1 files changed, 136 insertions, 0 deletions

diff --git a/bin/edi/table.c b/bin/edi/table.c
new file mode 100644
index 00000000..ad8f1f9d
--- /dev/null
+++ b/bin/edi/table.c
@@ -0,0 +1,136 @@
+/* Copyright (C) 2018  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <wchar.h>
+
+#include "edi.h"
+
+static struct Table *alloc(size_t cap) {
+	size_t size = sizeof(struct Table) + sizeof(struct Slice) * cap;
+	struct Table *table = malloc(size);
+	if (!table) err(EX_OSERR, "malloc");
+	table->len = 0;
+	return table;
+}
+
+struct Table *tableInsert(const struct Table *prev, size_t at, struct Slice slice) {
+	if (!prev || !prev->len) {
+		struct Table *next = alloc(1);
+		next->slices[next->len++] = slice;
+		return next;
+	}
+
+	struct Table *next = alloc(prev->len + 2);
+	struct Span span = { 0, 0 };
+	for (size_t i = 0; i < prev->len; ++i) {
+		span = spanNext(span, prev->slices[i].len);
+		if (span.at == at) {
+			next->slices[next->len++] = slice;
+			next->slices[next->len++] = prev->slices[i];
+		} else if (span.at < at && span.to > at) {
+			next->slices[next->len++] = (struct Slice) {
+				prev->slices[i].ptr,
+				at - span.at,
+			};
+			next->slices[next->len++] = slice;
+			next->slices[next->len++] = (struct Slice) {
+				&prev->slices[i].ptr[at - span.at],
+				prev->slices[i].len - (at - span.at),
+			};
+		} else {
+			next->slices[next->len++] = prev->slices[i];
+		}
+	}
+	if (span.to == at) {
+		next->slices[next->len++] = slice;
+	}
+	return next;
+}
+
+struct Table *tableDelete(const struct Table *prev, struct Span del) {
+	if (!prev || !prev->len) return alloc(0);
+
+	struct Table *next = alloc(prev->len + 1);
+	struct Span span = { 0, 0 };
+	for (size_t i = 0; i < prev->len; ++i) {
+		span = spanNext(span, prev->slices[i].len);
+		if (span.at >= del.at && span.to <= del.to) {
+			(void)prev->slices[i];
+		} else if (span.at < del.at && span.to > del.to) {
+			next->slices[next->len++] = (struct Slice) {
+				prev->slices[i].ptr,
+				del.at - span.at,
+			};
+			next->slices[next->len++] = (struct Slice) {
+				&prev->slices[i].ptr[del.to - span.at],
+				prev->slices[i].len - (del.to - span.at),
+			};
+		} else if (span.at < del.at && span.to > del.at) {
+			next->slices[next->len++] = (struct Slice) {
+				prev->slices[i].ptr,
+				del.at - span.at,
+			};
+		} else if (span.at < del.to && span.to > del.to) {
+			next->slices[next->len++] = (struct Slice) {
+				&prev->slices[i].ptr[del.to - span.at],
+				prev->slices[i].len - (del.to - span.at),
+			};
+		} else {
+			next->slices[next->len++] = prev->slices[i];
+		}
+	}
+	return next;
+}
+
+#ifdef TEST
+#include <assert.h>
+
+static struct Span span(size_t at, size_t to) {
+	return (struct Span) { at, to };
+}
+
+static struct Slice slice(const wchar_t *str) {
+	return (struct Slice) { str, wcslen(str) };
+}
+
+static int eq(const struct Table *table, const wchar_t *str) {
+	for (size_t i = 0; i < table->len; ++i) {
+		if (wcsncmp(str, table->slices[i].ptr, table->slices[i].len)) {
+			return 0;
+		}
+		str = &str[table->slices[i].len];
+	}
+	return 1;
+}
+
+int main() {
+	struct Table *abc = tableInsert(NULL, 0, slice(L"ABC"));
+	assert(eq(abc, L"ABC"));
+
+	assert(eq(tableInsert(abc, 0, slice(L"D")), L"DABC"));
+	assert(eq(tableInsert(abc, 3, slice(L"D")), L"ABCD"));
+	assert(eq(tableInsert(abc, 1, slice(L"D")), L"ADBC"));
+
+	assert(eq(tableDelete(abc, span(0, 1)), L"BC"));
+	assert(eq(tableDelete(abc, span(2, 3)), L"AB"));
+	assert(eq(tableDelete(abc, span(1, 2)), L"AC"));
+	assert(eq(tableDelete(abc, span(0, 3)), L""));
+}
+
+#endif