add if_match object comparing strings, floats and ints

In general, argument types should match, but for combined long and
double usage the long is being converted to double before evaluation.

A few examples:
${if_match ${cpu} < 30}
${if_match "asdf" != "qwer"}
${if_match 0.5 < 0.50001}
${if_match 49.999 < 50}

ChangeLog

@@ -1,3 +1,6 @@
+2008-12-20
+	* Add if_match object comparing strings, floats and ints
+
 2008-12-18
 	* Fix segfault for diskiograph*, note the changed order of arguments
 	* Fix documentation for all graph objects

README

@@ -965,15 +965,6 @@ conky(1)							      conky(1)
 	      $if_empty and the matching $endif
 
 
-       1mif_gw	22mif there is at least one default gateway, display everything be‐
-	      tween $if_gw and the matching $endif
-
-
-       1mif_running (process)0m
-	      if  PROCESS  is  running, display everything $if_running and the
-	      matching $endif
-
-
        1mif_existing file (string)0m
 	      if FILE exists, display everything between if_existing  and  the
 	      matching	$endif.	 The optional second paramater checks for FILE
@@ -981,6 +972,31 @@ conky(1)							      conky(1)
 	      $if_existing and the matching $endif.
 
 
+       1mif_gw	22mif there is at least one default gateway, display everything be‐
+	      tween $if_gw and the matching $endif
+
+
+       1mif_match expression0m
+	      Evaluates the given boolean expression, printing everything  be‐
+	      tween $if_match and the matching $endif depending on whether the
+	      evaluation returns true or not.  Valid expressions consist of  a
+	      left  side,  an  operator and a right side. Left and right sides
+	      are being parsed for contained text objects  before  evaluation.
+	      Recognised left and right side types are:
+
+	      1mdouble22m: argument consists of only digits and a single dot.
+	      1mlong22m: argument consists of only digits.
+	      1mstring22m: argument is enclosed in quotation mark or the checks for
+	      double and long failed before.
+
+	      Valid operands are: ’>’, ’<’, ’>=’, ’<=’, ’==’, ’!=’.
+
+
+       1mif_running (process)0m
+	      if PROCESS is running, display everything	 $if_running  and  the
+	      matching $endif
+
+
        1mif_mounted (mountpoint)0m
 	      if MOUNTPOINT is mounted, display everything between $if_mounted
 	      and the matching $endif

doc/conky.1

@@ -823,27 +823,62 @@ laptops's LCD (0-7).
 
 .TP 
 \fB\*(T<\fBif_empty\fR\*(T>\fR \*(T<\fB(var)\fR\*(T> 
-if conky variable VAR is empty, display everything between $if_empty and the matching $endif
+if conky variable VAR is empty, display everything
-
+between $if_empty and the matching $endif
-.TP 
-\fB\*(T<\fBif_gw\fR\*(T>\fR 
-if there is at least one default gateway, display everything between $if_gw and the matching $endif
-
-.TP 
-\fB\*(T<\fBif_running\fR\*(T>\fR \*(T<\fB(process)\fR\*(T> 
-if PROCESS is running, display everything $if_running and the matching $endif
 
 .TP 
 \fB\*(T<\fBif_existing\fR\*(T>\fR \*(T<\fBfile (string)\fR\*(T> 
-if FILE exists, display everything between if_existing and the matching $endif. The optional second paramater checks for FILE containing the specified string and prints everything between $if_existing and the matching $endif.
+if FILE exists, display everything between if_existing
+and the matching $endif. The optional second paramater
+checks for FILE containing the specified string and
+prints everything between $if_existing and the matching
+$endif.
+
+.TP 
+\fB\*(T<\fBif_gw\fR\*(T>\fR 
+if there is at least one default gateway, display
+everything between $if_gw and the matching $endif
+
+.TP 
+\fB\*(T<\fBif_match\fR\*(T>\fR \*(T<\fBexpression\fR\*(T> 
+Evaluates the given boolean expression, printing
+everything between $if_match and the matching $endif
+depending on whether the evaluation returns true or not.
+Valid expressions consist of a left side, an operator
+and a right side. Left and right sides are being parsed
+for contained text objects before evaluation. Recognised
+left and right side types are:
+
+\fBdouble\fR:
+argument consists of only digits and a
+single dot.
+.br
+\fBlong\fR:
+argument consists of only digits.
+.br
+\fBstring\fR:
+argument is enclosed in quotation mark
+or the checks for double and long failed
+before.
+
+Valid operands are:
+\&'>', '<', '>=', '<=', '==', '!='.
+
+.TP 
+\fB\*(T<\fBif_running\fR\*(T>\fR \*(T<\fB(process)\fR\*(T> 
+if PROCESS is running, display everything $if_running
+and the matching $endif
 
 .TP 
 \fB\*(T<\fBif_mounted\fR\*(T>\fR \*(T<\fB(mountpoint)\fR\*(T> 
-if MOUNTPOINT is mounted, display everything between $if_mounted and the matching $endif
+if MOUNTPOINT is mounted, display everything between
+$if_mounted and the matching $endif
 
 .TP 
 \fB\*(T<\fBif_smapi_bat_installed\fR\*(T>\fR \*(T<\fB(INDEX)\fR\*(T> 
-when using smapi, if the battery with index INDEX is installed, display everything between $if_smapi_bat_installed and the matching $endif
+when using smapi, if the battery with index INDEX is
+installed, display everything between
+$if_smapi_bat_installed and the matching $endif
 
 .TP 
 \fB\*(T<\fBif_up\fR\*(T>\fR \*(T<\fB(interface)\fR\*(T> 

doc/variables.xml

@@ -231,7 +231,7 @@
 			Title of current tune with optional maximum length specifier
 			<para></para></listitem>
 	</varlistentry>
-	
+
 	<varlistentry>
 		<term>
 			<command><option>audacious_main_volume</option></command>
@@ -1000,26 +1000,8 @@
 			<option>(var)</option>
 		</term>
 		<listitem>
-			if conky variable VAR is empty, display everything between $if_empty and the matching $endif
+			if conky variable VAR is empty, display everything
-			<para></para></listitem>
+			between $if_empty and the matching $endif
-	</varlistentry>
-
-	<varlistentry>
-		<term>
-			<command><option>if_gw</option></command>
-		</term>
-		<listitem>
-			if there is at least one default gateway, display everything between $if_gw and the matching $endif
-			<para></para></listitem>
-	</varlistentry>
-
-	<varlistentry>
-		<term>
-			<command><option>if_running</option></command>
-			<option>(process)</option>
-		</term>
-		<listitem>
-			if PROCESS is running, display everything $if_running and the matching $endif
 			<para></para></listitem>
 	</varlistentry>
 
@@ -1029,7 +1011,64 @@
 			<option>file (string)</option>
 		</term>
 		<listitem>
-			if FILE exists, display everything between if_existing and the matching $endif.  The optional second paramater checks for FILE containing the specified string and prints everything between $if_existing and the matching $endif.
+			if FILE exists, display everything between if_existing
+			and the matching $endif.  The optional second paramater
+			checks for FILE containing the specified string and
+			prints everything between $if_existing and the matching
+			$endif.
+			<para></para></listitem>
+	</varlistentry>
+
+	<varlistentry>
+		<term>
+			<command><option>if_gw</option></command>
+		</term>
+		<listitem>
+			if there is at least one default gateway, display
+			everything between $if_gw and the matching $endif
+			<para></para></listitem>
+	</varlistentry>
+
+	<varlistentry>
+		<term>
+			<command><option>if_match</option></command>
+			<option>expression</option>
+		</term>
+		<listitem>
+			Evaluates the given boolean expression, printing
+			everything between $if_match and the matching $endif
+			depending on whether the evaluation returns true or not.
+			Valid expressions consist of a left side, an operator
+			and a right side. Left and right sides are being parsed
+			for contained text objects before evaluation. Recognised
+			left and right side types are:
+			<simplelist>
+				<member><command>double</command>:
+					argument consists of only digits and a
+					single dot.
+				</member>
+				<member><command>long</command>:
+					argument consists of only digits.
+				</member>
+				<member><command>string</command>:
+					argument is enclosed in quotation mark
+					or the checks for double and long failed
+					before.
+				</member>
+			</simplelist>
+			Valid operands are:
+			'&gt;', '&lt;', '&gt;=', '&lt;=', '==', '!='.
+			<para></para></listitem>
+	</varlistentry>
+
+	<varlistentry>
+		<term>
+			<command><option>if_running</option></command>
+			<option>(process)</option>
+		</term>
+		<listitem>
+			if PROCESS is running, display everything $if_running
+			and the matching $endif
 			<para></para></listitem>
 	</varlistentry>
 
@@ -1039,7 +1078,8 @@
 			<option>(mountpoint)</option>
 		</term>
 		<listitem>
-			if MOUNTPOINT is mounted, display everything between $if_mounted and the matching $endif
+			if MOUNTPOINT is mounted, display everything between
+			$if_mounted and the matching $endif
 			<para></para></listitem>
 	</varlistentry>
 
@@ -1049,7 +1089,9 @@
 			<option>(INDEX)</option>
 		</term>
 		<listitem>
-			when using smapi, if the battery with index INDEX is installed, display everything between $if_smapi_bat_installed and the matching $endif
+			when using smapi, if the battery with index INDEX is
+			installed, display everything between
+			$if_smapi_bat_installed and the matching $endif
 			<para></para></listitem>
 	</varlistentry>
 

src/Makefile.am

@@ -145,7 +145,9 @@ conky_SOURCES = 		\
 	temphelper.c            \
 	temphelper.h            \
 	text_object.h           \
-	text_object.c
+	text_object.c           \
+	algebra.h               \
+	algebra.c
 
 conky_LDFLAGS = 				\
 	$(PTHREAD_LIBS)				\

src/algebra.c

@@ -0,0 +1,239 @@
+/* Conky, a system monitor, based on torsmo
+ *
+ * Any original torsmo code is licensed under the BSD license
+ *
+ * All code written since the fork of torsmo is licensed under the GPL
+ *
+ * Please see COPYING for details
+ *
+ * Copyright (c) 2004, Hannu Saransaari and Lauri Hakkarainen
+ * Copyright (c) 2005-2008 Brenden Matthews, Philip Kovacs, et. al.
+ *	(see AUTHORS)
+ * All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#define _GNU_SOURCE
+#include "config.h"
+#include "algebra.h"
+#include "logging.h"
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* find the operand in the given expression
+ * returns the index of the first op character or -1 on error
+ */
+int find_match_op(const char *expr)
+{
+	unsigned int idx;
+
+	for (idx = 0; idx < strlen(expr); idx++) {
+		switch (expr[idx]) {
+			case '=':
+			case '!':
+				if (expr[idx + 1] != '=')
+					return -1;
+				/* fall through */
+			case '<':
+			case '>':
+				return idx;
+				break;
+		}
+	}
+	return -1;
+}
+
+int get_match_type(const char *expr)
+{
+	int idx;
+	const char *str;
+
+	if ((idx = find_match_op(expr)) == -1)
+		return -1;
+	str = expr + idx;
+
+	if (*str == '=' && *(str + 1) == '=')
+		return OP_EQ;
+	else if (*str == '!' && *(str + 1) == '=')
+		return OP_NEQ;
+	else if (*str == '>') {
+		if (*(str + 1) == '=')
+			return OP_GEQ;
+		return OP_GT;
+	} else if (*str == '<') {
+		if (*(str + 1) == '=')
+			return OP_LEQ;
+		return OP_LT;
+	}
+	return -1;
+}
+
+
+
+/* generic compare function
+ *
+ * v is actually the difference of the compared values. For strings
+ * this is equal to the output of str(n)cmp(). Use a macro here, as
+ * it's type-independent.
+ */
+#define COMPARE(v, t) \
+	switch (t) { \
+		case OP_GT:  return (v > 0); \
+		case OP_LT:  return (v < 0); \
+		case OP_EQ:  return (v == 0); \
+		case OP_GEQ: return (v >= 0); \
+		case OP_LEQ: return (v <= 0); \
+		case OP_NEQ: return (v != 0); \
+	} \
+	return 0
+
+int lcompare(long a, enum match_type mtype, long b)
+{
+	DBGP2("comparing longs '%ld' and '%ld'", a, b);
+	COMPARE((a - b), mtype);
+}
+int dcompare(double a, enum match_type mtype, double b)
+{
+	DBGP2("comparing doubles '%.lf' and '%.lf'", a, b);
+	COMPARE((a - b), mtype);
+}
+
+int scompare(const char *a, enum match_type mtype, const char *b)
+{
+	DBGP2("comparing strings '%s' and '%s'", a, b);
+	COMPARE(strcmp(a, b), mtype);
+}
+
+enum arg_type get_arg_type(const char *arg)
+{
+	const char *p, *e;
+
+	p = arg;
+	e = arg + strlen(arg);
+
+	if (*(e - 1) == ' ')
+		e--;
+	while (*e && *e == ' ')
+		e--;
+	while (p != e && *p == ' ')
+		p++;
+
+	if (*p == '"' && *e == '"')
+		return ARG_STRING;
+
+	while (p != e) {
+		if (!isdigit(*p))
+			break;
+		p++;
+	}
+	if (p == e)
+		return ARG_LONG;
+	if (*p == '.') {
+		p++;
+		while (p != e) {
+			if (!isdigit(*p))
+				return ARG_STRING;
+			p++;
+		}
+		return ARG_DOUBLE;
+	}
+	return ARG_STRING;
+}
+
+char *arg_to_string(const char *arg)
+{
+	const char *start;
+	int len;
+
+	start = arg;
+	len = 0;
+	while (*start && *start == ' ')
+			start++;
+	if (!(*(start++) == '"'))
+		return NULL;
+	while (start[len] != '"')
+		len++;
+	return strndup(start, len);
+}
+double arg_to_double(const char *arg)
+{
+	double d;
+	if (sscanf(arg, "%lf", &d) != 1) {
+		ERR("converting '%s' to double failed", arg);
+		return 0.0;
+	}
+	return d;
+}
+long arg_to_long(const char *arg)
+{
+	long l;
+	if (sscanf(arg, "%ld", &l) != 1) {
+		ERR("converting '%s' to long failed", arg);
+		return 0;
+	}
+	return l;
+}
+int compare(const char *expr)
+{
+	char *expr_dup;
+	int idx, mtype;
+	enum arg_type type1, type2;
+
+	idx = find_match_op(expr);
+	mtype = get_match_type(expr);
+
+	if (!idx || mtype == -1) {
+		ERR("failed to parse compare string '%s'", expr);
+		return -2;
+	}
+
+	expr_dup = strdup(expr);
+	expr_dup[idx] = '\0';
+	if (expr_dup[idx + 1] == '=')
+		expr_dup[++idx] = '\0';
+
+	type1 = get_arg_type(expr_dup);
+	type2 = get_arg_type(expr_dup + idx + 1);
+	if (type1 == ARG_LONG && type2 == ARG_DOUBLE)
+		type1 = ARG_DOUBLE;
+	if (type1 == ARG_DOUBLE && type2 == ARG_LONG)
+		type2 = ARG_DOUBLE;
+	if (type1 != type2) {
+		ERR("trying to compare args '%s' and '%s' of different type",
+				expr_dup, (expr_dup + idx + 1));
+		return -2;
+	}
+	switch (type1) {
+		case ARG_STRING:
+			{
+				char *a, *b;
+				a = arg_to_string(expr_dup);
+				b = arg_to_string(expr_dup + idx + 1);
+				idx = scompare(a, mtype, b);
+				free(a);
+				free(b);
+				return idx;
+			}
+		case ARG_LONG:
+			return lcompare(arg_to_long(expr_dup), mtype,
+					arg_to_long(expr_dup + idx + 1));
+		case ARG_DOUBLE:
+			return dcompare(arg_to_double(expr_dup), mtype,
+					arg_to_double(expr_dup + idx + 1));
+	}
+	/* not reached */
+	return -2;
+}

src/algebra.h

@@ -0,0 +1,47 @@
+/* Conky, a system monitor, based on torsmo
+ *
+ * Any original torsmo code is licensed under the BSD license
+ *
+ * All code written since the fork of torsmo is licensed under the GPL
+ *
+ * Please see COPYING for details
+ *
+ * Copyright (c) 2004, Hannu Saransaari and Lauri Hakkarainen
+ * Copyright (c) 2005-2008 Brenden Matthews, Philip Kovacs, et. al.
+ *	(see AUTHORS)
+ * All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#ifndef _ALGEBRA_H
+#define _ALGEBRA_H
+
+enum match_type {
+	OP_LT = 1,	/* < */
+	OP_GT = 2,	/* > */
+	OP_EQ = 3,	/* == */
+	OP_LEQ = 4,	/* <= */
+	OP_GEQ = 5,	/* >= */
+	OP_NEQ = 6,	/* != */
+};
+
+enum arg_type {
+	ARG_STRING = 1, /* "asdf" */
+	ARG_LONG = 2,	/* 123456 */
+	ARG_DOUBLE = 3, /* 12.456 */
+};
+
+int compare(const char *);
+
+#endif /* _ALGEBRA_H */

src/conky.c

@@ -59,6 +59,7 @@
 #include <getopt.h>
 
 /* local headers */
+#include "algebra.h"
 #include "build.h"
 #include "diskio.h"
 #include "fs.h"
@@ -1267,6 +1268,7 @@ static void free_text_objects(struct text_object *root)
 				}
 				break;
 			case OBJ_if_empty:
+			case OBJ_if_match:
 			case OBJ_if_existing:
 			case OBJ_if_mounted:
 			case OBJ_if_running:
@@ -2517,6 +2519,14 @@ static struct text_object *construct_text_object(const char *s,
 			obj->data.ifblock.s = strndup(arg, text_buffer_size);
 		}
 		obj_be_ifblock_if(obj);
+	END OBJ(if_match, 0)
+		if (!arg) {
+			ERR("if_match needs arguments");
+			obj->data.ifblock.s = 0;
+		} else {
+			obj->data.ifblock.s = strndup(arg, text_buffer_size);
+		}
+		obj_be_ifblock_if(obj);
 	END OBJ(if_existing, 0)
 		if (!arg) {
 			ERR("if_existing needs an argument or two");
@@ -4572,6 +4582,28 @@ static void generate_text_internal(char *p, int p_max_size,
 				free_text_objects(&subroot);
 				free(tmp_info);
 			}
+			OBJ(if_match) {
+				char expression[max_user_text];
+				int val;
+				struct text_object subroot;
+				struct information *tmp_info;
+
+				tmp_info = malloc(sizeof(struct information));
+				memcpy(tmp_info, cur, sizeof(struct information));
+				parse_conky_vars(&subroot, obj->data.ifblock.s,
+						expression, tmp_info);
+				DBGP("parsed arg into '%s'", expression);
+
+				val = compare(expression);
+				if (val == -2) {
+					ERR("compare failed for expression '%s'",
+							expression);
+				} else if (!val) {
+					DO_JUMP;
+				}
+				free_text_objects(&subroot);
+				free(tmp_info);
+			}
 			OBJ(if_existing) {
 				if (obj->data.ifblock.str
 				    && !check_contains(obj->data.ifblock.s,

src/text_object.h

@@ -154,6 +154,7 @@ enum text_object_type {
 	OBJ_wireless_link_bar,
 #endif /* __linux__ */
 	OBJ_if_empty,
+	OBJ_if_match,
 	OBJ_if_existing,
 	OBJ_if_mounted,
 	OBJ_if_running,