stdlib.h

1 files changed, 174 insertions, 0 deletions

diff --git a/05/stdlib.h b/05/stdlib.h
index e98156b..c2f83eb 100644
--- a/05/stdlib.h
+++ b/05/stdlib.h
@@ -3,6 +3,21 @@
 
 #include <stdc_common.h>
 
+#define EXIT_FAILURE (-1)
+#define EXIT_SUCCESS 0
+#define RAND_MAX 2147483647
+// @NONSTANDARD: we don't define MB_CUR_MAX or any of the mbtowc functions
+
+typedef struct {
+	int quot;
+	int rem;
+} div_t;
+
+typedef struct {
+	long quot;
+	long rem;
+} ldiv_t;
+
 char *getenv(const char *name) {
 	int i, j;
 	for (i = 0; _envp[i]; ++i) {
@@ -16,4 +31,163 @@ char *getenv(const char *name) {
 	return NULL;
 }
 
+double atof(const char *nptr) {
+	return strtod(nptr, NULL);
+}
+
+int atoi(const char *nptr) {
+	return _clamp_long_to_int(strtol(nptr, NULL, 10));
+}
+
+long atol(const char *nptr) {
+	return strtol(nptr, NULL, 10);
+}
+
+int rand(void) {
+	// https://en.wikipedia.org/wiki/Linear_congruential_generator
+	// we're using musl/newlib's constants
+	_rand_seed = 6364136223846793005 * _rand_seed + 1;
+	return _rand_seed >> 33;
+}
+
+void srand(unsigned seed) {
+	_rand_seed = seed;
+}
+
+void *calloc(size_t nmemb, size_t size) {
+	if (nmemb > 0xffffffffffffffff / size)
+		return NULL;
+	// NB: our malloc implementation returns zeroed memory
+	return malloc(nmemb * size);
+}
+
+void *realloc(void *ptr, size_t size) {
+	if (!ptr) return malloc(size);
+	if (!size) {
+		free(ptr);
+		return NULL;
+	}
+	uint64_t *memory = (char *)ptr - 16;
+	uint64_t old_size = *memory;
+	uint64_t *new_memory = _mremap(memory, old_size, size, MREMAP_MAYMOVE);
+	if ((uint64_t)new_memory > 0xffffffffffff0000) return NULL;
+	*new_memory = size;
+	return (char *)new_memory + 16;
+}
+
+
+int atexit(void (*func)(void)) {
+	if (_n_exit_handlers >= 32) return -1;
+	_exit_handlers[_n_exit_handlers++] = func;
+	return 0;
+}
+
+int system(const char *string) {
+	if (!string) return 1;
+	
+	int pid = fork();
+	if (pid < 0) {
+		return -1;
+	} else if (pid == 0) {
+		// child
+		char *argv[] = {
+			"/bin/sh",
+			"-c",
+			0,
+			0
+		};
+		argv[2] = string;
+		execve("/bin/sh", argv, _envp);
+		// on success, execve does not return.
+		_Exit(-1);
+	} else {
+		// parent
+		int status = 0;
+		int ret = wait4(pid, &status, 0, NULL);
+		if (ret != pid) return -1;
+		if (_WIFSIGNALED(status)) return -1;
+		return _WEXITSTATUS(status);
+	}
+	
+}
+
+void *bsearch(const void *key, const void *base, size_t nmemb, size_t size, int (*compar)(const void *, const void *)) {
+	size_t lo = 0;
+	size_t hi = nmemb;
+	while (lo < hi) {
+		size_t mid = (lo + hi) >> 1;
+		void *elem = (char *)base + mid * size;
+		int cmp = compar(key, elem);
+		if (cmp < 0) {
+			// key < elem
+			hi = mid;
+		} else if (cmp) {
+			// key > elem
+			lo = mid + 1;
+		} else {
+			return elem;
+		}
+	}
+	return NULL;
+}
+
+void qsort(void *base, size_t nmemb, size_t size, int (*compar)(const void *, const void *)) {
+	// quicksort
+	if (nmemb < 2) return;
+	
+	void *temp = malloc(size);
+	void *mid = (char *)base + ((nmemb >> 1) * size); // choose middle element to speed up sorting an already-sorted array
+	size_t pivot_index = 0, i;
+	for (i = 0; i < nmemb; ++i) {
+		void *elem = (char *)base + i * size;
+		if (compar(elem, mid) < 0)
+			++pivot_index;
+	}
+	void *pivot = (char *)base + pivot_index * size;
+	memcpy(temp, pivot, size);
+	memcpy(pivot, mid, size);
+	memcpy(mid, temp, size);
+	
+	char *l, *r = (char *)base + (nmemb-1) * size;
+	for (l = base; l < r;) {
+		if (compar(l, pivot) > 0) {
+			// swap l and r
+			memcpy(temp, l, size);
+			memcpy(l, r, size);
+			memcpy(r, temp, size);
+			r -= size;
+		} else {
+			// l is already in the right place
+			l += size;
+		}
+	}
+	
+	qsort(base, pivot_index, size, compar);
+	qsort((char *)pivot + size, nmemb - 1 - pivot_index, size, compar);
+	
+	free(temp);
+}
+
+int abs(int x) {
+	return x >= 0 ? x : -x;
+}
+
+long labs(long x) {
+	return x >= 0 ? x : -x;
+}
+
+div_t div(int numer, int denom) {
+	div_t d;
+	d.quot = numer / denom;
+	d.rem = numer % denom;
+	return d;
+}
+
+ldiv_t ldiv(long numer, long denom) {
+	ldiv_t d;
+	d.quot = numer / denom;
+	d.rem = numer % denom;
+	return d;
+}
+
 #endif // _STDLIB_H