Fix 2162827: tag length calculation was incorrect.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@7230 c06c8d41-db1a-0410-9941-cceddc491573

1 files changed, 93 insertions, 0 deletions

diff --git a/crawl-ref/source/format.cc b/crawl-ref/source/format.cc
index e4280e5038..9cd282e058 100644
--- a/crawl-ref/source/format.cc
+++ b/crawl-ref/source/format.cc
@@ -577,3 +577,96 @@ int count_linebreaks(const formatted_string& fs)
     }
     return count;
 }
+
+// Return the actual (string) offset of character #loc to be printed,
+// i.e. ignoring tags. So for instance, if s == "<tag>ab</tag>", then
+// _find_string_location(s, 2) == 6.
+int _find_string_location(const std::string& s, int loc)
+{
+    int real_offset = 0;
+    bool in_tag = false;
+    int last_taglen = 0;
+    int offset = 0;
+    for (std::string::const_iterator ci = s.begin();
+         ci != s.end() && real_offset < loc;
+         ++ci, ++offset)
+    {
+        if (in_tag)
+        {
+            if (*ci == '<' && last_taglen == 1)
+            {
+                ++real_offset;
+                in_tag = false;
+            }
+            else if (*ci == '>')
+            {
+                in_tag = false;
+            }
+            else
+            {
+                ++last_taglen;
+            }
+        }
+        else if (*ci == '<')
+        {
+            in_tag = true;
+            last_taglen = 1;
+        }
+        else
+        {
+            ++real_offset;
+        }
+    }
+    return (offset);
+}
+
+// Return the substring of s from character start to character end,
+// where tags count as length 0.
+std::string tagged_string_substr(const std::string& s, int start, int end)
+{
+    return (s.substr(_find_string_location(s, start),
+                     _find_string_location(s, end)));
+}
+
+int tagged_string_printable_length(const std::string& s)
+{
+    int len = 0;
+    bool in_tag = false;
+    int last_taglen = 0;
+    for (std::string::const_iterator ci = s.begin(); ci != s.end(); ++ci)
+    {
+        if (in_tag)
+        {
+            if (*ci == '<' && last_taglen == 1) // "<<" sequence
+            {
+                in_tag = false;  // this is an escape for '<'
+                ++len;           // len wasn't incremented before
+            }
+            else if (*ci == '>') // tag close, still nothing printed
+            {
+                in_tag = false;
+            }
+            else                 // tag continues
+            {
+                ++last_taglen;
+            }
+        }
+        else if (*ci == '<')     // tag starts
+        {
+            in_tag = true;
+            last_taglen = 1;
+        }
+        else                     // normal, printable character
+        {
+            ++len;
+        }
+    }
+    return (len);
+}
+
+
+// Count the length of the tags in the string.
+int tagged_string_tag_length(const std::string& s)
+{
+    return s.size() - tagged_string_printable_length(s);
+}