document IDs instead of documents

1 files changed, 333 insertions, 0 deletions

diff --git a/ds.c b/ds.c
new file mode 100644
index 0000000..ef4a1b4
--- /dev/null
+++ b/ds.c
@@ -0,0 +1,333 @@
+/* VARIOUS DATA STRUCTURES
+- dynamic array
+- string builder
+- string hash table
+*/
+
+
+// functions in this file suffixed with _ are not meant to be used outside here, unless you
+// know what you're doing
+
+// IMPORTANT NOTE: If you are using this with structures containing `long double`s, do
+//  #define ARR_LONG_DOUBLE
+// before including this file
+// ( otherwise the long doubles will not be aligned.
+//   this does mean that arrays waste 8 bytes of memory.
+//    which isnt important unless you're making a lot of arrays.)
+
+#include <stddef.h>
+typedef union {
+	long num;
+	void *ptr;
+	void (*fnptr)(void);
+#ifdef ARR_LONG_DOUBLE
+	long
+#endif
+	double flt;
+} ArrMaxAlign;
+#if __STDC_VERSION__ < 199901L && !defined inline
+#define inline
+#endif
+
+
+typedef struct {
+	u32 len;
+	u32 cap;
+	ArrMaxAlign data[];
+} ArrHeader;
+
+// watch out! do not call this function if arr is NULL.
+static inline ArrHeader *arr_hdr_(void *arr) {
+	return (ArrHeader *)((char *)arr - offsetof(ArrHeader, data));
+}
+
+static inline u32 arr_len(const void *arr) {
+	return arr ? arr_hdr_((void*)arr)->len : 0;
+}
+
+static inline u32 arr_cap(void *arr) {
+	return arr ? arr_hdr_(arr)->cap : 0;
+}
+
+static inline unsigned arr_lenu(void *arr) {
+	return (unsigned)arr_len(arr);
+}
+
+// grow array to fit one more member
+static void *arr_grow1_(void *arr, size_t member_size) {
+	if (arr) {
+		ArrHeader *hdr = arr_hdr_(arr);
+		if (hdr->len >= hdr->cap) {
+			u32 new_capacity = hdr->cap * 2;
+			ArrHeader *old_hdr = hdr;
+			hdr = (ArrHeader *)realloc(old_hdr, sizeof(ArrHeader) + new_capacity * member_size);
+			if (hdr) {
+				hdr->cap = new_capacity;
+			} else {
+				free(old_hdr);
+				return NULL;
+			}
+		}
+		return hdr->data;
+	} else {
+		// create a new array
+		u32 initial_capacity = 2; // allocate enough space for two members
+		ArrHeader *ret = (ArrHeader *)calloc(1, sizeof(ArrHeader) + initial_capacity * member_size);
+		if (ret) {
+			ret->cap = initial_capacity;
+			return ret->data;
+		} else {
+			return NULL;
+		}
+	}
+}
+
+static inline void *arr_add_ptr_(void **arr, size_t member_size) {
+	u8 *ret;
+	*arr = arr_grow1_(*arr, member_size);
+	if (*arr) {
+		ret = (u8 *)*arr + member_size * (arr_hdr_(*arr)->len++);
+		memset(ret, 0, member_size);
+	} else {
+		ret = NULL;
+	}
+	return ret;
+}
+
+static void arr_reserve_(void **arr, size_t member_size, size_t n) {
+	if (n >= U32_MAX-1) { 
+		// too big; free arr.
+		if (*arr) free(arr_hdr_(*arr));
+		*arr = NULL;
+	}
+
+	if (!*arr) {
+		// create a new array with capacity n+1
+		// why n+1? i dont know i wrote this a while ago
+		ArrHeader *hdr = calloc(1, sizeof(ArrHeader) + (n+1) * member_size);
+		if (hdr) {
+			hdr->cap = (u32)n+1;
+			*arr = hdr->data;
+		}
+	} else {
+		// increase capacity of array
+		ArrHeader *hdr = arr_hdr_(*arr);
+		u32 curr_cap = hdr->cap;
+		if (n > curr_cap) {
+			ArrHeader *old_hdr = hdr;
+			while (n > curr_cap) {
+				if (curr_cap < U32_MAX/2)
+					curr_cap *= 2;
+				else
+					curr_cap = U32_MAX;
+			}
+			hdr = realloc(hdr, sizeof(ArrHeader) + curr_cap * member_size);
+			if (hdr) {
+				hdr->cap = curr_cap;
+			} else {
+				// growing failed
+				free(old_hdr);
+				*arr = NULL;
+				return;
+			}
+		}
+		*arr = hdr->data;
+	}
+}
+
+static void arr_set_len_(void **arr, size_t member_size, size_t n) {
+	arr_reserve_(arr, member_size, n);
+	if (*arr) {
+		ArrHeader *hdr = arr_hdr_(*arr);
+		if (n > hdr->len) {
+			// zero new elements
+			memset((char *)hdr->data + hdr->len * member_size, 0, (n - hdr->len) * member_size);
+		}
+		hdr->len = (u32)n;
+	}
+}
+
+static void *arr_remove_(void *arr, size_t member_size, size_t index) {
+	ArrHeader *hdr = arr_hdr_(arr);
+	assert(index < hdr->len);
+	memmove((char *)arr + index * member_size, (char *)arr + (index+1) * member_size, (hdr->len - (index+1)) * member_size);
+	if (--hdr->len == 0) {
+		free(hdr);
+		return NULL;
+	} else {
+		return arr;
+	}
+}
+
+#ifdef __cplusplus
+#define arr_cast_typeof(a) (decltype(a))
+#elif defined __GNUC__
+#define arr_cast_typeof(a) (__typeof__(a))
+#else
+#define arr_cast_typeof(a)
+#endif
+
+#define arr__join2(a,b) a##b
+#define arr__join(a,b) arr__join2(a,b) // macro used internally
+
+// if the array is not NULL, free it and set it to NULL
+#define arr_free(a) do { if (a) { free(arr_hdr_(a)); (a) = NULL; } } while (0)
+// a nice alias
+#define arr_clear(a) arr_free(a)
+// add an item to the array - if allocation fails, the array will be freed and set to NULL.
+// (how this works: if we can successfully grow the array, increase the length and add the item.)
+#define arr_add(a, x) do { if (((a) = arr_cast_typeof(a) arr_grow1_((a), sizeof *(a)))) ((a)[arr_hdr_(a)->len++] = (x)); } while (0)
+// like arr_add, but instead of passing it the value, it returns a pointer to the value. returns NULL if allocation failed.
+// the added item will be zero-initialized.
+#define arr_addp(a) arr_cast_typeof(a) arr_add_ptr_((void **)&(a), sizeof *(a))
+// set the length of `a` to `n`, increasing the capacity if necessary.
+// the newly-added elements are zero-initialized.
+#define arr_qsort(a, cmp) qsort((a), arr_len(a), sizeof *(a), (cmp))
+#define arr_remove_last(a) do { assert(a); if (--arr_hdr_(a)->len == 0) arr_free(a); } while (0)
+#define arr_remove(a, i) (void)((a) = arr_remove_((a), sizeof *(a), (i)))
+#define arr_insert(a, i, x) do { u32 _index = (i); (a) = arr_cast_typeof(a) arr_grow1_((a), sizeof *(a)); \
+	if (a) { memmove((a) + _index + 1, (a) + _index, (arr_len(a) - _index) * sizeof *(a));\
+	(a)[_index] = x; \
+	++arr_hdr_(a)->len; } } while (0)
+#define arr_pop_last(a) ((a)[--arr_hdr_(a)->len])
+#define arr_size_in_bytes(a) (arr_len(a) * sizeof *(a))
+#define arr_lastp(a) ((a) ? &(a)[arr_len(a)-1] : NULL)
+#define arr_foreach_ptr_end(a, type, var, end) type *end = (a) + arr_len(a); \
+	for (type *var = (a); var != end; ++var)
+// Iterate through each element of the array, setting var to a pointer to the element.
+// You can't use this like, e.g.:
+// if (something)
+//   arr_foreach_ptr(a, int, i);
+// You'll get an error. You will need to use braces because it expands to multiple statements.
+// (we need to name the end pointer something unique, which is why there's that arr__join thing
+// we can't just declare it inside the for loop, because type could be something like char *.)
+#define arr_foreach_ptr(a, type, var) arr_foreach_ptr_end(a, type, var, arr__join(_foreach_end,__LINE__))
+
+#define arr_reverse(a, type) do { \
+	u64 _i, _len = arr_len(a); \
+	for (_i = 0; 2*_i < _len; ++_i) { \
+		type *_x = &(a)[_i]; \
+		type *_y = &(a)[_len-1-_i]; \
+		type _tmp; \
+		_tmp = *_x; \
+		*_x = *_y; \
+		*_y = _tmp; \
+	} \
+	} while (0)
+
+// Ensure that enough space is allocated for n elements.
+#define arr_reserve(a, n) arr_reserve_((void **)&(a), sizeof *(a), (n)) 
+// Similar to arr_reserve, but also sets the length of the array to n.
+#define arr_set_len(a, n) arr_set_len_((void **)&(a), sizeof *(a), (n))
+
+#if 0
+static void arrcstr_append_strn_(char **a, char const *s, size_t s_len) {
+	size_t curr_len = arr_len(*a);
+	size_t new_len = curr_len + s_len;
+	arr_reserve(*a, new_len + 1);
+	arr_set_len(*a, new_len);
+	memcpy(*a + curr_len, s, s_len);
+	(*a)[curr_len + s_len] = '\0';
+}
+
+static void arrcstr_shrink_(char **a, u32 new_len) {
+	ArrHeader *hdr = arr_hdr_(*a);
+	assert(hdr->cap > new_len);
+	hdr->len = new_len;
+	(*a)[new_len] = '\0';
+}
+
+// append to a C-string array
+#define arrcstr_append_str(a, s) arrcstr_append_strn_(&(a), (s), strlen(s))
+// take at most n bytes from s
+#define arrcstr_append_strn(a, s, n) arrcstr_append_strn_(&(a), (s), (n))
+// make the string smaller
+#define arrcstr_shrink(a, n) arrcstr_shrink_(&(a), (n))
+#endif
+
+#ifndef NDEBUG
+static void arr_test(void) {
+	u32 *arr = NULL;
+	u32 i;
+	assert(arr_len(arr) == 0);
+	for (i = 0; i < 10000; ++i) {
+		arr_add(arr, i*i);
+	}
+	assert(arr_len(arr) == 10000);
+	arr_remove_last(arr);
+	assert(arr_len(arr) == 9999);
+	for (i = 0; i < arr_len(arr); ++i)
+		assert(arr[i] == i*i);
+	while (arr_len(arr))
+		arr_remove_last(arr);
+	assert(arr_len(arr) == 0);
+}
+#endif
+
+typedef struct {
+	// dynamic array, including a null byte.
+	char *str;
+} StrBuilder;
+
+void str_builder_create(StrBuilder *builder) {
+	memset(builder, 0, sizeof *builder);
+	arr_add(builder->str, 0);
+}
+
+StrBuilder str_builder_new(void) {
+	StrBuilder ret = {0};
+	str_builder_create(&ret);
+	return ret;
+}
+
+void str_builder_free(StrBuilder *builder) {
+	arr_free(builder->str);
+}
+
+void str_builder_clear(StrBuilder *builder) {
+	str_builder_free(builder);
+	str_builder_create(builder);
+}
+
+void str_builder_append(StrBuilder *builder, const char *s) {
+	assert(builder->str);
+	
+	size_t s_len = strlen(s);
+	size_t prev_size = arr_len(builder->str);
+	size_t prev_len = prev_size - 1; // null terminator
+	// note: this zeroes the newly created elements, so we have a new null terminator
+	arr_set_len(builder->str, prev_size + s_len);
+	// -1 for null terminator
+	memcpy(builder->str + prev_len, s, s_len);
+}
+
+void str_builder_appendf(StrBuilder *builder, PRINTF_FORMAT_STRING const char *fmt, ...) ATTRIBUTE_PRINTF(2, 3);
+void str_builder_appendf(StrBuilder *builder, const char *fmt, ...) {
+	// idk if you can always just pass NULL to vsnprintf
+	va_list args;
+	char fakebuf[2] = {0};
+	va_start(args, fmt);
+	int ret = vsnprintf(fakebuf, 1, fmt, args);
+	va_end(args);
+	
+	if (ret < 0) return; // bad format or something
+	u32 n = (u32)ret;
+	
+	size_t prev_size = arr_len(builder->str);
+	size_t prev_len = prev_size - 1; // null terminator
+	arr_set_len(builder->str, prev_size + n);
+	va_start(args, fmt);
+	vsnprintf(builder->str + prev_len, n + 1, fmt, args);
+	va_end(args);
+}
+
+// append n null bytes.
+void str_builder_append_null(StrBuilder *builder, size_t n) {
+	arr_set_len(builder->str, arr_len(builder->str) + n);
+}
+
+u32 str_builder_len(StrBuilder *builder) {
+	assert(builder->str);
+	return arr_len(builder->str) - 1;
+}
+