shithub: sox

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Something like a first working version of Lua formats

--- a/src/luaform.c

+++ b/src/luaform.c

@@ -28,7 +28,9 @@

 /* Private data */

 typedef struct luafile {

   lua_State *L;                 /* Lua state */

-  int scriptref;                /* reference to script function */

+  int readref;                  /* reference to read method */

+  int writeref;                 /* reference to write method */

+  int seekref;                  /* reference to seek method */

 } *lua_t;

 assert_static(sizeof(struct luafile) <= ST_MAX_FILE_PRIVSIZE, 

@@ -35,6 +37,29 @@

               /* else */ skel_PRIVSIZE_too_big);

 /*

+ * Get the given method, checking that it is a function

+ */          

+static bool get_method(lua_State *L, const char *lua_script, const char *meth, int *ref)

+{

+  int ty;

+

+  lua_getfield(L, -1, meth);

+  if ((ty = lua_type(L, -1)) == LUA_TNIL) {

+    st_fail("Lua script %s does not have a %s method", lua_script, meth);

+    lua_pop(L, 1);

+    return false;

+  } else if (ty != LUA_TFUNCTION) {

+    st_fail("Lua script %s's %s method is not a function", lua_script, meth);

+    lua_pop(L, 1);

+    return false;

+  }

+

+  *ref = luaL_ref(L, LUA_REGISTRYINDEX);

+

+  return true;

+}

+

+/*

  * Set up Lua state and read script.

  */

 static int lua_start(ft_t ft)

@@ -50,32 +75,22 @@

   } else if ((ret = luaL_loadfile(lua->L, ft->signal.lua_script)) != 0) {

     st_fail("cannot load Lua script %s: error %d", ft->signal.lua_script, ret);

     return ST_EOF;

-  }

-  fprintf(stderr, "type %d\n", lua_type(lua->L, -1));

-  lua->scriptref = luaL_ref(lua->L, LUA_REGISTRYINDEX);

+  } else if ((ret = lua_pcall(lua->L, 0, 1, 0)) != 0) {

+    st_fail("cannot get methods from Lua script %s: error %d", ft->signal.lua_script, ret);

+    return ST_EOF;

+  } else if (lua_type(lua->L, -1) != LUA_TTABLE) {

+    st_fail("Lua script %s did not return a table", ft->signal.lua_script);

+    return ST_EOF;

+  } else if (!get_method(lua->L, ft->signal.lua_script, "rea", &lua->readref) ||

+        !get_method(lua->L, ft->signal.lua_script, "writ", &lua->writeref) ||

+        !get_method(lua->L, ft->signal.lua_script, "see", &lua->seekref))

+    return ST_EOF;

+  lua_pop(lua->L, 1);           /* Discard function */

   return ST_SUCCESS;

 }

 /*

- * Call Lua script with (action, fp, array), and return return value

- * (an st_size_t) to the caller.

- */

-static st_size_t lua_callscript(lua_t lua)

-{

-  st_size_t done;

-  int ret;

-

-  lua_rawgeti(lua->L, LUA_REGISTRYINDEX, lua->scriptref);

-  if ((ret = lua_pcall(lua->L, 3, 1, 0)) != 0)

-    st_fail("error in Lua script: %d", ret);

-  done = lua_tointeger(lua->L, -1);

-  lua_pop(lua->L, 1);

-

-  return done;

-}

-

-/*

  * Read up to len samples of type st_sample_t from file into buf[].

  * Return number of samples read.

  */

@@ -83,15 +98,21 @@

 {

   lua_t lua = (lua_t)ft->priv;

   st_sample_t_array_t inarr;

+  st_size_t done;

+  int ret;

   inarr.size = len;

   inarr.data = buf;

-  lua_pushstring(lua->L, "read");

+  lua_rawgeti(lua->L, LUA_REGISTRYINDEX, lua->readref);

   st_lua_pushfile(lua->L, ft->fp);

   st_lua_pusharray(lua->L, inarr);

+  if ((ret = lua_pcall(lua->L, 2, 1, 0)) != 0)

+    st_fail("error in Lua script's read method: %d", ret);

+  done = lua_tointeger(lua->L, -1);

+  lua_pop(lua->L, 1);

-  return lua_callscript(lua);

+  return done;

 }

 /*

@@ -102,15 +123,22 @@

 {

   lua_t lua = (lua_t)ft->priv;

   st_sample_t_array_t outarr;

+  st_size_t done;

+  int ret;

   outarr.size = len;

   outarr.data = (st_sample_t *)buf;

-  lua_pushstring(lua->L, "write");

+  lua_rawgeti(lua->L, LUA_REGISTRYINDEX, lua->writeref);

   st_lua_pushfile(lua->L, ft->fp);

   st_lua_pusharray(lua->L, outarr);

+  if ((ret = lua_pcall(lua->L, 2, 1, 0)) != 0)

+    st_fail("error in Lua script's write method: %d", ret);

+  done = lua_tointeger(lua->L, -1);

+  fprintf(stderr, "done %d\n", done);

+  lua_pop(lua->L, 1);

-  return lua_callscript(lua);

+  return done;

 }

 /*

@@ -129,12 +157,18 @@

 static int lua_seek(ft_t ft, st_size_t offset)

 {

   lua_t lua = (lua_t)ft->priv;

+  int ret;

+  st_size_t done;

-  lua_pushstring(lua->L, "seek");

+  lua_rawgeti(lua->L, LUA_REGISTRYINDEX, lua->seekref);

   st_lua_pushfile(lua->L, ft->fp);

   lua_pushinteger(lua->L, offset);

+  if ((ret = lua_pcall(lua->L, 2, 1, 0)) != 0)

+    st_fail("error in Lua script's seek method: %d", ret);

+  done = lua_toboolean(lua->L, -1);

+  lua_pop(lua->L, 1);

-  return lua_callscript(lua);

+  return done;

 }

 /* Format file suffixes */