1 files changed, 115 insertions, 0 deletions
diff --git a/graphics/sketch/langver.c b/graphics/sketch/langver.c
new file mode 100644
index 0000000000..d68c1cd8e7
--- /dev/null
+++ b/graphics/sketch/langver.c
@@ -0,0 +1,115 @@
+#include <string.h>
+#include "langver.h"
+
+int
+is_digit (int ch)
+{
+  return '0' <= ch && ch <= '9';
+}
+
+int
+lower (int ch)
+{
+  return ('A' <= ch && ch <= 'Z') ? ch + ('a' - 'A') : ch;
+}
+
+int
+is_alpha(int ch)
+{
+  return ('a' <= ch && ch <= 'z') || ('A' <= ch && ch <= 'Z');
+}
+
+int
+parse_pst_version (PST_VERSION *v, char *str, SRC_LINE line)
+{
+#define M (sizeof v->key / 2)
+  int i = 0, iv = 0, i_minor = -1;
+
+  memset(v->key, '0', sizeof v->key);
+  memset(v->str, '\0', sizeof v->str);
+
+  if (strlen(str) > sizeof v->str - 1) 
+    {
+      err (line, "PSTricks version string too long");
+      return 1;
+    }
+  A : 
+    if ( is_digit (str[i]) )
+      {
+	v->str[iv++] = str[i++];
+	goto B;
+      }
+    else
+      {
+	err (line, "bad character '%c' in PSTricks version", str[i]);
+	return 2;
+      }
+  B :
+    if ( is_digit (str[i]) )
+      {
+	v->str[iv++] = str[i++];
+	goto B;
+      }
+    else if ( str[i] == '.' )
+      {
+	memcpy (&v->key[M - i], v->str, i); // save major in key
+	v->str[iv++] = str[i++];
+	i_minor = iv; // remember where minor version starts
+	goto C;
+      }
+    else 
+      {
+	err (line, "expected dot in PSTricks version");
+	return 3;
+      }
+  C :
+    if ( is_digit (str[i]) ) 
+      {
+	v->str[iv++] = str[i++];
+	goto D;
+      }
+    else
+      {
+	err (line, "expected digit after dot in PSTricks version");
+	return 4;
+      }
+  D :
+    if ( is_digit (str[i]) ) 
+      {
+	v->str[iv++] = str[i++];
+	goto D;
+      }
+    else if ( is_alpha(str[i]) ) 
+      {
+	v->str[iv++] = lower (str[i++]);
+	goto F;
+      }
+    else if ( str[i] == '\0' ) 
+      {
+	memcpy (&v->key[M], &v->str[i_minor], i - i_minor); // save minor in key
+	return 0; /* accept */
+      }
+    else
+      {
+	err (line, "expected digit or subversion letter in PSTricks version");
+	return 5;
+      }
+ F:
+  if ( str[i] == '\0' ) 
+    {
+      memcpy (&v->key[M], &v->str[i_minor], i - i_minor);
+      return 0; /* accept */
+    }
+  else
+    {
+      err (line, "expected end of PSTricks version, found '%c'", str[i]);
+      return 6;
+    }
+  return -1;
+}
+
+int
+pst_version_cmp(PST_VERSION *a, PST_VERSION *b)
+{
+  return strncmp(a->key, b->key, sizeof a->key);
+}