Add date builtins (fix #364)

Windows support for strptime() is missing.  We can add a copy of one
from a BSD later.

5 files changed, 104 insertions, 2 deletions

diff --git a/builtin.c b/builtin.c
index 0c1ee421..05d4c86c 100644
--- a/builtin.c
+++ b/builtin.c
@@ -1,4 +1,6 @@
+#define _XOPEN_SOURCE
 #include <assert.h>
+#include <ctype.h>
 #include <limits.h>
 #include <math.h>
 #ifdef HAVE_ONIGURUMA
@@ -6,6 +8,7 @@
 #endif
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include "builtin.h"
 #include "compile.h"
 #include "jq_parser.h"
@@ -912,6 +915,74 @@ static jv f_stderr(jq_state *jq, jv input) {
   return input;
 }
 
+#ifdef HAVE_STRPTIME
+static jv f_strptime(jq_state *jq, jv a, jv b) {
+  if (jv_get_kind(a) != JV_KIND_STRING || jv_get_kind(b) != JV_KIND_STRING)
+    return jv_invalid_with_msg(jv_string("strptime/2 requires string inputs and arguments"));
+
+  struct tm tm;
+  const char *input = jv_string_value(a);
+  const char *fmt = jv_string_value(b);
+  const char *end = strptime(input, fmt, &tm);
+
+  if (end == NULL || (*end != '\0' && !isspace(*end))) {
+    jv e = jv_invalid_with_msg(jv_string_fmt("date \"%s\" does not match format \"%s\"", input, fmt));
+    jv_free(a);
+    jv_free(b);
+    return e;
+  }
+  jv_free(a);
+  jv_free(b);
+  jv r = JV_ARRAY(jv_number(tm.tm_year + 1900),
+                  jv_number(tm.tm_mon),
+                  jv_number(tm.tm_mday),
+                  jv_number(tm.tm_hour),
+                  jv_number(tm.tm_min),
+                  jv_number(tm.tm_sec),
+                  jv_number(tm.tm_wday),
+                  jv_number(tm.tm_yday));
+  if (*end != '\0')
+    r = jv_array_append(r, jv_string(end));
+  return r;
+}
+#else
+static jv f_strptime(jq_state *jq, jv a, jv b) {
+    return jv_invalid_with_msg(jv_string("strptime/2 not implemented on this platform"));
+}
+#endif
+
+#define TO_TM_FIELD(t, j, i, k)                 \
+    do {                                        \
+      jv n = jv_array_get(jv_copy(j), (i));     \
+      if (jv_get_kind(n) != (k))                \
+        return jv_invalid_with_msg(jv_string("mktime() requires a 'gmtime' input (an array inputs of 8 numeric values)")); \
+      t = jv_number_value(n);                   \
+      jv_free(n);                               \
+    } while (0)
+
+static jv f_mktime(jq_state *jq, jv a) {
+  if (jv_get_kind(a) != JV_KIND_ARRAY)
+    return jv_invalid_with_msg(jv_string("mktime() requires array inputs"));
+  if (jv_array_length(jv_copy(a)) < 6)
+    return jv_invalid_with_msg(jv_string("mktime() requires a 'gmtime' input (an array inputs of 8 numeric values)"));
+  struct tm tm;
+  memset(&tm, 0, sizeof(tm));
+  TO_TM_FIELD(tm.tm_year, a, 0, JV_KIND_NUMBER);
+  TO_TM_FIELD(tm.tm_mon,  a, 1, JV_KIND_NUMBER);
+  TO_TM_FIELD(tm.tm_mday, a, 2, JV_KIND_NUMBER);
+  TO_TM_FIELD(tm.tm_hour, a, 3, JV_KIND_NUMBER);
+  TO_TM_FIELD(tm.tm_min, a, 4, JV_KIND_NUMBER);
+  TO_TM_FIELD(tm.tm_sec, a, 5, JV_KIND_NUMBER);
+  tm.tm_year -= 1900;
+  jv_free(a);
+  time_t t = mktime(&tm);
+  if (t == (time_t)-1)
+    return jv_invalid_with_msg(jv_string("invalid gmtime representation"));
+  return jv_number(t);
+}
+
+#undef TO_TM_FIELD
+
 
 #define LIBM_DD(name) \
   {(cfunction_ptr)f_ ## name, "_" #name, 1},
@@ -971,6 +1042,8 @@ static const struct cfunction function_list[] = {
   {(cfunction_ptr)f_input, "_input", 1},
   {(cfunction_ptr)f_debug, "debug", 1},
   {(cfunction_ptr)f_stderr, "stderr", 1},
+  {(cfunction_ptr)f_strptime, "strptime", 2},
+  {(cfunction_ptr)f_mktime, "mktime", 1},
 };
 #undef LIBM_DD
 
diff --git a/configure.ac b/configure.ac
index 33ed602e..616f52a5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -115,6 +115,7 @@ AM_CONDITIONAL([ENABLE_DOCS], [test "x$enable_docs" != xno])
 
 AC_FIND_FUNC([isatty], [c], [#include <unistd.h>], [0])
 AC_FIND_FUNC([_isatty], [c], [#include <io.h>], [0])
+AC_FIND_FUNC([strptime], [c], [#include <time.h>], [0])
 
 AC_ARG_ENABLE([pthread-tls],
               [AC_HELP_STRING([--enable-pthread-tls],
diff --git a/docs/content/3.manual/manual.yml b/docs/content/3.manual/manual.yml
index 02ca3caa..37f0eab4 100644
--- a/docs/content/3.manual/manual.yml
+++ b/docs/content/3.manual/manual.yml
@@ -1591,6 +1591,28 @@ sections:
             input: "\"O'Hara's Ale\""
             output: ["\"echo 'O'\\\\''Hara'\\\\''s Ale'\""]
 
+      - title: "Dates"
+        body: |
+
+          The `strptime(fmt)` function parses input strings matching the
+          `fmt` argument.  The output is an array of eight numbers: the
+          year, the month, the day of the month, the hour of the day,
+          the minute of the hour, the second of the minute, the day of
+          the week, and the day of the year, all zero-based except for
+          the year and the month, which are one-based.
+
+          The `mktime` function consumes outputs from `strptime/1` and
+          produces the time in seconds since the Unix epoch.
+
+        examples:
+          - program: 'strptime'
+            input: '"2015-03-05 23:51:47Z"'
+            output: ['[2015,2,5,23,51,47,4,63]']
+
+          - program: 'strptime|mktime'
+            input: '"2015-03-05 23:51:47Z"'
+            output: ['1425621107']
+
   - title: Conditionals and Comparisons
     entries:
       - title: "`==`, `!=`"
diff --git a/jv.h b/jv.h
index 8ed35c14..5f2b318c 100644
--- a/jv.h
+++ b/jv.h
@@ -87,9 +87,11 @@ jv jv_array_indexes(jv, jv);
 #define JV_ARRAY_5(e1,e2,e3,e4,e5) (jv_array_append(JV_ARRAY_4(e1,e2,e3,e4),e5))
 #define JV_ARRAY_6(e1,e2,e3,e4,e5,e6) (jv_array_append(JV_ARRAY_5(e1,e2,e3,e4,e5),e6))
 #define JV_ARRAY_7(e1,e2,e3,e4,e5,e6,e7) (jv_array_append(JV_ARRAY_6(e1,e2,e3,e4,e5,e6),e7))
-#define JV_ARRAY_IDX(_1,_2,_3,_4,_5,_6,_7,NAME,...) NAME
+#define JV_ARRAY_8(e1,e2,e3,e4,e5,e6,e7,e8) (jv_array_append(JV_ARRAY_7(e1,e2,e3,e4,e5,e6,e7),e8))
+#define JV_ARRAY_9(e1,e2,e3,e4,e5,e6,e7,e8,e9) (jv_array_append(JV_ARRAY_8(e1,e2,e3,e4,e5,e6,e7,e8),e9))
+#define JV_ARRAY_IDX(_1,_2,_3,_4,_5,_6,_7,_8,_9,NAME,...) NAME
 #define JV_ARRAY(...) \
-  JV_ARRAY_IDX(__VA_ARGS__, JV_ARRAY_7, JV_ARRAY_6, JV_ARRAY_5, JV_ARRAY_4, JV_ARRAY_3, JV_ARRAY_2, JV_ARRAY_1)(__VA_ARGS__)
+  JV_ARRAY_IDX(__VA_ARGS__, JV_ARRAY_9, JV_ARRAY_8, JV_ARRAY_7, JV_ARRAY_6, JV_ARRAY_5, JV_ARRAY_4, JV_ARRAY_3, JV_ARRAY_2, JV_ARRAY_1)(__VA_ARGS__)
 
 #ifdef __GNUC__
 #define JV_PRINTF_LIKE(fmt_arg_num, args_num) \
diff --git a/tests/all.test b/tests/all.test
index 0d3526e9..3b22f4de 100644
--- a/tests/all.test
+++ b/tests/all.test
@@ -1140,6 +1140,10 @@ bsearch(4)
 [1,2,3]
 -4
 
+[strptime("%Y-%m-%d %H:%M:%SZ")|(.,mktime)]
+"2015-03-05 23:51:47Z"
+[[2015,2,5,23,51,47,4,63],1425621107]
+
 # module system
 import "a" as foo; import "b" as bar; def fooa: foo::a; [fooa, bar::a, bar::b, foo::a]
 null