// Module encoders #include "module.h" #include "lauxlib.h" #include "lmem.h" #include #define BASE64_INVALID '\xff' #define BASE64_PADDING '=' #define ISBASE64(c) (unbytes64[c] != BASE64_INVALID) static const uint8 b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; static uint8 *toBase64 ( lua_State* L, const uint8 *msg, size_t *len){ size_t i, n = *len; if (!n) // handle empty string case return NULL; int buf_size = (n + 2) / 3 * 4; // estimated encoded size uint8 * q, *out = (uint8 *)luaM_malloc(L, buf_size); uint8 bytes64[sizeof(b64)]; memcpy(bytes64, b64, sizeof(b64)); //Avoid lots of flash unaligned fetches for (i = 0, q = out; i < n; i += 3) { int a = msg[i]; int b = (i + 1 < n) ? msg[i + 1] : 0; int c = (i + 2 < n) ? msg[i + 2] : 0; *q++ = bytes64[a >> 2]; *q++ = bytes64[((a & 3) << 4) | (b >> 4)]; *q++ = (i + 1 < n) ? bytes64[((b & 15) << 2) | (c >> 6)] : BASE64_PADDING; *q++ = (i + 2 < n) ? bytes64[(c & 63)] : BASE64_PADDING; } *len = q - out; out = luaM_realloc_(L, out, buf_size, *len); //reallocate to actual encoded length return out; } static uint8 *fromBase64 ( lua_State* L, const uint8 *enc_msg, size_t *len){ int i, n = *len, blocks = (n>>2), pad = 0; const uint8 *p; uint8 unbytes64[UCHAR_MAX+1], *msg, *q; if (!n) // handle empty string case return NULL; if (n & 3) luaL_error (L, "Invalid base64 string"); memset(unbytes64, BASE64_INVALID, sizeof(unbytes64)); for (i = 0; i < sizeof(b64)-1; i++) unbytes64[b64[i]] = i; // sequential so no exceptions if (enc_msg[n-1] == BASE64_PADDING) { pad = (enc_msg[n-2] != BASE64_PADDING) ? 1 : 2; blocks--; //exclude padding block } for (i = 0; i < n - pad; i++) if (!ISBASE64(enc_msg[i])) luaL_error (L, "Invalid base64 string"); unbytes64[BASE64_PADDING] = 0; int buf_size=1+ (3 * n / 4); // estimate decoded length msg = q = (uint8 *) luaM_malloc(L, buf_size); for (i = 0, p = enc_msg; i> 4); *q++ = (b << 4) | (c >> 2); *q++ = (c << 6) | d; } if (pad) { //now process padding block bytes uint8 a = unbytes64[*p++]; uint8 b = unbytes64[*p++]; *q++ = (a << 2) | (b >> 4); if (pad == 1) *q++ = (b << 4) | (unbytes64[*p] >> 2); } *len = q - msg; msg = luaM_realloc_(L, msg, buf_size, *len); //reallocate to actual decoded length return msg; } static inline uint8 to_hex_nibble(uint8 b) { return b + ( b < 10 ? '0' : 'a' - 10 ); } static uint8 *toHex ( lua_State* L, const uint8 *msg, size_t *len){ int i, n = *len; *len <<= 1; uint8 *q, *out = (uint8 *)luaM_malloc(L, *len); for (i = 0, q = out; i < n; i++) { *q++ = to_hex_nibble(msg[i] >> 4); *q++ = to_hex_nibble(msg[i] & 0xf); } return out; } static uint8 *fromHex ( lua_State* L, const uint8 *msg, size_t *len){ int i, n = *len; const uint8 *p; if (n &1) luaL_error (L, "Invalid hex string"); *len >>= 1; uint8 b, *q, *out = (uint8 *)luaM_malloc(L, *len); uint8 c = 0; for (i = 0, p = msg, q = out; i < n; i++) { if (*p >= '0' && *p <= '9') { b = *p++ - '0'; } else if (*p >= 'a' && *p <= 'f') { b = *p++ - ('a' - 10); } else if (*p >= 'A' && *p <= 'F') { b = *p++ - ('A' - 10); } else { luaN_freearray(L, out, *len); luaL_error (L, "Invalid hex string"); } if ((i&1) == 0) { c = b<<4; } else { *q++ = c+ b; } } return out; } // All encoder functions are of the form: // Lua: output_string = encoder.function(input_string) // Where input string maybe empty, but not nil // Hence these all call the do_func wrapper static int do_func (lua_State *L, uint8 * (*conv_func)(lua_State *, const uint8 *, size_t *)) { size_t len; const uint8 *input = luaL_checklstring(L, 1, &len); uint8 *output = conv_func(L, input, &len); if (output) { lua_pushlstring(L, output, len); luaN_freearray(L, output, len); } else { lua_pushstring(L, ""); } return 1; } #define DECLARE_FUNCTION(f) static int encoder_ ## f (lua_State *L) \ { return do_func(L, f); } DECLARE_FUNCTION(fromBase64); DECLARE_FUNCTION(toBase64); DECLARE_FUNCTION(fromHex); DECLARE_FUNCTION(toHex); // Module function map LROT_BEGIN(encoder, NULL, 0) LROT_FUNCENTRY( fromBase64, encoder_fromBase64 ) LROT_FUNCENTRY( toBase64, encoder_toBase64 ) LROT_FUNCENTRY( fromHex, encoder_fromHex ) LROT_FUNCENTRY( toHex, encoder_toHex ) LROT_END(encoder, NULL, 0) NODEMCU_MODULE(ENCODER, "encoder", encoder, NULL);