[codestring]: Add 'lineof' method for finding line numbers.

git-svn-id: https://svn.parrot.org/parrot/trunk@37937 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

src/pmc/codestring.pmc

@@ -127,6 +127,33 @@ A newline is automatically added to the end of the fmt.
 }
 
 
+/*
+
+=item lineof(INTVAL pos)
+
+Return the line number of the line at offset C<pos>.  This code
+assumes that the first line is line number zero.
+
+*/
+
+  METHOD lineof(INTVAL pos) {
+    STRING *str  = SELF.get_string();
+    INTVAL line  = 0;
+    INTVAL ipos  = 0;
+    INTVAL jpos;
+
+    jpos = Parrot_str_find_cclass(INTERP, enum_cclass_newline, str, ipos, pos);
+    while (jpos < pos) {
+        line++;
+        ipos = jpos + 1;
+        /* treat \r\n as a single line separator */
+        ipos += (string_ord(INTERP, str, jpos) == 13
+                 && string_ord(INTERP, str, jpos+1) == 10);
+        jpos = Parrot_str_find_cclass(INTERP, enum_cclass_newline, str, ipos, pos);
+    }
+    RETURN(INTVAL line);
+}
+
 
 /*
 

t/pmc/codestring.t

@@ -19,7 +19,7 @@ Tests the CodeString class directly.
 
 .sub main :main
     .include 'test_more.pir'
-    plan(24)
+    plan(38)
 
     create_codestring()
     calls_to_unique()
@@ -32,6 +32,7 @@ Tests the CodeString class directly.
     namespace_keys()
     first_char_repl_regression()
     ord_from_name()
+    lineof_tests()
 .end
 
 .sub create_codestring
@@ -189,6 +190,40 @@ CODE
     is($I0, -1, '<no such symbol>')
 .end
 
+.sub 'lineof_tests'
+    $P0 = new 'CodeString'
+    $P0 = "0123\n5678\r0123\r\n678\n"
+    $I0 = $P0.'lineof'(0)
+    is($I0, 0, "lineof - beginning of string")
+    $I0 = $P0.'lineof'(1)
+    is($I0, 0, "lineof - char on first line")
+    $I0 = $P0.'lineof'(4)
+    is($I0, 0, "lineof - immediately before nl")
+    $I0 = $P0.'lineof'(5)
+    is($I0, 1, "lineof - immediately after nl")
+    $I0 = $P0.'lineof'(8)
+    is($I0, 1, "lineof - char before cr")
+    $I0 = $P0.'lineof'(9)
+    is($I0, 1, "lineof - immediately before cr")
+    $I0 = $P0.'lineof'(10)
+    is($I0, 2, "lineof - immediately after cr")
+    $I0 = $P0.'lineof'(11)
+    is($I0, 2, "lineof - char after cr")
+    $I0 = $P0.'lineof'(13)
+    is($I0, 2, "lineof - char before crnl")
+    $I0 = $P0.'lineof'(14)
+    is($I0, 2, "lineof - immediately before crnl")
+    $I0 = $P0.'lineof'(15)
+    is($I0, 3, "lineof - middle of crnl")
+    $I0 = $P0.'lineof'(16)
+    is($I0, 3, "lineof - immediately after crnl")
+    $I0 = $P0.'lineof'(19)
+    is($I0, 3, "lineof - immediately before final nl")
+    $I0 = $P0.'lineof'(20)
+    is($I0, 4, "lineof - immediately after final nl")
+.end
+
+
 # Local Variables:
 #   mode: pir
 #   fill-column: 100