Add rudimentary register implementation

register.c

@@ -0,0 +1,62 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "register.h"
+#include "util.h"
+
+#define REG_SIZE 1024
+
+struct Register {
+	char *data;
+	size_t len;
+	size_t size;
+};
+
+bool register_alloc(Register *reg, size_t size) {
+	if (size < REG_SIZE)
+		size = REG_SIZE;
+	if (reg->size < size) {
+		reg->data = realloc(reg->data, size);
+		if (!reg->data) {
+			reg->size = 0;
+			reg->len = 0;
+			return false;
+		}
+		reg->size = size;
+	}
+	return true;
+}
+
+void register_free(Register *reg) {
+	if (!reg)
+		return;
+	free(reg->data);
+	reg->data = NULL;
+	reg->len = 0;
+	reg->size = 0;
+}
+
+bool register_store(Register *reg, const char *data, size_t len) {
+	if (!register_alloc(reg, len))
+		return false;
+	memcpy(reg->data, data, len);
+	reg->len = len;
+	return true;
+}
+
+bool register_put(Register *reg, Text *txt, Filerange *range) {
+	size_t len = range->end - range->start;
+	if (!register_alloc(reg, len))
+		return false;
+	reg->len = text_bytes_get(txt, range->start, len, reg->data);
+	return true;
+}
+
+bool register_append(Register *reg, Text *txt, Filerange *range) {
+	size_t rem = reg->size - reg->len;
+	size_t len = range->end - range->start;
+	if (len > rem && !register_alloc(reg, reg->size + len - rem))
+		return false;
+	reg->len += text_bytes_get(txt, range->start, len, reg->data + reg->len);
+	return true;
+}

register.h

@@ -0,0 +1,16 @@
+#ifndef REGISTER_H
+#define REGISTER_H
+
+#include <stddef.h>
+#include <stdbool.h>
+#include "text.h"
+
+typedef struct Register Register;
+
+bool register_alloc(Register *reg, size_t size);
+void register_free(Register *reg); 
+bool register_store(Register *reg, const char *data, size_t len);
+bool register_put(Register *reg, Text *txt, Filerange *range);
+bool register_append(Register *reg, Text *txt, Filerange *range); 
+
+#endif