1 files changed, 92 insertions, 0 deletions
diff --git a/tools/lz/uncomp.c b/tools/lz/uncomp.c
new file mode 100644
index 000000000..3544cd93b
--- /dev/null
+++ b/tools/lz/uncomp.c
@@ -0,0 +1,92 @@
+#include "proto.h"
+
+struct command * get_commands_from_file (const unsigned char * data, unsigned short * restrict size, unsigned short * restrict slack) {
+  struct command * result = malloc(*size * sizeof(struct command));
+  unsigned short remaining = *size;
+  struct command * current = result;
+  const unsigned char * rp = data;
+  while (1) {
+    if (!(remaining --)) goto error;
+    current -> command = *rp >> 5;
+    current -> count = *(rp ++) & 31;
+    if (current -> command == 7) {
+      current -> command = current -> count >> 2;
+      current -> count = (current -> count & 3) << 8;
+      if (current -> command == 7) {
+        // long commands inside long commands are not allowed, but if the count is 0x300 here, it means that the original byte was 0xff
+        if (current -> count == 0x300) break;
+        goto error;
+      }
+      if (!(remaining --)) goto error;
+      current -> count |= *(rp ++);
+    }
+    current -> count ++;
+    switch (current -> command) {
+      case 0:
+        if (remaining <= current -> count) goto error;
+        current -> value = rp - data;
+        rp += current -> count;
+        remaining -= current -> count;
+      case 3:
+        break;
+      case 1: case 2: {
+        unsigned char p;
+        if (remaining <= current -> command) goto error;
+        current -> value = 0;
+        for (p = 0; p < current -> command; p ++) current -> value |= *(rp ++) << (p << 3);
+        remaining -= current -> command;
+      } break;
+      default:
+        if (!(remaining --)) goto error;
+        if ((current -> value = *(rp ++)) & 128)
+          current -> value = 127 - current -> value;
+        else {
+          if (!(remaining --)) goto error;
+          current -> value = (current -> value << 8) | *(rp ++);
+        }
+    }
+    current ++;
+  }
+  if (slack) *slack = *size - (rp - data);
+  *size = current - result;
+  return realloc(result, *size * sizeof(struct command));
+  error:
+  free(result);
+  return NULL;
+}
+
+unsigned char * get_uncompressed_data (const struct command * commands, const unsigned char * compressed, unsigned short * size) {
+  const struct command * limit = commands + *size;
+  unsigned char * result = malloc(MAX_FILE_SIZE + MAX_COMMAND_COUNT);
+  unsigned char * current = result;
+  unsigned short p;
+  for (; commands < limit; commands ++) {
+    switch (commands -> command) {
+      case 0:
+        memcpy(current, compressed + commands -> value, commands -> count);
+        current += commands -> count;
+        break;
+      case 1: case 2:
+        for (p = 0; p < commands -> count; p ++) *(current ++) = commands -> value >> ((p % commands -> command) << 3);
+        break;
+      case 3:
+        memset(current, 0, commands -> count);
+        current += commands -> count;
+        break;
+      default: {
+        const unsigned char * ref = ((commands -> value < 0) ? current : result) + commands -> value;
+        for (p = 0; p < commands -> count; p ++) {
+          current[p] = ref[(commands -> command == 6) ? -(int) p : p];
+          if (commands -> command == 5) current[p] = bit_flipping_table[current[p]];
+        }
+        current += commands -> count;
+      }
+    }
+    if ((current - result) > MAX_FILE_SIZE) {
+      free(result);
+      return NULL;
+    }
+  }
+  *size = current - result;
+  return result;
+}