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Imported 'struct' module from dev branch.

This commit is contained in:
Johny Mattsson 2016-11-17 21:48:31 +11:00
parent 0f0cc93f7b
commit 6ce3e7a551
3 changed files with 597 additions and 0 deletions
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7
components/modules/Kconfig
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@ -79,6 +79,13 @@ config LUA_MODULE_NODE
help
Includes the node module (recommended).
config LUA_MODULE_STRUCT
bool "Struct module"
default "n"
help
Includes the struct module. This module provides [un]packing of raw
byte strings into Lua values and vice versa.
config LUA_MODULE_WIFI
bool "WiFi module"
default "y"

425
components/modules/struct.c Normal file
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@ -0,0 +1,425 @@
/*
** {======================================================
** Library for packing/unpacking structures.
** $Id: struct.c,v 1.4 2012/07/04 18:54:29 roberto Exp $
** See Copyright Notice at the end of this file
** =======================================================
*/
// Original: http://www.inf.puc-rio.br/~roberto/struct/
// This was ported to NodeMCU by Philip Gladstone, N1DQ
/*
** Valid formats:
** > - big endian
** < - little endian
** ![num] - alignment
** x - pading
** b/B - signed/unsigned byte
** h/H - signed/unsigned short
** l/L - signed/unsigned long
** T - size_t
** i/In - signed/unsigned integer with size `n' (default is size of int)
** cn - sequence of `n' chars (from/to a string); when packing, n==0 means
the whole string; when unpacking, n==0 means use the previous
read number as the string length
** s - zero-terminated string
** f - float
** d - double
** ' ' - ignored
*/
#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <stddef.h>
#include <string.h>
#include "module.h"
#include "lua.h"
#include "lauxlib.h"
/* basic integer type */
#if !defined(STRUCT_INT)
#define STRUCT_INT long
#endif
typedef STRUCT_INT Inttype;
/* corresponding unsigned version */
typedef unsigned STRUCT_INT Uinttype;
/* maximum size (in bytes) for integral types */
#ifdef LUA_NUMBER_INTEGRAL
#ifdef LUA_INTEGRAL_LONGLONG
#define MAXINTSIZE 8
#else
#define MAXINTSIZE 4
#endif
#else
#define MAXINTSIZE 32
#endif
/* is 'x' a power of 2? */
#define isp2(x) ((x) > 0 && ((x) & ((x) - 1)) == 0)
/* dummy structure to get alignment requirements */
struct cD {
char c;
double d;
};
#define PADDING (sizeof(struct cD) - sizeof(double))
#define MAXALIGN (PADDING > sizeof(int) ? PADDING : sizeof(int))
/* endian options */
#define BIG 0
#define LITTLE 1
static union {
int dummy;
char endian;
} const native = {1};
typedef struct Header {
int endian;
int align;
} Header;
static int getnum (const char **fmt, int df) {
if (!isdigit((unsigned char)**fmt)) /* no number? */
return df; /* return default value */
else {
int a = 0;
do {
a = a*10 + *((*fmt)++) - '0';
} while (isdigit((unsigned char)**fmt));
return a;
}
}
#define defaultoptions(h) ((h)->endian = native.endian, (h)->align = 1)
static size_t optsize (lua_State *L, char opt, const char **fmt) {
switch (opt) {
case 'B': case 'b': return sizeof(char);
case 'H': case 'h': return sizeof(short);
case 'L': case 'l': return sizeof(long);
case 'T': return sizeof(size_t);
#ifndef LUA_NUMBER_INTEGRAL
case 'f': return sizeof(float);
case 'd': return sizeof(double);
#endif
case 'x': return 1;
case 'c': return getnum(fmt, 1);
case 'i': case 'I': {
int sz = getnum(fmt, sizeof(int));
if (sz > MAXINTSIZE)
luaL_error(L, "integral size %d is larger than limit of %d",
sz, MAXINTSIZE);
return sz;
}
default: return 0; /* other cases do not need alignment */
}
}
/*
** return number of bytes needed to align an element of size 'size'
** at current position 'len'
*/
static int gettoalign (size_t len, Header *h, int opt, size_t size) {
if (size == 0 || opt == 'c') return 0;
if (size > (size_t)h->align)
size = h->align; /* respect max. alignment */
return (size - (len & (size - 1))) & (size - 1);
}
/*
** options to control endianess and alignment
*/
static void controloptions (lua_State *L, int opt, const char **fmt,
Header *h) {
switch (opt) {
case ' ': return; /* ignore white spaces */
case '>': h->endian = BIG; return;
case '<': h->endian = LITTLE; return;
case '!': {
int a = getnum(fmt, MAXALIGN);
if (!isp2(a))
luaL_error(L, "alignment %d is not a power of 2", a);
h->align = a;
return;
}
default: {
const char *msg = lua_pushfstring(L, "invalid format option '%c'", opt);
luaL_argerror(L, 1, msg);
}
}
}
static void putinteger (lua_State *L, luaL_Buffer *b, int arg, int endian,
int size) {
lua_Number n = luaL_checknumber(L, arg);
Uinttype value;
char buff[MAXINTSIZE];
if (n < 0)
value = (Uinttype)(Inttype)n;
else
value = (Uinttype)n;
if (endian == LITTLE) {
int i;
for (i = 0; i < size; i++) {
buff[i] = (value & 0xff);
value >>= 8;
}
}
else {
int i;
for (i = size - 1; i >= 0; i--) {
buff[i] = (value & 0xff);
value >>= 8;
}
}
luaL_addlstring(b, buff, size);
}
static void correctbytes (char *b, int size, int endian) {
if (endian != native.endian) {
int i = 0;
while (i < --size) {
char temp = b[i];
b[i++] = b[size];
b[size] = temp;
}
}
}
static int b_pack (lua_State *L) {
luaL_Buffer b;
const char *fmt = luaL_checkstring(L, 1);
Header h;
int arg = 2;
size_t totalsize = 0;
defaultoptions(&h);
lua_pushnil(L); /* mark to separate arguments from string buffer */
luaL_buffinit(L, &b);
while (*fmt != '\0') {
int opt = *fmt++;
size_t size = optsize(L, opt, &fmt);
int toalign = gettoalign(totalsize, &h, opt, size);
totalsize += toalign;
while (toalign-- > 0) luaL_addchar(&b, '\0');
switch (opt) {
case 'b': case 'B': case 'h': case 'H':
case 'l': case 'L': case 'T': case 'i': case 'I': { /* integer types */
putinteger(L, &b, arg++, h.endian, size);
break;
}
case 'x': {
luaL_addchar(&b, '\0');
break;
}
#ifndef LUA_NUMBER_INTEGRAL
case 'f': {
float f = (float)luaL_checknumber(L, arg++);
correctbytes((char *)&f, size, h.endian);
luaL_addlstring(&b, (char *)&f, size);
break;
}
case 'd': {
double d = luaL_checknumber(L, arg++);
correctbytes((char *)&d, size, h.endian);
luaL_addlstring(&b, (char *)&d, size);
break;
}
#endif
case 'c': case 's': {
size_t l;
const char *s = luaL_checklstring(L, arg++, &l);
if (size == 0) size = l;
luaL_argcheck(L, l >= (size_t)size, arg, "string too short");
luaL_addlstring(&b, s, size);
if (opt == 's') {
luaL_addchar(&b, '\0'); /* add zero at the end */
size++;
}
break;
}
default: controloptions(L, opt, &fmt, &h);
}
totalsize += size;
}
luaL_pushresult(&b);
return 1;
}
static lua_Number getinteger (const char *buff, int endian,
int issigned, int size) {
Uinttype l = 0;
int i;
if (endian == BIG) {
for (i = 0; i < size; i++) {
l <<= 8;
l |= (Uinttype)(unsigned char)buff[i];
}
}
else {
for (i = size - 1; i >= 0; i--) {
l <<= 8;
l |= (Uinttype)(unsigned char)buff[i];
}
}
if (!issigned)
return (lua_Number)l;
else { /* signed format */
Uinttype mask = (Uinttype)(~((Uinttype)0)) << (size*8 - 1);
if (l & mask) /* negative value? */
l |= mask; /* signal extension */
return (lua_Number)(Inttype)l;
}
}
static int b_unpack (lua_State *L) {
Header h;
const char *fmt = luaL_checkstring(L, 1);
size_t ld;
const char *data = luaL_checklstring(L, 2, &ld);
size_t pos = luaL_optinteger(L, 3, 1) - 1;
defaultoptions(&h);
lua_settop(L, 2);
while (*fmt) {
int opt = *fmt++;
size_t size = optsize(L, opt, &fmt);
pos += gettoalign(pos, &h, opt, size);
luaL_argcheck(L, pos+size <= ld, 2, "data string too short");
luaL_checkstack(L, 2, "too many results");
switch (opt) {
case 'b': case 'B': case 'h': case 'H':
case 'l': case 'L': case 'T': case 'i': case 'I': { /* integer types */
int issigned = islower(opt);
lua_Number res = getinteger(data+pos, h.endian, issigned, size);
lua_pushnumber(L, res);
break;
}
case 'x': {
break;
}
#ifndef LUA_NUMBER_INTEGRAL
case 'f': {
float f;
memcpy(&f, data+pos, size);
correctbytes((char *)&f, sizeof(f), h.endian);
lua_pushnumber(L, f);
break;
}
case 'd': {
double d;
memcpy(&d, data+pos, size);
correctbytes((char *)&d, sizeof(d), h.endian);
lua_pushnumber(L, d);
break;
}
#endif
case 'c': {
if (size == 0) {
if (!lua_isnumber(L, -1))
luaL_error(L, "format `c0' needs a previous size");
size = lua_tonumber(L, -1);
lua_pop(L, 1);
luaL_argcheck(L, pos+size <= ld, 2, "data string too short");
}
lua_pushlstring(L, data+pos, size);
break;
}
case 's': {
const char *e = (const char *)memchr(data+pos, '\0', ld - pos);
if (e == NULL)
luaL_error(L, "unfinished string in data");
size = (e - (data+pos)) + 1;
lua_pushlstring(L, data+pos, size - 1);
break;
}
default: controloptions(L, opt, &fmt, &h);
}
pos += size;
}
lua_pushinteger(L, pos + 1);
return lua_gettop(L) - 2;
}
static int b_size (lua_State *L) {
Header h;
const char *fmt = luaL_checkstring(L, 1);
size_t pos = 0;
defaultoptions(&h);
while (*fmt) {
int opt = *fmt++;
size_t size = optsize(L, opt, &fmt);
pos += gettoalign(pos, &h, opt, size);
if (opt == 's')
luaL_argerror(L, 1, "option 's' has no fixed size");
else if (opt == 'c' && size == 0)
luaL_argerror(L, 1, "option 'c0' has no fixed size");
if (!isalnum(opt))
controloptions(L, opt, &fmt, &h);
pos += size;
}
lua_pushinteger(L, pos);
return 1;
}
/* }====================================================== */
static const LUA_REG_TYPE thislib[] = {
{LSTRKEY("pack"), LFUNCVAL(b_pack)},
{LSTRKEY("unpack"), LFUNCVAL(b_unpack)},
{LSTRKEY("size"), LFUNCVAL(b_size)},
{LNILKEY, LNILVAL}
};
NODEMCU_MODULE(STRUCT, "struct", thislib, NULL);
/******************************************************************************
* Copyright (C) 2010-2012 Lua.org, PUC-Rio. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
******************************************************************************/

165
docs/en/modules/struct.md Normal file
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@ -0,0 +1,165 @@
# Struct Module
| Since | Origin / Contributor | Maintainer | Source |
| :----- | :-------------------- | :---------- | :------ |
| 2015-02-13 | [Roberto Ierusalimschy](http://www.inf.puc-rio.br/~roberto/struct/), [Philip Gladstone](https://github.com/pjsg) | [Philip Gladstone](https://github.com/pjsg) | [struct.c](../../../app/modules/struct.c)|
This module offers basic facilities to convert Lua values to and from C structs. Its main functions are `struct.pack`, which packs multiple Lua values into a struct-like string; and `struct.unpack`, which unpacks multiple Lua values from a given struct-like string.
The first argument to both functions is a *format string*, which describes the layout of the structure. The format string is a sequence of conversion elements, which respect the current endianess and the current alignment requirements. Initially, the current endianess is the machine's native endianness and the current alignment requirement is 1 (meaning no alignment at all). You can change these settings with appropriate directives in the format string.
Note that the float and double conversions are only available with a floating point NodeMCU build.
### Format String
The elements in the format string are as follows:
- `" "` (empty space) ignored.
- `"!n"` flag to set the current alignment requirement to *n*
(necessarily a power of 2); an absent *n* means the machine's native
alignment.
- `">"` flag to set mode to big endian.
- `"<"` flag to set mode to little endian.
- `"x"` a padding zero byte with no corresponding Lua value.
- `"b"` a signed `char`.
- `"B"` an unsigned `char`.
- `"h"` a signed `short` (native size).
- `"H"` an unsigned `short` (native size).
- `"l"` a signed `long` (native size).
- `"L"` an unsigned `long` (native size).
- `"T"` a `size_t` (native size).
- `"in"` a signed integer with *n* bytes. An absent *n* means the
native size of an `int`.
- `"In"` like `"in"` but unsigned.
- `"f"` a `float` (native size).
- `"d"` a `double` (native size).
- `"s"` a zero-terminated string.
- `"cn"` a sequence of exactly *n* chars corresponding to a single Lua
string. An absent *n* means 1. When packing, the given string must
have at least *n* characters (extra characters are discarded).
- `"c0"` this is like `"cn"`, except that the *n* is given by other
means: When packing, *n* is the length of the given string; when
unpacking, *n* is the value of the previous unpacked value (which
must be a number). In that case, this previous value is not
returned.
#### Examples
To pack and unpack the structure
struct Str {
char b;
int i[4];
};
you can use the string `"<!4biiii"`.
To pack a string with its length coded in its first byte, use the
following code:
x = struct.pack("Bc0", string.len(s), s)
To unpack that string, do as follows:
s = struct.unpack("Bc0", x)
Note that the length (read by the element `"B"`) is not returned.
To pack a string in a fixed-width field of 10 characters padded with
blanks, do as follows:
x = struct.pack("c10", s .. string.rep(" ", 10))
## struct.pack()
Returns a string containing the values `d1`, `d2`, etc. packed
according to the format string `fmt`.
#### Syntax
`struct.pack (fmt, d1, d2, ...)`
#### Parameters
- `fmt` The format string in the format above
- `d1` The first data item to be packed
- `d2` The second data item to be packed etc.
#### Returns
The packed string.
#### Example
```
s = struct.pack("I", 0x41424344)
print(s)
```
## struct.unpack()
Returns the values packed in string `s` according to the format
string `fmt`. An optional `i` marks where in `s` to start reading
(default is 1). After the read values, this function also returns
the index in `s` where it stopped reading, which is also where you
should start to read the rest of the string.
#### Syntax
`struct.unpack (fmt, s[, offset])`
#### Parameters
- `fmt` The format string in the format above
- `s` The string holding the data to be unpacked
- `offset` The position to start in the string (default is 1)
#### Returns
All the unpacked data.
#### Example
Suppose we have to decode a string `s` with an unknown number of
doubles; the end is marked by a zero value. We can use the following
code:
local a = {}
local i = 1 -- index where to read
while true do
local d
d, i = struct.unpack("d", s, i)
if d == 0 then break end
a[#a + 1] = d
end
## struct.size()
Returns the size of a string formatted according to the format
string `fmt`. The format string should contain neither the option
`s` nor the option `c0`.
#### Syntax
`struct.size (fmt)`
#### Parameters
- `fmt` The format string in the format above
#### Returns
The size of the string that would be output in a pack operation with this format string.
#### Example
```
print(struct.size("i"))
```
This prints the size of the native integer type.
### License
This package is distributed under the MIT license. See copyright notice
at the end of file `struct.c`.