From: Sebastian Harl <sh@tokkee.org>
Date: Sun, 27 Jul 2014 21:06:03 +0000 (+0200)
Subject: data: Added sdb_data_expr_eval().
X-Git-Tag: sysdb-0.3.0~27
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=1bbf53aa65770eeb26dbdbeb4de3871ad42cb9dd;p=sysdb.git

data: Added sdb_data_expr_eval().

This function may be used to evaluate simple operation expressions on data
values. Supported operators are +, -, *, /, %, and (for string and binary
values) concatenation.
---

diff --git a/src/Makefile.am b/src/Makefile.am
index 0130d42..2adc2e0 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -89,7 +89,7 @@ libsysdb_la_SOURCES = \
 		utils/unixsock.c include/utils/unixsock.h
 libsysdb_la_CFLAGS = $(AM_CFLAGS)
 libsysdb_la_CPPFLAGS = $(AM_CPPFLAGS) $(LTDLINCL)
-libsysdb_la_LDFLAGS = $(AM_LDFLAGS) -version-info 0:0:0 -pthread
+libsysdb_la_LDFLAGS = $(AM_LDFLAGS) -version-info 0:0:0 -pthread -lm
 libsysdb_la_LIBADD = libsysdb_fe_parser.la \
 		$(LIBLTDL) -lrt liboconfig/liboconfig.la
 libsysdb_la_DEPENDENCIES = libsysdb_fe_parser.la liboconfig/liboconfig.la
@@ -124,7 +124,7 @@ sysdbd_SOURCES = tools/sysdbd/main.c include/sysdb.h \
 		$(libsysdb_la_SOURCES)
 sysdbd_CFLAGS = $(AM_CFLAGS) -DBUILD_DATE="\"$$( date --utc '+%F %T' ) (UTC)\""
 sysdbd_CPPFLAGS = $(AM_CPPFLAGS) $(LTDLINCL)
-sysdbd_LDFLAGS = $(AM_LDFLAGS) -export-dynamic -pthread
+sysdbd_LDFLAGS = $(AM_LDFLAGS) -export-dynamic -pthread -lm
 sysdbd_LDADD = libsysdb_fe_parser.la liboconfig/liboconfig.la \
 		$(LIBLTDL) -lrt
 sysdbd_DEPENDENCIES = libsysdb_fe_parser.la liboconfig/liboconfig.la
diff --git a/src/core/data.c b/src/core/data.c
index 2381636..cdafac3 100644
--- a/src/core/data.c
+++ b/src/core/data.c
@@ -42,6 +42,60 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <math.h>
+
+/*
+ * private helper functions
+ */
+
+static int
+data_concat(const sdb_data_t *d1, const sdb_data_t *d2, sdb_data_t *res)
+{
+	unsigned char *new;
+	unsigned char *s1, *s2;
+	size_t len1, len2;
+
+	if (d1->type == SDB_TYPE_STRING) {
+		s1 = (unsigned char *)d1->data.string;
+		s2 = (unsigned char *)d2->data.string;
+		len1 = s1 ? strlen((char *)s1) : 0;
+		len2 = s2 ? strlen((char *)s2) : 0;
+	}
+	else if (d1->type == SDB_TYPE_BINARY) {
+		s1 = d1->data.binary.datum;
+		s2 = d2->data.binary.datum;
+		len1 = d1->data.binary.length;
+		len2 = d2->data.binary.length;
+	}
+	else
+		return -1;
+
+	if (s1 || s2) {
+		new = malloc(len1 + len2 + 1);
+		if (! new)
+			return -1;
+	}
+	else
+		new = NULL;
+
+	if (len1)
+		memcpy(new, s1, len1);
+	if (len2)
+		memcpy(new + len1, s2, len2);
+	if (new)
+		new[len1 + len2] = '\0';
+
+	res->type = d1->type;
+	if (res->type == SDB_TYPE_STRING) {
+		res->data.string = (char *)new;
+	}
+	else {
+		res->data.binary.datum = new;
+		res->data.binary.length = len1 + len2;
+	}
+	return 0;
+} /* data_concat */
+
 /*
  * public API
  */
@@ -150,6 +204,99 @@ sdb_data_cmp(const sdb_data_t *d1, const sdb_data_t *d2)
 #undef CMP_NULL
 } /* sdb_data_cmp */
 
+int
+sdb_data_expr_eval(int op, const sdb_data_t *d1, const sdb_data_t *d2,
+		sdb_data_t *res)
+{
+	if (d1->type != d2->type)
+		return -1;
+
+	switch (op) {
+		case SDB_DATA_CONCAT:
+			return data_concat(d1, d2, res);
+		case SDB_DATA_ADD:
+			switch (d1->type) {
+				case SDB_TYPE_INTEGER:
+					res->data.integer = d1->data.integer + d2->data.integer;
+					break;
+				case SDB_TYPE_DECIMAL:
+					res->data.decimal = d1->data.decimal + d2->data.decimal;
+					break;
+				case SDB_TYPE_DATETIME:
+					res->data.datetime = d1->data.datetime + d2->data.datetime;
+					break;
+				default:
+					return -1;
+			}
+			break;
+		case SDB_DATA_SUB:
+			switch (d1->type) {
+				case SDB_TYPE_INTEGER:
+					res->data.integer = d1->data.integer - d2->data.integer;
+					break;
+				case SDB_TYPE_DECIMAL:
+					res->data.decimal = d1->data.decimal - d2->data.decimal;
+					break;
+				case SDB_TYPE_DATETIME:
+					res->data.datetime = d1->data.datetime - d2->data.datetime;
+					break;
+				default:
+					return -1;
+			}
+			break;
+		case SDB_DATA_MUL:
+			switch (d1->type) {
+				case SDB_TYPE_INTEGER:
+					res->data.integer = d1->data.integer * d2->data.integer;
+					break;
+				case SDB_TYPE_DECIMAL:
+					res->data.decimal = d1->data.decimal * d2->data.decimal;
+					break;
+				case SDB_TYPE_DATETIME:
+					res->data.datetime = d1->data.datetime * d2->data.datetime;
+					break;
+				default:
+					return -1;
+			}
+			break;
+		case SDB_DATA_DIV:
+			switch (d1->type) {
+				case SDB_TYPE_INTEGER:
+					res->data.integer = d1->data.integer / d2->data.integer;
+					break;
+				case SDB_TYPE_DECIMAL:
+					res->data.decimal = d1->data.decimal / d2->data.decimal;
+					break;
+				case SDB_TYPE_DATETIME:
+					res->data.datetime = d1->data.datetime / d2->data.datetime;
+					break;
+				default:
+					return -1;
+			}
+			break;
+		case SDB_DATA_MOD:
+			switch (d1->type) {
+				case SDB_TYPE_INTEGER:
+					res->data.integer = d1->data.integer % d2->data.integer;
+					break;
+				case SDB_TYPE_DECIMAL:
+					res->data.decimal = fmod(d1->data.decimal, d2->data.decimal);
+					break;
+				case SDB_TYPE_DATETIME:
+					res->data.datetime = d1->data.datetime % d2->data.datetime;
+					break;
+				default:
+					return -1;
+			}
+			break;
+		default:
+			return -1;
+	}
+
+	res->type = d1->type;
+	return 0;
+} /* sdb_data_expr_eval */
+
 size_t
 sdb_data_strlen(const sdb_data_t *datum)
 {
diff --git a/src/include/core/data.h b/src/include/core/data.h
index 4d7fda3..2e9b90b 100644
--- a/src/include/core/data.h
+++ b/src/include/core/data.h
@@ -75,6 +75,7 @@ typedef struct {
 		} binary;             /* SDB_TYPE_BINARY */
 	} data;
 } sdb_data_t;
+#define SDB_DATA_INIT { 0, { .integer = 0 } }
 
 /*
  * sdb_data_copy:
@@ -114,6 +115,46 @@ sdb_data_free_datum(sdb_data_t *datum);
 int
 sdb_data_cmp(const sdb_data_t *d1, const sdb_data_t *d2);
 
+/*
+ * Operators supported by sdb_data_eval_expr.
+ */
+enum {
+	SDB_DATA_ADD = 1, /* addition */
+	SDB_DATA_SUB,     /* substraction */
+	SDB_DATA_MUL,     /* multiplication */
+	SDB_DATA_DIV,     /* division */
+	SDB_DATA_MOD,     /* modulo */
+	SDB_DATA_CONCAT,  /* string / binary data concatenation */
+};
+
+#define SDB_DATA_OP_TO_STRING(op) \
+	(((op) == SDB_DATA_ADD) \
+		? "+" \
+		: ((op) == SDB_DATA_SUB) \
+			? "-" \
+			: ((op) == SDB_DATA_MUL) \
+				? "*" \
+				: ((op) == SDB_DATA_DIV) \
+					? "/" \
+					: ((op) == SDB_DATA_MOD) \
+						? "%" \
+						: ((op) == SDB_DATA_CONCAT) \
+							? "||" : "UNKNOWN")
+
+/*
+ * sdb_data_expr_eval:
+ * Evaluate a simple arithmetic expression on two data points. The data-type
+ * of d1 and d2 have to be the same. String and binary data only support
+ * concatenation and all other data types only support the other operators.
+ *
+ * Returns:
+ *  - 0 on success
+ *  - a negative value else
+ */
+int
+sdb_data_expr_eval(int op, const sdb_data_t *d1, const sdb_data_t *d2,
+		sdb_data_t *res);
+
 /*
  * sdb_data_strlen:
  * Returns a (worst-case) estimate for the number of bytes required to format
diff --git a/t/unit/core/data_test.c b/t/unit/core/data_test.c
index e490a38..0fd61a5 100644
--- a/t/unit/core/data_test.c
+++ b/t/unit/core/data_test.c
@@ -290,6 +290,192 @@ START_TEST(test_cmp)
 }
 END_TEST
 
+START_TEST(test_expr_eval)
+{
+	struct {
+		sdb_data_t d1;
+		sdb_data_t d2;
+		sdb_data_t expected_add;
+		sdb_data_t expected_sub;
+		sdb_data_t expected_mul;
+		sdb_data_t expected_div;
+		sdb_data_t expected_mod;
+		sdb_data_t expected_concat;
+	} golden_data[] = {
+		{
+			{ SDB_TYPE_INTEGER, { .integer = 4711 } },
+			{ SDB_TYPE_INTEGER, { .integer = 47 } },
+			{ SDB_TYPE_INTEGER, { .integer = 4758 } },
+			{ SDB_TYPE_INTEGER, { .integer = 4664 } },
+			{ SDB_TYPE_INTEGER, { .integer = 221417 } },
+			{ SDB_TYPE_INTEGER, { .integer = 100 } },
+			{ SDB_TYPE_INTEGER, { .integer = 11 } },
+			SDB_DATA_INIT,
+		},
+		{
+			{ SDB_TYPE_DECIMAL, { .decimal = 35.0 } },
+			{ SDB_TYPE_DECIMAL, { .decimal = 17.5 } },
+			{ SDB_TYPE_DECIMAL, { .decimal = 52.5 } },
+			{ SDB_TYPE_DECIMAL, { .decimal = 17.5 } },
+			{ SDB_TYPE_DECIMAL, { .decimal = 612.5 } },
+			{ SDB_TYPE_DECIMAL, { .decimal = 2.0 } },
+			{ SDB_TYPE_DECIMAL, { .decimal = 0.0 } },
+			SDB_DATA_INIT,
+		},
+		{
+			{ SDB_TYPE_STRING, { .string = NULL } },
+			{ SDB_TYPE_STRING, { .string = "" } },
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			{ SDB_TYPE_STRING, { .string = "" } },
+		},
+		{
+			{ SDB_TYPE_STRING, { .string = NULL } },
+			{ SDB_TYPE_STRING, { .string = NULL } },
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			{ SDB_TYPE_STRING, { .string = NULL } },
+		},
+		{
+			{ SDB_TYPE_STRING, { .string = "" } },
+			{ SDB_TYPE_STRING, { .string = NULL } },
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			{ SDB_TYPE_STRING, { .string = "" } },
+		},
+		{
+			{ SDB_TYPE_STRING, { .string = "a" } },
+			{ SDB_TYPE_STRING, { .string = "b" } },
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			{ SDB_TYPE_STRING, { .string = "ab" } },
+		},
+		{
+			{ SDB_TYPE_DATETIME, { .datetime = 47114711 } },
+			{ SDB_TYPE_DATETIME, { .datetime = 4711 } },
+			{ SDB_TYPE_DATETIME, { .datetime = 47119422 } },
+			{ SDB_TYPE_DATETIME, { .datetime = 47110000 } },
+			{ SDB_TYPE_DATETIME, { .datetime = 221957403521 } },
+			{ SDB_TYPE_DATETIME, { .datetime = 10001 } },
+			{ SDB_TYPE_DATETIME, { .datetime = 0 } },
+			SDB_DATA_INIT,
+		},
+		{
+			{ SDB_TYPE_BINARY, { .binary = { 0, NULL } } },
+			{ SDB_TYPE_BINARY, { .binary = { 1, (unsigned char *)"a" } } },
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			{ SDB_TYPE_BINARY, { .binary = { 1, (unsigned char *)"a" } } },
+		},
+		{
+			{ SDB_TYPE_BINARY, { .binary = { 0, NULL } } },
+			{ SDB_TYPE_BINARY, { .binary = { 0, NULL } } },
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			{ SDB_TYPE_BINARY, { .binary = { 0, NULL } } },
+		},
+		{
+			{ SDB_TYPE_BINARY, { .binary = { 1, (unsigned char *)"a" } } },
+			{ SDB_TYPE_BINARY, { .binary = { 0, NULL } } },
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			{ SDB_TYPE_BINARY, { .binary = { 1, (unsigned char *)"a" } } },
+		},
+		{
+			{
+				SDB_TYPE_BINARY,
+				{ .binary = { 3, (unsigned char *)"a\0a" } },
+			},
+			{
+				SDB_TYPE_BINARY,
+				{ .binary = { 3, (unsigned char *)"b\0b" } },
+			},
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			SDB_DATA_INIT,
+			{
+				SDB_TYPE_BINARY,
+				{ .binary = { 6, (unsigned char *)"a\0ab\0b" } },
+			},
+		},
+	};
+
+	size_t i;
+
+	for (i = 0; i < SDB_STATIC_ARRAY_LEN(golden_data); ++i) {
+		struct {
+			int op;
+			sdb_data_t expected;
+		} tests[] = {
+			{ SDB_DATA_ADD, golden_data[i].expected_add },
+			{ SDB_DATA_SUB, golden_data[i].expected_sub },
+			{ SDB_DATA_MUL, golden_data[i].expected_mul },
+			{ SDB_DATA_DIV, golden_data[i].expected_div },
+			{ SDB_DATA_MOD, golden_data[i].expected_mod },
+			{ SDB_DATA_CONCAT, golden_data[i].expected_concat },
+		};
+
+		size_t j;
+		for (j = 0; j < SDB_STATIC_ARRAY_LEN(tests); ++j) {
+			sdb_data_t res;
+			int check;
+
+			char d1_str[64] = "", d2_str[64] = "";
+			sdb_data_format(&golden_data[i].d1, d1_str, sizeof(d1_str),
+					SDB_DOUBLE_QUOTED);
+			sdb_data_format(&golden_data[i].d2, d2_str, sizeof(d2_str),
+					SDB_DOUBLE_QUOTED);
+
+			check = sdb_data_expr_eval(tests[j].op,
+					&golden_data[i].d1, &golden_data[i].d2, &res);
+			fail_unless((check == 0) == (tests[j].expected.type != 0),
+					"sdb_data_expr_eval(%s, %s, %s) = %d; expected: %d",
+					SDB_DATA_OP_TO_STRING(tests[j].op), d1_str, d2_str, check,
+					tests[j].expected.type == 0 ? -1 : 0);
+			if (tests[j].expected.type == 0)
+				continue;
+
+			check = sdb_data_cmp(&res, &tests[j].expected);
+			if (check != 0) {
+				char res_str[64] = "", expected_str[64] = "";
+				sdb_data_format(&res, res_str, sizeof(res_str),
+						SDB_DOUBLE_QUOTED);
+				sdb_data_format(&tests[j].expected, expected_str,
+						sizeof(expected_str), SDB_DOUBLE_QUOTED);
+				fail("sdb_data_expr_eval(%s, %s, %s) evaluated to %s; "
+						"expected: %s", SDB_DATA_OP_TO_STRING(tests[j].op),
+						d1_str, d2_str, res_str, expected_str);
+			}
+
+			sdb_data_free_datum(&res);
+		}
+	}
+}
+END_TEST
+
 START_TEST(test_format)
 {
 	struct {
@@ -428,6 +614,7 @@ core_data_suite(void)
 	tc = tcase_create("core");
 	tcase_add_test(tc, test_data);
 	tcase_add_test(tc, test_cmp);
+	tcase_add_test(tc, test_expr_eval);
 	tcase_add_test(tc, test_format);
 	tcase_add_test(tc, test_parse);
 	suite_add_tcase(s, tc);