Add QPDFObjectHandle manipulation to C API

1 files changed, 114 insertions, 0 deletions

diff --git a/examples/pdf-c-objects.c b/examples/pdf-c-objects.c
new file mode 100644
index 00000000..d800b8af
--- /dev/null
+++ b/examples/pdf-c-objects.c
@@ -0,0 +1,114 @@
+/*
+ * This is an example program to demonstrate use of object handle
+ * functions in the C API.
+ */
+
+#include <qpdf/qpdf-c.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static char const* whoami = 0;
+
+static void usage()
+{
+    fprintf(stderr, "Usage: %s infile infile-password outfile\n", whoami);
+    exit(2);
+}
+
+QPDF_BOOL
+modify_file(qpdf_data qpdf)
+{
+    /* This small example performs the following operation on the
+     * document catalog (a.k.a. root):
+     * - Remove PageLayout
+     * - Remove OpenAction
+     * - If there are outlines, set PageMode to UseOutlines; otherwise,
+     *   remove it.
+     */
+
+    qpdf_oh root = qpdf_get_root(qpdf);
+    qpdf_oh_remove_key(qpdf, root, "/PageLayout");
+    qpdf_oh_remove_key(qpdf, root, "/OpenAction");
+    /* 0 is never a valid qpdf_oh */
+    qpdf_oh pagemode = 0;
+    if (qpdf_oh_is_dictionary(
+            qpdf, qpdf_oh_get_key(qpdf, root, "/PageLabels")))
+    {
+        pagemode = qpdf_oh_new_name(qpdf, "/UseOutlines");
+    }
+    else
+    {
+        pagemode = qpdf_oh_new_null(qpdf);
+    }
+    qpdf_oh_replace_or_remove_key(qpdf, root, "/PageMode", pagemode);
+
+    return QPDF_TRUE;
+}
+
+int main(int argc, char* argv[])
+{
+    char* infile = NULL;
+    char* password = NULL;
+    char* outfile = NULL;
+    qpdf_data qpdf = qpdf_init();
+    int warnings = 0;
+    int errors = 0;
+    char* p = 0;
+
+    if ((p = strrchr(argv[0], '/')) != NULL)
+    {
+	whoami = p + 1;
+    }
+    else if ((p = strrchr(argv[0], '\\')) != NULL)
+    {
+	whoami = p + 1;
+    }
+    else
+    {
+	whoami = argv[0];
+    }
+
+    if (argc != 4)
+    {
+	usage();
+    }
+
+    infile = argv[1];
+    password = argv[2];
+    outfile = argv[3];
+
+    if (((qpdf_read(qpdf, infile, password) & QPDF_ERRORS) == 0) &&
+        modify_file(qpdf) &&
+	((qpdf_init_write(qpdf, outfile) & QPDF_ERRORS) == 0))
+    {
+        /* Use static ID for testing only. For production, a
+         * non-static ID is used. See also
+         * qpdf_set_deterministic_ID. */
+	qpdf_set_static_ID(qpdf, QPDF_TRUE); /* for testing only */
+	qpdf_write(qpdf);
+    }
+    while (qpdf_more_warnings(qpdf))
+    {
+	warnings = 1;
+	printf("warning: %s\n",
+	       qpdf_get_error_full_text(qpdf, qpdf_next_warning(qpdf)));
+    }
+    if (qpdf_has_error(qpdf))
+    {
+	errors = 1;
+	printf("error: %s\n",
+	       qpdf_get_error_full_text(qpdf, qpdf_get_error(qpdf)));
+    }
+    qpdf_cleanup(&qpdf);
+    if (errors)
+    {
+	return 2;
+    }
+    else if (warnings)
+    {
+	return 3;
+    }
+
+    return 0;
+}