Development reference

Design, programming and version control.

Patterns

Major Objects Quick-http Continuous Integration Architecture of major open source apps Model View Controller String escape formatting across different languages and systems c++ to JSON: always use nlohmann::json j.dump() to encode, to ensure strings are properly escaped JSON to c++: always use nlohmann::json j.parse() " c++ to Javascript: use raw_to_Javascript() to properly escape c++ to sqlite: use SqliteLocalModel::safestr(), which uses double_doublequotes(str) Web design mantra DESIGN INPUT TO THE INPUT DEVICE respect the input device detect it and use a reasonable default guess allow manual override [mouse/pen]...[finger] sm-md-lg ... sm-md-lg DESIGN VISUALS TO THE SCREEN high-res = SHOW LOTS OF DETAIL responsive, zoomable git central shared repository Use bare repos for any central shared repositories. Use the [####.git] suffix on bare repo names. Bare repositories are designed to be shared. Maintenance on the central server is easier because you don't have local files to manage permissions or constant flux. Plus, you can always have a second repo on the central server where you check out a specific branch (e.g. to serve up with apache). If you want a dynamically updated central repo, clone the ###.git repo to ###, and add a post-receive hook (see bitpost quick-http.git for a good example). To configure the repo as shared: git config core.sharedRepository true To set it on a new git repo during initial setup, make sure devs are in the same group, and use: git init --shared=group Occam's razor Among competing hypotheses, the one with the fewest assumptions should be selected.

C++

Deleting multiple elements in a collection For sequences (vector, list...), best practice is to use the erase-remove STL pattern For associative containers (set, map...): just recurse and remove iterators, they won't muck up the sequence. example See MemoryModel::saveDirtyObjectsAsNeeded() for example code. c++ Create a portable C/C++ project Use QtCreator + CMake, both available everywhere! set up: create a Qt project as: New Project-> Non-Qt/Plain C Project (CMake Build) pick the PARENT and use the name of the existing folder set up a build folder in the existing folder, called (base)/qtcreator-release-build it creates CMakeLists.txt (THIS IS BASICALLY THE PROJECT FILE!) also creates main.c or something build it! make sure it works NOW we can edit CMakeLists.txt - change . to ./src to get it to scan the src folder for code! and easily add "known" libs! this was all i needed: TARGET_LINK_LIBRARIES(${PROJECT_NAME} pthread websockets) make sure it builds now we want a DEBUG build as well! Projects->Build&Run->pick Build in weird Build/Run pillbox->Edit build configs: Rename: release CMake build dir: Make sure build dir is set to release ie qtcreator-debug-build Add: Clone: release, name: debug for debug, add a custom build step BEFORE make step: command: /usr/bin/cmake args: -DCMAKE_BUILD_TYPE=Debug . working dir: %{buildDir} (add it, and move it up above make) (build em both) Projects->Build&Run->pick Run in weird Build/Run pillbox Run Configuration: rename to "{...} release" clone it into "{...} debug" change working dir to match Build path change any needed params Now you should have build+run debug+release configurations, selectable in the weird project icon in bottom of left-side toolbar ("mode selector") boost release and debug build for linux # download latest boost, eg: boost_1_59_0 m@wallee:~/development$ 7z x boost_1_59_0.7z cd boost_1_##_0 build_boost_release_and_debug.sh # then patch .bashrc as instructed # eclipse and server/nix/bootstrap.sh are customized to match To upgrade a project: cd nix make distclean # removes nasty .deps folders that link to old boost if you let them make clean # removes .o files etc cd ../build-Release && make distclean && make clean cd ../build-Debug && make distclean && make clean cd .. ./bootstrap force release ./bootstrap force debug boost release and debug build for Windows Open a VS2015 x64 Native Tools Command Prompt. EITHER: for new installs, you have to run bootstrap.bat first, it will build b2; OR: for reruns, remove boost dirs: [bin.v2, stage]. Then build 64-bit: cd "....\boost_1_59_0" b2 toolset=msvc variant=release,debug link=static address-model=64 rem trying to avoid excessive options, assuming I don't need these: threading=multi (old stuff) --toolset=msvc-14.0 address-model=64 --build-type=complete --stagedir=windows_lib\x64 stage Now open VS2013 x86 Native Tools Command Prompt and build 32-bit: cd "C:\Michael's Data\development\sixth_column\boost_1_55_0" bjam --toolset=msvc-12.0 address-model=32 --build-type=complete --stagedir=windows_lib\x86 stage c++11 include base constructor (etc) in derived class The awesome C++11 way to steal the constructor from the base class, oh man I've been waiting for this one... class HttpsServer : public Server<HTTPS> { // DOES THIS FOR YOU! /* HttpsServer(unsigned short port, size_t num_threads, const std::string& cert_file, const std::string& private_key_file)  : // Call base class Server<HTTPS>::Server(port, num_threads, cert_file, private_key_file) {} */ using Server<HTTPS>::Server; .... c++11 containers sorted_vector use when doing lots of unsorted insertions and maintaining constant sort would be expensive; vector is good for a big pile of things that only occasionally needs a sorted lookup map sorted binary search tree; always sorted by key; you can walk through in sorted order (choose unordered if not needed!) multimap same as map but allows dupe keys (not as common) unordered_map hashmap; always sorted by key; additional bucket required for hash collisions; no defined order when walking through unordered_multimap same as map but allows dupe keys; dupes are obviously in the same bucket, and you can walk just the dupes if needed set multiset unordered_set unordered_multiset sets are just like maps, except the key is embedded in the object, nice for encapsulation. Items must be const (!) since they are the key - sounds bad, but this is mitigated by the mutable keyword. You can use mutable on the variables that are not part of the key to remove the const. This changes the constness of the object from binary (completely const) to logical (constness is defined by the developer). So... set is a good way to achieve both encapsulation and logical const - make const work for you, not against!  :-) set (etc.) of pointers sets of pointers are the pinnacle of object stores The entire object can be dereferenced and accessed then without const issues. A pointer functor can be provided that does a sort by dereferencing the pointer to the object. Two requirements: you must make sure yourself that you do not change the key values - you can mark them const, provided in constructor; you must create sort/equal/hash functors that dereference the pointers to use object contents (the default will be by pointer address). The arguably biggest advantage, as a result, is that you can create multiple sets to reference the same group of objects with different sort funtors to create multiple indices. You just have to manage the keys carefully, so that they don't change (which would invalidate the sorting). The primary container can manage object allocation; using a heap-based unique_ptr allocation map vs key redux use a key in the set, derive a class from it with the contents + small key + encapsulation - requires mutable to solve the const problem use a key in the set, key includes a mutable object + encapsulation - weird bc everything uses a const object but we have const functions like save() that change the mutable subobject use a map + small key - no encapsulation, have to deal with a pair instead of an object can we just put a ref to key in the value? sure why not - err, bc we don't have access to it + solves const problem bc value is totally mutable by design + we can have multiple keys - and the value can have multiple refs to them + simpler equal and hash functions map: create an object with internal key(s) create map index(es) with duplicate key values outside the object - dupe data is the downside use set(s) with one static key for find(): create an object with internal key(s) create set index(es) with specific hash/equals functor(s) when finding, use one static key object (even across indexes!) so there isn't a big construction each time; just set the necessary key values that proves difficult when dealing with member vars that are references but to solve it, just set up a structure of dummy static key objects that use each other; then provide a function to setKey(Object& keyref) { keyref_ = keyref; } nope, can't reassign refs the solution: use pointers not references yes that's right just do it apparently there was a reason i was anti-reference for all those years two reasons to use pointers: dynamically allocated reassignment required there ya go. simple. get it done. when accessing find results from the set, use a const_cast on the object! WARNING: a separate base class with the key sounds good... but fails when you have more than one index on the object. just use a static key object for them all! c++11 example for large groups of objects with frequent crud AND search Best solution is an unordered set of pointers: typedef boost::unordered_set<MajorObject*> MajorObjects; c++11 example for large groups of objects with infrequent crud and frequent search Best solution is a vector of pointers sorted on demand (sorted_vector): TODO c++11 example to associate two complex objects (one the map key, one the map value) Use unordered_map with a custom object as key. You must add hash and equals functions. Boost makes it easy: static bool operator==(MyKeyObject const& m1, MyKeyObject const& m2) { return m1.id_0 == m2.id_0 && m1.id_1 == m2.id_1; } static std::size_t hash_value(MyKeyObject const& mko) { std::size_t seed = 0; boost::hash_combine(seed, mko.id_0); boost::hash_combine(seed, mko.id_1); return seed; } typedef boost::unordered_map<MyKeyObject, MyValueObject*> MyMap; Note that you can extend this to use a pointer to a key object, whoop. c++11 example for multiple unordered_set indexes into one group of objects Objects will be dynamically created. One set should include them all and be responsible for memory allocation cleanup: TODO c++11 example for set with specific sorting Use set with a specific sort functor. You can create as many of these indexes as you want! struct customers_set_sort_functor { bool operator()(const MyObject* l, const MyObject* r) const { // the id is the key return l->id_ < r->id_; } }; typedef set<MyObject*,myobject_sort_by_id_functor> MyObjectsById; c++11 loop through vector to erase some items Note that other containers' iterators may not be invalidated so you can just erase() as needed... For vectors, you have to play with iterators to get it right - watch for proper ++ pre/postfix! for (it = numbers.begin(); it != numbers.end(); ) // NOTE we increment below, only if we don't erase { if (*it.no_good()) { numbers.erase(it++); // NOTE that we ERASE THEN INCREMENT here. } else { ++it; } } I thought I had always looped backwards to do this, I *think* that's ok too, but I don't see it used in my code, I think I'll avoid.  :-) c++11 range based for loop, jacked with boost index if needed No iterator usage at all. Nice at times, not enough at others. Make SURE to always use a reference or you will be working on a COPY. Make it const if you aren't changing the object. for (auto& mc : my_container) mc.setString("default"); for (const auto& cmc : my_container) cout << cmc.asString(); boost index can give you the index if you need it, sweet: #include <boost/range/adaptor/indexed.hpp> ... for (const auto &element: boost::adaptors::index(mah_container)) cout << element.value() << element.index(); c++11 for loop using lambda This C++11 for loop is clean and elegant and a perfect way to check if your compiler is ready for c++11: vector<int> v; for_each( v.begin(), v.end(), [] (int val) { cout << val; } ); This is using a lambda function, we should switch from iterators and functors to those - but not quite yet, since we're writing cross-platform code. Do not touch this until we can be sure that all platforms provide compatible C++11 handling. c++11 integer types I really like the "fast" C++11 types, that give best performance for a guaranteed minimum bit width. Use them when you know a variable will not exceed the maximum value of that bit width, but does not have to be a precise bit width in memory or elsewhere. Pick specific-width fields whenever data is shared with other processes and components and you want a guarantee of its bit width. And when using pointer size and array indices you should use types defined for those specific situations. FAST types: int_fast8_t int_fast16_t fastest signed integer type with width of int_fast32_t at least 8, 16, 32 and 64 bits respectively int_fast64_t uint_fast8_t uint_fast16_t fastest unsigned integer type with width of uint_fast32_t at least 8, 16, 32 and 64 bits respectively uint_fast64_t SMALL types: int_least8_t int_least16_t smallest signed integer type with width of int_least32_t at least 8, 16, 32 and 64 bits respectively int_least64_t uint_least8_t uint_least16_t smallest unsigned integer type with width of uint_least32_t at least 8, 16, 32 and 64 bits respectively uint_least64_t EXACT types: int8_t signed integer type with width of int16_t exactly 8, 16, 32 and 64 bits respectively int32_t with no padding bits and using 2's complement for negative values int64_t (provided only if the implementation directly supports the type) uint8_t unsigned integer type with width of uint16_t exactly 8, 16, 32 and 64 bits respectively uint32_t (provided only if the implementation directly supports the type) uint64_t SPECIFIC-USE types: intptr_t integer type capable of holding a pointer uintptr_t unsigned integer type capable of holding a pointer size_t unsigned integer type capable of holding an array index (same size as uintptr_t) C++11 scoped enumeration C++11 has scoped enumeration, which lets you specify the SPECIFIC VARIABLE TYPE for the enum. Perfect, let's use uint_fast32_t. enum class STRING_PREF_INDEX int_fast32_t: { ... }; Unfortunately, gcc gives me a scary warning, and stuff fails. For some reason, it does not know about the provided type, although it is definitely defined. Revisit this later if you have time. warning: elaborated-type-specifier for a scoped enum must not use the ‘class’ keyword Old skool is still cool: typedef enum { // assert( SP_COUNT == 2 ); SP_FIRST = 0 , SP_SOME_PREF = SP_FIRST , SP_ANOTHA , SP_COUNT } STRING_PREF_INDEX; c++ in-memory storage of "major" objects OBSERVATION ONE Consider An Important Qt Design: QObjects cannot normally be copied their copy constructors and assignment operators are private why? A Qt Object... might have a unique QObject::objectName(). If we copy a Qt Object, what name should we give the copy? has a location in an object hierarchy. If we copy a Qt Object, where should the copy be located? can be connected to other Qt Objects to emit signals to them or to receive signals emitted by them. If we copy a Qt Object, how should we transfer these connections to the copy? can have new properties added to it at runtime that are not declared in the C++ class. If we copy a Qt Object, should the copy include the properties that were added to the original? in other words, a QObject is a pretty serious object that has the ability to be tied to other objects and resources in ways that make copying dangerous isn't this true of all serious objects? pretty much OBSERVATION TWO if you have a vector of objects, you often want to track them individually outside the vector if you use a vector of pointers, you can move the object around much more cheaply, and not worry about costly large vector reallocations a vector of objects (not pointers) only makes sense if the number of objects is initially known and does not change over time OBSERVATION THREE STL vectors can store your pointers, iterate thru them, etc. for a vector of any substantial size, you want to keep objects sorted so you can find them quickly that's what my sorted_vector class is for; it simply bolts vector together with sort calls and a b_sorted status following STL practices, to get sorting, you have to provide operator< for whatever is in your vector BUT... you are not allowed to do operator<(const MyObjectPtr* right) because it would require a reference to a pointer which is not allowed BUT... you can provide a FUNCTOR to do the job, then provide it when sorting/searching a functor is basically a structure with a bool operator()(const MyObjectPtr* left, const MyObjectPtr* right) OBSERVATION FOUR unordered_set works even better when combining frequent CRUD with frequent lookups SUMMARY Dealing with tons of objects is par for the course in any significant app. Finding a needle in the haystack of those objects is also standard fare. Having multiple indices into those objects is also essential. Using unordered_set with object pointers and is very powerful. c++ stl reverse iterator skeleton From SGI... reverse_iterator rfirst(V.end()); reverse_iterator rlast(V.begin()); while (rfirst != rlast) { cout << *rfirst << endl; ... rfirst++; } c++ stl reading a binary file into a string std::ifstream in("my.zip",std::ios::binary); if (!in) { std::cout << "problem with file open" << std::endl; return 0; } in.seekg(0,std::ios::end); unsigned long length = in.tellg(); in.seekg(0,std::ios::beg); string str(length,0); std::copy( std::istreambuf_iterator< char >(in) , std::istreambuf_iterator< char >() , str.begin() ); For more, see c++ stl reading a binary file C/C++ best-in-class tool selection I need to have easy setup of debug-level tool support for portable C++11 code. And I need to decide and stick to it to be efficient. Compiler selection linux and mac: gcc windows: Visual Studio IDE selection linux and mac: Qt Creator windows: Qt Creator (OR Visual Studio OR eclipse?) Debugger selection linux and mac: Qt Creator windows: Qt Creator (OR Visual Studio OR eclipse?)

C++

Deleting multiple elements in a collection For sequences (vector, list...), best practice is to use the erase-remove STL pattern For associative containers (set, map...): just recurse and remove iterators, they won't muck up the sequence. example See MemoryModel::saveDirtyObjectsAsNeeded() for example code. c++ Create a portable C/C++ project Use QtCreator + CMake, both available everywhere! set up: create a Qt project as: New Project-> Non-Qt/Plain C Project (CMake Build) pick the PARENT and use the name of the existing folder set up a build folder in the existing folder, called (base)/qtcreator-release-build it creates CMakeLists.txt (THIS IS BASICALLY THE PROJECT FILE!) also creates main.c or something build it! make sure it works NOW we can edit CMakeLists.txt - change . to ./src to get it to scan the src folder for code! and easily add "known" libs! this was all i needed: TARGET_LINK_LIBRARIES(${PROJECT_NAME} pthread websockets) make sure it builds now we want a DEBUG build as well! Projects->Build&Run->pick Build in weird Build/Run pillbox->Edit build configs: Rename: release CMake build dir: Make sure build dir is set to release ie qtcreator-debug-build Add: Clone: release, name: debug for debug, add a custom build step BEFORE make step: command: /usr/bin/cmake args: -DCMAKE_BUILD_TYPE=Debug . working dir: %{buildDir} (add it, and move it up above make) (build em both) Projects->Build&Run->pick Run in weird Build/Run pillbox Run Configuration: rename to "{...} release" clone it into "{...} debug" change working dir to match Build path change any needed params Now you should have build+run debug+release configurations, selectable in the weird project icon in bottom of left-side toolbar ("mode selector") boost release and debug build for linux # download latest boost, eg: boost_1_59_0 m@wallee:~/development$ 7z x boost_1_59_0.7z cd boost_1_##_0 build_boost_release_and_debug.sh # then patch .bashrc as instructed # eclipse and server/nix/bootstrap.sh are customized to match To upgrade a project: cd nix make distclean # removes nasty .deps folders that link to old boost if you let them make clean # removes .o files etc cd ../build-Release && make distclean && make clean cd ../build-Debug && make distclean && make clean cd .. ./bootstrap force release ./bootstrap force debug boost release and debug build for Windows Open a VS2015 x64 Native Tools Command Prompt. EITHER: for new installs, you have to run bootstrap.bat first, it will build b2; OR: for reruns, remove boost dirs: [bin.v2, stage]. Then build 64-bit: cd "....\boost_1_59_0" b2 toolset=msvc variant=release,debug link=static address-model=64 rem trying to avoid excessive options, assuming I don't need these: threading=multi (old stuff) --toolset=msvc-14.0 address-model=64 --build-type=complete --stagedir=windows_lib\x64 stage Now open VS2013 x86 Native Tools Command Prompt and build 32-bit: cd "C:\Michael's Data\development\sixth_column\boost_1_55_0" bjam --toolset=msvc-12.0 address-model=32 --build-type=complete --stagedir=windows_lib\x86 stage c++11 include base constructor (etc) in derived class The awesome C++11 way to steal the constructor from the base class, oh man I've been waiting for this one... class HttpsServer : public Server<HTTPS> { // DOES THIS FOR YOU! /* HttpsServer(unsigned short port, size_t num_threads, const std::string& cert_file, const std::string& private_key_file)  : // Call base class Server<HTTPS>::Server(port, num_threads, cert_file, private_key_file) {} */ using Server<HTTPS>::Server; .... c++11 containers sorted_vector use when doing lots of unsorted insertions and maintaining constant sort would be expensive; vector is good for a big pile of things that only occasionally needs a sorted lookup map sorted binary search tree; always sorted by key; you can walk through in sorted order (choose unordered if not needed!) multimap same as map but allows dupe keys (not as common) unordered_map hashmap; always sorted by key; additional bucket required for hash collisions; no defined order when walking through unordered_multimap same as map but allows dupe keys; dupes are obviously in the same bucket, and you can walk just the dupes if needed set multiset unordered_set unordered_multiset sets are just like maps, except the key is embedded in the object, nice for encapsulation. Items must be const (!) since they are the key - sounds bad, but this is mitigated by the mutable keyword. You can use mutable on the variables that are not part of the key to remove the const. This changes the constness of the object from binary (completely const) to logical (constness is defined by the developer). So... set is a good way to achieve both encapsulation and logical const - make const work for you, not against!  :-) set (etc.) of pointers sets of pointers are the pinnacle of object stores The entire object can be dereferenced and accessed then without const issues. A pointer functor can be provided that does a sort by dereferencing the pointer to the object. Two requirements: you must make sure yourself that you do not change the key values - you can mark them const, provided in constructor; you must create sort/equal/hash functors that dereference the pointers to use object contents (the default will be by pointer address). The arguably biggest advantage, as a result, is that you can create multiple sets to reference the same group of objects with different sort funtors to create multiple indices. You just have to manage the keys carefully, so that they don't change (which would invalidate the sorting). The primary container can manage object allocation; using a heap-based unique_ptr allocation map vs key redux use a key in the set, derive a class from it with the contents + small key + encapsulation - requires mutable to solve the const problem use a key in the set, key includes a mutable object + encapsulation - weird bc everything uses a const object but we have const functions like save() that change the mutable subobject use a map + small key - no encapsulation, have to deal with a pair instead of an object can we just put a ref to key in the value? sure why not - err, bc we don't have access to it + solves const problem bc value is totally mutable by design + we can have multiple keys - and the value can have multiple refs to them + simpler equal and hash functions map: create an object with internal key(s) create map index(es) with duplicate key values outside the object - dupe data is the downside use set(s) with one static key for find(): create an object with internal key(s) create set index(es) with specific hash/equals functor(s) when finding, use one static key object (even across indexes!) so there isn't a big construction each time; just set the necessary key values that proves difficult when dealing with member vars that are references but to solve it, just set up a structure of dummy static key objects that use each other; then provide a function to setKey(Object& keyref) { keyref_ = keyref; } nope, can't reassign refs the solution: use pointers not references yes that's right just do it apparently there was a reason i was anti-reference for all those years two reasons to use pointers: dynamically allocated reassignment required there ya go. simple. get it done. when accessing find results from the set, use a const_cast on the object! WARNING: a separate base class with the key sounds good... but fails when you have more than one index on the object. just use a static key object for them all! c++11 example for large groups of objects with frequent crud AND search Best solution is an unordered set of pointers: typedef boost::unordered_set<MajorObject*> MajorObjects; c++11 example for large groups of objects with infrequent crud and frequent search Best solution is a vector of pointers sorted on demand (sorted_vector): TODO c++11 example to associate two complex objects (one the map key, one the map value) Use unordered_map with a custom object as key. You must add hash and equals functions. Boost makes it easy: static bool operator==(MyKeyObject const& m1, MyKeyObject const& m2) { return m1.id_0 == m2.id_0 && m1.id_1 == m2.id_1; } static std::size_t hash_value(MyKeyObject const& mko) { std::size_t seed = 0; boost::hash_combine(seed, mko.id_0); boost::hash_combine(seed, mko.id_1); return seed; } typedef boost::unordered_map<MyKeyObject, MyValueObject*> MyMap; Note that you can extend this to use a pointer to a key object, whoop. c++11 example for multiple unordered_set indexes into one group of objects Objects will be dynamically created. One set should include them all and be responsible for memory allocation cleanup: TODO c++11 example for set with specific sorting Use set with a specific sort functor. You can create as many of these indexes as you want! struct customers_set_sort_functor { bool operator()(const MyObject* l, const MyObject* r) const { // the id is the key return l->id_ < r->id_; } }; typedef set<MyObject*,myobject_sort_by_id_functor> MyObjectsById; c++11 loop through vector to erase some items Note that other containers' iterators may not be invalidated so you can just erase() as needed... For vectors, you have to play with iterators to get it right - watch for proper ++ pre/postfix! for (it = numbers.begin(); it != numbers.end(); ) // NOTE we increment below, only if we don't erase { if (*it.no_good()) { numbers.erase(it++); // NOTE that we ERASE THEN INCREMENT here. } else { ++it; } } I thought I had always looped backwards to do this, I *think* that's ok too, but I don't see it used in my code, I think I'll avoid.  :-) c++11 range based for loop, jacked with boost index if needed No iterator usage at all. Nice at times, not enough at others. Make SURE to always use a reference or you will be working on a COPY. Make it const if you aren't changing the object. for (auto& mc : my_container) mc.setString("default"); for (const auto& cmc : my_container) cout << cmc.asString(); boost index can give you the index if you need it, sweet: #include <boost/range/adaptor/indexed.hpp> ... for (const auto &element: boost::adaptors::index(mah_container)) cout << element.value() << element.index(); c++11 for loop using lambda This C++11 for loop is clean and elegant and a perfect way to check if your compiler is ready for c++11: vector<int> v; for_each( v.begin(), v.end(), [] (int val) { cout << val; } ); This is using a lambda function, we should switch from iterators and functors to those - but not quite yet, since we're writing cross-platform code. Do not touch this until we can be sure that all platforms provide compatible C++11 handling. c++11 integer types I really like the "fast" C++11 types, that give best performance for a guaranteed minimum bit width. Use them when you know a variable will not exceed the maximum value of that bit width, but does not have to be a precise bit width in memory or elsewhere. Pick specific-width fields whenever data is shared with other processes and components and you want a guarantee of its bit width. And when using pointer size and array indices you should use types defined for those specific situations. FAST types: int_fast8_t int_fast16_t fastest signed integer type with width of int_fast32_t at least 8, 16, 32 and 64 bits respectively int_fast64_t uint_fast8_t uint_fast16_t fastest unsigned integer type with width of uint_fast32_t at least 8, 16, 32 and 64 bits respectively uint_fast64_t SMALL types: int_least8_t int_least16_t smallest signed integer type with width of int_least32_t at least 8, 16, 32 and 64 bits respectively int_least64_t uint_least8_t uint_least16_t smallest unsigned integer type with width of uint_least32_t at least 8, 16, 32 and 64 bits respectively uint_least64_t EXACT types: int8_t signed integer type with width of int16_t exactly 8, 16, 32 and 64 bits respectively int32_t with no padding bits and using 2's complement for negative values int64_t (provided only if the implementation directly supports the type) uint8_t unsigned integer type with width of uint16_t exactly 8, 16, 32 and 64 bits respectively uint32_t (provided only if the implementation directly supports the type) uint64_t SPECIFIC-USE types: intptr_t integer type capable of holding a pointer uintptr_t unsigned integer type capable of holding a pointer size_t unsigned integer type capable of holding an array index (same size as uintptr_t) C++11 scoped enumeration C++11 has scoped enumeration, which lets you specify the SPECIFIC VARIABLE TYPE for the enum. Perfect, let's use uint_fast32_t. enum class STRING_PREF_INDEX int_fast32_t: { ... }; Unfortunately, gcc gives me a scary warning, and stuff fails. For some reason, it does not know about the provided type, although it is definitely defined. Revisit this later if you have time. warning: elaborated-type-specifier for a scoped enum must not use the ‘class’ keyword Old skool is still cool: typedef enum { // assert( SP_COUNT == 2 ); SP_FIRST = 0 , SP_SOME_PREF = SP_FIRST , SP_ANOTHA , SP_COUNT } STRING_PREF_INDEX; c++ in-memory storage of "major" objects OBSERVATION ONE Consider An Important Qt Design: QObjects cannot normally be copied their copy constructors and assignment operators are private why? A Qt Object... might have a unique QObject::objectName(). If we copy a Qt Object, what name should we give the copy? has a location in an object hierarchy. If we copy a Qt Object, where should the copy be located? can be connected to other Qt Objects to emit signals to them or to receive signals emitted by them. If we copy a Qt Object, how should we transfer these connections to the copy? can have new properties added to it at runtime that are not declared in the C++ class. If we copy a Qt Object, should the copy include the properties that were added to the original? in other words, a QObject is a pretty serious object that has the ability to be tied to other objects and resources in ways that make copying dangerous isn't this true of all serious objects? pretty much OBSERVATION TWO if you have a vector of objects, you often want to track them individually outside the vector if you use a vector of pointers, you can move the object around much more cheaply, and not worry about costly large vector reallocations a vector of objects (not pointers) only makes sense if the number of objects is initially known and does not change over time OBSERVATION THREE STL vectors can store your pointers, iterate thru them, etc. for a vector of any substantial size, you want to keep objects sorted so you can find them quickly that's what my sorted_vector class is for; it simply bolts vector together with sort calls and a b_sorted status following STL practices, to get sorting, you have to provide operator< for whatever is in your vector BUT... you are not allowed to do operator<(const MyObjectPtr* right) because it would require a reference to a pointer which is not allowed BUT... you can provide a FUNCTOR to do the job, then provide it when sorting/searching a functor is basically a structure with a bool operator()(const MyObjectPtr* left, const MyObjectPtr* right) OBSERVATION FOUR unordered_set works even better when combining frequent CRUD with frequent lookups SUMMARY Dealing with tons of objects is par for the course in any significant app. Finding a needle in the haystack of those objects is also standard fare. Having multiple indices into those objects is also essential. Using unordered_set with object pointers and is very powerful. c++ stl reverse iterator skeleton From SGI... reverse_iterator rfirst(V.end()); reverse_iterator rlast(V.begin()); while (rfirst != rlast) { cout << *rfirst << endl; ... rfirst++; } c++ stl reading a binary file into a string std::ifstream in("my.zip",std::ios::binary); if (!in) { std::cout << "problem with file open" << std::endl; return 0; } in.seekg(0,std::ios::end); unsigned long length = in.tellg(); in.seekg(0,std::ios::beg); string str(length,0); std::copy( std::istreambuf_iterator< char >(in) , std::istreambuf_iterator< char >() , str.begin() ); For more, see c++ stl reading a binary file C/C++ best-in-class tool selection I need to have easy setup of debug-level tool support for portable C++11 code. And I need to decide and stick to it to be efficient. Compiler selection linux and mac: gcc windows: Visual Studio IDE selection linux and mac: Qt Creator windows: Qt Creator (OR Visual Studio OR eclipse?) Debugger selection linux and mac: Qt Creator windows: Qt Creator (OR Visual Studio OR eclipse?)

C++

Deleting multiple elements in a collection For sequences (vector, list...), best practice is to use the erase-remove STL pattern For associative containers (set, map...): just recurse and remove iterators, they won't muck up the sequence. example See MemoryModel::saveDirtyObjectsAsNeeded() for example code. c++ Create a portable C/C++ project Use QtCreator + CMake, both available everywhere! set up: create a Qt project as: New Project-> Non-Qt/Plain C Project (CMake Build) pick the PARENT and use the name of the existing folder set up a build folder in the existing folder, called (base)/qtcreator-release-build it creates CMakeLists.txt (THIS IS BASICALLY THE PROJECT FILE!) also creates main.c or something build it! make sure it works NOW we can edit CMakeLists.txt - change . to ./src to get it to scan the src folder for code! and easily add "known" libs! this was all i needed: TARGET_LINK_LIBRARIES(${PROJECT_NAME} pthread websockets) make sure it builds now we want a DEBUG build as well! Projects->Build&Run->pick Build in weird Build/Run pillbox->Edit build configs: Rename: release CMake build dir: Make sure build dir is set to release ie qtcreator-debug-build Add: Clone: release, name: debug for debug, add a custom build step BEFORE make step: command: /usr/bin/cmake args: -DCMAKE_BUILD_TYPE=Debug . working dir: %{buildDir} (add it, and move it up above make) (build em both) Projects->Build&Run->pick Run in weird Build/Run pillbox Run Configuration: rename to "{...} release" clone it into "{...} debug" change working dir to match Build path change any needed params Now you should have build+run debug+release configurations, selectable in the weird project icon in bottom of left-side toolbar ("mode selector") boost release and debug build for linux # download latest boost, eg: boost_1_59_0 m@wallee:~/development$ 7z x boost_1_59_0.7z cd boost_1_##_0 build_boost_release_and_debug.sh # then patch .bashrc as instructed # eclipse and server/nix/bootstrap.sh are customized to match To upgrade a project: cd nix make distclean # removes nasty .deps folders that link to old boost if you let them make clean # removes .o files etc cd ../build-Release && make distclean && make clean cd ../build-Debug && make distclean && make clean cd .. ./bootstrap force release ./bootstrap force debug boost release and debug build for Windows Open a VS2015 x64 Native Tools Command Prompt. EITHER: for new installs, you have to run bootstrap.bat first, it will build b2; OR: for reruns, remove boost dirs: [bin.v2, stage]. Then build 64-bit: cd "....\boost_1_59_0" b2 toolset=msvc variant=release,debug link=static address-model=64 rem trying to avoid excessive options, assuming I don't need these: threading=multi (old stuff) --toolset=msvc-14.0 address-model=64 --build-type=complete --stagedir=windows_lib\x64 stage Now open VS2013 x86 Native Tools Command Prompt and build 32-bit: cd "C:\Michael's Data\development\sixth_column\boost_1_55_0" bjam --toolset=msvc-12.0 address-model=32 --build-type=complete --stagedir=windows_lib\x86 stage c++11 include base constructor (etc) in derived class The awesome C++11 way to steal the constructor from the base class, oh man I've been waiting for this one... class HttpsServer : public Server<HTTPS> { // DOES THIS FOR YOU! /* HttpsServer(unsigned short port, size_t num_threads, const std::string& cert_file, const std::string& private_key_file)  : // Call base class Server<HTTPS>::Server(port, num_threads, cert_file, private_key_file) {} */ using Server<HTTPS>::Server; .... c++11 containers sorted_vector use when doing lots of unsorted insertions and maintaining constant sort would be expensive; vector is good for a big pile of things that only occasionally needs a sorted lookup map sorted binary search tree; always sorted by key; you can walk through in sorted order (choose unordered if not needed!) multimap same as map but allows dupe keys (not as common) unordered_map hashmap; always sorted by key; additional bucket required for hash collisions; no defined order when walking through unordered_multimap same as map but allows dupe keys; dupes are obviously in the same bucket, and you can walk just the dupes if needed set multiset unordered_set unordered_multiset sets are just like maps, except the key is embedded in the object, nice for encapsulation. Items must be const (!) since they are the key - sounds bad, but this is mitigated by the mutable keyword. You can use mutable on the variables that are not part of the key to remove the const. This changes the constness of the object from binary (completely const) to logical (constness is defined by the developer). So... set is a good way to achieve both encapsulation and logical const - make const work for you, not against!  :-) set (etc.) of pointers sets of pointers are the pinnacle of object stores The entire object can be dereferenced and accessed then without const issues. A pointer functor can be provided that does a sort by dereferencing the pointer to the object. Two requirements: you must make sure yourself that you do not change the key values - you can mark them const, provided in constructor; you must create sort/equal/hash functors that dereference the pointers to use object contents (the default will be by pointer address). The arguably biggest advantage, as a result, is that you can create multiple sets to reference the same group of objects with different sort funtors to create multiple indices. You just have to manage the keys carefully, so that they don't change (which would invalidate the sorting). The primary container can manage object allocation; using a heap-based unique_ptr allocation map vs key redux use a key in the set, derive a class from it with the contents + small key + encapsulation - requires mutable to solve the const problem use a key in the set, key includes a mutable object + encapsulation - weird bc everything uses a const object but we have const functions like save() that change the mutable subobject use a map + small key - no encapsulation, have to deal with a pair instead of an object can we just put a ref to key in the value? sure why not - err, bc we don't have access to it + solves const problem bc value is totally mutable by design + we can have multiple keys - and the value can have multiple refs to them + simpler equal and hash functions map: create an object with internal key(s) create map index(es) with duplicate key values outside the object - dupe data is the downside use set(s) with one static key for find(): create an object with internal key(s) create set index(es) with specific hash/equals functor(s) when finding, use one static key object (even across indexes!) so there isn't a big construction each time; just set the necessary key values that proves difficult when dealing with member vars that are references but to solve it, just set up a structure of dummy static key objects that use each other; then provide a function to setKey(Object& keyref) { keyref_ = keyref; } nope, can't reassign refs the solution: use pointers not references yes that's right just do it apparently there was a reason i was anti-reference for all those years two reasons to use pointers: dynamically allocated reassignment required there ya go. simple. get it done. when accessing find results from the set, use a const_cast on the object! WARNING: a separate base class with the key sounds good... but fails when you have more than one index on the object. just use a static key object for them all! c++11 example for large groups of objects with frequent crud AND search Best solution is an unordered set of pointers: typedef boost::unordered_set<MajorObject*> MajorObjects; c++11 example for large groups of objects with infrequent crud and frequent search Best solution is a vector of pointers sorted on demand (sorted_vector): TODO c++11 example to associate two complex objects (one the map key, one the map value) Use unordered_map with a custom object as key. You must add hash and equals functions. Boost makes it easy: static bool operator==(MyKeyObject const& m1, MyKeyObject const& m2) { return m1.id_0 == m2.id_0 && m1.id_1 == m2.id_1; } static std::size_t hash_value(MyKeyObject const& mko) { std::size_t seed = 0; boost::hash_combine(seed, mko.id_0); boost::hash_combine(seed, mko.id_1); return seed; } typedef boost::unordered_map<MyKeyObject, MyValueObject*> MyMap; Note that you can extend this to use a pointer to a key object, whoop. c++11 example for multiple unordered_set indexes into one group of objects Objects will be dynamically created. One set should include them all and be responsible for memory allocation cleanup: TODO c++11 example for set with specific sorting Use set with a specific sort functor. You can create as many of these indexes as you want! struct customers_set_sort_functor { bool operator()(const MyObject* l, const MyObject* r) const { // the id is the key return l->id_ < r->id_; } }; typedef set<MyObject*,myobject_sort_by_id_functor> MyObjectsById; c++11 loop through vector to erase some items Note that other containers' iterators may not be invalidated so you can just erase() as needed... For vectors, you have to play with iterators to get it right - watch for proper ++ pre/postfix! for (it = numbers.begin(); it != numbers.end(); ) // NOTE we increment below, only if we don't erase { if (*it.no_good()) { numbers.erase(it++); // NOTE that we ERASE THEN INCREMENT here. } else { ++it; } } I thought I had always looped backwards to do this, I *think* that's ok too, but I don't see it used in my code, I think I'll avoid.  :-) c++11 range based for loop, jacked with boost index if needed No iterator usage at all. Nice at times, not enough at others. Make SURE to always use a reference or you will be working on a COPY. Make it const if you aren't changing the object. for (auto& mc : my_container) mc.setString("default"); for (const auto& cmc : my_container) cout << cmc.asString(); boost index can give you the index if you need it, sweet: #include <boost/range/adaptor/indexed.hpp> ... for (const auto &element: boost::adaptors::index(mah_container)) cout << element.value() << element.index(); c++11 for loop using lambda This C++11 for loop is clean and elegant and a perfect way to check if your compiler is ready for c++11: vector<int> v; for_each( v.begin(), v.end(), [] (int val) { cout << val; } ); This is using a lambda function, we should switch from iterators and functors to those - but not quite yet, since we're writing cross-platform code. Do not touch this until we can be sure that all platforms provide compatible C++11 handling. c++11 integer types I really like the "fast" C++11 types, that give best performance for a guaranteed minimum bit width. Use them when you know a variable will not exceed the maximum value of that bit width, but does not have to be a precise bit width in memory or elsewhere. Pick specific-width fields whenever data is shared with other processes and components and you want a guarantee of its bit width. And when using pointer size and array indices you should use types defined for those specific situations. FAST types: int_fast8_t int_fast16_t fastest signed integer type with width of int_fast32_t at least 8, 16, 32 and 64 bits respectively int_fast64_t uint_fast8_t uint_fast16_t fastest unsigned integer type with width of uint_fast32_t at least 8, 16, 32 and 64 bits respectively uint_fast64_t SMALL types: int_least8_t int_least16_t smallest signed integer type with width of int_least32_t at least 8, 16, 32 and 64 bits respectively int_least64_t uint_least8_t uint_least16_t smallest unsigned integer type with width of uint_least32_t at least 8, 16, 32 and 64 bits respectively uint_least64_t EXACT types: int8_t signed integer type with width of int16_t exactly 8, 16, 32 and 64 bits respectively int32_t with no padding bits and using 2's complement for negative values int64_t (provided only if the implementation directly supports the type) uint8_t unsigned integer type with width of uint16_t exactly 8, 16, 32 and 64 bits respectively uint32_t (provided only if the implementation directly supports the type) uint64_t SPECIFIC-USE types: intptr_t integer type capable of holding a pointer uintptr_t unsigned integer type capable of holding a pointer size_t unsigned integer type capable of holding an array index (same size as uintptr_t) C++11 scoped enumeration C++11 has scoped enumeration, which lets you specify the SPECIFIC VARIABLE TYPE for the enum. Perfect, let's use uint_fast32_t. enum class STRING_PREF_INDEX int_fast32_t: { ... }; Unfortunately, gcc gives me a scary warning, and stuff fails. For some reason, it does not know about the provided type, although it is definitely defined. Revisit this later if you have time. warning: elaborated-type-specifier for a scoped enum must not use the ‘class’ keyword Old skool is still cool: typedef enum { // assert( SP_COUNT == 2 ); SP_FIRST = 0 , SP_SOME_PREF = SP_FIRST , SP_ANOTHA , SP_COUNT } STRING_PREF_INDEX; c++ in-memory storage of "major" objects OBSERVATION ONE Consider An Important Qt Design: QObjects cannot normally be copied their copy constructors and assignment operators are private why? A Qt Object... might have a unique QObject::objectName(). If we copy a Qt Object, what name should we give the copy? has a location in an object hierarchy. If we copy a Qt Object, where should the copy be located? can be connected to other Qt Objects to emit signals to them or to receive signals emitted by them. If we copy a Qt Object, how should we transfer these connections to the copy? can have new properties added to it at runtime that are not declared in the C++ class. If we copy a Qt Object, should the copy include the properties that were added to the original? in other words, a QObject is a pretty serious object that has the ability to be tied to other objects and resources in ways that make copying dangerous isn't this true of all serious objects? pretty much OBSERVATION TWO if you have a vector of objects, you often want to track them individually outside the vector if you use a vector of pointers, you can move the object around much more cheaply, and not worry about costly large vector reallocations a vector of objects (not pointers) only makes sense if the number of objects is initially known and does not change over time OBSERVATION THREE STL vectors can store your pointers, iterate thru them, etc. for a vector of any substantial size, you want to keep objects sorted so you can find them quickly that's what my sorted_vector class is for; it simply bolts vector together with sort calls and a b_sorted status following STL practices, to get sorting, you have to provide operator< for whatever is in your vector BUT... you are not allowed to do operator<(const MyObjectPtr* right) because it would require a reference to a pointer which is not allowed BUT... you can provide a FUNCTOR to do the job, then provide it when sorting/searching a functor is basically a structure with a bool operator()(const MyObjectPtr* left, const MyObjectPtr* right) OBSERVATION FOUR unordered_set works even better when combining frequent CRUD with frequent lookups SUMMARY Dealing with tons of objects is par for the course in any significant app. Finding a needle in the haystack of those objects is also standard fare. Having multiple indices into those objects is also essential. Using unordered_set with object pointers and is very powerful. c++ stl reverse iterator skeleton From SGI... reverse_iterator rfirst(V.end()); reverse_iterator rlast(V.begin()); while (rfirst != rlast) { cout << *rfirst << endl; ... rfirst++; } c++ stl reading a binary file into a string std::ifstream in("my.zip",std::ios::binary); if (!in) { std::cout << "problem with file open" << std::endl; return 0; } in.seekg(0,std::ios::end); unsigned long length = in.tellg(); in.seekg(0,std::ios::beg); string str(length,0); std::copy( std::istreambuf_iterator< char >(in) , std::istreambuf_iterator< char >() , str.begin() ); For more, see c++ stl reading a binary file C/C++ best-in-class tool selection I need to have easy setup of debug-level tool support for portable C++11 code. And I need to decide and stick to it to be efficient. Compiler selection linux and mac: gcc windows: Visual Studio IDE selection linux and mac: Qt Creator windows: Qt Creator (OR Visual Studio OR eclipse?) Debugger selection linux and mac: Qt Creator windows: Qt Creator (OR Visual Studio OR eclipse?)

C++ libraries
Simple-Web-Server C++ https libraries Configure Qt development on Windows + Mac + linux Build the TagLib library with Visual Studio 2013

C/C++ building/linking

gcc makefile pain I went through a LOT of pain to determine that gcc requires libraries to be listed AFTER the source and output parameters set LD_LIBRARY_PATH to point to your libs if they are not in system location Make sure Makefile uses TABS NOT SPACES. it's a FACT OF LIFE. hate it if you want. plenty more things to hate about linux/C as well. gcc install multiple versions in ubuntu (4 and 5 in wily, eg) My code will not compile with gcc 5, the version provided with Ubuntu wily. It gives warnings like this: /home/m/development/boost_1_59_0/boost/smart_ptr/shared_ptr.hpp:547:34: warning: ‘template<class> class std::auto_ptr’ is deprecated [-Wdeprecated-declarations] and outright errors like this: depbase=`echo AtServer.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\ g++ -DPACKAGE_NAME=\"at_server\" -DPACKAGE_TARNAME=\"at_server\" -DPACKAGE_VERSION=\"1.0\" -DPACKAGE_STRING=\"at_server\ 1.0\" -DPACKAGE_BUGREPORT=\"[email protected]\" -DPACKAGE_URL=\"\" -DPACKAGE=\"at_server\" -DVERSION=\"1.0\" -I. -I../../src -I/home/m/development/Reusable/c++ -I/home/m/development/Reusable/c++/sqlite -std=c++11 -I/home/m/development/boost_1_59_0 -ggdb3 -O0 -std=c++11 -MT AtServer.o -MD -MP -MF $depbase.Tpo -c -o AtServer.o ../../src/AtServer.cpp &&\ mv -f $depbase.Tpo $depbase.Po In file included from /usr/include/c++/5/bits/stl_algo.h:60:0, from /usr/include/c++/5/algorithm:62, from /usr/include/c++/5/ext/slist:47, from /home/m/development/boost_1_59_0/boost/algorithm/string/std/slist_traits.hpp:16, from /home/m/development/boost_1_59_0/boost/algorithm/string/std_containers_traits.hpp:23, from /home/m/development/boost_1_59_0/boost/algorithm/string.hpp:18, from /home/m/development/Reusable/c++/utilities.hpp:4, from ../../src/MemoryModel.hpp:11, from ../../src/SqliteLocalModel.hpp:13, from ../../src/AtServer.cpp:70: /usr/include/c++/5/bits/algorithmfwd.h:573:13: error: initializer provided for function noexcept(__and_<is_nothrow_move_constructible<_Tp>, ^ /usr/include/c++/5/bits/algorithmfwd.h:582:13: error: initializer provided for function noexcept(noexcept(swap(*__a, *__b))) You can set up the update-alternatives tool to switch out the symlinks: sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.9 60 --slave /usr/bin/g++ g++ /usr/bin/g++-4.9 sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-5 20 --slave /usr/bin/g++ g++ /usr/bin/g++-5 BUT that seems BAD to me to switch out the compiler used by the SYSTEM. Instead, we should specify the compiler required by the PROJECT. This is supposed to do it, but it still uses /usr/include/c++/5, which seems wrong, and gives me errors: CC=gcc-4.9

C/C++ debugging

Qt Creator I was able to build lws in debug, install in /usr/local, then I could step right into its code m@case:~/development/causam/git/np/nop-bigress-client-c$ ./build_lws_debug Install the project... -- Install configuration: "DEBUG" -- Installing: /usr/local/lib/pkgconfig/libwebsockets.pc -- Installing: /usr/local/lib/libwebsockets.a -- Up-to-date: /usr/local/include/libwebsockets.h (etc) valgrind is easy to use. Just find debugger pane top-left dropdown, switch mode from Debugger to Memcheck, and restart debugger. Signals: At some point I needed to force gdb to pass SIGINT, SIGPIPE... signals to the app instead of gdb, after ssl kept causing Qt to pop a message and break in the debugger. To do so: Qt Creator->Options->Debugger-> [ ] Show a message box when receiving a signal Debugger Helper Customization: handle SIGPIPE pass nostop noprint You should be able to install debug builds of libraries into /usr/local (as mentioned above). Older notes if you can't get that going: To debug into an included library that is not installed system-wide: use Tools->Options->General->Source Paths Map source: /home/m/development/causam/git/nop-bigress-client-c/cmake-debug that's the COMPLETE PATH TO DEBUG EXE target: /home/m/development/causam/git/libwebsockets-master/lib at first i thought this would work: /usr/local/lib but i did a static build so i needed teh actual exe! COOL c/c++ gdb debugging (gdb) help break Set breakpoint at specified line or function. Argument may be line number, function name, or "*" and an address. If line number is specified, break at start of code for that line. If function is specified, break at start of code for that function. If an address is specified, break at that exact address. With no arg, uses current execution address of selected stack frame. This is useful for breaking on return to a stack frame. Multiple breakpoints at one place are permitted, and useful if conditional. Do "help breakpoints" for info on other commands dealing with breakpoints. ddd gives you a front end. I need to use it more, compare to other options

C

Library handling in linux gcc library basics (good to know for autotools and CMake too) The gcc -l command line option specifies a specific library NAME. It will add the rest to give you (eg) lib[NAME].a Specify the library search path with the -L option. Things that you as a user install seem to default to /usr/local/lib This will link myprogram with the static library libfoo.a in the folder /home/me/foo/lib. gcc -o myprogram -lfoo -L/home/me/foo/lib myprogram.c Tools to check library dependencies: ldd [executable] objdump -p /path/to/program | grep NEEDED objdump -x [object.so] readelf -d [exe] sudo pldd <PID> sudo pmap <PID> Cross Compiling C - Create a portable command line C project in Visual Studio Visual Studio: File -> New -> project Visual C++ -> Win32 -> Win32 Console Application name: oms_with_emap next -> click OFF precompiled header checkbox (even tho it didn't seem to respect it) you'll get a _tmain(..., TCHAR*...) change it to main(..., char*...) change the project to explicitly say "Not using precompiled header" remove the f'in stdafx.h recompile! should be clean vs will recognize C files and compile accordingly

Bootstrap

Single Page Application css: .mdm-scrollable-div { height: 100%; overflow: auto; } html: <-- header --> <div class="frame" id="frame1top"> <div class="mdm-scrollable-div"> ... </div> </div> <-- footer --> js: // We need to adjust layout on resize, in ready handler, and programmatically as needed. $(window).resize(adjustLayout).resize(); $( document ).ready(function() { // We need to adjust in ready handler, on resize, and programmatically as needed adjustLayout(); /* your other page load code here*/ }); function adjustLayout(){ // ---------------------- // Fundamental dimensions var hh = $('#theheader').outerHeight(); var fh = $('#thefooter').outerHeight(); var workspace_height = $(window).height() - hh - fh; var workspace_width = $(window).width(); // ---------------------- var cols = 1; var col_gap = 16; // Margin is based on percent of one column width, so it goes to zero before column width does.  :-) // Width is based on total width minus margins, then split between columns. var margin = ($(window).width() / cols) * .04; var w = ($(window).width() - (margin * (cols + 1))) / cols; var h1 = workspace_height; $('#frame1top').css({ display:'block', position:'absolute', left: margin * 1 + w * 0, top: hh, width: w, height: h1 }); } Button handlers Buttons can be represented with labels; in that case, use a click handler: jQuery('<label id="'+cycle.apsID+'" class="btn">MahButt</label>') .appendTo('#'+chartid+'-apsbar') .on('click', function(){ $(location).attr('href','/v1/parameters/'+this.id+'.html'); }); You can also get the checked state, and prevent the button from being pressed, among other things: jQuery('<label id="'+cycle.run+'" ... .on('click', function(e){ var run = this.id; // Look for the (label->input) if (this.firstChild.checked) ... // To prevent checked/pressed state if desired: e.stopPropagation(); } Button bars are represented by labels wrapped around inputs: <div class="btn-group live-buttons" data-toggle="buttons"><div class="btn-group"><label class="btn"><input type="checkbox">text... In that case use a change handler on the input: var label = jQuery('<label class="btn btn-sm btn-'+color+'"></label>').appendTo(action_button_bar); var input = jQuery('<input class="run-'+cmd+'" type="checkbox" autocomplete="off" value="'+cycle.run+'">').appendTo(label) .on('change', cycle.owned? function(){ patchPick(this.value,'{ "action" : "run-hold" }'); } : function() { patchPick(this.value,'{ "action" : "run-buy" }'); }); var text = jQuery('<span class="glyphicon glyphicon-'+glyph+'"></span> <span class="hidden-xs">'+cmd+'</span>').appendTo(label); If you just need clicks from the button bar, you do NOT NEED input: <div class="btn-group live-buttons" data-toggle="buttons"><div class="btn-group"><label class="btn">text... Then you can put the change handler right on the label: var applybar = jQuery('<div id="applybar-'+cycle.run+'" class="btn-group pull-right" data-toggle="buttons" />'); var apply_button = jQuery('<label id="apply-'+cycle.run+'" class="btn btn-sm btn-moneygreen"><span class="glyphicon glyphicon-ok"></span><span class="hidden-xs"> Apply</span></input></label>') .on('click', function(e) { // Do work e.stopPropagation(); }) .appendTo(applybar)  ; Programmatically pressing a button You MUST DO TWO THINGS: Set the active class on the button/label Set the input to checked <label class="btn active"> <input type="checkbox" autocomplete="off" checked> Click me </label> Collapsible panel Use a unique id on content div, data-target to connect panel header to content, mdm-panel-collapser so javascript can find icon, abt-scrollable-panel for margin. HTML for each panel (starts collapsed) <div class="panel panel-default abt-scrollable-panel"> <div class="panel-heading collapsed" data-toggle="collapse" data-target="#my-content-block-one">Software development skills<span class="mdm-panel-collapser text-muted glyphicon glyphicon-chevron-down pull-right"></span></div> <div class="collapse" id="my-content-block-one"> <div class="mdm-panel-body"> <!-- CONTENT, can include another nested panel, just add .mdm-nested-panel to class; example: --> <div class="panel panel-default mdm-scrollable-panel mdm-nested-panel"> <div class="panel-heading collapsed mdm-job-panel-heading" data-toggle="collapse" data-target="#toshiba-job"><p><strong>Senior Developer and Offshore Manager</strong><i> - Toshiba Global Commerce Solutions, Inc.</i><span class="mdm-panel-collapser text-muted glyphicon glyphicon-chevron-up pull-right"></span></p><p><small>April 2014 – August 2015</small></p></div> <div class="collapse in" id="toshiba-job"> <div class="mdm-panel-body"> <!-- SUBCONT(IN)ENT im so funny --> </div> </div> </div> </div> </div> </div> For an expanded panel, simply change icon from down to up, and add "in" to content div: ... glyphicon-chevron-up ... <div class="collapse in mdm-panel-body" id="collapseOrderItems1"> Define Javascript collapser once on load $('.collapse').on('hide.bs.collapse show.bs.collapse', toggleCollapser ); CSS .mdm-nested-panel { margin-top: 1em; margin-left: 1em; } collapse.mdm-panel-body collapsing.mdm-panel-body { margin: 1em; } Common reusable function: function toggleCollapser(e) { $(e.target) .prev('.panel-heading') .find('.mdm-panel-collapser') .toggleClass('glyphicon-chevron-down glyphicon-chevron-up'); // Prevent bubble up to any parent collapsers. // This allows nested collapsers, whoop. e.stopPropagation(); }

D3

ALWAYS initialize incoming data Hard-earned data-import lessons: tsv() will do complete date formatting, so when you remove it to use JSON directly, you HAVE TO convert JSON timestamps of ANY kind to full Javascript date objects: var data = [{"date":"2017-04-01T04:00:00.000Z",... // MDM WE MUST MASSAGE DATA HERE // JSON VALUES ARE ALWAYS STRINGS, we need to change to Javascript DATE! // Incoming datasets need a bit of massaging. // We do that in a function so we can reuse it on incoming dataset updates. function initializeDataset(dataset) { // TIME ON X // Convert date strings to actual date values. // MDM MAKE SURE this matches the incoming format. // Adding date so we can run the chart across days without trouble. // var parseDate = d3.time.format("%H:%M:%S %m-%d-%Y").parse; // var parseDate = d3.timeParse("%Y %b %d"); var parseDate = d3.utcParse("%Y-%m-%dT%H:%M:%S.%LZ"); dataset.forEach(function(d) { // there is NO SKIPING THIS STEP, you have to get valid Javascript date objects out of JSON strings d.date = parseDate(d.date); // we WOULD have to divide all data by zero, // but we already grabbed post-data that was already converted // This WORKS but makes data / 10000 (very small numbers) //for (var i = 1, n = dataset.columns.length; i < n; ++i) d[dataset.columns[i]] = d[dataset.columns[i]] / 100; }); } initializeDataset(data); tsv() will create an ARRAY but it also jams in a columns PROPERY; it takes two steps to duplicate that: var data = [ {"date":"2015-06-15T04:00:00.000Z","Google Chrome":0.48090000000000005,...}, {"date":"2015-06-22T04:00:00.000Z","Google Chrome":0.48979999999999996,...), ]; data.columns = ["date","Google Chrome","Internet Explorer",... ]; ALWAYS set range and domain properly You have to know your display size (range) and the min and max of your data (domain), on each axis. From Mike's docs: D3’s scales specify a mapping from data space (domain) to display space (range). D3’s scales can also be used to interpolate many other types of display-space values, such as paths, color spaces and geometric transforms. var x = d3.scale.linear() .domain([0, d3.max(data)]) .range([0, 420]); Although x here looks like an object, it is also a function that returns the scaled display value in the range for a given data value in the domain. For example, an input value of 4 returns 40, and an input value of 16 returns 160. To use the new scale, simply replace the hard-coded multiplication by calling the scale function: d3.select(".chart") .selectAll("div") .data(data) .enter().append("div") .style("width", function(d) { return x(d) + "px"; }) .text(function(d) { return d; }); Watch out for Mike's examples where he (trickily) doesn't bother to set a domain because his data is in the [0..1] set, and that's the default domain, apparently.

RESTFul http
Verbs get - to make requests that are simple -response may be complex post - to push a form or JSON to the server

Javascript and JQuery

Formatting examples (numbers dates etc.) // Javascript sucks at dates. // d3 to the rescue! var parseInitDate = d3.utcParse("%Y-%m-%dT%H:%M:%SZ"); var initDate = parseInitDate(initial_managed_value_date); var initDateString = initDate.getUTCFullYear() +"/"+ (initDate.getUTCMonth()+1) +"/"+ initDate.getUTCDate() + " " + initDate.getUTCHours() + ":" + initDate.getUTCMinutes() + ":" + initDate.getUTCSeconds(); var rightNow = new Date; var initToNow_DecimalDays = parseFloat(rightNow - initDate) / 864e5; // 86,400,000 ms/day var initToNow_PercentOfYear = initToNow_DecimalDays / 365.0; var change_in_value = (parseFloat(total_managed_value) - parseFloat(initial_managed_value))/parseFloat(initial_managed_value); $('#initial_managed_value').val(initial_managed_value.toFixed(2)); $('#initial_managed_value_date').val(initDateString); $('#change_in_value').val((change_in_value*100.0).toFixed(1)+ "%"); $('#equivalent_apr').val((change_in_value/initToNow_PercentOfYear*100.0).toFixed(1)+ "%"); $('#total_managed_value_readonly').val(total_managed_value.toFixed(2)); Array vs Object lifetime // If the JSON data were an array, we would need to slice-to-clone to keep it around: // var dataCopy = data.slice(); // updateStockData(run,dataCopy); // We have an object so we can pass a reference, and it will keep the object around. Event handlers Three basic methods: Attach a function to an event of a specific element; charts.js example: var label = jQuery('<label class="btn btn-sm btn-'+color+'"></label>').appendTo(action_button_bar); var input = jQuery('<input class="run-'+cmd+'" type="checkbox" autocomplete="off" value="'+cycle.run+'">').appendTo(label) .on('change', cycle.owned? function(){ patchPick(this.value,'{ "action" : "run-hold" }'); } : function() { patchPick(this.value,'{ "action" : "run-buy" }'); }); var text = jQuery(' '+cmd+'').appendTo(label); Add a function handler once, for a class of elements; picks.js example: $("input[type='checkbox'][class='run-top' ]").change(function() { patchPick(this.value,'{ "action" : "run-move-top" }'); }); Event delegation: Javascript takes events and "bubbles them up" through the chain of parents; set up a handler on a parent to listen for these bubbles. Debug clicks on ANY PAGE Press F12 => Sources => Event Listener Breakpoints righthand pane => Mouse => [x] click B O O M we have it captured and can step into ANYTHING. JWT flow Client is easy! Client application API -------- ----------- | | | GET /api/employees | |----------------------------------------------------->| | 403 Forbidden | |<-----------------------------------------------------| | | | | | POST /api/authenticate | | { login: "john.doe", password: "password" } | |----------------------------------------------------->| | 200 Success | | { token: "my.personal.token" } | |<-----------------------------------------------------| | | | | | GET /api/employees | | Header { "Authorization: Token "my.personal.token" } | |----------------------------------------------------->| | 200 Success | |<-----------------------------------------------------| | |

Node.js

Node.js installation Node create a new module Register with npm A one-time registration is required on a new machine if you want to publish from it: npm adduser Username: moodboom Password: (see private) Email: (this IS public) [email protected] Publish a node module sudo npm install -g # keep doing this until you are happy with local install # update version in package.json # this creates a FULL "annotated" tag, not a "lightweight" tag that doesn't show up for [git describe] - it also removes the need for a separate commit git tag -a 1.0.5 -m "changes include..." git push && git push --tags # NOTE: bitpost has a git hook to push changes all the way up to github npm publish Update a node module's dependencies # make sure dependency in package.json has a carat at the beginning of its version (^x means "at least" version x) # make sure the dependency has a new version available - completely publish it first if it is your own # then you can simply reinstall from within the module folder to get all dependencies upgraded sudo npm install -g Develop several node modules at once Convert dependencies to use local packages instead of published versions, eg: cd ~/development/mah-haus npm install -S /home/m/development/thedigitalage/rad-scripts Then reinstall everything (local dependent modules, then parent modules, pita - consider links if doing longer-term dev) sudo npm install -g Then convert back to published versions as they become available (it's up to me to stabilize and publish new module versions): cd ~/development/mah-haus npm install -S rad-scripts auto AWS npm install -g aws-sdk Add credentials here: C:\Users\Administrator\.aws see existing scripts, anything is possible install bootstrap npm install -g grunt-cli mkdir mysite && cd mysite npm install bootstrap cd node_modules/bootstrap npm install # to actually pull down dependencies grunt dist # builds and minifies so you're good to go!

css
/* class="first second" */ .first.second {} /* class="first" OR class="second" */ .first, .second {} /* class="first second", or class="second", or class="third second", or class="second third" */ .second {} /* apply to any .child at any depth under .parent */ .parent .child {} /* apply to .child if it is DIRECTLY under .parent */ .parent > .child {}

SQL
Sqlite timestamp-to-readable-date query select quote, strftime('%d-%m-%Y %H:%M:%S', datetime(timestamp, 'unixepoch')) from StockQuotes as s where s.symbol="TSLA" order by timestamp;

Java

Scala

PHP
php debugging Tail these: tail -f /var/log/apache2/sitelogs/thedigitalage.org/ssl_error_log tail -f /var/log/ampache-tda/ampache.(today).log This leads to too much noise, not needed... emacs /etc/php/apache2-php5.3/php.ini display_errors = On /etc/init.d/apache restart

git

misc

SVN repo move across servers use a tool like VisualSVN to stop SVN server copy the repo's entire svn server directory, eg: c:\svn\Software copy it into the new server under a unique name, eg: c:\svn\NewSoftware use a tool like VisualSVN to restart SVN server You should now have the new code, accessible as usual from svn. NOTE from Tom: If you move code around, make sure you tag it, then copy the tag, to preserve history (as opposed to directly moving the folder). Weird but true. SQL Server 2008+ proper upsert using MERGE -- We need an "upsert": if record exists, update it, otherwise insert. -- There are several options to do that. -- Trying to do it correctly means... -- 1) use a lock or transaction to make the upsert atomic -- 2) use the best-available operation to maximize performance -- SQL Server 2008 has MERGE which may be slightly more efficient than -- separate check && (insert||update) steps. And we can do it with -- a single lock instead of a full transaction (which may be better?). -- It's messy to code up though since three blocks of fields must be specified. -- Cest la vie. MERGE [dbo].[FACT_DCSR_RemPeriodMonthlyReport] WITH (HOLDLOCK) AS rpmr USING (SELECT @ID AS ID) AS new_foo ON rpmr.ID = new_foo.ID @last_months_year as DCSRYear, @last_month as DCSRMonth, @last_month_name as MonthName, Device_Type_ID, WHEN MATCHED THEN UPDATE SET f.UpdateSpid = @@SPID, UpdateTime = SYSDATETIME() WHEN NOT MATCHED THEN INSERT ( ID, InsertSpid, InsertTime ) VALUES ( new_foo.ID, @@SPID, SYSDATETIME() ); Web Services Firefox Addon development c++ Create a portable autotools C++ project in linux (OLD, USE CMAKE NOW) For anything serious, it's best to clone an existing project's skeleton. main.cpp MVC code nix/copy_from folder make sure .bashrc is configured for boost nix$ bootstrap_autotools_project.sh force release debug set up eclipse according to screenshots in Eclipse c++ Create a portable C++ project in Visual Studio (OLD, USE CMAKE NOW) If you don't have existing code, it's probably best to create a project_name.cpp file with your main() function. int main( int argc, char * argv[] ) { return 0; } Then in Visual Studio... File->New->Project from existing code C++ (then use mostly defaults on this page, once you provide file location and project name) Project file location: <base>\project_name Project name: project_name [x] Add files from these folders Add subs [x] <base>\project_name NEXT Use Visual Studio Console application project No ATL, MFC, CLR NEXT NEXT FINISH Then add Reusable and boost include and lib paths: Example if you built boost according to notes below: Project->Properties->All Configurations->Configuration Properties->VC++ Directories->Include Directories-> $(VC_IncludePath);$(WindowsSDK_IncludePath);..\..\..\Reusable\c++ INCLUDE: C:\Software Development\boost_1_53_0 LIB: C:\Software Development\boost_1_53_0\stage\lib