syslinreader.rs pre-create FixedOffset strings

Pre-create strings of the FixedOffset used by SyslineReader.
Avoid creating a new String for every sysline processed.

Issue #84

src/data/datetime.rs

@@ -4963,6 +4963,7 @@ pub(crate) fn captures_to_buffer_bytes(
     captures: &regex::bytes::Captures,
     year_opt: &Option<Year>,
     tz_offset: &FixedOffset,
+    tz_offset_string: &String,
     dtfs: &DTFSSet,
 ) -> usize {
     defn!("(…, …, year_opt {:?}, tz_offset {:?}, …)", year_opt, tz_offset);
@@ -5177,9 +5178,7 @@ pub(crate) fn captures_to_buffer_bytes(
     defo!("process <tz>…");
     match dtfs.tz {
         DTFS_Tz::_fill => {
-            // TODO: cost-savings: pass pre-created TZ `&str`
-            let tzs: String = tz_offset.to_string();
-            copy_slice_to_buffer!(tzs.as_bytes(), buffer, at);
+            copy_slice_to_buffer!(tz_offset_string.as_bytes(), buffer, at);
         }
         DTFS_Tz::z | DTFS_Tz::zc | DTFS_Tz::zp => {
             // for data passed to chrono `DateTime::parse_from_str`,
@@ -5235,24 +5234,18 @@ pub(crate) fn captures_to_buffer_bytes(
                         true => {
                             // given an ambiguous timezone name, fallback to
                             // passed TZ offset
-                            // TODO: cost-savings: pre-create the `tz_offset` entries as bytes
-                            let tzs: String = tz_offset.to_string();
-                            copy_slice_to_buffer!(tzs.as_bytes(), buffer, at);
+                            copy_slice_to_buffer!(tz_offset_string.as_bytes(), buffer, at);
                         }
                         false => {
-                            // given an unambiguous timezone name, use
-                            // associated offset
-                            // TODO: cost-savings: pre-create the `tz_offset` entries as bytes
-                            let tzs: String = tz_offset_val.to_string();
-                            copy_slice_to_buffer!(tzs.as_bytes(), buffer, at);
+                            // given an unambiguous timezone name, use associated offset
+                            copy_slice_to_buffer!(tz_offset_val.as_bytes(), buffer, at);
                         }
                     }
                 }
                 None => {
                     // cannot find entry in MAP_TZZ_TO_TZz, use passed TZ offset
-                    // TODO: cost-savings: pre-create the `tz_offset` entries as bytes
-                    let tzs: String = tz_offset.to_string();
-                    copy_slice_to_buffer!(tzs.as_bytes(), buffer, at);
+                    debug_panic!("captured named timezone {:?} not found in MAP_TZZ_TO_TZz", tzZ);
+                    copy_slice_to_buffer!(tz_offset_string.as_bytes(), buffer, at);
                 }
             }
         }
@@ -5275,8 +5268,9 @@ pub fn bytes_to_regex_to_datetime(
     index: &DateTimeParseInstrsIndex,
     year_opt: &Option<Year>,
     tz_offset: &FixedOffset,
+    tz_offset_string: &String,
 ) -> Option<CapturedDtData> {
-    defn!("(…, {:?}, {:?}, {:?})", index, year_opt, tz_offset);
+    defn!("(…, {:?}, {:?}, {:?}, {:?})", index, year_opt, tz_offset, tz_offset_string);
 
     let regex_: &Regex = match DATETIME_PARSE_DATAS_REGEX_VEC.get(*index) {
         Some(val) => val,
@@ -5351,7 +5345,14 @@ pub fn bytes_to_regex_to_datetime(
     // TODO: [2022/06/26] cost-savings: avoid a `String` alloc by passing precreated buffer
     const BUFLEN: usize = 35;
     let mut buffer: [u8; BUFLEN] = [0; BUFLEN];
-    let copiedn = captures_to_buffer_bytes(&mut buffer, &captures, year_opt, tz_offset, &dtpd.dtfs);
+    let copiedn = captures_to_buffer_bytes(
+        &mut buffer,
+        &captures,
+        year_opt,
+        tz_offset,
+        tz_offset_string,
+        &dtpd.dtfs
+    );
 
     // use the `dt_format` to parse the buffer of regex matches
     let buffer_s: &str = u8_to_str(&buffer[0..copiedn]).unwrap();

src/readers/syslinereader.rs

@@ -223,6 +223,8 @@ pub struct SyslineReader {
     ///
     /// [`FixedOffset`]: https://docs.rs/chrono/0.4.22/chrono/offset/struct.FixedOffset.html
     tz_offset: FixedOffset,
+    /// precompute `tz_offset` as a `String`
+    tz_offset_string: String,
     /// Enable or disable the internal LRU cache for `find_sysline()`.
     find_sysline_lru_cache_enabled: bool,
     /// Internal [LRU cache] for `find_sysline()`.
@@ -480,6 +482,7 @@ impl SyslineReader {
             dt_patterns_counts,
             dt_patterns_indexes,
             tz_offset,
+            tz_offset_string: tz_offset.to_string(),
             find_sysline_lru_cache_enabled: SyslineReader::CACHE_ENABLE_DEFAULT,
             find_sysline_lru_cache: SyslinesLRUCache::new(
                 std::num::NonZeroUsize::new(SyslineReader::FIND_SYSLINE_LRU_CACHE_SZ).unwrap(),
@@ -1144,6 +1147,7 @@ impl SyslineReader {
         charsz: CharSz,
         year_opt: &Option<Year>,
         tz_offset: &FixedOffset,
+        tz_offset_string: &String,
         get_boxptrs_singleptr: &mut Count,
         get_boxptrs_doubleptr: &mut Count,
         get_boxptrs_multiptr: &mut Count,
@@ -1304,7 +1308,7 @@ impl SyslineReader {
             let dt_beg: LineIndex;
             let dt_end: LineIndex;
             (dt_beg, dt_end, dt) =
-                match bytes_to_regex_to_datetime(slice_, index, year_opt, tz_offset) {
+                match bytes_to_regex_to_datetime(slice_, index, year_opt, tz_offset, tz_offset_string) {
                     None => continue,
                     Some(val) => val,
             };
@@ -1582,6 +1586,7 @@ impl SyslineReader {
             charsz,
             year_opt,
             &self.tz_offset,
+            &self.tz_offset_string,
             &mut self.get_boxptrs_singleptr,
             &mut self.get_boxptrs_doubleptr,
             &mut self.get_boxptrs_multiptr,

src/tests/common.rs

@@ -67,6 +67,7 @@ lazy_static! {
 
     // FixedOffset Local
     pub static ref FO_L: FixedOffset = *LOCAL_NOW.offset();
+    pub static ref FO_L_STR: String = String::from(&*FO_L.to_string());
     // FixedOffset Zulu / UTC
     pub static ref FO_Z: FixedOffset = FixedOffset::east_opt(0).unwrap();
     pub static ref FO_0: FixedOffset = FixedOffset::east_opt(0).unwrap();

src/tests/datetime_tests.rs

@@ -709,7 +709,7 @@ fn test_DATETIME_PARSE_DATAS_test_cases(index: usize) {
             year_opt = Some(YEAR_FALLBACKDUMMY_VAL);
         }
         let s = buffer_to_String_noraw(data);
-        match bytes_to_regex_to_datetime(data, &index, &year_opt, &FO_L) {
+        match bytes_to_regex_to_datetime(data, &index, &year_opt, &FO_L, &FO_L_STR) {
             Some(capdata) => {
                 eprintln!(
                     "Passed dtpd declared at line {} result {:?}, test data {:?}",

src/tests/syslinereader_tests.rs

@@ -5227,7 +5227,7 @@ fn test_ezcheck_slice(
     0,
     4,
     0,
-    476,
+    484,
     0,
     0,
     0,
@@ -5236,9 +5236,10 @@ fn test_ezcheck_slice(
     24,
     0,
     7,
-    452,
+    460,
     0,
-    7
+    7;
+    "NTF_GZ_8BYTE_FPATH"
 )]
 #[test_case(
     &*NTF_SYSLINE_1_PATH,
@@ -5265,7 +5266,7 @@ fn test_ezcheck_slice(
     1,
     0,
     4,
-    70,
+    71,
     0,
     0,
     0,
@@ -5274,8 +5275,9 @@ fn test_ezcheck_slice(
     4,
     0,
     0,
-    70,
-    0
+    71,
+    0;
+    "NTF_SYSLINE_1_PATH (cache)"
 )]
 #[test_case(
     &*NTF_SYSLINE_1_PATH,
@@ -5302,7 +5304,7 @@ fn test_ezcheck_slice(
     0,
     0,
     4,
-    70,
+    71,
     0,
     0,
     0,
@@ -5311,8 +5313,9 @@ fn test_ezcheck_slice(
     4,
     0,
     0,
-    70,
-    0
+    71,
+    0;
+    "NTF_SYSLINE_1_PATH (no cache)"
 )]
 #[test_case(
     &*NTF_SYSLINE_2_PATH,
@@ -5340,16 +5343,17 @@ fn test_ezcheck_slice(
     0,
     0,
     0,
-    148,
+    150,
     0,
     0,
     0,
     0,
     8,
     0,
     0,
-    140,
-    0
+    142,
+    0;
+    "NTF_SYSLINE_2_PATH"
 )]
 fn test_syslinereadersummary(
     path: &FPath,