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Update encoder files after #925 & #1072 review comments
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TerryE committed Feb 26, 2016
1 parent ffa7ee9 commit 8353991
Showing 3 changed files with 44 additions and 35 deletions.
6 changes: 3 additions & 3 deletions app/modules/crypto.c
Original file line number Diff line number Diff line change
@@ -38,7 +38,7 @@ static int crypto_sha1( lua_State* L )
}

#ifdef LUA_USE_MODULES_ENCODER
static int call_endcoder( lua_State* L, const char *function ) {
static int call_encoder( lua_State* L, const char *function ) {
if (lua_gettop(L) != 1) {
luaL_error(L, "%s must have one argument", function);
}
@@ -54,10 +54,10 @@ static int call_endcoder( lua_State* L, const char *function ) {
}

static int crypto_base64_encode (lua_State* L) {
return call_endcoder(L, "toBase64");
return call_encoder(L, "toBase64");
}
static int crypto_hex_encode (lua_State* L) {
return call_endcoder(L, "toHex");
return call_encoder(L, "toHex");
}
#else
static const char* bytes64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
59 changes: 32 additions & 27 deletions app/modules/encoder.c
Original file line number Diff line number Diff line change
@@ -8,16 +8,16 @@
#define BASE64_PADDING '='
#define ISBASE64(c) (unbytes64[c] != BASE64_INVALID)

static const char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const uint8 b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static char *toBase64 ( lua_State* L, const char *msg, size_t *len){
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;

char* q, *out = (char*)luaM_malloc(L, (n + 2) / 3 * 4);
char bytes64[sizeof(b64)];
uint8 * q, *out = (uint8 *)luaM_malloc(L, (n + 2) / 3 * 4);
uint8 bytes64[sizeof(b64)];
c_memcpy(bytes64, b64, sizeof(b64)); //Avoid lots of flash unaligned fetches

for (i = 0, q = out; i < n; i += 3) {
@@ -33,51 +33,56 @@ static char *toBase64 ( lua_State* L, const char *msg, size_t *len){
return out;
}

static char *fromBase64 ( lua_State* L, const char *enc_msg, size_t *len){
int i, n = *len, pad = 0;
unsigned const char *p;
unsigned char unbytes64[CHAR_MAX+1-CHAR_MIN], *msg, *q, a, b, c, d;
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 % 4)
if (n & 3)
luaL_error (L, "Invalid base64 string");

c_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;

msg = q = (unsigned char*) luaM_malloc(L, 1+ (3 * n / 4));
for (i = 0, p = (unsigned char*) enc_msg;; i+=4) {
a = unbytes64[*p++], b = unbytes64[*p++], c = unbytes64[*p++], d = unbytes64[*p++] ;
if (i > n-4) break;
msg = q = (uint8 *) luaM_malloc(L, 1+ (3 * n / 4));
for (i = 0, p = enc_msg; i<blocks; i++) {
uint8 a = unbytes64[*p++];
uint8 b = unbytes64[*p++];
uint8 c = unbytes64[*p++];
uint8 d = unbytes64[*p++];
*q++ = (a << 2) | (b >> 4);
*q++ = (b << 4) | (c >> 2);
*q++ = (c << 6) | d;
}

if (pad) {
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) | (c >> 2);
if (pad == 1) *q++ = (b << 4) | (unbytes64[*p] >> 2);
}
*len = q - msg;
return (char *) msg;
return msg;
}

static inline char to_hex_nibble(unsigned char b) {
static inline uint8 to_hex_nibble(uint8 b) {
return b + ( b < 10 ? '0' : 'a' - 10 );
}

static char *toHex ( lua_State* L, const char *msg, size_t *len){
static uint8 *toHex ( lua_State* L, const uint8 *msg, size_t *len){
int i, n = *len;
char *q, *out = (char*)luaM_malloc(L, n * 2);
uint8 *q, *out = (uint8 *)luaM_malloc(L, n * 2);
for (i = 0, q = out; i < n; i++) {
*q++ = to_hex_nibble(msg[i] >> 4);
*q++ = to_hex_nibble(msg[i] & 0xf);
@@ -86,11 +91,11 @@ static char *toHex ( lua_State* L, const char *msg, size_t *len){
return out;
}

static char *fromHex ( lua_State* L, const char *msg, size_t *len){
static uint8 *fromHex ( lua_State* L, const uint8 *msg, size_t *len){
int i, n = *len;
const char *p;
char b, *q, *out = (char*)luaM_malloc(L, n * 2);
unsigned char c;
const uint8 *p;
uint8 b, *q, *out = (uint8 *)luaM_malloc(L, n * 2);
uint8 c;

if (n &1)
luaL_error (L, "Invalid hex string");
@@ -118,12 +123,12 @@ static char *fromHex ( lua_State* L, const char *msg, size_t *len){
// 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 chare the do_func wrapper
static int do_func (lua_State *L, char * (*conv_func)(lua_State *, const char *, size_t *)) {
// 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 l;
const char *input = luaL_checklstring(L, 1, &l);
const uint8 *input = luaL_checklstring(L, 1, &l);
// luaL_argcheck(L, l>0, 1, "input string empty");
char *output = conv_func(L, input, &l);
uint8 *output = conv_func(L, input, &l);

if (output) {
lua_pushlstring(L, output, l);
14 changes: 9 additions & 5 deletions docs/en/modules/encoder.md
Original file line number Diff line number Diff line change
@@ -17,12 +17,13 @@ A Base64 encoded string.

#### Example
```lua
print(encoder.toBase64(cyrpto.hash("sha1","abc")))
print(encoder.toBase64(crypto.hash("sha1","abc")))
```

## encoder.fromBase64()

Decodes a Base64 representation of a (binary) Lua string back into the original string.
Decodes a Base64 representation of a (binary) Lua string back into the original string. An error is
thrown if the string is not a valid base64 encoding.

#### Syntax
`binary_string = encoder.toBase64(b64)`
@@ -40,7 +41,8 @@ print(encoder.fromBase64(encoder.toBase64("hello world")))

## encoder.toHex()

Provides an ASCII hex representation of a (binary) Lua string. Each byte in the input string is represented as two hex characters in the output.
Provides an ASCII hex representation of a (binary) Lua string. Each byte in the input string is
represented as two hex characters in the output.

#### Syntax
`hexstr = encoder.toHex(binary)`
@@ -58,10 +60,12 @@ print(encoder.toHex(crypto.hash("sha1","abc")))

## encoder.fromHex()

Provides a Lua binary string decode of a ASCII hex string. Each byte in the output string is represented as two hex characters in the input.
Returns the Lua binary string decode of a ASCII hex string. Each byte in the output string is
represented as two hex characters in the input. An error is thrown if the string is not a
valid base64 encoding.

#### Syntax
`binary = encoder.toHex(hexstr)`
`binary = encoder.fromHex(hexstr)`

#### Parameters
`hexstr` An ASCII hex string.

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