1 files changed, 114 insertions, 3 deletions
diff --git a/src/pow_lua.c b/src/pow_lua.c
index 0d0214d..70b32ad 100644
--- a/src/pow_lua.c
+++ b/src/pow_lua.c
@@ -1,11 +1,122 @@
 #include "pow_lua.h"
 
+#include "archive.h"
+#include "archive_entry.h"
 #include "lauxlib.h"
-#include "lualib.h"
+#include "stdlib.h"
+#include "string.h"
 
-int pow_lua_hello(lua_State *L) { printf("hi\n"); }
+int pow_lua_extract(lua_State *L) {
+  int r;
+  ssize_t size;
 
-luaL_Reg libpow[] = {{"hello", pow_lua_hello}};
+  struct archive *a;
+  struct archive_entry *entry;
+
+  if (!lua_isstring(L, 1)) {
+    lua_pushnil(L);
+    lua_pushstring(L, "arg 1 must be string (src)");
+
+    return 2;
+  }
+
+  if (!lua_isstring(L, 2)) {
+    lua_pushnil(L);
+    lua_pushstring(L, "arg 2 must be string (dest)");
+
+    return 2;
+  }
+
+  const char *filename = lua_tostring(L, 1);
+  const char *dest = lua_tostring(L, 2);
+
+  a = archive_read_new();
+
+  archive_read_support_filter_all(a);
+  archive_read_support_format_all(a);
+
+  if ((r = archive_read_open_filename(a, filename, 10240))) {
+    return 0;
+  }
+
+  for (;;) {
+    r = archive_read_next_header(a, &entry);
+
+    if (r == ARCHIVE_EOF)
+      break;
+    if (r < ARCHIVE_OK)
+      printf("warn while unpacking: %s\n", archive_error_string(a));
+    if (r < ARCHIVE_WARN) {
+      printf("error while unpacking: %s\n", archive_error_string(a));
+
+      lua_pop(L, 1);
+
+      char *error_msg = malloc(256);
+
+      lua_pushnil(L);
+
+      if (!error_msg) {
+        lua_pushstring(L, "error while unpacking and failed to malloc to push "
+                          "real error message");
+        printf("error while unpacking and failed to push real error message\n");
+
+        return 2;
+      }
+
+      snprintf(error_msg, 256, "error while unpacking: %s",
+               archive_error_string(a));
+
+      lua_pushstring(L, error_msg);
+
+      free(error_msg);
+
+      return 2;
+    }
+
+    const char *cur = archive_entry_pathname(entry);
+
+    if (cur) {
+      size_t need = strlen(dest) + strlen(cur) + 2;
+
+      char *full = malloc(need);
+
+      if (!full) {
+        lua_pushnil(L);
+        lua_pushstring(L, "failed to malloc entry path\n");
+
+        archive_read_close(a);
+        archive_read_free(a);
+
+        return 2;
+      }
+
+      snprintf(full, need, "%s/%s", dest, cur);
+      archive_entry_set_pathname(entry, full);
+    }
+
+    r = archive_read_extract(a, entry, 0);
+
+    if (r < ARCHIVE_WARN) {
+      lua_pushnil(L);
+      lua_pushfstring(
+          L, "failed to extract '%s': %s", archive_entry_pathname(entry),
+          archive_error_string(a) ? archive_error_string(a) : "unknown");
+      archive_read_close(a);
+      archive_read_free(a);
+
+      return 2;
+    }
+  }
+
+  archive_read_close(a);
+  archive_read_free(a);
+
+  lua_pushboolean(L, 1);
+
+  return 1;
+}
+
+luaL_Reg libpow[] = {{"extract", pow_lua_extract}, {NULL, NULL}};
 
 int pow_lua_load(lua_State *L) {
   luaL_newlib(L, libpow);