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-rw-r--r--kit/astar.h400
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diff --git a/kit/astar.h b/kit/astar.h
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--- a/kit/astar.h
+++ /dev/null
@@ -1,400 +0,0 @@
-// ================================================================
-//
-// A* graph search algorithm
-//
-// ================================================================
-
-// TODO
-// - Nearest: save the nearest node when the search is failed or not
-// yet finished.
-// - Sight: when two nodes are in direct sight of each other, skip
-// nodes between them (Theta*).
-
-#ifndef KIT_ASTAR_H
-#define KIT_ASTAR_H
-
-#include "types.h"
-#include "status.h"
-
-#include <assert.h>
-#include <stddef.h>
-#include <string.h>
-
-enum {
- ASTAR_PROGRESS = 0,
- ASTAR_SUCCESS,
- ASTAR_FAIL,
- ASTAR_OUT_OF_MEMORY,
- ASTAR_INVALID_ARGUMENT,
-};
-
-typedef struct {
- b8 stop;
- b8 skip;
- i64 neighbor;
- i64 distance;
-} Astar_Link;
-
-typedef struct {
- i64 id;
- i64 previous;
- i64 exact_distance;
- i64 estimate;
-} Astar_Node;
-
-typedef struct {
- i64 capacity;
- i64 size;
- Astar_Node *values;
-} Astar_Set;
-
-typedef struct {
- Astar_Set open;
- Astar_Set closed;
- void * user_data;
- i64 source;
- i64 destination;
-} Astar_State;
-
-#ifdef __GNUC__
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wunused-function"
-# pragma GCC diagnostic ignored "-Wunknown-pragmas"
-# pragma GCC push_options
-# pragma GCC optimize("O3")
-#endif
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-static s32 astar_init(
- Astar_State *state,
- Astar_Set open,
- Astar_Set closed,
- void * user_data,
- i64 source,
- i64 destination
-) {
- assert(
- state != NULL &&
- open.capacity > 0 &&
- open.values != NULL &&
- closed.capacity > 0 &&
- closed.values != NULL
- );
-
- if (state == NULL)
- return KIT_ERROR_INVALID_ARGUMENT;
-
- memset(state, 0, sizeof *state);
-
- state->source = source;
- state->destination = destination;
- state->open = open;
- state->closed = closed;
- state->user_data = user_data;
-
- if (state->open.capacity <= 0)
- return KIT_ERROR_INVALID_ARGUMENT;
-
- state->open.values[0] = (Astar_Node) {
- .id = source,
- .previous = -1,
- .exact_distance = 0,
- .estimate = 0x7fffffffffffffffll,
- };
-
- state->open.size = 1;
- state->closed.size = 0;
-
- return KIT_OK;
-}
-
-static s32 astar_path(Astar_State *state, i64 *size, i64 *path) {
- assert(state != NULL && size != NULL);
-
- if (state == NULL || size == NULL)
- return KIT_ERROR_INVALID_ARGUMENT;
-
- i64 path_size = *size;
-
- *size = 1;
-
- i64 id = state->destination;
-
- while (id != state->source) {
- if (*size > state->closed.size)
- return KIT_ERROR_INTERNAL;
-
- i64 index = 0;
- for (; index < state->closed.size; index++)
- if (state->closed.values[index].id == id)
- break;
- if (index == state->closed.size)
- return KIT_ERROR_INTERNAL;
-
- if (path != NULL && *size <= path_size)
- path[*size - 1] = id;
-
- id = state->closed.values[index].previous;
- ++*size;
- }
-
- if (path != NULL && *size <= path_size)
- path[*size - 1] = id;
-
- if (path != NULL) {
- if (*size < path_size)
- path_size = *size;
-
- for (i64 i = 0; i < path_size / 2; ++i) {
- i64 z = path[i];
- path[i] = path[path_size - 1 - i];
- path[path_size - 1 - i] = z;
- }
- }
-
- return KIT_OK;
-}
-
-#ifdef __cplusplus
-}
-#endif
-
-#ifdef __GNUC__
-# pragma GCC pop_options
-# pragma GCC diagnostic pop
-#endif
-
-#endif
-
-// ================================================================
-//
-// Algorithm template
-//
-// ================================================================
-
-#ifdef ASTAR_TEMPLATE
-
-#ifndef ASTAR_SUFFIX
-# define ASTAR_SUFFIX
-#endif
-
-#ifndef ASTAR_NEIGHBOR
-# define ASTAR_NEIGHBOR(user_data_, node_, index_) \
- (Astar_Link) { \
- .stop = 1, \
- }
-#endif
-
-#ifndef ASTAR_HEURISTIC
-# define ASTAR_HEURISTIC(user_data_, node_0_, node_2_) \
- 0x7fffffffffffffffll
-#endif
-
-#ifdef __GNUC__
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wunused-function"
-# pragma GCC diagnostic ignored "-Wunknown-pragmas"
-# pragma GCC push_options
-# pragma GCC optimize("O3")
-#endif
-
-#define CAT1_(x, y) x##y
-#define CAT2_(x, y) CAT1_(x, y)
-#define NAME_(x) CAT2_(x, ASTAR_SUFFIX)
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-static s32 NAME_(astar_iteration)(Astar_State *state) {
- assert(state != NULL);
-
- if (state == NULL)
- return ASTAR_INVALID_ARGUMENT;
-
- if (state->open.size == 0)
- return ASTAR_FAIL;
-
- if (state->open.values == NULL || state->closed.values == NULL)
- return ASTAR_OUT_OF_MEMORY;
-
- // Find a node in the open set that is closest to the destination
- //
- Astar_Node nearest_node;
- {
- i64 index_in_open = 0;
- for (i64 i = 1; i < state->open.size; i++)
- if (state->open.values[i].estimate < state->open.values[index_in_open].estimate)
- index_in_open = i;
- nearest_node = state->open.values[index_in_open];
- if (index_in_open != state->open.size - 1)
- state->open.values[index_in_open] = state->open.values[state->open.size - 1];
- --state->open.size;
- }
-
- // Check if we reached the destination
- //
- if (nearest_node.id == state->destination) {
- if (state->closed.size + 1 > state->closed.capacity) {
- // Restore the state
- state->open.values[state->open.size] = nearest_node;
- ++state->open.size;
-
- return ASTAR_OUT_OF_MEMORY;
- }
-
- // Add the nearest node to the closed set
- //
- state->closed.values[state->closed.size] = nearest_node;
- ++state->closed.size;
-
- // Finish the search
- return ASTAR_SUCCESS;
- }
-
- // Enumerate all neighbors
- //
- for (i64 k = 0;; ++k) {
- // Get a link to the next neighbor node
- //
- (void) state->user_data;
- (void) k;
- Astar_Link link = ASTAR_NEIGHBOR(state->user_data, nearest_node.id, k);
-
- // If there is no more neighbors, break the loop
- if (link.stop)
- break;
- // If there is no link, proceed to the next link
- if (link.skip)
- continue;
-
- // Calculate distance estimations
- //
- (void) state->user_data;
- (void) state->destination;
-
- Astar_Node neighbor_node = {
- .id = link.neighbor,
- .previous = nearest_node.id,
- .exact_distance = nearest_node.exact_distance + link.distance,
- .estimate = ASTAR_HEURISTIC(state->user_data, link.neighbor, state->destination),
- };
-
- // Check if we reached the destination
- //
- if (neighbor_node.id == state->destination) {
- if (state->closed.size + 2 > state->closed.capacity) {
- // Restore the state
- state->open.values[state->open.size] = nearest_node;
- ++state->open.size;
-
- return ASTAR_OUT_OF_MEMORY;
- }
-
- // Add the nearest node to the closed set
- //
- state->closed.values[state->closed.size] = nearest_node;
- ++state->closed.size;
-
- // Add the neighbor node to the closed set
- //
- state->closed.values[state->closed.size] = neighbor_node;
- ++state->closed.size;
-
- // Finish the search
- return ASTAR_SUCCESS;
- }
-
- // Check if this node is already in the closed set
- //
- {
- i64 index_in_closed = -1;
- for (i64 i = 0; i < state->closed.size; ++i)
- if (state->closed.values[i].id == neighbor_node.id) {
- index_in_closed = i;
- break;
- }
- if (index_in_closed != -1) {
- // Check if this node has a better distance
- //
- if (neighbor_node.exact_distance < state->closed.values[index_in_closed].exact_distance)
- // Replace the node
- state->closed.values[index_in_closed] = neighbor_node;
-
- // Skip this node
- continue;
- }
- }
-
- // Check if this node is already in the open set
- //
- {
- i64 index_in_open = -1;
- for (i64 i = 0; i < state->closed.size; ++i)
- if (state->open.values[i].id == neighbor_node.id) {
- index_in_open = i;
- break;
- }
- if (index_in_open != -1) {
- // Check if this node has a better distance
- //
- if (neighbor_node.exact_distance < state->open.values[index_in_open].exact_distance)
- // Replace the node
- state->open.values[index_in_open] = neighbor_node;
-
- // Skip this node
- continue;
- }
- }
-
- if (state->open.size + 1 > state->open.capacity) {
- // Restore the state
- state->open.values[state->open.size] = nearest_node;
- ++state->open.size;
-
- return ASTAR_OUT_OF_MEMORY;
- }
-
- // Add this node to the open set
- //
- state->open.values[state->open.size] = neighbor_node;
- ++state->open.size;
- }
-
- // Check if we can add a node to the closed set
- //
- if (state->closed.size + 1 > state->closed.capacity) {
- // Restore the state
- state->open.values[state->open.size - 1] = nearest_node;
- ++state->open.size;
-
- return ASTAR_OUT_OF_MEMORY;
- }
-
- // Add the nearest node to the closed set
- //
- state->closed.values[state->closed.size] = nearest_node;
- ++state->closed.size;
-
- // Continue the search
- return ASTAR_PROGRESS;
-}
-
-#ifdef __cplusplus
-}
-#endif
-
-#undef NAME_
-#undef CAT1_
-#undef CAT2_
-
-#ifdef __GNUC__
-# pragma GCC pop_options
-# pragma GCC diagnostic pop
-#endif
-
-#undef ASTAR_TEMPLATE
-#endif
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