src/loslib.js: Use our own strftime implementation; removes dependency

3 files changed, 283 insertions, 21 deletions

diff --git a/NEWS b/NEWS
index fbb983b..2e13a83 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,7 @@
 UNRELEASED
 
   - More node 6 compatibility fixes
+  - Use own strftime code (drops strftime npm package dependency)
 
 
 0.1.1 - 2018-04-03
diff --git a/package.json b/package.json
index 9988883..ca4c18f 100644
--- a/package.json
+++ b/package.json
@@ -36,7 +36,6 @@
   "dependencies": {
     "readline-sync": "^1.4.9",
     "sprintf-js": "^1.1.1",
-    "strftime": "^0.10.0",
     "tmp": "^0.0.33"
   },
   "sideEffects": false,
diff --git a/src/loslib.js b/src/loslib.js
index 6240ed9..5768113 100644
--- a/src/loslib.js
+++ b/src/loslib.js
@@ -42,16 +42,13 @@ const {
 } = require('./lauxlib.js');
 const {
     luastring_eq,
-    luastring_indexOf,
     to_jsstring,
     to_luastring
 } = require("./fengaricore.js");
 
-const strftime = require('strftime');
-
 /* options for ANSI C 89 (only 1-char options) */
-const L_STRFTIMEC89 = to_luastring("aAbBcdHIjmMpSUwWxXyYZ%");
-const LUA_STRFTIMEOPTIONS = L_STRFTIMEC89;
+// const L_STRFTIMEC89 = to_luastring("aAbBcdHIjmMpSUwWxXyYZ%");
+// const LUA_STRFTIMEOPTIONS = L_STRFTIMEC89;
 
 /* options for ISO C 99 and POSIX */
 // const L_STRFTIMEC99 = to_luastring("aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%||EcECExEXEyEYOdOeOHOIOmOMOSOuOUOVOwOWOy");  /* two-char options */
@@ -61,6 +58,18 @@ const LUA_STRFTIMEOPTIONS = L_STRFTIMEC89;
 // const L_STRFTIMEWIN = to_luastring("aAbBcdHIjmMpSUwWxXyYzZ%||#c#x#d#H#I#j#m#M#S#U#w#W#y#Y");  /* two-char options */
 // const LUA_STRFTIMEOPTIONS = L_STRFTIMEWIN;
 
+/* options for our own strftime implementation
+  - should be superset of C89 options for compat
+  - missing from C99:
+      - ISO 8601 week specifiers: gGV
+      - > single char specifiers
+  - beyond C99:
+      - %k: TZ extension: space-padded 24-hour
+      - %l: TZ extension: space-padded 12-hour
+      - %P: GNU extension: lower-case am/pm
+*/
+const LUA_STRFTIMEOPTIONS = to_luastring("aAbBcCdDeFhHIjklmMnpPrRStTuUwWxXyYzZ%");
+
 
 const setfield = function(L, key, value) {
     lua_pushinteger(L, value);
@@ -100,7 +109,272 @@ const getfield = function(L, key, d, delta) {
     return res;
 };
 
-const checkoption = function(L, conv, i, buff) {
+
+const locale = {
+    days: ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" ].map((s) => to_luastring(s)),
+    shortDays: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"].map((s) => to_luastring(s)),
+    months: ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"].map((s) => to_luastring(s)),
+    shortMonths: ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"].map((s) => to_luastring(s)),
+    AM: to_luastring("AM"),
+    PM: to_luastring("PM"),
+    am: to_luastring("am"),
+    pm: to_luastring("pm"),
+    formats: {
+        c: to_luastring("%a %b %e %H:%M:%S %Y"),
+        D: to_luastring("%m/%d/%y"),
+        F: to_luastring("%Y-%m-%d"),
+        R: to_luastring("%H:%M"),
+        r: to_luastring("%I:%M:%S %p"),
+        T: to_luastring("%H:%M:%S"),
+        X: to_luastring("%T"),
+        x: to_luastring("%D")
+    }
+};
+
+const week_number = function(date, start_of_week) {
+    // This works by shifting the weekday back by one day if we
+    // are treating Monday as the first day of the week.
+    let weekday = date.getDay();
+    if (start_of_week === 'monday') {
+        if (weekday === 0) // Sunday
+            weekday = 6;
+        else
+            weekday--;
+    }
+    let yday = (date - new Date(date.getFullYear(), 0, 1)) / 86400000;
+    return Math.floor((yday + 7 - weekday) / 7);
+};
+
+const push_pad_2 = function(b, n, pad) {
+    if (n < 10)
+        luaL_addchar(b, pad);
+    luaL_addstring(b, to_luastring(String(n)));
+};
+
+const strftime = function(L, b, s, date) {
+    let i = 0;
+    while (i < s.length) {
+        if (s[i] !== 37 /* % */) {  /* not a conversion specifier? */
+            luaL_addchar(b, s[i++]);
+        } else {
+            i++;  /* skip '%' */
+            let len = checkoption(L, s, i);
+            /* each `case` has an example output above it for the UTC epoch */
+            switch(s[i]) {
+                // '%'
+                case 37 /* % */:
+                    luaL_addchar(b, 37);
+                    break;
+
+                // 'Thursday'
+                case 65 /* A */:
+                    luaL_addstring(b, locale.days[date.getDay()]);
+                    break;
+
+                // 'January'
+                case 66 /* B */:
+                    luaL_addstring(b, locale.months[date.getMonth()]);
+                    break;
+
+                // '19'
+                case 67 /* C */:
+                    push_pad_2(b, Math.floor(date.getFullYear() / 100), 48 /* 0 */);
+                    break;
+
+                // '01/01/70'
+                case 68 /* D */:
+                    strftime(L, b, locale.formats.D, date);
+                    break;
+
+                // '1970-01-01'
+                case 70 /* F */:
+                    strftime(L, b, locale.formats.F, date);
+                    break;
+
+                // '00'
+                case 72 /* H */:
+                    push_pad_2(b, date.getHours(), 48 /* 0 */);
+                    break;
+
+                // '12'
+                case 73 /* I */:
+                    push_pad_2(b, (date.getHours() + 11) % 12 + 1, 48 /* 0 */);
+                    break;
+
+                // '00'
+                case 77 /* M */:
+                    push_pad_2(b, date.getMinutes(), 48 /* 0 */);
+                    break;
+
+                // 'am'
+                case 80 /* P */:
+                    luaL_addstring(b, date.getHours() < 12 ? locale.am : locale.pm);
+                    break;
+
+                // '00:00'
+                case 82 /* R */:
+                    strftime(L, b, locale.formats.R, date);
+                    break;
+
+                // '00'
+                case 83 /* S */:
+                    push_pad_2(b, date.getSeconds(), 48 /* 0 */);
+                    break;
+
+                // '00:00:00'
+                case 84 /* T */:
+                    strftime(L, b, locale.formats.T, date);
+                    break;
+
+                // '00'
+                case 85 /* U */:
+                    push_pad_2(b, week_number(date, "sunday"), 48 /* 0 */);
+                    break;
+
+                // '00'
+                case 87 /* W */:
+                    push_pad_2(b, week_number(date, "monday"), 48 /* 0 */);
+                    break;
+
+                // '16:00:00'
+                case 88 /* X */:
+                    strftime(L, b, locale.formats.X, date);
+                    break;
+
+                // '1970'
+                case 89 /* Y */:
+                    luaL_addstring(b, to_luastring(String(date.getFullYear())));
+                    break;
+
+                // 'GMT'
+                case 90 /* Z */: {
+                    let tzString = date.toString().match(/\(([\w\s]+)\)/);
+                    if (tzString)
+                        luaL_addstring(b, to_luastring(tzString[1]));
+                    break;
+                }
+
+                // 'Thu'
+                case 97 /* a */:
+                    luaL_addstring(b, locale.shortDays[date.getDay()]);
+                    break;
+
+                // 'Jan'
+                case 98 /* b */:
+                case 104 /* h */:
+                    luaL_addstring(b, locale.shortMonths[date.getMonth()]);
+                    break;
+
+                // ''
+                case 99 /* c */:
+                    strftime(L, b, locale.formats.c, date);
+                    break;
+
+                // '01'
+                case 100 /* d */:
+                    push_pad_2(b, date.getDate(), 48 /* 0 */);
+                    break;
+
+                // ' 1'
+                case 101 /* e */:
+                    push_pad_2(b, date.getDate(), 32 /* space */);
+                    break;
+
+                // '000'
+                case 106 /* j */: {
+                    let yday = Math.floor((date - new Date(date.getFullYear(), 0, 1)) / 86400000);
+                    if (yday < 100) {
+                        if (yday < 10)
+                            luaL_addchar(b, 48 /* 0 */);
+                        luaL_addchar(b, 48 /* 0 */);
+                    }
+                    luaL_addstring(b, to_luastring(String(yday)));
+                    break;
+                }
+
+                // ' 0'
+                case 107 /* k */:
+                    push_pad_2(b, date.getHours(), 32 /* space */);
+                    break;
+
+                // '12'
+                case 108 /* l */:
+                    push_pad_2(b, (date.getHours() + 11) % 12 + 1, 32 /* space */);
+                    break;
+
+                // '01'
+                case 109 /* m */:
+                    push_pad_2(b, date.getMonth() + 1, 48 /* 0 */);
+                    break;
+
+                // '\n'
+                case 110 /* n */:
+                    luaL_addchar(b, 10);
+                    break;
+
+                // 'AM'
+                case 112 /* p */:
+                    luaL_addstring(b, date.getHours() < 12 ? locale.AM : locale.PM);
+                    break;
+
+                // '12:00:00 AM'
+                case 114 /* r */:
+                    strftime(L, b, locale.formats.r, date);
+                    break;
+
+                // '0'
+                case 115 /* s */:
+                    luaL_addstring(b, to_luastring(String(Math.floor(date / 1000))));
+                    break;
+
+                // '\t'
+                case 116 /* t */:
+                    luaL_addchar(b, 8);
+                    break;
+
+                // '4'
+                case 117 /* u */: {
+                    let day = date.getDay();
+                    luaL_addstring(b, to_luastring(String(day === 0 ? 7 : day)));
+                    break;
+                }
+
+                // '4'
+                case 119 /* w */:
+                    luaL_addstring(b, to_luastring(String(date.getDay())));
+                    break;
+
+                // '12/31/69'
+                case 120 /* x */:
+                    strftime(L, b, locale.formats.x, date);
+                    break;
+
+                // '70'
+                case 121 /* y */:
+                    push_pad_2(b, date.getFullYear() % 100, 48 /* 0 */);
+                    break;
+
+                // '+0000'
+                case 122 /* z */: {
+                    let off = date.getTimezoneOffset();
+                    if (off > 0) {
+                        luaL_addchar(b, 45 /* - */);
+                    } else {
+                        off = -off;
+                        luaL_addchar(b, 43 /* + */);
+                    }
+                    push_pad_2(b, Math.floor(off/60), 48 /* 0 */);
+                    push_pad_2(b, off % 60, 48 /* 0 */);
+                    break;
+                }
+            }
+            i += len;
+        }
+    }
+};
+
+
+const checkoption = function(L, conv, i) {
     let option = LUA_STRFTIMEOPTIONS;
     let o = 0;
     let oplen = 1;  /* length of options being checked */
@@ -108,8 +382,7 @@ const checkoption = function(L, conv, i, buff) {
         if (option[o] === '|'.charCodeAt(0))  /* next block? */
             oplen++;  /* will check options with next length (+1) */
         else if (luastring_eq(conv.subarray(i, i+oplen), option.subarray(o, o+oplen))) {  /* match? */
-            buff.set(conv.subarray(i, i+oplen)); /* copy valid option to buffer */
-            return i + oplen;  /* return next item */
+            return oplen;  /* return length */
         }
     }
     luaL_argerror(L, 1,
@@ -137,18 +410,7 @@ const os_date = function(L) {
         cc[0] = "%".charCodeAt(0);
         let b = new luaL_Buffer();
         luaL_buffinit(L, b);
-        while (i < s.length) {
-            if (s[i] !== '%'.charCodeAt(0)) {  /* not a conversion specifier? */
-                luaL_addchar(b, s[i++]);
-            } else {
-                i++;  /* skip '%' */
-                i = checkoption(L, s, i, cc.subarray(1));  /* copy specifier to 'cc' */
-                let len = luastring_indexOf(cc, 0);
-                if (len === -1) len = void 0;
-                let buff = strftime(to_jsstring(cc, 0, len), stm);
-                luaL_addstring(b, to_luastring(buff));
-            }
-        }
+        strftime(L, b, s, stm);
         luaL_pushresult(b);
     }
     return 1;