mirror of
https://github.com/lua/lua
synced 2024-11-22 12:51:30 +03:00
'dumpint' and related functions replaced by 'string.pack'/'string.unpack'
This commit is contained in:
Roberto Ierusalimschy
parent
f8e0d33b25
commit
c172a4f7c2
521
lstrlib.c
521
lstrlib.c
@ -1,5 +1,5 @@
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/*
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** $Id: lstrlib.c,v 1.201 2014/08/20 22:06:41 roberto Exp roberto $
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** $Id: lstrlib.c,v 1.202 2014/10/01 11:54:56 roberto Exp roberto $
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** Standard library for string operations and pattern-matching
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** See Copyright Notice in lua.h
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*/
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@ -950,212 +950,397 @@ static int str_format (lua_State *L) {
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*/
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/* maximum size for the binary representation of an integer */
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#define MAXINTSIZE 16
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/* number of bits in a character */
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#define NB CHAR_BIT
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/* mask for one character (NB 1's) */
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#define MC ((1 << NB) - 1)
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/* mask for one character without sign bit ((NB - 1) 1's) */
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#define SM (MC >> 1)
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/* size of a lua_Integer */
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#define SZINT ((int)sizeof(lua_Integer))
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/* maximum size for the binary representation of an integer */
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#define MAXINTSIZE 12
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/* mask for all ones in last byte in a lua Integer */
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#define HIGHERBYTE ((lua_Unsigned)MC << (NB * (SZINT - 1)))
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static union {
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/* dummy union to get native endianness */
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static const union {
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int dummy;
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char little; /* true iff machine is little endian */
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} const nativeendian = {1};
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} nativeendian = {1};
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static int getendian (lua_State *L, int arg) {
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const char *endian = luaL_optstring(L, arg,
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(nativeendian.little ? "l" : "b"));
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if (*endian == 'n') /* native? */
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return nativeendian.little;
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luaL_argcheck(L, *endian == 'l' || *endian == 'b', arg,
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"endianness must be 'l'/'b'/'n'");
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return (*endian == 'l');
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/* dummy structure to get native alignment requirements */
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struct cD {
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char c;
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union { double d; void *p; lua_Integer i; lua_Number n; } u;
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};
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#define MAXALIGN (offsetof(struct cD, u))
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/*
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** Union for serializing floats
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*/
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typedef union Ftypes {
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float f;
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double d;
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lua_Number n;
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char buff[5 * sizeof(lua_Number)]; /* enough for any float type */
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} Ftypes;
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/*
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** information to pack/unpack stuff
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*/
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typedef struct Header {
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lua_State *L;
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int islittle;
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int maxalign;
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} Header;
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typedef enum KOption {Kint, Kuint, Kfloat, Kchar, Kstring, Kstring0,
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Kspace, Kpadding, Kpaddalig} KOption;
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/*
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** Read an integer numeral from string 'fmt' or return 'df' if
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** there is no numeral
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*/
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static int digit (int c) { return '0' <= c && c <= '9'; }
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static int getnum (const char **fmt, int df) {
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if (!digit(**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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a = a*10 + *((*fmt)++) - '0';
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} while (digit(**fmt) && a < (INT_MAX/10 - 10));
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return a;
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}
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}
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static int getintsize (lua_State *L, int arg) {
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lua_Integer size = luaL_optinteger(L, arg, 0);
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if (size == 0) size = SZINT;
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luaL_argcheck(L, 1 <= size && size <= MAXINTSIZE, arg,
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"integer size out of valid range");
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return (int)size;
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/*
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** Read an integer numeral and raises an error if it is larger
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** than the maximum size for integers.
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*/
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static int getnumlimit (Header *h, const char **fmt, int df) {
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int sz = getnum(fmt, df);
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if (sz > MAXINTSIZE || sz <= 0)
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luaL_error(h->L, "integral size (%d) out of limits [1,%d]", sz, MAXINTSIZE);
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return sz;
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}
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/* mask for all ones in last byte in a lua Integer */
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#define HIGHERBYTE ((lua_Unsigned)MC << (NB * (SZINT - 1)))
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/*
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** Reads an option endianness indication ('<'/'>') and
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** returns true if operation should use little endian.
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*/
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static int getendian (const char **fmt) {
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if (**fmt == '<' || **fmt == '>') /* explicit endianness? */
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return (*((*fmt)++) == '<'); /* true iff little endian */
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else /* no endian indication */
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return nativeendian.little; /* use native */
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}
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static int dumpint (char *buff, lua_Integer m, int littleendian, int size) {
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int i;
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lua_Unsigned n = (lua_Unsigned)m;
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lua_Unsigned mask = (m >= 0) ? 0 : HIGHERBYTE; /* sign extension */
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if (littleendian) {
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for (i = 0; i < size - 1; i++) {
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buff[i] = (n & MC);
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n = (n >> NB) | mask;
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/*
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** Read and return maximum alignment to be used
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*/
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static int getalignment (Header *h, const char **fmt) {
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if (**fmt == '!') { /* explicit alignment? */
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(*fmt)++; /* skip '!' */
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return getnumlimit(h, fmt, MAXALIGN);
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}
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else
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return 1; /* default is no alignment */
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}
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/*
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** Read optional endianness and alignment indications
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*/
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static void getheader (lua_State *L, Header *h, const char **fmt) {
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h->L = L;
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h->islittle = getendian(fmt);
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h->maxalign = getalignment(h, fmt);
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}
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/*
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** Read and classify next option. 'size' is filled with option's size.
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*/
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static KOption getoption (Header *h, const char **fmt, int *size) {
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int opt = *((*fmt)++);
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switch (opt) {
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case 'b': *size = sizeof(char); return Kint;
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case 'B': *size = sizeof(char); return Kuint;
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case 'h': *size = sizeof(short); return Kint;
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case 'H': *size = sizeof(short); return Kuint;
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case 'l': *size = sizeof(long); return Kint;
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case 'L': *size = sizeof(long); return Kuint;
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case 'j': *size = sizeof(lua_Integer); return Kint;
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case 'J': *size = sizeof(lua_Integer); return Kuint;
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case 'T': *size = sizeof(size_t); return Kuint;
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case 'f': *size = sizeof(float); return Kfloat;
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case 'd': *size = sizeof(double); return Kfloat;
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case 'n': *size = sizeof(lua_Number); return Kfloat;
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case 'i': *size = getnumlimit(h, fmt, sizeof(int)); return Kint;
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case 'I': *size = getnumlimit(h, fmt, sizeof(int)); return Kuint;
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case 's': *size = getnumlimit(h, fmt, sizeof(size_t)); return Kstring;
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case 'c': *size = getnum(fmt, 1); return Kchar;
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case 'z': *size = 0; return Kstring0;
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case 'x': *size = 1; return Kpadding;
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case 'X': *size = 0; return Kpaddalig;
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case ' ': *size = 0; return Kspace;
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default: {
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*size = 0; /* to avoid warnings */
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luaL_error(h->L, "invalid format option '%c'", opt);
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return (KOption)0;
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}
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}
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}
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/*
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** Read, classify, and fill other details about the next option.
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** 'psize' is filled with option's size, 'notoalign' with its
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** alignment requirements.
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** Local variable 'size' gets the size to be aligned. (Kpadal option
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** always gets its full alignment, other options are limited by
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** the maximum alignment ('maxalign). Kchar option needs no aligment
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** despite its size.
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*/
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static KOption getdetails (Header *h, size_t totalsize,
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const char **fmt, int *psize, int *ntoalign) {
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KOption opt = getoption(h, fmt, psize);
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int align = *psize; /* usually, alignment follows size */
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if (opt == Kpaddalig) {
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if (**fmt == '\0' || strchr("Xc ", **fmt) != NULL)
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luaL_argerror(h->L, 1, "invalid next option for option 'X'");
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getoption(h, fmt, &align); /* get next element's size for alignment */
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}
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if (align <= 1 || opt == Kchar) /* need no alignment? */
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*ntoalign = 0;
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else {
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if (align > h->maxalign)
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align = h->maxalign;
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if ((align & (align - 1)) != 0) /* is 'align' not a power of 2? */
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luaL_argerror(h->L, 1, "format asks for alignment not power of 2");
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*ntoalign = (align - (int)(totalsize & (align - 1))) & (align - 1);
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}
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return opt;
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}
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static void packint (luaL_Buffer *b, lua_Unsigned n,
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int islittle, int size, lua_Unsigned mask) {
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char *buff = luaL_prepbuffsize(b, size);
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int i;
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for (i = 0; i < size - 1; i++) {
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buff[islittle ? i : size - 1 - i] = (n & MC);
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n = (n >> NB) | mask;
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}
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buff[islittle ? i : size - 1 - i] = (n & MC);
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luaL_addsize(b, size); /* add result to buffer */
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}
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/*
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** Copy 'size' bytes from 'src' to 'dest', correcting endianness if
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** given 'islittle' is different from native endianness.
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*/
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static void copywithendian (volatile char *dest, volatile const char *src,
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int size, int islittle) {
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if (islittle == nativeendian.little) {
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while (size-- != 0)
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*(dest++) = *(src++);
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}
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else {
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for (i = size - 1; i > 0; i--) {
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buff[i] = (n & MC);
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n = (n >> NB) | mask;
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}
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dest += size - 1;
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while (size-- != 0)
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*(dest--) = *(src++);
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}
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buff[i] = (n & MC); /* last byte */
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if (size < SZINT) { /* need test for overflow? */
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/* OK if there are only zeros left in higher bytes,
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or only ones left (excluding non-signal bits in last byte) */
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return ((n & ~(lua_Unsigned)MC) == 0 ||
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(n | SM) == ~(lua_Unsigned)0);
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}
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else return 1; /* no overflow can occur with full size */
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}
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static int dumpint_l (lua_State *L) {
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char buff[MAXINTSIZE];
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lua_Integer n = luaL_checkinteger(L, 1);
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int size = getintsize(L, 2);
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int endian = getendian(L, 3);
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if (dumpint(buff, n, endian, size))
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lua_pushlstring(L, buff, size);
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else
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luaL_error(L, "integer does not fit into given size (%d)", size);
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static int str_pack (lua_State *L) {
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luaL_Buffer b;
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Header h;
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const char *fmt = luaL_checkstring(L, 1); /* format string */
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int arg = 1; /* current argument to pack */
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size_t totalsize = 0; /* accumulate total size of result */
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getheader(L, &h, &fmt);
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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 size, ntoalign;
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KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
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totalsize += ntoalign + size;
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while (ntoalign-- > 0) luaL_addchar(&b, '\0'); /* fill alignment */
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arg++;
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switch (opt) {
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case Kint: { /* signed integers */
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lua_Integer n = luaL_checkinteger(L, arg);
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lua_Unsigned mask = (n < 0) ? HIGHERBYTE : 0; /* sign extension */
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if (size < SZINT) { /* need overflow check? */
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lua_Integer lim = (lua_Integer)1 << ((size * NB) - 1);
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luaL_argcheck(L, -lim <= n && n < lim, arg, "integer overflow");
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}
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packint(&b, (lua_Unsigned)n, h.islittle, size, mask);
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break;
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}
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case Kuint: { /* unsigned integers */
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lua_Integer n = luaL_checkinteger(L, arg);
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if (size < SZINT) /* need overflow check? */
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luaL_argcheck(L, (lua_Unsigned)n < ((lua_Unsigned)1 << (size * NB)),
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arg, "unsigned overflow");
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packint(&b, (lua_Unsigned)n, h.islittle, size, 0);
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break;
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}
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case Kfloat: { /* floating-point options */
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volatile Ftypes u;
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char *buff = luaL_prepbuffsize(&b, size);
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lua_Number n = luaL_checknumber(L, arg); /* get argument */
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if (size == sizeof(u.f)) u.f = (float)n; /* copy it into 'u' */
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else if (size == sizeof(u.d)) u.d = (double)n;
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else u.n = n;
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/* move 'u' to final result, correcting endianness if needed */
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copywithendian(buff, u.buff, size, h.islittle);
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luaL_addsize(&b, size);
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break;
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}
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case Kchar: { /* fixed-size string */
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size_t len;
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const char *s = luaL_checklstring(L, arg, &len);
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luaL_argcheck(L, len == (size_t)size, arg, "wrong length");
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luaL_addlstring(&b, s, size);
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break;
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}
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case Kstring: { /* strings with length count */
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size_t len;
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const char *s = luaL_checklstring(L, arg, &len);
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luaL_argcheck(L, size >= (int)sizeof(size_t) ||
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len < ((size_t)1 << (size * NB)),
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arg, "string length does not fit in given size");
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packint(&b, (lua_Unsigned)len, h.islittle, size, 0); /* pack length */
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luaL_addlstring(&b, s, len);
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totalsize += len;
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break;
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}
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case Kstring0: { /* zero-terminated string */
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size_t len;
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const char *s = luaL_checklstring(L, arg, &len);
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luaL_argcheck(L, strlen(s) == len, arg, "string contains zeros");
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luaL_addlstring(&b, s, len);
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luaL_addchar(&b, '\0'); /* add zero at the end */
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totalsize += len + 1;
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break;
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}
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case Kpadding: luaL_addchar(&b, '\0'); /* go through */
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case Kpaddalig: case Kspace:
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arg--; /* undo increment */
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break;
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}
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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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/* mask to check higher-order byte + signal bit of next (lower) byte */
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#define HIGHERBYTE1 (HIGHERBYTE | (HIGHERBYTE >> 1))
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static int undumpint (const char *buff, lua_Integer *res,
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int littleendian, int size) {
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lua_Unsigned n = 0;
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static lua_Integer unpackint (lua_State *L, const char *str,
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int islittle, int size, int issigned) {
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lua_Unsigned res = 0;
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int i;
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for (i = 0; i < size; i++) {
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if (i >= SZINT) { /* will throw away a byte? */
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/* check for overflow: it is OK to throw away leading zeros for a
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positive number, leading ones for a negative number, and a
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leading zero byte to allow unsigned integers with a 1 in
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its "signal bit" */
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if (!((n & HIGHERBYTE1) == 0 || /* zeros for positive number */
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(n & HIGHERBYTE1) == HIGHERBYTE1 || /* ones for negative number */
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(i == size - 1 && (n & HIGHERBYTE) == 0))) /* leading zero */
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return 0; /* overflow */
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}
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n <<= NB;
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n |= (lua_Unsigned)(unsigned char)buff[littleendian ? size - 1 - i : i];
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int limit = (size <= SZINT) ? size : SZINT;
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for (i = limit - 1; i >= 0; i--) {
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res <<= NB;
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res |= (lua_Unsigned)(unsigned char)str[islittle ? i : size - 1 - i];
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}
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if (size < SZINT) { /* need sign extension? */
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lua_Unsigned mask = (lua_Unsigned)1 << (size*NB - 1);
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*res = (lua_Integer)((n ^ mask) - mask); /* do sign extension */
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}
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else
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*res = (lua_Integer)n;
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return 1;
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}
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static int undumpint_l (lua_State *L) {
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lua_Integer res;
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size_t len;
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const char *s = luaL_checklstring(L, 1, &len);
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lua_Integer pos = posrelat(luaL_optinteger(L, 2, 1), len);
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int size = getintsize(L, 3);
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int endian = getendian(L, 4);
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luaL_argcheck(L, 1 <= pos && (size_t)pos + size - 1 <= len, 1,
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"string too short");
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if(undumpint(s + pos - 1, &res, endian, size))
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lua_pushinteger(L, res);
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else
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luaL_error(L, "result does not fit into a Lua integer");
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return 1;
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}
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static void correctendianness (lua_State *L, char *b, int size, int endianarg) {
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int endian = getendian(L, endianarg);
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if (endian != nativeendian.little) { /* not native endianness? */
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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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if (size < SZINT) { /* real size smaller than lua_Integer? */
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if (issigned) { /* needs sign extension? */
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lua_Unsigned mask = (lua_Unsigned)1 << (size*NB - 1);
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res = ((res ^ mask) - mask); /* do sign extension */
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}
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||||
}
|
||||
else { /* must check unread bytes */
|
||||
int mask = (!issigned || (lua_Integer)res >= 0) ? 0 : MC;
|
||||
for (i = limit; i < size; i++) {
|
||||
if ((unsigned char)str[islittle ? i : size - 1 - i] != mask)
|
||||
luaL_error(L, "%d-bit integer does not fit into Lua Integer", size);
|
||||
}
|
||||
}
|
||||
return (lua_Integer)res;
|
||||
}
|
||||
|
||||
|
||||
static int getfloatsize (lua_State *L, int arg) {
|
||||
const char *size = luaL_optstring(L, arg, "n");
|
||||
if (*size == 'n') return sizeof(lua_Number);
|
||||
luaL_argcheck(L, *size == 'd' || *size == 'f', arg,
|
||||
"size must be 'f'/'d'/'n'");
|
||||
return (*size == 'd' ? sizeof(double) : sizeof(float));
|
||||
}
|
||||
|
||||
|
||||
static int dumpfloat_l (lua_State *L) {
|
||||
float f; double d;
|
||||
char *pn; /* pointer to number */
|
||||
lua_Number n = luaL_checknumber(L, 1);
|
||||
int size = getfloatsize(L, 2);
|
||||
if (size == sizeof(lua_Number))
|
||||
pn = (char*)&n;
|
||||
else if (size == sizeof(float)) {
|
||||
f = (float)n;
|
||||
pn = (char*)&f;
|
||||
}
|
||||
else { /* native lua_Number may be neither float nor double */
|
||||
lua_assert(size == sizeof(double));
|
||||
d = (double)n;
|
||||
pn = (char*)&d;
|
||||
static int str_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 = (size_t)posrelat(luaL_optinteger(L, 3, 1), ld) - 1;
|
||||
int n = 0; /* number of results */
|
||||
luaL_argcheck(L, pos <= ld, 3, "initial position out of string");
|
||||
getheader(L, &h, &fmt);
|
||||
while (*fmt) {
|
||||
int size, ntoalign;
|
||||
KOption opt = getdetails(&h, pos, &fmt, &size, &ntoalign);
|
||||
if ((size_t)ntoalign + size > ~pos || pos + ntoalign + size > ld)
|
||||
luaL_argerror(L, 2, "data string too short");
|
||||
pos += ntoalign;
|
||||
/* stack space for item + next position */
|
||||
luaL_checkstack(L, 2, "too many results");
|
||||
n++;
|
||||
switch (opt) {
|
||||
case Kint:
|
||||
case Kuint: {
|
||||
lua_Integer res = unpackint(L, data + pos, h.islittle, size,
|
||||
(opt == Kint));
|
||||
lua_pushinteger(L, res);
|
||||
break;
|
||||
}
|
||||
case Kfloat: {
|
||||
volatile Ftypes u;
|
||||
lua_Number num;
|
||||
copywithendian(u.buff, data + pos, size, h.islittle);
|
||||
if (size == sizeof(u.f)) num = (lua_Number)u.f;
|
||||
else if (size == sizeof(u.d)) num = (lua_Number)u.d;
|
||||
else num = u.n;
|
||||
lua_pushnumber(L, num);
|
||||
break;
|
||||
}
|
||||
case Kchar: {
|
||||
lua_pushlstring(L, data + pos, size);
|
||||
break;
|
||||
}
|
||||
case Kstring: {
|
||||
size_t len = (size_t)unpackint(L, data + pos, h.islittle, size, 0);
|
||||
luaL_argcheck(L, pos + len + size <= ld, 2, "data string too short");
|
||||
lua_pushlstring(L, data + pos + size, len);
|
||||
pos += len;
|
||||
break;
|
||||
}
|
||||
case Kstring0: {
|
||||
size_t len = (int)strlen(data + pos);
|
||||
lua_pushlstring(L, data + pos, len);
|
||||
pos += len + 1; /* skip final '\0' */
|
||||
break;
|
||||
}
|
||||
case Kpaddalig: case Kpadding: case Kspace:
|
||||
n--; /* undo increment */
|
||||
break;
|
||||
}
|
||||
pos += size;
|
||||
}
|
||||
correctendianness(L, pn, size, 3);
|
||||
lua_pushlstring(L, pn, size);
|
||||
return 1;
|
||||
}
|
||||
|
||||
|
||||
static int undumpfloat_l (lua_State *L) {
|
||||
lua_Number res;
|
||||
size_t len;
|
||||
const char *s = luaL_checklstring(L, 1, &len);
|
||||
lua_Integer pos = posrelat(luaL_optinteger(L, 2, 1), len);
|
||||
int size = getfloatsize(L, 3);
|
||||
luaL_argcheck(L, 1 <= pos && (size_t)pos + size - 1 <= len, 1,
|
||||
"string too short");
|
||||
if (size == sizeof(lua_Number)) {
|
||||
memcpy(&res, s + pos - 1, size);
|
||||
correctendianness(L, (char*)&res, size, 4);
|
||||
}
|
||||
else if (size == sizeof(float)) {
|
||||
float f;
|
||||
memcpy(&f, s + pos - 1, size);
|
||||
correctendianness(L, (char*)&f, size, 4);
|
||||
res = (lua_Number)f;
|
||||
}
|
||||
else { /* native lua_Number may be neither float nor double */
|
||||
double d;
|
||||
lua_assert(size == sizeof(double));
|
||||
memcpy(&d, s + pos - 1, size);
|
||||
correctendianness(L, (char*)&d, size, 4);
|
||||
res = (lua_Number)d;
|
||||
}
|
||||
lua_pushnumber(L, res);
|
||||
return 1;
|
||||
lua_pushinteger(L, pos + 1); /* next position */
|
||||
return n + 1;
|
||||
}
|
||||
|
||||
/* }====================================================== */
|
||||
@ -1176,10 +1361,8 @@ static const luaL_Reg strlib[] = {
|
||||
{"reverse", str_reverse},
|
||||
{"sub", str_sub},
|
||||
{"upper", str_upper},
|
||||
{"dumpfloat", dumpfloat_l},
|
||||
{"dumpinteger", dumpint_l},
|
||||
{"undumpfloat", undumpfloat_l},
|
||||
{"undumpinteger", undumpint_l},
|
||||
{"pack", str_pack},
|
||||
{"unpack", str_unpack},
|
||||
{NULL, NULL}
|
||||
};
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user