diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index ac221b58..6e8d1aaf 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -57,7 +57,7 @@ log format has matched yet, each line will be passed through the log format
 regular expressions to try and find a match.  Each line that is read is added
 to an index
 
-### Why is `mmap()` not used?
+#### Why is `mmap()` not used?
 
 Note that file contents are consumed using `pread(2)`/`read(2)` and not
 `mmap(2)` since `mmap(2)` does not react well to files changing out from
@@ -71,10 +71,21 @@ As files are being indexed, if a matching format is found, the file is
 it is added to the [logfile_sub_source](src/logfile_sub_source.hh), which
 collates all log messages together into a single index.
 
+## Log Formats
+
+[log_format](src/log_format.hh) instances are used to parse lines from files
+into `logline` objects.  The majority of log formats are
+[external_log_format](src/log_format_ext.hh) objects that are create from
+[JSON format definitions](https://lnav.readthedocs.io/en/latest/formats.html).
+The built-in definitions are located in the [formats](src/formats) directory.
+Log formats that cannot be handled through a simple regular expression are
+implemented in the [log_format_impls.cc](src/log_format_impls.cc) file.
+
 ## User Interface
 
 [![lnav TUI](docs/lnav-tui.png)](https://whimsical.com/lnav-tui-MQjXc7Vx23BxQTHrnuNp5F)
 
 The lnav text-user-interface is built on top of the basic drawing functionality
-of [ncurses](https://invisible-island.net/ncurses/announce.html).  However,
-
+provided by [ncurses](https://invisible-island.net/ncurses/announce.html).
+However, the higher-level functionality of panels, widgets, and such is not
+used.
diff --git a/docs/lnav-architecture.png b/docs/lnav-architecture.png
index 75414508..dc9fae9f 100644
Binary files a/docs/lnav-architecture.png and b/docs/lnav-architecture.png differ
diff --git a/src/base/date_time_scanner.cc b/src/base/date_time_scanner.cc
index 5089be3d..6e3aab8d 100644
--- a/src/base/date_time_scanner.cc
+++ b/src/base/date_time_scanner.cc
@@ -208,3 +208,33 @@ const char *date_time_scanner::scan(const char *time_dest,
 
     return retval;
 }
+
+void date_time_scanner::to_localtime(time_t t, exttm &tm_out)
+{
+    if (t < (24 * 60 * 60)) {
+        // Don't convert and risk going past the epoch.
+        return;
+    }
+
+    if (t < this->dts_local_offset_valid ||
+        t >= this->dts_local_offset_expiry) {
+        time_t new_gmt;
+
+        localtime_r(&t, &tm_out.et_tm);
+#ifdef HAVE_STRUCT_TM_TM_ZONE
+        tm_out.et_tm.tm_zone = nullptr;
+#endif
+        tm_out.et_tm.tm_isdst = 0;
+
+        new_gmt = tm2sec(&tm_out.et_tm);
+        this->dts_local_offset_cache = t - new_gmt;
+        this->dts_local_offset_valid = t;
+        this->dts_local_offset_expiry = t + (EXPIRE_TIME - 1);
+        this->dts_local_offset_expiry -=
+            this->dts_local_offset_expiry % EXPIRE_TIME;
+    }
+    else {
+        time_t adjust_gmt = t - this->dts_local_offset_cache;
+        gmtime_r(&adjust_gmt, &tm_out.et_tm);
+    }
+}
diff --git a/src/base/date_time_scanner.hh b/src/base/date_time_scanner.hh
index f95f525a..a85fd50c 100644
--- a/src/base/date_time_scanner.hh
+++ b/src/base/date_time_scanner.hh
@@ -39,12 +39,15 @@
 
 #include "time_util.hh"
 
+/**
+ * Scans a timestamp string to discover the date-time format using the custom
+ * ptimec parser.  Once a format is found, it is locked in so that the next
+ * time a timestamp needs to be scanned, the format does not have to be
+ * rediscovered.  The discovered date-time format can also be used to convert
+ * an exttm struct to a string using the ftime() method.
+ */
 struct date_time_scanner {
-    date_time_scanner() : dts_keep_base_tz(false),
-                          dts_local_time(false),
-                          dts_local_offset_cache(0),
-                          dts_local_offset_valid(0),
-                          dts_local_offset_expiry(0) {
+    date_time_scanner() {
         this->clear();
     };
 
@@ -55,6 +58,9 @@ struct date_time_scanner {
         this->dts_fmt_len = -1;
     };
 
+    /**
+     * Unlock this scanner so that the format is rediscovered.
+     */
     void unlock() {
         this->dts_fmt_lock = -1;
         this->dts_fmt_len = -1;
@@ -72,44 +78,17 @@ struct date_time_scanner {
      * every call, so we cache the result and only call it again if the
      * requested time falls outside of a fifteen minute range.
      */
-    void to_localtime(time_t t, struct exttm &tm_out) {
-        if (t < (24 * 60 * 60)) {
-            // Don't convert and risk going past the epoch.
-            return;
-        }
+    void to_localtime(time_t t, struct exttm &tm_out);
 
-        if (t < this->dts_local_offset_valid ||
-            t >= this->dts_local_offset_expiry) {
-            time_t new_gmt;
-
-            localtime_r(&t, &tm_out.et_tm);
-#ifdef HAVE_STRUCT_TM_TM_ZONE
-            tm_out.et_tm.tm_zone = nullptr;
-#endif
-            tm_out.et_tm.tm_isdst = 0;
-
-            new_gmt = tm2sec(&tm_out.et_tm);
-            this->dts_local_offset_cache = t - new_gmt;
-            this->dts_local_offset_valid = t;
-            this->dts_local_offset_expiry = t + (EXPIRE_TIME - 1);
-            this->dts_local_offset_expiry -=
-                this->dts_local_offset_expiry % EXPIRE_TIME;
-        }
-        else {
-            time_t adjust_gmt = t - this->dts_local_offset_cache;
-            gmtime_r(&adjust_gmt, &tm_out.et_tm);
-        }
-    };
-
-    bool dts_keep_base_tz;
-    bool dts_local_time;
-    time_t dts_base_time;
+    bool dts_keep_base_tz{false};
+    bool dts_local_time{false};
+    time_t dts_base_time{0};
     struct exttm dts_base_tm;
-    int dts_fmt_lock;
-    int dts_fmt_len;
-    time_t dts_local_offset_cache;
-    time_t dts_local_offset_valid;
-    time_t dts_local_offset_expiry;
+    int dts_fmt_lock{-1};
+    int dts_fmt_len{-1};
+    time_t dts_local_offset_cache{0};
+    time_t dts_local_offset_valid{0};
+    time_t dts_local_offset_expiry{0};
 
     static const int EXPIRE_TIME = 15 * 60;
 
diff --git a/src/base/humanize.hh b/src/base/humanize.hh
index fcbf2666..fc8dbffe 100644
--- a/src/base/humanize.hh
+++ b/src/base/humanize.hh
@@ -36,6 +36,12 @@
 
 namespace humanize {
 
+/**
+ * Format the given size as a human-friendly string.
+ *
+ * @param value The value to format.
+ * @return The formatted string.
+ */
 std::string file_size(ssize_t value);
 
 }
diff --git a/src/data_scanner_re.cc b/src/data_scanner_re.cc
index e9302aa1..9154d30b 100644
--- a/src/data_scanner_re.cc
+++ b/src/data_scanner_re.cc
@@ -1,4 +1,4 @@
-/* Generated by re2c 2.0.3 on Wed Jan 27 16:33:33 2021 */
+/* Generated by re2c 2.0.3 on Sat Feb 13 21:35:28 2021 */
 #line 1 "../../lnav/src/data_scanner_re.re"
 /**
  * Copyright (c) 2015, Timothy Stack
@@ -53,7 +53,7 @@ bool data_scanner::tokenize2(pcre_context &pc, data_token_t &token_out)
     static const unsigned char *EMPTY = (const unsigned char *) "";
     pcre_input &pi = this->ds_pcre_input;
     struct _YYCURSOR {
-        const YYCTYPE operator*() const {
+        YYCTYPE operator*() const {
             if (this->val < this->lim) {
                 return *val;
             }
diff --git a/src/data_scanner_re.re b/src/data_scanner_re.re
index ce07c3d5..3b3e5e51 100644
--- a/src/data_scanner_re.re
+++ b/src/data_scanner_re.re
@@ -51,7 +51,7 @@ bool data_scanner::tokenize2(pcre_context &pc, data_token_t &token_out)
     static const unsigned char *EMPTY = (const unsigned char *) "";
     pcre_input &pi = this->ds_pcre_input;
     struct _YYCURSOR {
-        const YYCTYPE operator*() const {
+        YYCTYPE operator*() const {
             if (this->val < this->lim) {
                 return *val;
             }
diff --git a/src/files_sub_source.cc b/src/files_sub_source.cc
index d3c2bdbe..94ffe43c 100644
--- a/src/files_sub_source.cc
+++ b/src/files_sub_source.cc
@@ -62,9 +62,9 @@ bool files_sub_source::list_input_handle_key(listview_curses &lv, int ch)
             auto& lss = lnav_data.ld_log_source;
             auto &lf = fc.fc_files[sel];
 
-            lss.find_data(lf) | [&lss](auto ld) {
+            lss.find_data(lf) | [](auto ld) {
                 ld->set_visibility(true);
-                lss.text_filters_changed();
+                lnav_data.ld_log_source.text_filters_changed();
             };
 
             if (lf->get_format() != nullptr) {
diff --git a/src/log_format_loader.cc b/src/log_format_loader.cc
index afa7846a..3f9dd78d 100644
--- a/src/log_format_loader.cc
+++ b/src/log_format_loader.cc
@@ -792,7 +792,7 @@ static void write_sample_file()
         extract_metadata(sf.data(), sf.length(), meta);
         snprintf(path, sizeof(path), "formats/default/%s.lnav", meta.sm_name.c_str());
         auto script_path = dotlnav_path() / path;
-        if (statp(script_path, &st) == 0 && (size_t) st.st_size == sf.length()) {
+        if (statp(script_path, &st) == 0 && st.st_size == sf.length()) {
             // Assume it's the right contents and move on...
             continue;
         }
diff --git a/src/pcrepp/pcrepp.cc b/src/pcrepp/pcrepp.cc
index 9f427276..551ac209 100644
--- a/src/pcrepp/pcrepp.cc
+++ b/src/pcrepp/pcrepp.cc
@@ -165,7 +165,7 @@ void pcrepp::find_captures(const char *pattern)
         }
     }
 
-    ensure(this->p_capture_count == this->p_captures.size());
+    ensure((size_t) this->p_capture_count == this->p_captures.size());
 }
 
 bool pcrepp::match(pcre_context &pc, pcre_input &pi, int options) const
diff --git a/src/ptimec.c b/src/ptimec.c
index a23e7084..2bd304a3 100644
--- a/src/ptimec.c
+++ b/src/ptimec.c
@@ -129,7 +129,7 @@ int main(int argc, char *argv[])
         printf("    { \"%s\", ptime_f%d, ftime_f%d },\n", argv[lpc], lpc, lpc);
     }
     printf("\n");
-    printf("    { NULL, NULL }\n");
+    printf("    { nullptr, nullptr, nullptr }\n");
     printf("};\n");
 
     printf("const char *PTIMEC_FORMAT_STR[] = {\n");
@@ -137,7 +137,7 @@ int main(int argc, char *argv[])
         printf("    \"%s\",\n", argv[lpc]);
     }
     printf("\n");
-    printf("    NULL\n");
+    printf("    nullptr\n");
     printf("};\n");
 
     return retval;
diff --git a/src/ptimec.hh b/src/ptimec.hh
index 025d4796..3c517e91 100644
--- a/src/ptimec.hh
+++ b/src/ptimec.hh
@@ -47,13 +47,13 @@
 #include "base/time_util.hh"
 
 #define PTIME_CONSUME(amount, block) \
-    if ((off_inout + amount) > len) { \
+    if ((off_inout + (amount)) > len) { \
         return false; \
     } \
     \
     block \
     \
-    off_inout += amount;
+    off_inout += (amount);
 
 #define PTIME_APPEND(ch) \
     if ((off_inout + 2) >= len) { \
diff --git a/src/views_vtab.cc b/src/views_vtab.cc
index 7b6f726a..026f66ea 100644
--- a/src/views_vtab.cc
+++ b/src/views_vtab.cc
@@ -514,13 +514,13 @@ CREATE TABLE lnav_view_filters (
                    text_filter::type_t type,
                    pair<string, auto_mem<pcre>> pattern) {
         auto view_index = lnav_view_t(rowid >> 32);
-        int filter_index = rowid & 0xffffffffLL;
+        auto filter_index = rowid & 0xffffffffLL;
         textview_curses &tc = lnav_data.ld_views[view_index];
         text_sub_source *tss = tc.get_sub_source();
         filter_stack &fs = tss->get_filters();
         auto iter = fs.begin();
         for (; iter != fs.end(); ++iter) {
-            if ((*iter)->get_index() == filter_index) {
+            if ((*iter)->get_index() == (size_t) filter_index) {
                 break;
             }
         }