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no more use of 'scanf' for reading numbers

This commit is contained in:
Roberto Ierusalimschy 2014-05-21 12:24:21 -03:00
parent c4eff10322
commit e966e53791
2 changed files with 82 additions and 27 deletions
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98
liolib.c
View File

@ -1,5 +1,5 @@
/*
** $Id: liolib.c,v 2.123 2014/05/13 19:40:28 roberto Exp roberto $
** $Id: liolib.c,v 2.124 2014/05/15 15:21:06 roberto Exp $
** Standard I/O (and system) library
** See Copyright Notice in lua.h
*/
@ -15,7 +15,9 @@
#endif
#include <ctype.h>
#include <errno.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@ -361,26 +363,91 @@ static int io_lines (lua_State *L) {
*/
static int read_integer (lua_State *L, FILE *f) {
lua_Integer d;
if (fscanf(f, LUA_INTEGER_SCAN, &d) == 1) {
lua_pushinteger(L, d);
return 1;
}
/* maximum length of a numeral */
#define MAXRN 200
/* auxiliary structure used by 'read_number' */
typedef struct {
FILE *f; /* file being read */
int c; /* current character (look ahead) */
int n; /* number of elements in buffer 'buff' */
char buff[MAXRN];
} RN;
/*
** Add current char to buffer (if not out of space) and read next one
*/
static int nextc (RN *rn) {
if (rn->n >= MAXRN) /* buffer overflow? */
return 0; /* fail */
else {
lua_pushnil(L); /* "result" to be removed */
return 0; /* read fails */
rn->buff[rn->n++] = rn->c; /* save current char */
rn->c = l_getc(rn->f); /* read next one */
return 1;
}
}
/*
** Accept current char if it is in 'set' (of size 1 or 2)
*/
static int test2 (RN *rn, const char *set) {
if (rn->c == set[0] || (rn->c == set[1] && rn->c != '\0'))
return nextc(rn);
else return 0;
}
/*
** Read a sequence of (hexa)digits
*/
static int readdigits (RN *rn, int hexa) {
int count = 0;
while ((hexa ? isxdigit(rn->c) : isdigit(rn->c)) && nextc(rn))
count++;
return count;
}
/* access to locale "radix character" (decimal point) */
#if !defined(getlocaledecpoint)
#define getlocaledecpoint() (localeconv()->decimal_point[0])
#endif
/*
** Read a number: first reads a valid prefix of a numeral into a buffer.
** Then it calls 'lua_strtonum' to check whether the format is correct
** and to convert it to a Lua number
*/
static int read_number (lua_State *L, FILE *f) {
lua_Number d;
if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1) {
lua_pushnumber(L, d);
return 1;
RN rn;
int count = 0;
int hexa = 0;
char decp[2] = ".";
rn.f = f; rn.n = 0;
decp[0] = getlocaledecpoint(); /* get decimal point from locale */
l_lockfile(rn.f);
do { rn.c = l_getc(rn.f); } while (isspace(rn.c)); /* skip spaces */
test2(&rn, "-+"); /* optional signal */
if (test2(&rn, "0")) {
if (test2(&rn, "xX")) hexa = 1; /* numeral is hexadecimal */
else count = 1; /* count initial '0' as a valid digit */
}
else {
count += readdigits(&rn, hexa); /* integral part */
if (test2(&rn, decp)) /* decimal point? */
count += readdigits(&rn, hexa); /* fractionary part */
if (count > 0 && test2(&rn, (hexa ? "pP" : "eE"))) { /* exponent mark? */
test2(&rn, "-+"); /* exponent signal */
readdigits(&rn, 0); /* exponent digits */
}
ungetc(rn.c, rn.f); /* unread look-ahead char */
l_unlockfile(rn.f);
rn.buff[rn.n] = '\0'; /* finish string */
if (lua_strtonum(L, rn.buff)) /* is this a valid number? */
return 1; /* ok */
else { /* invalid format */
lua_pushnil(L); /* "result" to be removed */
return 0; /* read fails */
}
@ -456,9 +523,6 @@ static int g_read (lua_State *L, FILE *f, int first) {
const char *p = luaL_checkstring(L, n);
if (*p == '*') p++; /* skip optional '*' (for compatibility) */
switch (*p) {
case 'i': /* integer */
success = read_integer(L, f);
break;
case 'n': /* number */
success = read_number(L, f);
break;

11
luaconf.h
View File

@ -1,5 +1,5 @@
/*
** $Id: luaconf.h,v 1.201 2014/05/11 13:03:48 roberto Exp roberto $
** $Id: luaconf.h,v 1.202 2014/05/15 15:24:32 roberto Exp roberto $
** Configuration file for Lua
** See Copyright Notice in lua.h
*/
@ -431,7 +431,6 @@
@@ over a floating number.
**
@@ LUA_NUMBER_FRMLEN is the length modifier for writing floats.
@@ LUA_NUMBER_SCAN is the format for reading floats.
@@ LUA_NUMBER_FMT is the format for writing floats.
@@ lua_number2str converts a float to a string.
**
@ -447,7 +446,6 @@
#define LUAI_UACNUMBER double
#define LUA_NUMBER_FRMLEN ""
#define LUA_NUMBER_SCAN "%f"
#define LUA_NUMBER_FMT "%.7g"
#define l_mathop(op) op##f
@ -462,7 +460,6 @@
#define LUAI_UACNUMBER long double
#define LUA_NUMBER_FRMLEN "L"
#define LUA_NUMBER_SCAN "%Lf"
#define LUA_NUMBER_FMT "%.19Lg"
#define l_mathop(op) op##l
@ -476,7 +473,6 @@
#define LUAI_UACNUMBER double
#define LUA_NUMBER_FRMLEN ""
#define LUA_NUMBER_SCAN "%lf"
#define LUA_NUMBER_FMT "%.14g"
#define l_mathop(op) op
@ -552,7 +548,6 @@
@@ LUAI_UACINT is the result of an 'usual argument conversion'
@@ over a lUA_INTEGER.
@@ LUA_INTEGER_FRMLEN is the length modifier for reading/writing integers.
@@ LUA_INTEGER_SCAN is the format for reading integers.
@@ LUA_INTEGER_FMT is the format for writing integers.
@@ LUA_MAXINTEGER is the maximum value for a LUA_INTEGER.
@@ LUA_MININTEGER is the minimum value for a LUA_INTEGER.
@ -563,7 +558,6 @@
/* The following definitions are good for most cases here */
#define LUA_INTEGER_SCAN "%" LUA_INTEGER_FRMLEN "d"
#define LUA_INTEGER_FMT "%" LUA_INTEGER_FRMLEN "d"
#define lua_integer2str(s,n) sprintf((s), LUA_INTEGER_FMT, (n))
@ -634,9 +628,6 @@
#undef LUAI_UACINT
#define LUAI_UACINT int
#undef LUA_INTEGER_SCAN
#define LUA_INTEGER_SCAN "%hd"
#undef LUAI_MAXSTACK
#define LUAI_MAXSTACK 15000