+ * This file 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+
+#include "util.h"
+#include "ccparray.h"
+
+
+/* A simple implementation of a dynamic array of const char pointers.
+ * The example code:
+ *
+ *   ccparray_t ccp;
+ *   const char **argv;
+ *   int i;
+ *
+ *   ccparray_init (&ccp, 0);
+ *   ccparray_put (&ccp, "First arg");
+ *   ccparray_put (&ccp, "Second arg");
+ *   ccparray_put (&ccp, NULL);
+ *   ccparray_put (&ccp, "Fourth arg");
+ *   argv = ccparray_get (&ccp, NULL);
+ *   if (!argv)
+ *     die ("error building array: %s\n", strerror (errno));
+ *   for (i=0; argv[i]; i++)
+ *     printf ("[%d] = '%s'\n", i, argv[i]);
+ *   xfree (argv);
+ *
+ * will result in this output:
+ *
+ *   [0] = 'First arg'
+ *   [1] = 'Second arg'
+ *
+ * Note that allocation errors are detected but only returned with the
+ * final ccparray_get(); this helps not to clutter the code with out
+ * of core checks.
+ */
+
+void
+ccparray_init (ccparray_t *cpa, unsigned int initialsize)
+{
+  if (!initialsize)
+    cpa->size = 16;
+  else if (initialsize < (1<<16))
+    cpa->size = initialsize;
+  else
+    cpa->size = (1<<16);
+
+  cpa->count = 0;
+  cpa->out_of_core = 0;
+  cpa->array = xtrycalloc (cpa->size, sizeof *cpa->array);
+  if (!cpa->array)
+    cpa->out_of_core = errno;
+}
+
+
+void
+ccparray_put (ccparray_t *cpa, const char *value)
+{
+  if (cpa->out_of_core)
+    return;
+
+  if (cpa->count + 1 >= cpa->size)
+    {
+      const char **newarray;
+      size_t n, newsize;
+
+      if (cpa->size < 8)
+        newsize = 16;
+      else if (cpa->size < 4096)
+        newsize = 2 * cpa->size;
+      else if (cpa->size < (1<<16))
+        newsize = cpa->size + 2048;
+      else
+        {
+          cpa->out_of_core = ENOMEM;
+          return;
+        }
+
+      newarray = xtrycalloc (newsize, sizeof *newarray);
+      if (!newarray)
+        {
+          cpa->out_of_core = errno ? errno : ENOMEM;
+          return;
+        }
+      for (n=0; n < cpa->size; n++)
+        newarray[n] = cpa->array[n];
+      cpa->array = newarray;
+      cpa->size = newsize;
+
+    }
+  cpa->array[cpa->count++] = value;
+}
+
+
+const char **
+ccparray_get (ccparray_t *cpa, size_t *r_count)
+{
+  const char **result;
+
+  if (cpa->out_of_core)
+    {
+      if (cpa->array)
+        {
+          xfree (cpa->array);
+          cpa->array = NULL;
+        }
+      gpg_err_set_errno (cpa->out_of_core);
+      return NULL;
+    }
+
+  result= cpa->array;
+  if (r_count)
+    *r_count = cpa->count;
+  cpa->array = NULL;
+  cpa->out_of_core = ENOMEM; /* hack to make sure it won't get reused. */
+  return result;
+}

common/ccparray.h

@@ -0,0 +1,51 @@
+/* ccparray.c - A simple dynamic array for character pointer.
+ * Copyright (C) 2016 g10 Code GmbH
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either
+ *
+ *   - the GNU Lesser General Public License as published by the Free
+ *     Software Foundation; either version 3 of the License, or (at
+ *     your option) any later version.
+ *
+ * or
+ *
+ *   - 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.
+ *
+ * or both in parallel, as here.
+ *
+ * This file 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GNUPG_COMMON_CCPARRAY_H
+#define GNUPG_COMMON_CCPARRAY_H
+
+/* The definition of the structure is private, we only need it here,
+ * so it can be allocated on the stack.  */
+struct _ccparray_private_s
+{
+  unsigned int count;
+  unsigned int size;
+  int out_of_core;
+  const char **array;
+};
+
+typedef struct _ccparray_private_s ccparray_t;
+
+
+void ccparray_init (ccparray_t *cpa, unsigned int initialsize);
+void ccparray_put (ccparray_t *cpa, const char *value);
+const char **ccparray_get (ccparray_t *cpa, size_t *r_nelems);
+
+
+#endif /*GNUPG_COMMON_CCPARRAY_H*/

common/t-ccparray.c

@@ -0,0 +1,93 @@
+/* t-ccparray.c - Module test for ccparray.c
+ * Copyright (C) 2016 g10 Code GmbH
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG 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.
+ *
+ * GnuPG 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "util.h"
+#include "ccparray.h"
+
+#define pass()  do { ; } while(0)
+#define fail(a)  do { fprintf (stderr, "%s:%d: test %d failed\n",\
+                               __FILE__,__LINE__, (a));          \
+                       exit (1);                                 \
+                    } while(0)
+
+
+static void
+run_test_1 (void)
+{
+  ccparray_t ccp;
+  const char **argv;
+  size_t nelem;
+
+  ccparray_init (&ccp, 0);
+  ccparray_put (&ccp, "First arg");
+  ccparray_put (&ccp, "Second arg");
+  ccparray_put (&ccp, NULL);
+  ccparray_put (&ccp, "Fourth arg");
+  argv = ccparray_get (&ccp, &nelem);
+  if (!argv)
+    {
+      fprintf (stderr, "error building array: %s\n", strerror (errno));
+      exit (1);
+    }
+
+  if (nelem != 4)
+    fail (1);
+
+  /* for (i=0; argv[i]; i++) */
+  /*   printf ("[%d] = '%s'\n", i, argv[i]); */
+  xfree (argv);
+}
+
+
+static void
+run_test_var (int count)
+{
+  ccparray_t ccp;
+  size_t nelem;
+  int i;
+
+  ccparray_init (&ccp, 0);
+  for (i=0; i < count; i++)
+    ccparray_put (&ccp, "An arg");
+  xfree (ccparray_get (&ccp, &nelem));
+  if (nelem != i)
+    fail (2);
+}
+
+
+int
+main (int argc, char **argv)
+{
+  (void)argc;
+  (void)argv;
+
+  run_test_1 ();
+  run_test_var (0);
+  run_test_var (7);
+  run_test_var (8);
+  run_test_var (9);
+  run_test_var (4096);
+
+  return 0;
+}