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diff --git a/docs/ccommon_api.md b/docs/ccommon_api.md deleted file mode 100644 index 7a3c3196..00000000 --- a/docs/ccommon_api.md +++ /dev/null @@ -1,505 +0,0 @@ -# STC Algorithms - ---- -## Ranged for-loops - -### c_foreach, c_foreach_rv, c_forpair - -| Usage | Description | -|:-----------------------------------------|:------------------------------------------| -| `c_foreach (it, ctype, container)` | Iteratate all elements | -| `c_foreach (it, ctype, it1, it2)` | Iterate the range [it1, it2) | -| `c_foreach_rv (it, ctype, container)` | Iteratate in reverse (cstack, cvec, cdeq) | -| `c_forpair (key, val, ctype, container)` | Iterate with structured binding | - -```c -#define i_key int -#define i_val int -#define i_tag ii -#include <stc/csmap.h> -... -csmap_ii map = c_make(csmap_ii, { {23,1}, {3,2}, {7,3}, {5,4}, {12,5} }); - -c_foreach (i, csmap_ii, map) - printf(" %d", i.ref->first); -// 3 5 7 12 23 -// same without using c_foreach: -for (csmap_ii_iter i = csmap_ii_begin(&map); i.ref; csmap_ii_next(&i)) - printf(" %d", i.ref->first); - -csmap_ii_iter it = csmap_ii_find(&map, 7); -// iterate from it to end -c_foreach (i, csmap_ii, it, csmap_ii_end(&map)) - printf(" %d", i.ref->first); -// 7 12 23 - -// structured binding: -c_forpair (id, count, csmap_ii, map) - printf(" (%d %d)", *_.id, *_.count); -// (3 2) (5 4) (7 3) (12 5) (23 1) -``` - -### c_forlist -Iterate compound literal array elements. Additional to `i.ref`, you can access `i.data`, `i.size`, and `i.index` of the input list/element. -```c -// apply multiple push_backs -c_forlist (i, int, {1, 2, 3}) - cvec_i_push_back(&vec, *i.ref); - -// insert in existing map -c_forlist (i, cmap_ii_raw, { {4, 5}, {6, 7} }) - cmap_ii_insert(&map, i.ref->first, i.ref->second); - -// string literals pushed to a stack of cstr: -c_forlist (i, const char*, {"Hello", "crazy", "world"}) - cstack_str_emplace(&stk, *i.ref); -``` - ---- -## Range algorithms - -### c_forrange -Abstraction for iterating sequence of integers. Like python's **for** *i* **in** *range()* loop. - -| Usage | Python equivalent | -|:---------------------------------------------|:-------------------------------------| -| `c_forrange (stop)` | `for _ in range(stop):` | -| `c_forrange (i, stop) // i type = long long` | `for i in range(stop):` | -| `c_forrange (i, start, stop)` | `for i in range(start, stop):` | -| `c_forrange (i, start, stop, step)` | `for i in range(start, stop, step):` | - -```c -c_forrange (5) printf("x"); -// xxxxx -c_forrange (i, 5) printf(" %lld", i); -// 0 1 2 3 4 -c_forrange (i, -3, 3) printf(" %lld", i); -// -3 -2 -1 0 1 2 -c_forrange (i, 30, 0, -5) printf(" %lld", i); -// 30 25 20 15 10 5 -``` - -### crange -A number sequence generator type, similar to [boost::irange](https://www.boost.org/doc/libs/release/libs/range/doc/html/range/reference/ranges/irange.html). The **crange_value** type is `long long`. Below *start*, *stop*, and *step* are of type *crange_value*: -```c -crange& crange_obj(...) // create a compound literal crange object -crange crange_make(stop); // will generate 0, 1, ..., stop-1 -crange crange_make(start, stop); // will generate start, start+1, ... stop-1 -crange crange_make(start, stop, step); // will generate start, start+step, ... upto-not-including stop - // note that step may be negative. -crange_iter crange_begin(crange* self); -crange_iter crange_end(crange* self); -void crange_next(crange_iter* it); - -// 1. All primes less than 32: -crange r1 = crange_make(3, 32, 2); -printf("2"); // first prime -c_forfilter (i, crange, r1, isPrime(*i.ref)) - printf(" %lld", *i.ref); -// 2 3 5 7 11 13 17 19 23 29 31 - -// 2. The first 11 primes: -printf("2"); -c_forfilter (i, crange, crange_obj(3, INT64_MAX, 2), - isPrime(*i.ref) && - c_flt_take(10) -){ - printf(" %lld", *i.ref); -} -// 2 3 5 7 11 13 17 19 23 29 31 -``` - -### c_forfilter -Iterate a container/range with chained range filtering. - -| Usage | Description | -|:----------------------------------------------------|:---------------------------------------| -| `c_forfilter (it, ctype, container, filter)` | Filter out items in chain with && | -| `c_forfilter_it (it, ctype, startit, filter)` | Filter from startit position | - -| Built-in filter | Description | -|:----------------------------------|:-------------------------------------------| -| `c_flt_skip(it, numItems)` | Skip numItems (inc count) | -| `c_flt_take(it, numItems)` | Take numItems (inc count) | -| `c_flt_skipwhile(it, predicate)` | Skip items until predicate is false | -| `c_flt_takewhile(it, predicate)` | Take items until predicate is false | -| `c_flt_counter(it)` | Increment current and return count | -| `c_flt_getcount(it)` | Number of items passed skip*/take*/counter | - -[ [Run this example](https://godbolt.org/z/n9aYrYPv8) ] -```c -#include <stc/calgo.h> -#include <stdio.h> - -bool isPrime(long long i) { - for (long long j=2; j*j <= i; ++j) - if (i % j == 0) return false; - return true; -} - -int main() { - // Get 10 prime numbers starting from 1000. Skip the first 15 primes, - // then select every 25th prime (including the initial). - crange R = crange_make(1001, INT64_MAX, 2); // 1001, 1003, ... - - c_forfilter (i, crange, R, - isPrime(*i.ref) && - c_flt_skip(i, 15) && - c_flt_counter(i) % 25 == 1 && - c_flt_take(i, 10) - ){ - printf(" %lld", *i.ref); - } -} -// out: 1097 1289 1481 1637 1861 2039 2243 2417 2657 2803 -``` -Note that `c_flt_take()` and `c_flt_takewhile()` breaks the loop on false. - ---- -## Generic algorithms - -### c_make, c_drop - -Make any container from an initializer list: -```c -#define i_val_str // owned cstr string value type -#include <stc/cset.h> - -#define i_key int -#define i_val int -#include <stc/cmap.h> -... -// Initializes with const char*, internally converted to cstr! -cset_str myset = c_make(cset_str, {"This", "is", "the", "story"}); -cset_str myset2 = c_clone(myset); - -int x = 7, y = 8; -cmap_int mymap = c_make(cmap_int, { {1, 2}, {3, 4}, {5, 6}, {x, y} }); -``` -Drop multiple containers of the same type: -```c -c_drop(cset_str, &myset, &myset2); -``` - -### c_find_if, c_erase_if, c_eraseremove_if -Find or erase linearily in containers using a predicate -- For `c_find_if(iter, C, c, pred)`, ***iter*** is in/out and must be declared prior to call. -- Use `c_erase_if(iter, C, c, pred)` with **clist**, **cmap**, **cset**, **csmap**, and **csset**. -- Use `c_eraseremove_if(iter, C, c, pred)` with **cstack**, **cvec**, **cdeq**, and **cqueue**. -```c -// Search vec for first value > 2: -cvec_i_iter i; -c_find_if(i, cvec_i, vec, *i.ref > 2); -if (i.ref) printf("%d\n", *i.ref); - -// Erase all values > 2 in vec: -c_eraseremove_if(i, cvec_i, vec, *i.ref > 2); - -// Search map for a string containing "hello" and erase it: -cmap_str_iter it, it1 = ..., it2 = ...; -c_find_if(it, csmap_str, it1, it2, cstr_contains(it.ref, "hello")); -if (it.ref) cmap_str_erase_at(&map, it); - -// Erase all strings containing "hello" in a sorted map: -c_erase_if(i, csmap_str, map, cstr_contains(i.ref, "hello")); -``` - -### csort - two times faster qsort - -When very fast array sorting is required, **csort** is about twice as fast as *qsort()*, and often simpler to use. -You may customize `i_tag` and the comparison function `i_cmp` or `i_less`. - -There is a [benchmark/test file here](../misc/benchmarks/various/csort_bench.c). -```c -#define i_val int -#include <stc/algo/csort.h> - -int main() { - int array[] = {5, 3, 5, 9, 7, 4, 7, 2, 4, 9, 3, 1, 2, 6, 4}; - csort_int(array, c_arraylen(array)); -} -``` - - -### c_new, c_delete - -- `c_new(Type, val)` - Allocate *and init* a new object on the heap -- `c_delete(Type, ptr)` - Drop *and free* an object allocated on the heap. NULL is OK. -```c -#include <stc/cstr.h> - -cstr *str_p = c_new(cstr, cstr_from("Hello")); -printf("%s\n", cstr_str(str_p)); -c_delete(cstr, str_p); -``` - -### c_malloc, c_calloc, c_realloc, c_free -Memory allocator wrappers that uses signed sizes. - -### c_arraylen -Return number of elements in an array. array must not be a pointer! -```c -int array[] = {1, 2, 3, 4}; -intptr_t n = c_arraylen(array); -``` - -### c_swap, c_const_cast -```c -// Safe macro for swapping internals of two objects of same type: -c_swap(cmap_int, &map1, &map2); - -// Type-safe casting a from const (pointer): -const char cs[] = "Hello"; -char* s = c_const_cast(char*, cs); // OK -int* ip = c_const_cast(int*, cs); // issues a warning! -``` - -### Predefined template parameter functions - -**crawstr** - Non-owned `const char*` "class" element type: `#define i_valclass crawstr` -```c -typedef const char* crawstr; -int crawstr_cmp(const crawstr* x, const crawstr* y); -bool crawstr_eq(const crawstr* x, const crawstr* y); -uint64_t crawstr_hash(const crawstr* x); -``` -Default implementations -```c -int c_default_cmp(const Type*, const Type*); // <=> -bool c_default_less(const Type*, const Type*); // < -bool c_default_eq(const Type*, const Type*); // == -uint64_t c_default_hash(const Type*); -Type c_default_clone(Type val); // return val -Type c_default_toraw(const Type* p); // return *p -void c_default_drop(Type* p); // does nothing -``` - ---- -## Coroutines -This is a much improved implementation of -[Simon Tatham's coroutines](https://www.chiark.greenend.org.uk/~sgtatham/coroutines.html), -which utilizes the *Duff's device* trick. Tatham's implementation is not typesafe, -and it always allocates the coroutine's internal state dynamically. But crucially, -it does not let the coroutine do self-cleanup on early finish - i.e. it -only frees the initial dynamically allocated memory. - -In this implementation, a coroutine may have any signature, but it should -take a struct pointer as parameter, which must contain the member `int cco_state;` -The struct should normally store all the *local* variables to be used in the -coroutine. It can also store input and output data if desired. - -The coroutine example below generates Pythagorian triples, but the calling loop -skips the triples which are upscaled version of smaller ones, by checking -the gcd() function. It also ensures that it stops when the diagonal size >= 100: - -[ [Run this code](https://godbolt.org/z/coqqrfbd5) ] -```c -#include <stc/calgo.h> - -struct triples { - int n; // input: max number of triples to be generated. - int a, b, c; - int cco_state; // required member -}; - -bool triples_next(struct triples* i) { // coroutine - cco_begin(i); - for (i->c = 5; i->n; ++i->c) { - for (i->a = 1; i->a < i->c; ++i->a) { - for (i->b = i->a + 1; i->b < i->c; ++i->b) { - if ((int64_t)i->a*i->a + (int64_t)i->b*i->b == (int64_t)i->c*i->c) { - cco_yield(true); - if (--i->n == 0) cco_return; - } - } - } - } - cco_final: // required label - puts("done"); - cco_end(false); -} - -int gcd(int a, int b) { // greatest common denominator - while (b) { - int t = a % b; - a = b; - b = t; - } - return a; -} - -int main() -{ - struct triples t = {.n=INT32_MAX}; - int n = 0; - - while (triples_next(&t)) { - // Skip triples with GCD(a,b) > 1 - if (gcd(t.a, t.b) > 1) - continue; - - // Stop when c >= 100 - if (t.c < 100) - printf("%d: [%d, %d, %d]\n", ++n, t.a, t.b, t.c); - else - cco_stop(&t); // cleanup in next coroutine call/resume - } -} -``` -### Coroutine API -**Note**: *cco_yield()* may not be called inside a `switch` statement. Use `if-else-if` constructs instead. -To resume the coroutine from where it was suspended with *cco_yield()*, simply call the coroutine again. - -| | Function / operator | Description | -|:----------|:-------------------------------------|:----------------------------------------| -| | `cco_final:` | Obligatory label in coroutine | -| | `cco_return;` | Early return from the coroutine | -| `bool` | `cco_alive(ctx)` | Is coroutine in initial or suspended state? | -| `bool` | `cco_suspended(ctx)` | Is coroutine in suspended state? | -| `void` | `cco_begin(ctx)` | Begin coroutine block | -| `rettype` | `cco_end(retval)` | End coroutine block with return value | -| `void` | `cco_end()` | End coroutine block | -| `rettype` | `cco_yield(retval)` | Suspend execution and return a value | -| `void` | `cco_yield()` | Suspend execution | -| `rettype` | `cco_yield(corocall2, ctx2, retval)` | Yield from another coroutine and return val | -| `void` | `cco_yield(corocall2, ctx2)` | Yield from another coroutine | -| | From the caller side: | | -| `void` | `cco_stop(ctx)` | Next call of coroutine returns `cco_end()` | -| `void` | `cco_reset(ctx)` | Reset state to initial (for reuse) | - ---- -## RAII scope macros -General ***defer*** mechanics for resource acquisition. These macros allows you to specify the -freeing of the resources at the point where the acquisition takes place. -The **checkauto** utility described below, ensures that the `c_auto*` macros are used correctly. - -| Usage | Description | -|:---------------------------------------|:----------------------------------------------------------| -| `c_defer (drop...)` | Defer `drop...` to end of scope | -| `c_scope (init, drop)` | Execute `init` and defer `drop` to end of scope | -| `c_scope (init, pred, drop)` | Adds a predicate in order to exit early if init failed | -| `c_with (Type var=init, drop)` | Declare `var`. Defer `drop...` to end of scope | -| `c_with (Type var=init, pred, drop)` | Adds a predicate in order to exit early if init failed | -| `c_auto (Type, var1,...,var4)` | `c_with (Type var1=Type_init(), Type_drop(&var1))` ... | -| `continue` | Exit a defer-block without resource leak | - -```c -// `c_defer` executes the expression(s) when leaving scope. -cstr s1 = cstr_lit("Hello"), s2 = cstr_lit("world"); -c_defer (cstr_drop(&s1), cstr_drop(&s2)) -{ - printf("%s %s\n", cstr_str(&s1), cstr_str(&s2)); -} - -// `c_scope` syntactically "binds" initialization and defer. -static pthread_mutex_t mut; -c_scope (pthread_mutex_lock(&mut), pthread_mutex_unlock(&mut)) -{ - /* Do syncronized work. */ -} - -// `c_with` is similar to python `with`: declare a variable and defer the drop call. -c_with (cstr str = cstr_lit("Hello"), cstr_drop(&str)) -{ - cstr_append(&str, " world"); - printf("%s\n", cstr_str(&str)); -} - -// `c_auto` automatically initialize and drops up to 4 variables: -c_auto (cstr, s1, s2) -{ - cstr_append(&s1, "Hello"); - cstr_append(&s1, " world"); - cstr_append(&s2, "Cool"); - cstr_append(&s2, " stuff"); - printf("%s %s\n", cstr_str(&s1), cstr_str(&s2)); -} -``` -**Example 1**: Use multiple **c_with** in sequence: -```c -bool ok = false; -c_with (uint8_t* buf = malloc(BUF_SIZE), buf != NULL, free(buf)) -c_with (FILE* fp = fopen(fname, "rb"), fp != NULL, fclose(fp)) -{ - int n = fread(buf, 1, BUF_SIZE, fp); - if (n <= 0) continue; // auto cleanup! NB do not break or return here. - ... - ok = true; -} -return ok; -``` -**Example 2**: Load each line of a text file into a vector of strings: -```c -#include <errno.h> -#include <stc/cstr.h> - -#define i_val_str -#include <stc/cvec.h> - -// receiver should check errno variable -cvec_str readFile(const char* name) -{ - cvec_str vec = {0}; // returned - c_with (FILE* fp = fopen(name, "r"), fp != NULL, fclose(fp)) - c_with (cstr line = {0}, cstr_drop(&line)) - while (cstr_getline(&line, fp)) - cvec_str_emplace(&vec, cstr_str(&line)); - return vec; -} - -int main() -{ - c_with (cvec_str vec = readFile(__FILE__), cvec_str_drop(&vec)) - c_foreach (i, cvec_str, vec) - printf("| %s\n", cstr_str(i.ref)); -} -``` - -### The **checkauto** utility program (for RAII) -The **checkauto** program will check the source code for any misuses of the `c_auto*` macros which -may lead to resource leakages. The `c_auto*`- macros are implemented as one-time executed **for-loops**, -so any `return` or `break` appearing within such a block will lead to resource leaks, as it will disable -the cleanup/drop method to be called. A `break` may originally be intended to break a loop or switch -outside the `c_auto` scope. - -NOTE: One must always make sure to unwind temporary allocated resources before a `return` in C. However, by using `c_auto*`-macros, -- it is much easier to automatically detect misplaced return/break between resource acquisition and destruction. -- it prevents forgetting to call the destructor at the end. - -The **checkauto** utility will report any misusages. The following example shows how to correctly break/return -from a `c_auto` scope: -```c -int flag = 0; -for (int i = 0; i<n; ++i) { - c_auto (cstr, text) - c_auto (List, list) - { - for (int j = 0; j<m; ++j) { - List_push_back(&list, i*j); - if (cond1()) - break; // OK: breaks current for-loop only - } - // WRONG: - if (cond2()) - break; // checkauto ERROR! break inside c_auto. - - if (cond3()) - return -1; // checkauto ERROR! return inside c_auto - - // CORRECT: - if (cond2()) { - flag = 1; // flag to break outer for-loop - continue; // cleanup and leave c_auto block - } - if (cond3()) { - flag = -1; // return -1 - continue; // cleanup and leave c_auto block - } - ... - } - // do the return/break outside of c_auto - if (flag < 0) return flag; - else if (flag > 0) break; - ... -} -``` |