From: glenlow <devnull@localhost>
Date: Sat, 2 Feb 2008 06:42:23 +0000 (+0000)
Subject: gvRenderData outputs non-null terminated string and string length, reduced reallocations
X-Git-Tag: LAST_LIBGRAPH~32^2~4784
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=eddb205ce1c69094ee444006782f1aad758a438b;p=graphviz

gvRenderData outputs non-null terminated string and string length, reduced reallocations
---

diff --git a/lib/gvc/gvc.h b/lib/gvc/gvc.h
index d8103e5fe..cd417ec21 100644
--- a/lib/gvc/gvc.h
+++ b/lib/gvc/gvc.h
@@ -91,7 +91,7 @@ extern int gvRender(GVC_t *gvc, graph_t *g, char *format, FILE *out);
 extern int gvRenderFilename(GVC_t *gvc, graph_t *g, char *format, char *filename);
 
 /* Render layout in a specified format to a malloc'ed string */
-extern int gvRenderData(GVC_t *gvc, graph_t *g, char *format, char **result);
+extern int gvRenderData(GVC_t *gvc, graph_t *g, char *format, char **result, unsigned int *length);
 
 /* Render layout according to -T and -o options found by gvParseArgs */
 extern int gvRenderJobs(GVC_t *gvc, graph_t *g);
diff --git a/lib/gvc/gvdevice.c b/lib/gvc/gvdevice.c
index fd44b2b34..0c4058afe 100644
--- a/lib/gvc/gvdevice.c
+++ b/lib/gvc/gvdevice.c
@@ -49,6 +49,8 @@
 #include "gvcint.h"
 #include "gvcproc.h"
 
+static const int PAGE_ALIGN = 4095;		/* align to a 4K boundary (less one), typical for Linux, Mac OS X and Windows memory allocation */
+
 size_t gvdevice_write (GVJ_t * job, const unsigned char *s, unsigned int len)
 {
     if (job->gvc->write_fn && job->output_file == stdout)   /* externally provided write dicipline */
@@ -59,15 +61,15 @@ size_t gvdevice_write (GVJ_t * job, const unsigned char *s, unsigned int len)
 #endif
     }
     else if (job->output_data) {
-	if (len > (job->output_data_allocated - (job->output_data_position + 1))) {
-	    job->output_data_allocated = job->output_data_position + len + 1000;
+	if (len > job->output_data_allocated - job->output_data_position) {
+	    job->output_data_allocated = (job->output_data_position + len + PAGE_ALIGN) & ~PAGE_ALIGN;
 	    job->output_data = realloc(job->output_data, job->output_data_allocated);
 	    if (!job->output_data) {
 		fprintf(stderr, "failure realloc'ing for result string\n");
 		return 0;
 	    }
 	}
-	strcpy(job->output_data + job->output_data_position, (char*)s);
+	memcpy(job->output_data + job->output_data_position, s, len);
         job->output_data_position += len;
 	return len;
     }
diff --git a/tclpkg/gv/gv.cpp b/tclpkg/gv/gv.cpp
index 38614b618..e43d31f8f 100644
--- a/tclpkg/gv/gv.cpp
+++ b/tclpkg/gv/gv.cpp
@@ -873,9 +873,12 @@ char* renderdata(Agraph_t *g, char *format)
 {
     int err;
     char *data;
+	unsigned int length;
 
-    err = gvRenderData(gvc, g, format, &data);
+    err = gvRenderData(gvc, g, format, &data, &length);
     if (err) return NULL;
+	data = (char*)realloc(data, length + 1);
+	if (data) data[length] = '\0';
     return data;
 }