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Oct 3, 2026
Merged

Add pop_back_while, remove_suffix_until, and trimming enhancement… #581

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148 changes: 144 additions & 4 deletions include/daw/daw_string_view.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1379,6 +1379,45 @@ namespace daw {
return result;
}

/// @brief Searches backwards for the first non-match of where, returns
/// the matching suffix, then removes it from the string_view
/// @param where The character to extract
/// @return substring after the last non-matching character
[[nodiscard]] constexpr basic_string_view pop_back_while( CharT where ) {
auto const pos = find_last_not_of( where );
auto const count =
pos == npos ? size( ) : static_cast<size_type>( size( ) - pos - 1U );
return pop_back( count );
}

/// @brief Searches backwards for the first character not in where,
/// returns the matching suffix, then removes it from the string_view
/// @param where The characters to extract
/// @return substring after the last non-matching character
[[nodiscard]] constexpr basic_string_view
pop_back_while( basic_string_view where ) {
auto const pos = find_last_not_of( where );
auto const count =
pos == npos ? size( ) : static_cast<size_type>( size( ) - pos - 1U );
return pop_back( count );
}

/// @brief Searches backwards until pred is false, returns the matching
/// suffix, then removes it from the string_view
/// @tparam UnaryPredicate A predicate taking a single CharT
/// @param pred Predicate identifying characters to extract
/// @return substring after the last character where pred is false
template<typename UnaryPredicate DAW_REQ_UNARY_PRED( UnaryPredicate,
CharT )>
DAW_REQ_UNARY_PRED_REQ( UnaryPredicate, CharT )
[[nodiscard]] constexpr basic_string_view
pop_back_while( UnaryPredicate pred ) {
auto const pos = find_last_not_of_if( std::move( pred ) );
auto const count =
pos == npos ? size( ) : static_cast<size_type>( size( ) - pos - 1U );
return pop_back( count );
}

/// @brief searches for last where, returns substring between
/// where and end, then pops off the substring
/// @param where string to split on and remove from back
Expand Down Expand Up @@ -1798,6 +1837,80 @@ namespace daw {
return *this;
}

/// @brief Searches backwards for where and removes it and everything
/// after it
/// @param where Character to find and consume
/// @return A reference to the current string_view object
DAW_ATTRIB_INLINE constexpr basic_string_view &
remove_suffix_until( CharT where ) {
auto const pos = rfind( where );
resize( pos == npos ? 0U : pos );
return *this;
}

/// @brief Searches backwards for where and removes everything after it
/// @param where Character to find and retain
/// @return A reference to the current string_view object
DAW_ATTRIB_INLINE constexpr basic_string_view &
remove_suffix_until( CharT where, nodiscard_t ) {
auto const pos = rfind( where );
resize( pos == npos ? 0U : pos + 1U );
return *this;
}

/// @brief Searches backwards for where and removes it and everything
/// after it
/// @param where String to find and consume
/// @return A reference to the current string_view object
DAW_ATTRIB_INLINE constexpr basic_string_view &
remove_suffix_until( basic_string_view where ) {
auto const pos = rfind( where );
resize( pos == npos ? 0U : pos );
return *this;
}

/// @brief Searches backwards for where and removes everything after it
/// @param where String to find and retain
/// @return A reference to the current string_view object
DAW_ATTRIB_INLINE constexpr basic_string_view &
remove_suffix_until( basic_string_view where, nodiscard_t ) {
auto const pos = rfind( where );
resize( pos == npos ? 0U : pos + where.size( ) );
return *this;
}

/// @brief Removes the suffix starting at the last position where pred is
/// true
/// @tparam UnaryPredicate A predicate taking a single CharT
/// @param pred Predicate identifying where to stop
/// @return A reference to the current string_view object
template<typename UnaryPredicate DAW_REQ_UNARY_PRED( UnaryPredicate,
CharT )>
DAW_REQ_UNARY_PRED_REQ( UnaryPredicate, CharT )
DAW_ATTRIB_INLINE constexpr basic_string_view &remove_suffix_until(
UnaryPredicate pred ) {
auto const pos = find_last_of_if( pred );
resize( pos == npos ? 0U : pos );
return *this;
}

/// @brief Removes the suffix after the last position where pred is true
/// @tparam UnaryPredicate A predicate taking a single CharT
/// @param pred Predicate identifying where to stop
/// @return A reference to the current string_view object
template<typename UnaryPredicate DAW_REQ_UNARY_PRED( UnaryPredicate,
CharT )>
DAW_REQ_UNARY_PRED_REQ( UnaryPredicate, CharT )
DAW_ATTRIB_INLINE
constexpr basic_string_view &remove_suffix_until( UnaryPredicate pred,
nodiscard_t ) {
auto const pos = find_last_of_if( pred );
resize( pos == npos
? 0U
: pos + sv2_details::find_predicate_result_size( pred ) );
return *this;
}

/// @brief Set the size of the range
/// @param new_size New size of range
/// @pre size( ) >= new_size
Expand Down Expand Up @@ -2532,13 +2645,12 @@ namespace daw {
return find_first_not_of( basic_string_view<CharT>( s, N - 1 ), 0 );
}

[[nodiscard]] constexpr bool
all_of( basic_string_view v, size_type pos = 0 ) const {
[[nodiscard]] constexpr bool all_of( basic_string_view v,
size_type pos = 0 ) const {
return find_first_not_of( v, pos ) == npos;
}

[[nodiscard]] constexpr bool all_of( CharT c,
size_type pos = 0 ) const {
[[nodiscard]] constexpr bool all_of( CharT c, size_type pos = 0 ) const {
return find_first_not_of( c, pos ) == npos;
}

Expand Down Expand Up @@ -2858,6 +2970,13 @@ namespace daw {
return *this;
}

DAW_ATTRIB_INLINE constexpr basic_string_view &
remove_prefix_while( basic_string_view characters ) noexcept {
auto const pos = find_first_not_of( characters );
remove_prefix( pos );
return *this;
}

constexpr basic_string_view &trim_prefix( ) noexcept {
remove_prefix_while( is_space{ } );
return *this;
Expand Down Expand Up @@ -2886,6 +3005,13 @@ namespace daw {
return *this;
}

DAW_ATTRIB_INLINE constexpr basic_string_view &
remove_suffix_while( basic_string_view characters ) noexcept {
auto const pos = find_last_not_of( characters );
resize( pos + 1U );
return *this;
}

constexpr basic_string_view &trim_suffix( ) noexcept {
remove_suffix_while( is_space{ } );
return *this;
Expand All @@ -2909,6 +3035,20 @@ namespace daw {
return result;
}

constexpr basic_string_view &
trim( basic_string_view while_this ) noexcept {
(void)remove_prefix_while( while_this );
(void)remove_suffix_while( while_this );
return *this;
}

[[nodiscard]] constexpr basic_string_view
trim_copy( basic_string_view while_this ) const noexcept {
auto result = *this;
result.trim( while_this );
return result;
}

/// @brief Decrement the data( ) pointer by 1.
/// @pre data( ) != null and data( ) - 1 is a valid object
constexpr void expand_prefix( ) noexcept {
Expand Down
126 changes: 126 additions & 0 deletions tests/daw_string_view2_test.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1368,6 +1368,36 @@ namespace daw {
daw_expecting( result, " "_sv );
}

void daw_pop_back_while_sv_test_001( ) {
daw::sv2::string_view sv = "This is a test ";
auto result = sv.pop_back_while( ' ' );
daw_expecting( sv, "This is a test"_sv );
daw_expecting( result, " "_sv );
}

void daw_pop_back_while_sv_test_002( ) {
daw::sv2::string_view sv = "This is a test \t\n";
auto result = sv.pop_back_while( " \t\n" );
daw_expecting( sv, "This is a test"_sv );
daw_expecting( result, " \t\n"_sv );
}

void daw_pop_back_while_pred_test_001( ) {
daw::sv2::string_view sv = "test123";
auto result = sv.pop_back_while( []( char c ) {
return c >= '0' and c <= '9';
} );
daw_expecting( sv, "test"_sv );
daw_expecting( result, "123"_sv );

daw::sv2::string_view all = "123";
daw_expecting( all.pop_back_while( []( char c ) {
return c >= '0' and c <= '9';
} ),
"123"_sv );
daw_expecting( all.empty( ), true );
}

void daw_pop_front_test_001( ) {
daw::sv2::string_view sv = "This is a test";
auto result = sv.pop_front( );
Expand Down Expand Up @@ -1716,6 +1746,50 @@ namespace daw {
daw_expecting( sz, 5 );
}

void daw_remove_suffix_until_test_001( ) {
daw::sv2::string_view sv = "0123456789";
sv.remove_suffix_until( '5' );
daw_expecting( sv, "01234"_sv );
}

void daw_remove_suffix_until_test_002( ) {
daw::sv2::string_view sv = "0123456789";
sv.remove_suffix_until( '5', daw::nodiscard );
daw_expecting( sv, "012345"_sv );
}

void daw_remove_suffix_until_test_003( ) {
daw::sv2::string_view sv = "left::middle::right";
sv.remove_suffix_until( "::" );
daw_expecting( sv, "left::middle"_sv );

daw::sv2::string_view retained = "left::middle::right";
retained.remove_suffix_until( "::", daw::nodiscard );
daw_expecting( retained, "left::middle::"_sv );
}

void daw_remove_suffix_until_test_004( ) {
daw::sv2::string_view sv = "abc1def2ghi";
sv.remove_suffix_until( []( char c ) {
return c >= '0' and c <= '9';
} );
daw_expecting( sv, "abc1def"_sv );

daw::sv2::string_view retained = "abc1def2ghi";
retained.remove_suffix_until(
[]( char c ) {
return c >= '0' and c <= '9';
},
daw::nodiscard );
daw_expecting( retained, "abc1def2"_sv );
}

void daw_remove_suffix_until_test_005( ) {
daw::sv2::string_view sv = "test";
sv.remove_suffix_until( 'x' );
daw_expecting( sv.empty( ), true );
}

struct FooSV {
using iterator = char const *;
using size_type = std::size_t;
Expand Down Expand Up @@ -1835,6 +1909,47 @@ namespace daw {
daw_expecting( sv2, "Hello" );
}

void daw_trim_characters( ) {
daw::sv2::string_view sv = " \t,;Hello, world;\n ";
auto const *const original_data = sv.data( );
auto &result = sv.trim( " \t\n,;" );
daw_expecting( std::addressof( result ), std::addressof( sv ) );
daw_expecting( sv, "Hello, world" );
daw_expecting( sv.data( ), original_data + 4 );
}

void daw_trim_characters_copy( ) {
daw::sv2::string_view sv = "...Hello!?";
auto const result = sv.trim_copy( ".!?" );
daw_expecting( result, "Hello" );
daw_expecting( sv, "...Hello!?" );
}

void daw_trim_characters_edge_cases( ) {
daw::sv2::string_view no_matches = "Hello";
no_matches.trim( ".!?" );
daw_expecting( no_matches, "Hello" );

daw::sv2::string_view all_matches = ".!?..!";
all_matches.trim( ".!?" );
daw_expecting( all_matches.empty( ), true );

daw::sv2::string_view empty_set = "Hello";
empty_set.trim( "" );
daw_expecting( empty_set, "Hello" );

daw::sv2::string_view empty = "";
empty.trim( ".!?" );
daw_expecting( empty.empty( ), true );
}

constexpr bool daw_trim_characters_constexpr( ) {
daw::sv2::string_view sv = "--value++";
return sv.trim_copy( "+-" ) == "value" and
sv.trim( "+-" ) == "value";
}
static_assert( daw_trim_characters_constexpr( ) );

namespace daw_array_ctad_impl {
template<typename S>
constexpr auto foo( S &&s ) {
Expand Down Expand Up @@ -2172,6 +2287,9 @@ int main( )
daw::daw_pop_front_until_sv_test_001( );
daw::daw_pop_front_while_sv_test_001( );
daw::daw_pop_front_while_sv_test_002( );
daw::daw_pop_back_while_sv_test_001( );
daw::daw_pop_back_while_sv_test_002( );
daw::daw_pop_back_while_pred_test_001( );
daw::daw_pop_back_count_test_001( );
daw::daw_pop_back_until_sv_test_001( );
daw::daw_pop_back_until_sv_test_002( );
Expand Down Expand Up @@ -2201,6 +2319,11 @@ int main( )
daw::daw_remove_prefix_until_test_004( );
daw::daw_remove_suffix_while_test_001( );
daw::daw_remove_suffix_while_test_002( );
daw::daw_remove_suffix_until_test_001( );
daw::daw_remove_suffix_until_test_002( );
daw::daw_remove_suffix_until_test_003( );
daw::daw_remove_suffix_until_test_004( );
daw::daw_remove_suffix_until_test_005( );
daw::daw_arbutrary_string_view_list_001( );
daw::daw_trim_prefix_test_001( );
daw::daw_trim_prefix_test_002( );
Expand All @@ -2220,6 +2343,9 @@ int main( )
#endif
daw::daw_trim( );
daw::daw_trim_copy( );
daw::daw_trim_characters( );
daw::daw_trim_characters_copy( );
daw::daw_trim_characters_edge_cases( );
daw::daw_array_ctad( );
daw::daw_find_first_match( );
#if defined( DAW_HAS_CPP20_3WAY_COMPARE )
Expand Down
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