437 lines
11 KiB
C
437 lines
11 KiB
C
/*
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** {======================================================
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** Library for packing/unpacking structures.
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** $Id: struct.c,v 1.4 2012/07/04 18:54:29 roberto Exp $
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** See Copyright Notice at the end of this file
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** =======================================================
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*/
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// Original: http://www.inf.puc-rio.br/~roberto/struct/
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// This was ported to NodeMCU by Philip Gladstone, N1DQ
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/*
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** Valid formats:
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** > - big endian
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** < - little endian
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** ![num] - alignment
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** x - pading
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** b/B - signed/unsigned byte
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** h/H - signed/unsigned short
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** l/L - signed/unsigned long
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** T - size_t
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** i/In - signed/unsigned integer with size `n' (default is size of int)
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** cn - sequence of `n' chars (from/to a string); when packing, n==0 means
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the whole string; when unpacking, n==0 means use the previous
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read number as the string length
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** s - zero-terminated string
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** f - float
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** d - double
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** ' ' - ignored
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*/
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#include <assert.h>
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#include <ctype.h>
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#include <limits.h>
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#include <stddef.h>
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#include <string.h>
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#include "module.h"
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#include "lauxlib.h"
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/* basic integer type */
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#if !defined(STRUCT_INT)
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#define STRUCT_INT long
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#endif
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typedef STRUCT_INT Inttype;
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/* corresponding unsigned version */
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typedef unsigned STRUCT_INT Uinttype;
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/* maximum size (in bytes) for integral types */
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#ifdef LUA_NUMBER_INTEGRAL
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#ifdef LUA_INTEGRAL_LONGLONG
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#define MAXINTSIZE 8
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#else
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#define MAXINTSIZE 4
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#endif
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#else
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#define MAXINTSIZE 32
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#endif
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#ifndef LUA_MININTEGER
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#define LUA_MININTEGER INT_MIN
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#endif
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#ifndef LUA_MAXINTEGER
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#define LUA_MAXINTEGER INT_MAX
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#endif
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/* is 'x' a power of 2? */
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#define isp2(x) ((x) > 0 && ((x) & ((x) - 1)) == 0)
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/* dummy structure to get alignment requirements */
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struct cD {
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char c;
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double d;
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};
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#define PADDING (sizeof(struct cD) - sizeof(double))
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#define MAXALIGN (PADDING > sizeof(int) ? PADDING : sizeof(int))
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/* endian options */
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#define BIG 0
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#define LITTLE 1
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static union {
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int dummy;
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char endian;
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} const native = {1};
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typedef struct Header {
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int endian;
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int align;
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} Header;
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static int getnum (lua_State *L, const char **fmt, int df) {
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if (!isdigit(**fmt)) /* no number? */
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return df; /* return default value */
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else {
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int a = 0;
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do {
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if (a > (INT_MAX / 10) || a * 10 > (INT_MAX - (**fmt - '0')))
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luaL_error(L, "integral size overflow");
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a = a*10 + *((*fmt)++) - '0';
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} while (isdigit(**fmt));
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return a;
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}
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}
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#define defaultoptions(h) ((h)->endian = native.endian, (h)->align = 1)
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static size_t optsize (lua_State *L, char opt, const char **fmt) {
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switch (opt) {
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case 'B': case 'b': return sizeof(char);
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case 'H': case 'h': return sizeof(short);
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case 'L': case 'l': return sizeof(long);
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case 'T': return sizeof(size_t);
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#ifndef LUA_NUMBER_INTEGRAL
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case 'f': return sizeof(float);
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case 'd': return sizeof(double);
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#endif
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case 'x': return 1;
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case 'c': return getnum(L, fmt, 1);
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case 'i': case 'I': {
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int sz = getnum(L, fmt, sizeof(int));
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if (sz > MAXINTSIZE)
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luaL_error(L, "integral size %d is larger than limit of %d",
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sz, MAXINTSIZE);
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return sz;
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}
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default: return 0; /* other cases do not need alignment */
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}
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}
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/*
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** return number of bytes needed to align an element of size 'size'
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** at current position 'len'
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*/
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static int gettoalign (size_t len, Header *h, int opt, size_t size) {
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if (size == 0 || opt == 'c') return 0;
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if (size > (size_t)h->align)
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size = h->align; /* respect max. alignment */
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return (size - (len & (size - 1))) & (size - 1);
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}
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/*
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** options to control endianess and alignment
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*/
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static void controloptions (lua_State *L, int opt, const char **fmt,
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Header *h) {
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switch (opt) {
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case ' ': return; /* ignore white spaces */
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case '>': h->endian = BIG; return;
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case '<': h->endian = LITTLE; return;
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case '!': {
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int a = getnum(L, fmt, MAXALIGN);
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if (!isp2(a))
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luaL_error(L, "alignment %d is not a power of 2", a);
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h->align = a;
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return;
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}
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default: {
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const char *msg = lua_pushfstring(L, "invalid format option '%c'", opt);
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luaL_argerror(L, 1, msg);
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}
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}
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}
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static void putinteger (lua_State *L, luaL_Buffer *b, int arg, int endian,
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int size) {
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int32_t n = luaL_checkinteger(L, arg);
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Uinttype value;
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char buff[MAXINTSIZE];
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if (n < 0)
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value = (Uinttype)(Inttype)n;
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else
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value = (Uinttype)n;
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if (endian == LITTLE) {
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int i;
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for (i = 0; i < size; i++) {
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buff[i] = (value & 0xff);
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value >>= 8;
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}
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}
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else {
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int i;
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for (i = size - 1; i >= 0; i--) {
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buff[i] = (value & 0xff);
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value >>= 8;
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}
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}
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luaL_addlstring(b, buff, size);
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}
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static void correctbytes (char *b, int size, int endian) {
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if (endian != native.endian) {
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int i = 0;
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while (i < --size) {
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char temp = b[i];
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b[i++] = b[size];
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b[size] = temp;
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}
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}
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}
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static int b_pack (lua_State *L) {
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luaL_Buffer b;
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const char *fmt = luaL_checkstring(L, 1);
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Header h;
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int arg = 2;
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size_t totalsize = 0;
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defaultoptions(&h);
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lua_pushnil(L); /* mark to separate arguments from string buffer */
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luaL_buffinit(L, &b);
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while (*fmt != '\0') {
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int opt = *fmt++;
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size_t size = optsize(L, opt, &fmt);
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int toalign = gettoalign(totalsize, &h, opt, size);
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totalsize += toalign;
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while (toalign-- > 0) luaL_addchar(&b, '\0');
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switch (opt) {
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case 'b': case 'B': case 'h': case 'H':
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case 'l': case 'L': case 'T': case 'i': case 'I': { /* integer types */
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putinteger(L, &b, arg++, h.endian, size);
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break;
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}
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case 'x': {
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luaL_addchar(&b, '\0');
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break;
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}
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#ifndef LUA_NUMBER_INTEGRAL
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case 'f': {
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float f = (float)luaL_checknumber(L, arg++);
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correctbytes((char *)&f, size, h.endian);
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luaL_addlstring(&b, (char *)&f, size);
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break;
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}
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case 'd': {
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double d = luaL_checknumber(L, arg++);
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correctbytes((char *)&d, size, h.endian);
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luaL_addlstring(&b, (char *)&d, size);
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break;
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}
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#endif
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case 'c': case 's': {
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size_t l;
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const char *s = luaL_checklstring(L, arg++, &l);
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if (size == 0) size = l;
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luaL_argcheck(L, l >= (size_t)size, arg, "string too short");
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luaL_addlstring(&b, s, size);
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if (opt == 's') {
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luaL_addchar(&b, '\0'); /* add zero at the end */
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size++;
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}
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break;
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}
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default: controloptions(L, opt, &fmt, &h);
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}
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totalsize += size;
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}
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luaL_pushresult(&b);
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return 1;
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}
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static int64_t getinteger (const char *buff, int endian,
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int issigned, int size) {
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uint64_t l = 0;
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int i;
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if (endian == BIG) {
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for (i = 0; i < size; i++) {
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l <<= 8;
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l |= (unsigned char)buff[i];
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}
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}
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else {
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for (i = size - 1; i >= 0; i--) {
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l <<= 8;
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l |= (unsigned char)buff[i];
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}
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}
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if (!issigned)
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return (int64_t)l;
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else { /* signed format */
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uint64_t mask = (uint64_t)(~((uint64_t)0)) << (size*8 - 1);
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if (l & mask) /* negative value? */
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l |= mask; /* signal extension */
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return (int64_t)l;
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}
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}
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static int b_unpack (lua_State *L) {
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Header h;
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const char *fmt = luaL_checkstring(L, 1);
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size_t ld;
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const char *data = luaL_checklstring(L, 2, &ld);
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size_t pos = luaL_optinteger(L, 3, 1) - 1;
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defaultoptions(&h);
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lua_settop(L, 2);
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while (*fmt) {
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int opt = *fmt++;
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size_t size = optsize(L, opt, &fmt);
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pos += gettoalign(pos, &h, opt, size);
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luaL_argcheck(L, pos+size <= ld, 2, "data string too short");
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luaL_checkstack(L, 2, "too many results");
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switch (opt) {
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case 'b': case 'B': case 'h': case 'H':
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case 'l': case 'L': case 'T': case 'i': case 'I': { /* integer types */
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int issigned = islower(opt);
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int64_t res = getinteger(data+pos, h.endian, issigned, size);
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if (res >= LUA_MININTEGER && res <= LUA_MAXINTEGER) {
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lua_pushinteger(L, res);
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} else {
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lua_pushnumber(L, res);
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}
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break;
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}
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case 'x': {
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break;
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}
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#ifndef LUA_NUMBER_INTEGRAL
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case 'f': {
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float f;
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memcpy(&f, data+pos, size);
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correctbytes((char *)&f, sizeof(f), h.endian);
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lua_pushnumber(L, f);
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break;
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}
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case 'd': {
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double d;
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memcpy(&d, data+pos, size);
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correctbytes((char *)&d, sizeof(d), h.endian);
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lua_pushnumber(L, d);
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break;
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}
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#endif
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case 'c': {
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if (size == 0) {
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if (!lua_isnumber(L, -1))
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luaL_error(L, "format `c0' needs a previous size");
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size = lua_tointeger(L, -1);
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lua_pop(L, 1);
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luaL_argcheck(L, pos+size <= ld, 2, "data string too short");
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}
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lua_pushlstring(L, data+pos, size);
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break;
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}
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case 's': {
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const char *e = (const char *)memchr(data+pos, '\0', ld - pos);
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if (e == NULL)
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luaL_error(L, "unfinished string in data");
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size = (e - (data+pos)) + 1;
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lua_pushlstring(L, data+pos, size - 1);
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break;
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}
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default: controloptions(L, opt, &fmt, &h);
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}
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pos += size;
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}
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lua_pushinteger(L, pos + 1);
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return lua_gettop(L) - 2;
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}
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static int b_size (lua_State *L) {
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Header h;
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const char *fmt = luaL_checkstring(L, 1);
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size_t pos = 0;
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defaultoptions(&h);
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while (*fmt) {
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int opt = *fmt++;
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size_t size = optsize(L, opt, &fmt);
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pos += gettoalign(pos, &h, opt, size);
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if (opt == 's')
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luaL_argerror(L, 1, "option 's' has no fixed size");
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else if (opt == 'c' && size == 0)
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luaL_argerror(L, 1, "option 'c0' has no fixed size");
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if (!isalnum(opt))
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controloptions(L, opt, &fmt, &h);
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pos += size;
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}
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lua_pushinteger(L, pos);
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return 1;
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}
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/* }====================================================== */
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LROT_BEGIN(thislib, NULL, 0)
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LROT_FUNCENTRY( pack, b_pack )
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LROT_FUNCENTRY( unpack, b_unpack )
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LROT_FUNCENTRY( size, b_size )
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LROT_END(thislib, NULL, 0)
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NODEMCU_MODULE(STRUCT, "struct", thislib, NULL);
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/******************************************************************************
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* Copyright (C) 2010-2012 Lua.org, PUC-Rio. All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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******************************************************************************/
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