1 files changed, 54 insertions, 0 deletions
diff --git a/tools/lz/util.c b/tools/lz/util.c
new file mode 100644
index 000000000..d77ac7bcc
--- /dev/null
+++ b/tools/lz/util.c
@@ -0,0 +1,54 @@
+#include "proto.h"
+
+noreturn error_exit (int error_code, const char * error, ...) {
+  va_list ap;
+  va_start(ap, error);
+  fputs("error: ", stderr);
+  vfprintf(stderr, error, ap);
+  va_end(ap);
+  fputc('\n', stderr);
+  exit(error_code);
+}
+
+unsigned char * read_file_into_buffer (const char * file, unsigned short * size) {
+  FILE * fp = file ? fopen(file, "rb") : stdin;
+  if (!fp) error_exit(1, "could not open file %s for reading", file);
+  unsigned char * buf = malloc(MAX_FILE_SIZE + 1);
+  int rv = fread(buf, 1, MAX_FILE_SIZE + 1, fp);
+  if (file) fclose(fp);
+  if (rv < 0) error_exit(1, "could not read from file %s", file);
+  if (rv > MAX_FILE_SIZE) error_exit(1, "file %s is too big", file ? file : "<standard input>");
+  *size = rv;
+  return buf;
+}
+
+struct command pick_best_command (unsigned count, struct command command, ...) {
+  struct command result = command;
+  va_list ap;
+  va_start(ap, command);
+  while (-- count) {
+    command = va_arg(ap, struct command);
+    if (is_better(command, result)) result = command;
+  }
+  va_end(ap);
+  return result;
+}
+
+int is_better (struct command new, struct command old) {
+  if (new.command == 7) return 0;
+  if (old.command == 7) return 1;
+  short new_savings = new.count - command_size(new), old_savings = old.count - command_size(old);
+  return new_savings > old_savings;
+}
+
+short command_size (struct command command) {
+  short header_size = 1 + (command.count > SHORT_COMMAND_COUNT);
+  if (command.command & 4) return header_size + 1 + (command.value >= 0);
+  return header_size + command.command[(short []) {command.count, 1, 2, 0}];
+}
+
+unsigned short compressed_length (const struct command * commands, unsigned short count) {
+  unsigned short current, total = 0;
+  for (current = 0; current < count; current ++) if (commands[current].command != 7) total += command_size(commands[current]);
+  return total;
+}