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Lua replace fscanf

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Rocklua was using the full fscanf implementation
to simply read %ld for the file:read("*n") function
wasting 1k on unneeded/unused functionality

Instead, I've implemented a filetol function to duplicate it
without the extra overhead using strtol which as an added bonus
ERANGE errors now resolve to LONG_MIN and LONGMAX instead of
integer overflow

filetol()
   reads long int from an open file, skips preceding
   whitespaces returns -1 if error, 1 on success.
   *num set to LONG_MAX or LONG_MIN on overflow.
   If number of digits is > than LUAI_MAXNUMBER2STR
   filepointer will continue till the next non digit
   but buffer will stop being filled with characters.
   Preceding zero is ignored.

Change-Id: Ia42d0f73c63a894625bca4581e9b7e1cc7387fd2
This commit is contained in:
William Wilgus 2018-10-29 02:54:35 -04:00
parent cc0a4c632a
commit eab73b3dee
6 changed files with 66 additions and 295 deletions
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63
apps/plugins/lua/rockaux.c
View file

@ -8,6 +8,7 @@
* $Id$
*
* Copyright (C) 2008 Dan Everton (safetydan)
* Copyright (C) 2018 William Wilgus
* String function implementations taken from dietlibc 0.31 (GPLv2 License)
*
* This program is free software; you can redistribute it and/or
@ -24,6 +25,8 @@
#define _ROCKCONF_H_ /* Protect against unwanted include */
#include "lua.h"
extern long strtol(const char *nptr, char **endptr, int base);
#if (CONFIG_PLATFORM & PLATFORM_NATIVE)
int errno = 0;
#endif
@ -101,3 +104,63 @@ int get_current_path(lua_State *L, int level)
lua_pushnil(L);
return 1;
}
/* filetol()
reads long int from an open file, skips preceding
whitespaces returns -1 if error, 1 on success.
*num set to LONG_MAX or LONG_MIN on overflow.
If number of digits is > than LUAI_MAXNUMBER2STR
filepointer will continue till the next non digit
but buffer will stop being filled with characters.
Preceding zero is ignored
*/
int filetol(int fd, long *num)
{
static char buffer[LUAI_MAXNUMBER2STR];
int retn = -1;
char chbuf = 0;
size_t count = 0;
bool neg = false;
long val;
while (rb->read(fd, &chbuf, 1) == 1)
{
if(!isspace(chbuf) || retn == 1)
{
if(chbuf == '0') /* strip preceeding zeros */
{
*num = 0;
retn = 1;
}
else if(chbuf == '-' && retn != 1)
neg = true;
else
{
rb->lseek(fd, -1, SEEK_CUR);
break;
}
}
}
while (rb->read(fd, &chbuf, 1) == 1)
{
if(!isdigit(chbuf))
{
rb->lseek(fd, -1, SEEK_CUR);
break;
}
else if (count < LUAI_MAXNUMBER2STR - 2)
buffer[count++] = chbuf;
}
if(count)
{
buffer[count] = '\0';
val = strtol(buffer, NULL, 10);
*num = (neg)? -val:val;
retn = 1;
}
return retn;
}