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Introduce nob_da_lower_bound(), nob_da_insert_at(), nob_swap_auto() #231

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Introduce nob_da_lower_bound(), nob_da_insert_at(), nob_swap_auto() #231

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82 changes: 82 additions & 0 deletions nob.h
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Original file line number Diff line number Diff line change
Expand Up @@ -348,6 +348,12 @@ NOBDEF void nob_dir_entry_close(Nob_Dir_Entry dir);
#define NOB_DECLTYPE_CAST(T)
#endif // __cplusplus

#ifdef __cplusplus
#define NOB_TYPEOF(T) decltype(T)
#else
#define NOB_TYPEOF(T) __typeof__(T)
#endif // __cplusplus

#define nob_da_reserve(da, expected_capacity) \
do { \
if ((expected_capacity) > (da)->capacity) { \
Expand All @@ -369,6 +375,16 @@ NOBDEF void nob_dir_entry_close(Nob_Dir_Entry dir);
(da)->items[(da)->count++] = (item); \
} while (0)

// Append an item to a dynamic array at position
#define nob_da_insert_at(da, pos, item) \
do { \
nob_da_reserve((da), (da)->count + 1); \
for (size_t it = (pos); it < (da)->count; ++it) { \
nob_swap_auto((da)->items[it], (item)); \
} \
(da)->items[(da)->count++] = (item); \
} while (0)

#define nob_da_free(da) NOB_FREE((da).items)

// Append several items to a dynamic array
Expand All @@ -395,6 +411,65 @@ NOBDEF void nob_dir_entry_close(Nob_Dir_Entry dir);
(da)->items[j] = (da)->items[--(da)->count]; \
} while(0)

// Implementation of lower bound algorithm to search a
// position of `item` within an ordered dynamic array.
// Position will be written into `pos` and points to first element
// which is greater of or equal to the searching one.
//
// The following example will produce an array `xs` of unique elements:
// ```c
// typedef struct {
// int value;
// size_t count;
// } NumberStat;
//
// typedef struct {
// NumberStat *items;
// size_t count;
// size_t capacity;
// } Numbers;
//
// // Compare in ascending order
// static inline int number_cmp(NumberStat *lhs, int *rhs) {
// return (lhs->value == *rhs) ? 0 : (lhs->value < *rhs ? -1 : 1);
// }
//
// Numbers xs = {0};
//
// int input[] = {1337, 69, 420, 69};
// for (size_t n = 0; n < 4; ++n) {
// size_t pos = 0;
// nob_da_lower_bound(&xs, input[n], number_cmp, pos);
// if (pos < xs.count && number_cmp(&xs.items[pos], &input[n]) == 0) {
// // do update things for non-generic types
// xs.items[pos].count++;
// continue;
// }
// NumberStat item = {.value = input[n], .count = 1};
// nob_da_insert_at(&xs, pos, item);
// }
//
// nob_da_foreach(Number, x, &xs) {
// // `x` here is a pointer to the current element. You can get its index by taking a difference
// // between `x` and the start of the array which is `x.items`.
// size_t index = x - xs.items;
// nob_log(INFO, "%zu: %d (%zu)", index, x->value, x->count);
// }
// ```
#define nob_da_lower_bound(da, item, cmp_fn, pos) \
do { \
pos = 0; \
for (size_t count = (da)->count; count > 0;) { \
size_t step = count / 2; \
if ((cmp_fn)(&(da)->items[pos + step], &(item)) < 0) { \
pos += ++step; \
count -= step; \
} else { \
count = step; \
} \
} \
} while (0)

// Foreach over Dynamic Arrays. Example:
// ```c
// typedef struct {
Expand Down Expand Up @@ -430,6 +505,7 @@ typedef struct {
} Nob_String_Builder;

#define nob_swap(T, a, b) do { T t = a; a = b; b = t; } while (0)
#define nob_swap_auto(a, b) do { NOB_TYPEOF(a) t = (a); (a) = (b); (b) = t; } while (0)

NOBDEF bool nob_read_entire_file(const char *path, Nob_String_Builder *sb);
NOBDEF int nob_sb_appendf(Nob_String_Builder *sb, const char *fmt, ...) NOB_PRINTF_FORMAT(2, 3);
Expand Down Expand Up @@ -2915,6 +2991,7 @@ NOBDEF char *nob_temp_running_executable_path(void)
#define dir_entry_close nob_dir_entry_close
#define return_defer nob_return_defer
#define da_append nob_da_append
#define da_insert_at nob_da_insert_at
#define da_free nob_da_free
#define da_append_many nob_da_append_many
#define da_resize nob_da_resize
Expand All @@ -2923,6 +3000,7 @@ NOBDEF char *nob_temp_running_executable_path(void)
#define da_first nob_da_first
#define da_pop nob_da_pop
#define da_remove_unordered nob_da_remove_unordered
#define da_lower_bound nob_da_lower_bound
#define da_foreach nob_da_foreach
#define fa_append nob_fa_append
#define swap nob_swap
Expand Down Expand Up @@ -3029,6 +3107,10 @@ NOBDEF char *nob_temp_running_executable_path(void)
Revision history:

3.8.2 (2026-04-01) Fix the broken type safety of nob_cmd_append() (by @aalmkainzi)
Add NOB_TYPEOF()
Add nob_swap_auto()
Add nob_da_insert_at()
Add nob_da_lower_bound()
3.8.1 (2026-04-01) Fix annoying clang warning
3.8.0 (2026-03-24) Add NOB_CLIT()
Fix compliation on MSVC with /TP
Expand Down