From e56bbf48fef0c0702f3d9c55be39619c57deac73 Mon Sep 17 00:00:00 2001
From: Michael Mueller <michaeldmueller7@gmail.com>
Date: Wed, 27 Aug 2014 10:50:26 -0400
Subject: [PATCH 1/2] Made line comments work with whitespace delim and custom
 line terminator

---
 pandas/io/tests/test_parsers.py |  8 ++++++++
 pandas/src/parser/tokenizer.c   | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/pandas/io/tests/test_parsers.py b/pandas/io/tests/test_parsers.py
index fd1febc37caac..14e69179f9ff4 100644
--- a/pandas/io/tests/test_parsers.py
+++ b/pandas/io/tests/test_parsers.py
@@ -2944,6 +2944,14 @@ def test_line_comment(self):
                     [5., np.nan, 10.]]
         df = self.read_csv(StringIO(data), comment='#')
         tm.assert_almost_equal(df.values, expected)
+        # check with delim_whitespace=True
+        df = self.read_csv(StringIO(data.replace(',', ' ')), comment='#',
+                            delim_whitespace=True)
+        tm.assert_almost_equal(df.values, expected)
+        # check with custom line terminator
+        df = self.read_csv(StringIO(data.replace('\n', '*')), comment='#',
+                            lineterminator='*')
+        tm.assert_almost_equal(df.values, expected)
 
     def test_comment_skiprows(self):
         data = """# empty
diff --git a/pandas/src/parser/tokenizer.c b/pandas/src/parser/tokenizer.c
index 1e9576487b9ed..b30706f85894b 100644
--- a/pandas/src/parser/tokenizer.c
+++ b/pandas/src/parser/tokenizer.c
@@ -969,6 +969,10 @@ int tokenize_delim_customterm(parser_t *self, size_t line_limit)
                 END_LINE();
                 break;
             }
+            else if (c == self->commentchar) {
+                self->state = EAT_LINE_COMMENT;
+                break;
+            }
             /* normal character - handle as START_FIELD */
             self->state = START_FIELD;
             /* fallthru */
@@ -1103,6 +1107,13 @@ int tokenize_delim_customterm(parser_t *self, size_t line_limit)
             }
             break;
 
+        case EAT_LINE_COMMENT:
+            if (c == self->lineterminator) {
+                self->file_lines++;
+                self->state = START_RECORD;
+            }
+            break;
+
         case EAT_COMMENT:
             if (c == self->lineterminator) {
                 END_LINE();
@@ -1186,6 +1197,9 @@ int tokenize_whitespace(parser_t *self, size_t line_limit)
             } else if (IS_WHITESPACE(c)) {
                 self->state = EAT_WHITESPACE;
                 break;
+            } else if (c == self->commentchar) {
+                self->state = EAT_LINE_COMMENT;
+                break;
             } else {
                 /* normal character - handle as START_FIELD */
                 self->state = START_FIELD;
@@ -1231,6 +1245,16 @@ int tokenize_whitespace(parser_t *self, size_t line_limit)
             }
             break;
 
+        case EAT_LINE_COMMENT:
+            if (c == '\n') {
+                self->file_lines++;
+                self->state = START_RECORD;
+            } else if (c == '\r') {
+                self->file_lines++;
+                self->state = EAT_CRNL_NOP;
+            }
+            break;
+
         case ESCAPED_CHAR:
             /* if (c == '\0') */
             /*  c = '\n'; */
@@ -1351,6 +1375,15 @@ int tokenize_whitespace(parser_t *self, size_t line_limit)
             }
             break;
 
+        case EAT_CRNL_NOP: // inside an ignored comment line
+            self->state = START_RECORD;
+            /* \r line terminator -- parse this character again */
+            if (c != '\n' && c != self->delimiter) {
+                --i;
+                --buf;
+            }
+            break;
+
         case EAT_COMMENT:
             if (c == '\n') {
                 END_LINE();

From 9a877dd1da5fac8eb5a2169993cd18033e2e2cfa Mon Sep 17 00:00:00 2001
From: Michael Mueller <michaeldmueller7@gmail.com>
Date: Thu, 28 Aug 2014 09:22:03 -0400
Subject: [PATCH 2/2] Added a release note

---
 doc/source/v0.15.0.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/doc/source/v0.15.0.txt b/doc/source/v0.15.0.txt
index 95bf2918f8992..21e4e0e87473f 100644
--- a/doc/source/v0.15.0.txt
+++ b/doc/source/v0.15.0.txt
@@ -638,6 +638,8 @@ Bug Fixes
 - Bug in ``Float64Index`` where ``iat`` and ``at`` were not testing and were
   failing (:issue:`8092`).
 
+- Bug in ``read_csv`` where line comments were not handled correctly given
+  a custom line terminator or ``delim_whitespace=True`` (:issue:`8122`).