string: add nstrtrim

include/neo/_nstr.h

@@ -207,6 +207,36 @@ nstr_t *nstrcat(const nstr_t *s1, const nstr_t *s2, error *err);
  */
 nstr_t *nstrcat_put(nstr_t *s1, nstr_t *s2, error *err);
 
+/**
+ * @brief Remove whitespace from the beginning and end of a string.
+ *
+ * Whether a character is whitespace is deteermined by the `isspace()` function
+ * from POSIX.  In the default C locale, this includes:
+ *
+ * - space (ASCII `0x20`)
+ * - form feed (`'\f'`, ASCII `0x0c`)
+ * - line feed (`'\n'`, ASCII `0x0a`)
+ * - carriage return (`'\r'`, ASCII `0x0d`)
+ * - horizontal tab (`'\t'`, ASCII `0x09`)
+ * - vertical tab (`'\v'`, ASCII `0x0b`)
+ *
+ * @param s String to trim
+ * @param err Error pointer
+ * @returns A new string instance with outer whitespace removed,
+ *	unless an error occurred
+ */
+nstr_t *nstrtrim(const nstr_t *s, error *err);
+
+/**
+ * @brief The same as `nstrtrim()`, but `nput()` is called on `s` afterwards.
+ *
+ * @param s String to trim
+ * @param err Error pointer
+ * @returns A new string instance with outer whitespace removed,
+ *	unless an error occurred
+ */
+nstr_t *nstrtrim_put(nstr_t *s, error *err);
+
 /**
  * @brief Compare two strings character by character.
  *

src/string/nstrtrim.c

@@ -0,0 +1,57 @@
+/* See the end of this file for copyright and license terms. */
+
+#include <ctype.h>
+#include <errno.h>
+#include <string.h>
+
+#include "neo/_error.h"
+#include "neo/_nalloc.h"
+#include "neo/_nref.h"
+#include "neo/_nstr.h"
+#include "neo/_stddef.h"
+#include "neo/_types.h"
+
+nstr_t *nstrtrim(const nstr_t *s, error *err)
+{
+	if (s == nil) {
+		yeet(err, EFAULT, "String is nil");
+		return nil;
+	}
+
+	const char *start = s->_data;
+	const char *end = start + s->_size - 5; /* 4 NUL terminators */
+
+	while (isspace(*start++));
+		/* nothing */
+	start--;
+
+	while (isspace(*end) && end > start)
+		end--;
+	end++;
+
+	return nnstr(start, end - start, err);
+}
+
+nstr_t *nstrtrim_put(nstr_t *s, error *err)
+{
+	nstr_t *ret = nstrtrim(s, err);
+	catch(err) {
+		return nil;
+	}
+
+	nput(s);
+	return ret;
+}
+
+/*
+ * This file is part of libneo.
+ * Copyright (c) 2021 Fefie <owo@fef.moe>.
+ *
+ * libneo is non-violent software: you may only use, redistribute,
+ * and/or modify it under the terms of the CNPLv6+ as found in
+ * the LICENSE file in the source code root directory or at
+ * <https://git.pixie.town/thufie/CNPL>.
+ *
+ * libneo comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPLv6+ for details.
+ */

src/string/string.cmake

@@ -4,6 +4,7 @@ target_sources(neo PRIVATE
     ./string/nstrcmp.c
     ./string/nstrdup.c
     ./string/nstrmul.c
+    ./string/nstrtrim.c
     ./string/leftpad.c
     ./string/utf.c
     ./string/x2nstr.c

src/string/utf.c

@@ -17,7 +17,7 @@
 usize utf8_check(const char *restrict s, error *err)
 {
 	usize ret = 0;
-	nchar c;
+	nchar c = 0xffffffff; /* not a valid Unicode character */
 
 	while (*s != '\0') {
 		ret++;
@@ -27,13 +27,16 @@ usize utf8_check(const char *restrict s, error *err)
 		}
 	}
 
+	if (c == 0xffffffff) /* loop hasn't executed at all */
+		neat(err);
+
 	return ret;
 }
 
 usize utf8_ncheck(const char *restrict s, usize maxsize, error *err)
 {
 	usize ret = 0;
-	nchar c;
+	nchar c = 0xffffffff; /* not a valid Unicode character */
 
 	while (*s != '\0' && maxsize != 0) {
 		ret++;
@@ -45,6 +48,9 @@ usize utf8_ncheck(const char *restrict s, usize maxsize, error *err)
 		}
 	}
 
+	if (c == 0xffffffff) /* loop hasn't executed at all */
+		neat(err);
+
 	return ret;
 }
 

test/string/nstrtrim.cpp

@@ -0,0 +1,157 @@
+/* See the end of this file for copyright and license terms. */
+
+#include <catch2/catch.hpp>
+#include <errno.h>
+
+#include <neo.h>
+
+TEST_CASE( "nstrtrim: Trim leading whitespace", "[string/nstrtrim.c]" )
+{
+	error err;
+	nstr_t *s = nstr(" \v\v aaaaa", nil);
+
+	nstr_t *expected = nstr("aaaaa", nil);
+	nstr_t *actual = nstrtrim(s, &err);
+
+	REQUIRE( actual != nil );
+	REQUIRE( nlen(actual) == 5 );
+	REQUIRE( nstreq(expected, actual, nil) );
+	REQUIRE( errnum(&err) == 0 );
+
+	nput(s);
+	nput(expected);
+	nput(actual);
+}
+
+TEST_CASE( "nstrtrim: Trim trailing whitespace", "[string/nstrtrim.c]" )
+{
+	error err;
+	nstr_t *s = nstr("aaaaa \t \r\n \f \n", nil);
+
+	nstr_t *expected = nstr("aaaaa", nil);
+	nstr_t *actual = nstrtrim(s, &err);
+
+	REQUIRE( actual != nil );
+	REQUIRE( nlen(actual) == 5 );
+	REQUIRE( nstreq(expected, actual, nil) );
+	REQUIRE( errnum(&err) == 0 );
+
+	nput(s);
+	nput(expected);
+	nput(actual);
+}
+
+TEST_CASE( "nstrtrim: Trim both leading and trailing whitespace", "[string/nstrtrim.c]" )
+{
+	error err;
+	nstr_t *s = nstr(" \v\v aaaaa \t \r\n \f \n", nil);
+
+	nstr_t *expected = nstr("aaaaa", nil);
+	nstr_t *actual = nstrtrim(s, &err);
+
+	REQUIRE( actual != nil );
+	REQUIRE( nlen(actual) == 5 );
+	REQUIRE( nstreq(expected, actual, nil) );
+	REQUIRE( errnum(&err) == 0 );
+
+	nput(s);
+	nput(expected);
+	nput(actual);
+}
+
+TEST_CASE( "nstrtrim: Don't modify empty string", "[string/nstrtrim.c]" )
+{
+	error err;
+	nstr_t *s = nstr("", nil);
+
+	nstr_t *expected = nstr("", nil);
+	nstr_t *actual = nstrtrim(s, &err);
+
+	REQUIRE( actual != nil );
+	REQUIRE( nlen(actual) == 0 );
+	REQUIRE( nstreq(expected, actual, nil) );
+	REQUIRE( errnum(&err) == 0 );
+
+	nput(s);
+	nput(expected);
+	nput(actual);
+}
+
+TEST_CASE( "nstrtrim: Empty string if input is whitespace only", "[string/nstrtrim.c]" )
+{
+	error err;
+	nstr_t *s = nstr(" ", nil);
+
+	nstr_t *expected = nstr("", nil);
+	nstr_t *actual = nstrtrim(s, &err);
+
+	REQUIRE( actual != nil );
+	REQUIRE( nlen(actual) == 0 );
+	REQUIRE( nstreq(expected, actual, nil) );
+	REQUIRE( errnum(&err) == 0 );
+
+	nput(s);
+	nput(expected);
+	nput(actual);
+}
+
+TEST_CASE( "nstrtrim: Error if string is nil", "[string/nstrtim.c]" )
+{
+	error err;
+	nstr_t *tr = nstrtrim(nil, &err);
+
+	nstr_t *expected_msg = nstr("String is nil", nil);
+
+	REQUIRE( tr == nil );
+	REQUIRE( errnum(&err) == EFAULT );
+	REQUIRE( nstreq(expected_msg, errmsg(&err), nil) );
+
+	errput(&err);
+}
+
+TEST_CASE( "nstrtrim_put: Decrement refcount", "[string/nstrtrim.c]" )
+{
+	error err;
+	nstr_t *s = nstr(" aaaaa ", nil);
+
+	nstr_t *expected = nstr("aaaaa", nil);
+
+	nget(s);
+	nstr_t *actual = nstrtrim_put(s, &err);
+
+	REQUIRE( nref_count(s) == 1 );
+	REQUIRE( actual != nil );
+	REQUIRE( nstreq(expected, actual, nil) );
+	REQUIRE( errnum(&err) == 0 );
+
+	nput(s);
+	nput(expected);
+	nput(actual);
+}
+
+TEST_CASE( "nstrtrim_put: Error if string is nil", "[string/nstrtim.c]" )
+{
+	error err;
+	nstr_t *tr = nstrtrim_put(nil, &err);
+
+	nstr_t *expected_msg = nstr("String is nil", nil);
+
+	REQUIRE( tr == nil );
+	REQUIRE( errnum(&err) == EFAULT );
+	REQUIRE( nstreq(expected_msg, errmsg(&err), nil) );
+
+	errput(&err);
+}
+
+/*
+ * This file is part of libneo.
+ * Copyright (c) 2021 Fefie <owo@fef.moe>.
+ *
+ * libneo is non-violent software: you may only use, redistribute,
+ * and/or modify it under the terms of the CNPLv6+ as found in
+ * the LICENSE file in the source code root directory or at
+ * <https://git.pixie.town/thufie/CNPL>.
+ *
+ * libneo comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPLv6+ for details.
+ */

test/string/string.cmake

@@ -10,6 +10,7 @@ target_sources(neo_test PRIVATE
     string/nstrcmp.cpp
     string/nstrdup.cpp
     string/nstrmul.cpp
+    string/nstrtrim.cpp
     string/u2nstr.cpp
 )