src: implement own btree

meson.build

@@ -10,7 +10,7 @@ libtoml_dep = dependency(
 
 exe = executable(
 	'smeargle',
-	['src/main.c', 'src/font.c', 'src/script.c'],
+	['src/main.c', 'src/node.c', 'src/font.c', 'src/script.c'],
 	dependencies: libtoml_dep,
 	install: true
 )

src/font.c

@@ -4,19 +4,15 @@
 #include "util.h"
 #include "font.h"
 
-void *fontdb;
-
-int font_compare(const void *a, const void *b) {
-	const font_t *x = (const font_t *)a;
-	const font_t *y = (const font_t *)b;
+int font_compare(const node_t *a, const node_t *b) {
+	const font_t *x = (const font_t *)a->data;
+	const font_t *y = (const font_t *)b->data;
 
 	return strcmp(x->name, y->name);
 }
 
-font_t *load_fonts(toml_table_t *table, const char *base_path) {
-	font_t *fonts = calloc(32, sizeof(font_t));
-	font_t *fontptr = fonts;
-	fontdb = NULL;
+node_t *load_fonts(toml_table_t *table, const char *base_path) {
+	node_t *root = NULL;
 
 	// vast majority of projects should have only 1-2 fonts, but let's offer
 	// some room in case there's more.
@@ -24,23 +20,24 @@ font_t *load_fonts(toml_table_t *table, const char *base_path) {
 		const char *key = toml_key_in(table, i);
 		if (!key) break;
 		char fullname[200];
+		font_t font;
 
 		toml_datum_t filename = toml_string_in(table, key);
 		if (!filename.ok) {
 			error("couldn't load font ", key);
 		}
 		snprintf(fullname, 200, "%s/%s", base_path, filename.u.s);
-		fonts[i] = font_create(key, fullname);
-
-		tsearch((void *)fontptr, (void **)fontdb, font_compare);
-		fontptr++;
+		font = font_create(key, fullname);
+		root = node_insert(root, &font, font_compare);
 	}
-	return fonts;
+	return root;
 }
-font_t *font_find(const char *key) {
-	font_t *font = (font_t *)tfind(key, (void **)fontdb, font_compare);
+font_t *font_find(node_t *root, const char *key) {
+	font_t search = {.name = key};
+	node_t *node = node_search(root, &search, font_compare);
+	font_t *font = (font_t *)node->data;
 
-	if (!font) {
+	if (font == NULL) {
 		error("couldn't find requested font ", key);
 	}
 

src/font.h

@@ -1,6 +1,8 @@
 #ifndef _SMEARGLE_FONT_H
 #define _SMEARGLE_FONT_H
 
+#include "node.h"
+
 typedef struct map_t {
 	const char *glyph;
 	unsigned int index;
@@ -9,8 +11,8 @@ typedef struct map_t {
 } map_t;
 
 typedef struct {
-	char *name;
-	char *image_filename;
+	const char *name;
+	const char *image_filename;
 	unsigned char bits_per_pixel;
 	unsigned int width;
 	unsigned int height;
@@ -20,8 +22,8 @@ typedef struct {
 
 extern void *fontdb;
 
-font_t *load_fonts(toml_table_t *table, const char *base_path);
-font_t *font_find(const char *key);
+node_t *load_fonts(toml_table_t *table, const char *base_path);
+font_t *font_find(node_t *root, const char *key);
 font_t font_create(const char *name, const char *filename);
 void font_destroy(font_t font);
 unsigned int map_create(toml_table_t *table, map_t **map);

src/main.c

@@ -2,6 +2,8 @@
 #include <toml.h>
 
 #include "util.h"
+#include "node.h"
+#include "font.h"
 #include "script.h"
 
 #define ERRBUFSZ 200
@@ -40,7 +42,7 @@ int main(int argc, char **argv) {
 	if (!font) {
 		error("couldn't find font table in ", argv[1]);
 	}
-	font_t *fonts = load_fonts(font, base_path);
+	node_t *fonts = load_fonts(font, base_path);
 
 	toml_array_t *scripts = toml_array_in(conf, "script");
 

src/node.c

@@ -0,0 +1,91 @@
+
+#include <stdlib.h>
+#include "node.h"
+
+node_t *node_create(void *data) {
+	node_t *temp = malloc(sizeof(node_t));
+
+	temp->data = data;
+	temp->left = temp->right = NULL;
+
+	return temp;
+}
+
+node_t *node_search(node_t *root, void *data, node_comparator func) {
+	int cmp;
+	if (root == NULL) {
+		return root;
+	}
+
+	node_t *temp = node_create(data);
+	cmp = func(root, temp);
+	free(temp);
+
+	if (cmp == 0) {
+		return root;
+	}
+
+	if (cmp < 0) {
+		return node_search(root->left, data, func);
+	} else {
+		return node_search(root->right, data, func);
+	}
+}
+
+node_t *node_insert(node_t *node, void *data, node_comparator func) {
+	if (node == NULL) {
+		return node_create(data);
+	}
+
+	node_t *temp = node_create(data);
+	int cmp = func(node, temp);
+	free(temp);
+
+	if (cmp < 0) {
+		node->left = node_insert(node->left, data, func);
+	} else {
+		node->right = node_insert(node->right, data, func);
+	}
+	return node;
+}
+
+node_t *node_find_leftmost(node_t *root) {
+	if (root == NULL) {
+		return NULL;
+	} else if (root->left != NULL) {
+		return node_find_leftmost(root->left);
+	}
+	return root;
+}
+
+node_t *node_remove(node_t *root, void *data, node_comparator func) {
+	if (root == NULL) {
+		return NULL;
+	}
+	node_t *temp = node_create(data);
+	int cmp = func(root, temp);
+	free(temp);
+
+	if (cmp > 0) {
+		root->right = node_remove(root->right, data, func);
+	} else if (cmp < 0) {
+		root->left = node_remove(root->left, data, func);
+	} else {
+		if ((root->left == NULL) && (root->right == NULL)) {
+			free(root);
+			return NULL;
+		} else if ((root->left == NULL) || (root->right == NULL)) {
+			if (root->left == NULL) {
+				temp = root->right;
+			} else {
+				temp = root->left;
+			}
+			free(temp);
+		} else {
+			temp = node_find_leftmost(root->right);
+			root->data = temp->data;
+			root->right = node_remove(root->right, temp->data, func);
+		}
+	}
+	return root;
+}

src/node.h

@@ -0,0 +1,17 @@
+#ifndef _SMEARGLE_NODE_H
+#define _SMEARGLE_NODE_H
+
+typedef struct node_t {
+	void *data;
+	struct node_t *left, *right;
+} node_t;
+
+typedef int(node_comparator)(const node_t *a, const node_t *b);
+
+node_t *node_create(void *data);
+node_t *node_search(node_t *root, void *data, node_comparator func);
+node_t *node_insert(node_t *node, void *data, node_comparator func);
+node_t *node_find_leftmost(node_t *root);
+node_t *node_remove(node_t *root, void *data, node_comparator func);
+
+#endif

src/script.c

@@ -5,7 +5,7 @@
 #include "font.h"
 #include "util.h"
 
-script_t script_create(toml_table_t *table, const char *base_path, font_t *fonts) {
+script_t script_create(toml_table_t *table, const char *base_path, node_t *fonts) {
 	script_t script;
 
 #define TOML_GET_KEY(var, key, func) toml_datum_t (var) = func(table, (key));\
@@ -29,7 +29,11 @@ script_t script_create(toml_table_t *table, const char *base_path, font_t *fonts
 	TOML_GET_KEY(little_endian, "little_endian", toml_bool_in)
 #undef TOML_GET_KEY
 
-	font_t *font = font_find(font_name.u.s);
+	node_t *node = font_find(fonts, font_name.u.s);
+	if (node == NULL) {
+		error("couldn't find font ", font_name.u.s);
+	}
+	font_t *font = node->data;
 
 	script.filename = filename.u.s;
 	script.font = *font;

src/script.h

@@ -6,6 +6,7 @@
 #include <libgen.h>
 
 #include "font.h"
+#include "node.h"
 
 typedef struct {
 	char *name;
@@ -22,7 +23,7 @@ typedef struct {
 	bool little_endian;
 } script_t;
 
-script_t script_create(toml_table_t *table, const char *base_path, font_t *fonts);
+script_t script_create(toml_table_t *table, const char *base_path, node_t *fonts);
 void script_destroy(script_t script);
 
 #endif

src/util.h

@@ -5,7 +5,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
-#include <search.h>
 
 static void error(const char *msg, const char *msg1) {
 	fprintf(stderr, "Error: %s%s\n", msg, msg1 ? msg1 : "");