- "Officially" added cregex - powerful regular expressions.
- Added back coption - command line argument parsing.
- Some changes in cstr and csview API.
- See detailed changes for version 3.
STC is a modern, templated, user-friendly, type-safe, very fast and compact container library for C99. The API is fairly similar to c++ STL, but a bit more uniform across the containers and takes inspiration from Rust and Python too. It is an advantage to know how these containers work in other languages, like Java, C# or C++, but it's not required.
This library allows you to manage both trivial to very complex data in a wide variety of containers without the need for boilerplate code. You may specify element-cloning, -comparison, -destruction and more on complex container hierarchies without resorting to cumbersome function pointers with type casting. Usage with trivial data types is simple to use compared to most generic container libraries for C because of its type safety with an intuitive and consistent API.
Three standout features of STC are
- the centralized analysis of template arguments: It assigns good defaults to non-specified templates. You may specify a number of "standard" template arguments for each container, but as minimum only one is required (two for maps). In the latter case, STC assumes the elements are basic types. For more complex types, additional template arguments must be defined.
- the general "heterogeneous lookup"-like feature: Allows specification of an alternative type to use
for lookup in containers. E.g. for containers with string type (cstr) elements,
const char*may be used as lookup type. It will then use the inputconst char*directly when comparing with the string data in the container. This avoids the construction of a newcstr(which possible allocates memory) for the lookup. Finally, destruction of the lookup key (i.e. string literal) after usage is not needed (or allowed), which is convenient in C. The alternative lookup type may also be used for adding entries into containers by using the emplace-functions. E.g.MyCStrVec_emplace_back(&vec, "Hello"), which further simplifies usage of STC. - the design of iterators: All container can be iterated the same way, and uses the
same element access syntax. E.g.
c_foreach (it, IntContainer, container) printf(" %d", *it.ref);will work for every type of container defined asIntContainerwithintelements. Also the formc_foreach (it, IntContainer, it1, it2)may be used to iterate fromit1up toit2.
The library is mature and well tested, so you may use it in projects. However, minor breaking API changes may still happen. The main development of this project is finished, but I will handle PRs with bugs and improvements in the future, and do minor modifications.
- carc - std::shared_ptr alike type
- carr2, carr3 - 2D and 3D array types
- cbits - std::bitset alike type
- cbox - std::unique_ptr alike type
- cdeq - std::deque alike type
- clist - std::forward_list alike type
- cmap - std::unordered_map alike type
- cpque - std::priority_queue alike type
- cset - std::unordered_set alike type
- csmap - std::map sorted map alike type
- csset - std::set sorted set alike type
- cstack - std::stack alike type
- cstr - std::string alike type
- csview - std::string_view alike type
- cvec - std::vector alike type
- ccommon - RAII and iterator macros
- coption - getopt() alike command line args parser
- crandom - A novel very fast PRNG named stc64
- cregex - Regular expression parser (extended from Rob Pike's regexp9)
- User friendly - Just include the headers and you are good. The API and functionality is very close to c++ STL, and is fully listed in the docs.
- Templates - Use
#define i_{arg}to specify container template arguments. There are templates for element-type, -comparison, -destruction, -cloning, -conversion types, and more. - Unparalleled performance - Some containers are much faster than the c++ STL containers, the rest are about equal in speed.
- Fully memory managed - All containers will destruct keys/values via destructor defined as macro parameters before including the container header. Also, shared pointers are supported and can be stored in containers, see carc.
- Fully type safe - Because of templating, it avoids error-prone casting of container types and elements back and forth from the containers.
- Uniform, easy-to-learn API - Methods to construct, initialize, iterate and destruct have uniform and intuitive usage across the various containers.
- Small footprint - Small source code and generated executables. The executable from the example below with six different containers is 22 kb in size compiled with gcc -Os on linux.
- Dual mode compilation - By default it is a simple header-only library with inline and static methods only, but you can easily switch to create a traditional library with shared symbols, without changing existing source files. See the Installation section.
- No callback functions - All passed template argument functions/macros are directly called from the implementation, no slow callbacks which requires storage.
- Compiles with C++ and C99 - C code can be compiled with C++ (container element types must be POD).
- Container prefix and forward declaration - Templated containers may have user defined prefix, e.g. myvec_push_back(). They may also be forward declared without including the full API/implementation. See documentation below.
Benchmark notes:
- The barchart shows average test times over three platforms: Mingw64 10.30, Win-Clang 12, VC19. CPU: Ryzen 7 2700X CPU @4Ghz.
- Containers uses value types
uint64_tand pairs ofuint64_tfor the maps. - Black bars indicates performance variation between various platforms/compilers.
- Iterations are repeated 4 times over n elements.
- find(): not executed for forward_list, deque, and vector because these c++ containers does not have native find().
- deque: insert: n/3 push_front(), n/3 push_back()+pop_front(), n/3 push_back().
- map and unordered map: insert: n/2 random numbers, n/2 sequential numbers. erase: n/2 keys in the map, n/2 random keys.
The usage of the containers is similar to the c++ standard containers in STL, so it should be easy if you are familiar with them. All containers are generic/templated, except for cstr and cbits. No casting is used, so containers are type-safe like templates in c++. A basic usage example:
#define i_type FVec // if not defined, vector type would be cvec_float
#define i_val float // element type
#include <stc/cvec.h> // defines the FVec type
int main(void) {
FVec vec = FVec_init();
FVec_push_back(&vec, 10.f);
FVec_push_back(&vec, 20.f);
FVec_push_back(&vec, 30.f);
for (size_t i = 0; i < FVec_size(vec); ++i)
printf(" %g", vec.data[i]);
FVec_drop(&vec); // free memory
}An alternative and often preferred way to write this code with STL is:
int main(void) {
c_auto (FVec, vec) // RAII - specify create and destruct at one place.
{
c_apply(v, FVec_push_back(&vec, *v), float, {10.f, 20.f, 30.f});
c_foreach (i, FVec, vec) // generic iteration and element access
printf(" %g", *i.ref);
}
}In order to include two cvecs with different element types, include cvec.h twice. For struct, a i_cmp
compare function is required to enable sorting and searching (< and == operators is default and works
for integral types only). Alternatively, #define i_opt c_no_cmp to disable methods using comparison.
Similarly, if a destructor i_valdrop is defined, either define a i_valclone clone function
or #define i_opt c_no_clone to disable cloning and emplace methods. Unless these requirements are met,
compile errors are generated.
#define i_val struct One
#define i_opt c_no_cmp
#define i_tag one
#include <stc/cvec.h>
#define i_val struct Two
#define i_opt c_no_cmp
#define i_tag two
#include <stc/cvec.h>
...
cvec_one v1 = cvec_one_init();
cvec_two v2 = cvec_two_init();With six different containers:
#include <stdio.h>
#include <stc/ccommon.h>
struct Point { float x, y; };
int Point_cmp(const struct Point* a, const struct Point* b) {
int cmp = c_default_cmp(&a->x, &b->x);
return cmp ? cmp : c_default_cmp(&a->y, &b->y);
}
#define i_key int
#include <stc/cset.h> // cset_int: unordered set
#define i_val struct Point
#define i_cmp Point_cmp
#define i_tag pnt
#include <stc/cvec.h> // cvec_pnt: vector of struct Point
#define i_val int
#include <stc/cdeq.h> // cdeq_int: deque of int
#define i_val int
#include <stc/clist.h> // clist_int: singly linked list
#define i_val int
#include <stc/cstack.h>
#define i_key int
#define i_val int
#include <stc/csmap.h> // csmap_int: sorted map int => int
int main(void) {
// define six containers with automatic call of init and drop (destruction after scope exit)
c_auto (cset_int, set)
c_auto (cvec_pnt, vec)
c_auto (cdeq_int, deq)
c_auto (clist_int, lst)
c_auto (cstack_int, stk)
c_auto (csmap_int, map)
{
// add some elements to each container
c_apply(v, cset_int_insert(&set, *v), int, {10, 20, 30});
c_apply(v, cvec_pnt_push_back(&vec, *v), struct Point, { {10, 1}, {20, 2}, {30, 3} });
c_apply(v, cdeq_int_push_back(&deq, *v), int, {10, 20, 30});
c_apply(v, clist_int_push_back(&lst, *v), int, {10, 20, 30});
c_apply(v, cstack_int_push(&stk, *v), int, {10, 20, 30});
c_apply(v, csmap_int_insert(&map, c_pair(v)),
csmap_int_raw, { {20, 2}, {10, 1}, {30, 3} });
// add one more element to each container
cset_int_insert(&set, 40);
cvec_pnt_push_back(&vec, (struct Point){40, 4});
cdeq_int_push_front(&deq, 5);
clist_int_push_front(&lst, 5);
cstack_int_push(&stk, 40);
csmap_int_insert(&map, 40, 4);
// find an element in each container
cset_int_iter i1 = cset_int_find(&set, 20);
cvec_pnt_iter i2 = cvec_pnt_find(&vec, (struct Point){20, 2});
cdeq_int_iter i3 = cdeq_int_find(&deq, 20);
clist_int_iter i4 = clist_int_find(&lst, 20);
csmap_int_iter i5 = csmap_int_find(&map, 20);
printf("\nFound: %d, (%g, %g), %d, %d, [%d: %d]\n", *i1.ref, i2.ref->x, i2.ref->y,
*i3.ref, *i4.ref,
i5.ref->first, i5.ref->second);
// erase the elements found
cset_int_erase_at(&set, i1);
cvec_pnt_erase_at(&vec, i2);
cdeq_int_erase_at(&deq, i3);
clist_int_erase_at(&lst, i4);
csmap_int_erase_at(&map, i5);
printf("After erasing elements found:");
printf("\n set:"); c_foreach (i, cset_int, set) printf(" %d", *i.ref);
printf("\n vec:"); c_foreach (i, cvec_pnt, vec) printf(" (%g, %g)", i.ref->x, i.ref->y);
printf("\n deq:"); c_foreach (i, cdeq_int, deq) printf(" %d", *i.ref);
printf("\n lst:"); c_foreach (i, clist_int, lst) printf(" %d", *i.ref);
printf("\n stk:"); c_foreach (i, cstack_int, stk) printf(" %d", *i.ref);
printf("\n map:"); c_foreach (i, csmap_int, map) printf(" [%d: %d]", i.ref->first,
i.ref->second);
}
}Output
Found: 20, (20, 2), 20, 20, [20: 2]
After erasing elements found:
set: 10 30 40
vec: (10, 1) (30, 3) (40, 4)
deq: 5 10 30
lst: 5 10 30
stk: 10 20 30 40
map: [10: 1] [30: 3] [40: 4]
8000
Because it is headers-only, headers can simply be included in your program. By default, functions are static (some inlined). You may add the include folder to the CPATH environment variable to let GCC, Clang, and TinyC locate the headers.
If containers are used across several translation units with common instantiated container types, it is
recommended to build as a "library" with external linking to minimize executable size. To enable this,
specify -DSTC_HEADER as compiler option in your build environment. Next, place all the instantiations
of the containers used inside a single C-source file as in the example below, and #define STC_IMPLEMENT at top.
You may also cherry-pick shared linking mode on individual containers by #define i_header and
#define i_implement, or force static symbols by #define i_static before container includes.
As a special case, there may be non-templated functions in templated containers that should be implemented only
once if needed. Currently, for clist, define i_extern before including clist.h for sorting functionality
(global STC_EXTERN may alternatively be defined).
Conveniently, src\libstc.c implements non-templated functions as shared symbols for cstr, csview,
cbits and crandom. When building in shared mode (-DSTC_HEADER), you may include this file in your project,
or define your own as descibed above.
// stc_libs.c
#define STC_IMPLEMENT
#include <stc/cstr.h>
#include "Point.h"
#define i_key int
#define i_val int
#define i_tag ii
#include <stc/cmap.h> // cmap_ii: int => int
#define i_key int64_t
#define i_tag ix
#include <stc/cset.h> // cset_ix
#define i_val int
#include <stc/cvec.h> // cvec_int
#define i_val Point
#define i_tag pnt
#include <stc/clist.h> // clist_pntEach templated type requires one #include, even if it's the same container base type, as described earlier.
The template parameters are given by a #define i_xxxx statement, where xxxx is the parameter name.
The list of template parameters:
i_key- Element key type for map/set only. [required].i_val- Element value type. [required for] cmap/csmap, it is the mapped value type.i_cmp- Three-way comparison of two i_keyraw* or i_valraw* - [required for] non-integral i_keyraw types unless i_opt is defined with c_no_cmp.i_hash- Hash function taking i_keyraw* - defaults to c_default_hash. [required for] non-POD keyraw types.i_eq- Equality comparison of two i_keyraw* - defaults to !i_cmp. Companion with i_hash.
Properties:
i_tag- Container type name tag. Defaults to i_key name.i_type- Full container type name. Alternative to i_tag.i_opt- Boolean properties: may combine c_no_cmp, c_no_clone, c_no_atomic, c_is_fwd, c_static, c_header with the | separator.
Key:
i_keydrop- Destroy map/set key func - defaults to empty destructor.i_keyclone- [required if] i_keydrop is defined (not required for carc).i_keyraw- Convertion "raw" type - defaults to i_key.i_keyfrom- Convertion func i_key <- i_keyraw. [required if] i_keyraw is definedi_keyto- Convertion func i_key* -> i_keyraw.
Val:
i_valdrop- Destroy mapped or value func - defaults to empty destruct.i_valclone- [required if] i_valdrop is defined.i_valraw- Convertion "raw" type - defaults to i_val.i_valfrom- Convertion func i_val <- i_valraw.i_valto- Convertion func i_val* -> i_valraw.
Specials:
i_key_str- Define key type cstr and container i_tag = str. It binds type convertion from/to const char*, and the cmp, eq, hash, and keydrop functions.i_key_ssv- Define key type cstr and container i_tag = ssv. It binds type convertion from/to csview, and its cmp, eq, hash, and keydrop functions.i_key_arcbox TYPE- Define container key type where TYPE is a smart pointer carc or cbox. NB: not to be used when defining carc/cbox types themselves.i_key_bind TYPE- General version of the two above - will auto-bind to standard named functions: TYPE_clone, TYPE_drop, TYPE_cmp, TYPE_eq, TYPE_hash. Ifi_keyrawis defined, TYPE_toraw func. is bound toi_keyto. Only functions required by the particular container need to be defined. E.g., only cmap and cset and smart pointers uses TYPE_hash and TYPE_eq. cstack does not use TYPE_cmp. TYPE_clone is not used if #define i_opt c_no_clone is specified. Likewise, TYPE_cmp is not used if #define i_opt c_no_cmp is specified.i_val_str,i_val_bind,i_val_arcbox- Similar rules as for key.
Notes:
- Instead of defining
i_cmp, you may define i_opt c_no_cmp to disable searching and sorting functions. - Instead of defining
i_*clone, you may define i_opt c_no_clone to disable emplace and clone-functions. i_keyraw RAWTYPE- If defined along with i_key_bind, the two functions TYPE TYPE_from(RAWTYPE) and RAWTYPE TYPE_toraw(TYPE*) are expected in addition to TYPE TYPE_clone(TYPE). Note the signature for cmp, eq, hash now: int RAWTYPE_cmp(const RAWTYPE*, const RAWTYPE*), and similar for the two others.
STC, like c++ STL, has two sets of methods for adding elements to containers. One set begins with emplace, e.g. cvec_X_emplace_back(). This is a convenient alternative to cvec_X_push_back() when dealing non-trivial container elements, e.g. strings, shared pointers or other elements using dynamic memory or shared resources.
The emplace methods constructs or clones the given elements when they are added to the container. In contrast, the non-emplace methods moves the given elements into the container.
Note: For containers with integral/trivial element types, or when neither i_keyraw/i_valraw is defined,
the emplace functions are not available (or needed), as it can easier lead to mistakes.
| non-emplace: Move | emplace: Embedded copy | Container |
|---|---|---|
| insert(), push() | emplace() | cmap, csmap, cset, csset |
| insert_or_assign() | emplace_or_assign() | cmap, csmap |
| push() | emplace() | cqueue, cpque, cstack |
| push_back(), push() | emplace_back() | cdeq, clist, cvec |
| push_front() | emplace_front() | cdeq, clist |
Strings are the most commonly used non-trivial data type. STC containers have proper pre-defined definitions for cstr container elements, so they are fail-safe to use both with the emplace and non-emplace methods:
#define i_implement // define in ONE file to implement longer functions in cstr
#include <stc/cstr.h>
#define i_val_str // special macro to enable container of cstr
#include <stc/cvec.h> // vector of string (cstr)
...
c_auto (cvec_str, vec) // declare and call cvec_str_init() and defer cvec_str_drop(&vec)
c_autovar (cstr s = cstr_new("a string literal"), cstr_drop(&s)) // c_autovar is a more general c_auto.
{
const char* hello = "Hello";
cvec_str_push_back(&vec, cstr_from(hello); // construct and add string from const char*
cvec_str_push_back(&vec, cstr_clone(s)); // clone and append a cstr
cvec_str_emplace_back(&vec, "Yay, literal"); // internally constructs cstr from const char*
cvec_str_emplace_back(&vec, cstr_clone(s)); // <-- COMPILE ERROR: expects const char*
cvec_str_emplace_back(&vec, cstr_str(&s)); // Ok: const char* input type.
}This is made possible because the type configuration may be given an optional conversion/"rawvalue"-type as template parameter, along with a back and forth conversion methods to the container value type.
Rawvalues are primarily beneficial for lookup and map insertions, however the
emplace methods constructs cstr-objects from the rawvalues, but only when required:
cmap_str_emplace(&map, "Hello", "world");
// Two cstr-objects were constructed by emplace
cmap_str_emplace(&map, "Hello", "again");
// No cstr was constructed because "Hello" was already in the map.
cmap_str_emplace_or_assign(&map, "Hello", "there");
// Only cstr_new("there") constructed. "world" was destructed and replaced.
cmap_str_insert(&map, cstr_new("Hello"), cstr_new("you"));
// Two cstr's constructed outside call, but both destructed by insert
// because "Hello" existed. No mem-leak but less efficient.
it = cmap_str_find(&map, "Hello");
// No cstr constructed for lookup, although keys are cstr-type.Apart from strings, maps and sets are normally used with trivial value types. However, the last example on the cmap page demonstrates how to specify a map with non-trivial keys.
| Name | Description | Container |
|---|---|---|
| erase() | key based | csmap, csset, cmap, cset, cstr |
| erase_at() | iterator based | csmap, csset, cmap, cset, cvec, cdeq, clist |
| erase_range() | iterator based | csmap, csset, cvec, cdeq, clist |
| erase_n() | index based | cvec, cdeq, cstr |
| remove() | remove all matching values | clist |
It is possible to forward declare containers. This is useful when a container is part of a struct, but still not expose or include the full implementation / API of the container.
// Header file
#include <stc/forward.h> // only include data structures
forward_cstack(cstack_pnt, struct Point); // declare cstack_pnt and cstack_pnt_value, cstack_pnt_iter;
// the element may be forward declared type as well
typedef struct Dataset {
cstack_pnt vertices;
cstack_pnt colors;
} Dataset;
...
// Implementation
#define c_opt c_is_fwd // flag that the container was forward declared.
#define i_val struct Point
#define i_tag pnt
#include <stc/cstack.h>Define i_type instead of i_tag:
#define i_type MyVec
#define i_val int
#include <stc/cvec.h>
myvec vec = MyVec_init();
MyVec_push_back(&vec, 1);
...- cstr, cvec: Type size: 1 pointer. The size and capacity is stored as part of the heap allocation that also holds the vector elements.
- clist: Type size: 1 pointer. Each node allocates a struct which stores the value and next pointer.
- cdeq: Type size: 2 pointers. Otherwise like cvec.
- cmap: Type size: 4 pointers. cmap uses one table of keys+value, and one table of precomputed hash-value/used bucket, which occupies only one byte per bucket. The closed hashing has a default max load factor of 85%, and hash table scales by 1.6x when reaching that.
- csmap: Type size: 1 pointer. csmap manages its own array of tree-nodes for allocation efficiency. Each node uses only two 32-bit ints for child nodes, and one byte for
level. - carr2, carr3: Type size: 1 pointer plus dimension variables. Arrays are allocated as one contiguous block of heap memory, and one allocation for pointers of indices to the array.
- carc: Type size: 2 pointers, one for the data and one for the reference counter.
- Overhauled some cstr and csview API:
- Changed cstr_replace*() =>
cstr_replace_at*(self, pos, len, repl): Replace at specific position. - Changed
cstr_replace_all() cstr_replace*(self, search, repl, count): Replace count occurences. - Renamed
cstr_find_from()=>cstr_find_at() - Renamed
cstr_*_u8()=>cstr_u8_*() - Renamed
csview_*_u8()=>csview_u8_*() - Added cstr_u8_slice() and csview_u8_slice().
- Removed
csview_from_s(): Usecstr_sv(s)instead. - Removed
csview_from_n(): Usec_sv(str, n)instead. - Added back file coption.h
- Simplified cbits usage: all inlined.
- Updated docs.
- Changed cstr_replace*() =>
- NB! Changed self argument from value to const pointer on containers (does not apply to cstr):
CNT_size(const CNT *self)CNT_capacity(const CNT *self)CNT_empty(const CNT *self)
- Now both cstack and cbits can be used with template
i_capparameter:#define i_cap <NUM>. They then use fixed sized arrays, and no heap allocated memory. - Renamed cstr_rename_n() => cstr_rename_with_n() as it could be confused with replacing n instances instead of n bytes.
- Renamed macro c_apply_arr() => c_apply_array()
- Fixed bug in
csmap.h: begin() on empty map was not fully initialized.
- Swapped to new cstr (short string optimized, aka SSO). Note that
cstr_str(&s)must be used,s.stris no longer usable. - Removed redundant size argument to
i_hashtemplate parameter andc_default_hash. Please update your code. - Added general
i_keyclone/i_valclonetemplate parameter: containers of smart pointers (carc, cbox) now correctly cloned. - Allows for
i_key*template parameters instead ofi_val*for all containers, not only for cset and csset. - Optimized c_default_hash(). Therefore c_hash32() and c_hash64() are removed (same speed).
- Added .._push() and .._emplace() function to all containers to allow for more generic coding.
- Renamed global PRNGs stc64_random() and stc64_srandom() to crandom() and csrandom().
- Added some examples and benchmarks for SSO and heterogenous lookup comparison with c++20 (string_bench_*.cpp).
- Renamed: all _del to
_drop(like destructors in Rust). - Renamed: all _compare to
_cmp - Renamed: i_equ to
i_eq, and _equalto to_eq. - Renamed: i_cnt to
i_typefor defining the complete container type name. - Renamed: type csptr to carc (atomic reference counted) smart pointer.
- Renamed: i_key_csptr / i_val_csptr to
i_key_arcbox/i_val_arcboxfor specifying carc and cbox values in containers. - Renamed: csptr_X_make() to
carc_X_from(). - Renamed: cstr_lit() to
cstr_new(literal), and cstr_assign_fmt() tocstr_printf(). - Renamed: c_default_fromraw() to
c_default_from(). - Changed: the c_apply macros API.
- Replaced: csview_first_token() and csview_next_token() with one function:
csview_token(). - Added: checkauto tool for checking that c-source files uses
c_auto*macros correctly. - Added: general
i_key_bind/i_val_bindtemplate parameters which auto-binds template functions. - Added:
i_opttemplate parameter: compile-time options:c_no_cmp,c_no_clone,c_no_atomic,c_is_fwd; may be combined with| - Added: cbox type: smart pointer, similar to Rust Box and std::unique_ptr.
- Added: c_forpair macro: for-loop with "structured binding"
Replace (regular expression) globally in code base (VS Code):
_del\b⟶_drop_compare\b⟶_cmp_rawvalue\b⟶_raw_equ\b⟶_eq
Replace (whole word + match case):
i_keydel⟶i_keydropi_valdel⟶i_valdropi_cnt⟶i_typecstr_lit⟶cstr_newi_key_sptr⟶i_key_arcboxi_val_sptr⟶i_val_arcbox
Non-regex, global match case replace:
csptr⟶carc