Remove dependency on std::regex

std::regex is not available for GCC 4.8. It’s also a bit bloated. The
reason for not using POSIX regex functionality is that it’s not
available in MinGW.

diff --git a/src/Util.cpp b/src/Util.cpp
index ebbcc483a40760912d98e93bd00bf3b0c4da51de..9218aa93fde727aaa49519af0afb70baaceb7e01 100644 (file)
--- a/src/Util.cpp
+++ b/src/Util.cpp
@@ -26,7 +26,6 @@
 
 #include <algorithm>
 #include <fstream>
-#include <regex>
 
 #ifdef HAVE_LINUX_FS_H
 #  include <linux/magic.h>
@@ -44,6 +43,40 @@ using nonstd::string_view;
 
 namespace {
 
+// Search for the first match of the following regular expression:
+//
+//   \x1b\[[\x30-\x3f]*[\x20-\x2f]*[Km]
+//
+// The primary reason for not using std::regex is that it's not available for
+// GCC 4.8. It's also a bit bloated. The reason for not using POSIX regex
+// functionality is that it's are not available in MinGW.
+string_view
+find_first_ansi_csi_seq(string_view string)
+{
+  size_t pos = 0;
+  while (pos < string.length() && string[pos] != 0x1b) {
+    ++pos;
+  }
+  if (pos + 1 >= string.length() || string[pos + 1] != '[') {
+    return {};
+  }
+  size_t start = pos;
+  pos += 2;
+  while (pos < string.length()
+         && (string[pos] >= 0x30 && string[pos] <= 0x3f)) {
+    ++pos;
+  }
+  while (pos < string.length()
+         && (string[pos] >= 0x20 && string[pos] <= 0x2f)) {
+    ++pos;
+  }
+  if (pos < string.length() && (string[pos] == 'K' || string[pos] == 'm')) {
+    return string.substr(start, pos + 1 - start);
+  } else {
+    return {};
+  }
+}
+
 size_t
 path_max(const char* path)
 {
@@ -221,29 +254,6 @@ dir_name(string_view path)
   }
 }
 
-std::string
-edit_ansi_csi_seqs(string_view string, const SubstringEditor& editor)
-{
-  static const std::regex csi_regex(
-    "\x1B\\[[\x30-\x3F]*[\x20-\x2F]*[\x40-\x7E]");
-  std::string ret;
-  std::string substr;
-  ret.reserve(string.size());
-  for (std::cregex_token_iterator itr(
-         string.begin(), string.end(), csi_regex, {-1, 0});
-       itr != std::cregex_token_iterator{};
-       ++itr) {
-    ret.append(itr->first, itr->second);
-    if (++itr == std::cregex_token_iterator{}) {
-      break;
-    }
-    substr.assign(itr->first, itr->second);
-    editor(itr->first - string.begin(), substr);
-    ret.append(substr);
-  }
-  return ret;
-}
-
 bool
 ends_with(string_view string, string_view suffix)
 {
@@ -778,14 +788,25 @@ starts_with(string_view string, string_view prefix)
 }
 
 std::string
-strip_ansi_csi_seqs(string_view string, string_view strip_actions)
+strip_ansi_csi_seqs(string_view string)
 {
-  return edit_ansi_csi_seqs(
-    string, [=](string_view::size_type /*pos*/, std::string& substr) {
-      if (strip_actions.find(substr.back()) != string_view::npos) {
-        substr.clear();
-      }
-    });
+  size_t pos = 0;
+  std::string result;
+
+  while (true) {
+    auto seq_span = find_first_ansi_csi_seq(string.substr(pos));
+    auto data_start = string.data() + pos;
+    auto data_length =
+      seq_span.empty() ? string.length() - pos : seq_span.data() - data_start;
+    result.append(data_start, data_length);
+    if (seq_span.empty()) {
+      // Reached tail.
+      break;
+    }
+    pos += data_length + seq_span.length();
+  }
+
+  return result;
 }
 
 std::string

diff --git a/src/Util.hpp b/src/Util.hpp
index c6c2657a44f3d0981ecb3d391a73f2920ad2df59..c455b2fb11dbde68e1f1849472c80fc7eac07593 100644 (file)
--- a/src/Util.hpp
+++ b/src/Util.hpp
@@ -114,12 +114,6 @@ std::pair<int, std::string> create_temp_fd(nonstd::string_view path_prefix);
 // Get directory name of path.
 nonstd::string_view dir_name(nonstd::string_view path);
 
-// Returns a copy of string with any contained ANSI CSI sequences edited by the
-// given SubstringEditor, which is invoked once for each ANSI CSI sequence
-// encountered in string. The original string is not modified.
-[[gnu::warn_unused_result]] std::string
-edit_ansi_csi_seqs(nonstd::string_view string, const SubstringEditor& editor);
-
 // Return true if suffix is a suffix of string.
 bool ends_with(nonstd::string_view string, nonstd::string_view suffix);
 
@@ -321,8 +315,7 @@ bool starts_with(nonstd::string_view string, nonstd::string_view prefix);
 
 // Returns a copy of string with the specified ANSI CSI sequences removed.
 [[gnu::warn_unused_result]] std::string
-strip_ansi_csi_seqs(nonstd::string_view string,
-                    nonstd::string_view strip_actions = "Km");
+strip_ansi_csi_seqs(nonstd::string_view string);
 
 // Strip whitespace from left and right side of a string.
 [[gnu::warn_unused_result]] std::string

diff --git a/unittest/test_Util.cpp b/unittest/test_Util.cpp
index 678c8c69d9c9d573f23adc868de5c51af0ed6872..3421fcb3732bc1abb2599148ea30bbf0f198566a 100644 (file)
--- a/unittest/test_Util.cpp
+++ b/unittest/test_Util.cpp
@@ -130,58 +130,15 @@ TEST_CASE("Util::dir_name")
   CHECK(Util::dir_name("/foo/bar/f.txt") == "/foo/bar");
 }
 
-TEST_CASE("Util::{edit,strip}_ansi_csi_seqs")
+TEST_CASE("Util::strip_ansi_csi_seqs")
 {
-  static constexpr auto input =
-    "Normal, "
-    "\x1B[K\x1B[1mbold\x1B[m, "
-    "\x1B[31mred\x1B[m, "
-    "\x1B[1;32mbold green\x1B[m.\n";
+  const char input[] =
+    "Normal,"
+    " \x1B[K\x1B[1mbold\x1B[m,"
+    " \x1B[31mred\x1B[m,"
+    " \x1B[1;32mbold green\x1B[m.\n";
 
-  SUBCASE("Remove bold attributes")
-  {
-    CHECK(Util::edit_ansi_csi_seqs(input,
-              [](nonstd::string_view::size_type,
-                 std::string& substr)
-              {
-                if (substr.size() > 3 && substr.back() == 'm') {
-                  nonstd::string_view attrs = substr;
-                  attrs.remove_prefix(2); // ESC [
-                  attrs.remove_suffix(1); // m
-                  std::string edited;
-                  edited.reserve(attrs.size());
-                  for (auto& attr : Util::split_into_views(attrs, ";")) {
-                    if (attr != "1") {
-                      if (!edited.empty()) {
-                        edited += ';';
-                      }
-                      edited.append(attr.begin(), attr.end());
-                    }
-                  }
-                  if (edited.empty()) {
-                    substr.clear();
-                  } else {
-                    substr.replace(2, attrs.size(), std::move(edited));
-                  }
-                }
-              }) ==
-          "Normal, "
-          "\x1B[Kbold\x1B[m, "
-          "\x1B[31mred\x1B[m, "
-          "\x1B[32mbold green\x1B[m.\n");
-  }
-
-  SUBCASE("Strip SGR sequences only")
-  {
-    CHECK(Util::strip_ansi_csi_seqs(input, "m")
-          == "Normal, \x1B[Kbold, red, bold green.\n");
-  }
-
-  SUBCASE("Strip default set of CSI sequences")
-  {
-    CHECK(Util::strip_ansi_csi_seqs(input)
-          == "Normal, bold, red, bold green.\n");
-  }
+  CHECK(Util::strip_ansi_csi_seqs(input) == "Normal, bold, red, bold green.\n");
 }
 
 TEST_CASE("Util::ends_with")