Lua replace fscanf

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

6 files changed, 66 insertions, 295 deletions

diff --git a/apps/plugins/lua/SOURCES b/apps/plugins/lua/SOURCES
index ff40046eb0..8877a4164d 100644
--- a/apps/plugins/lua/SOURCES
+++ b/apps/plugins/lua/SOURCES
@@ -30,7 +30,6 @@ rockaux.c
 rocklib.c
 rocklib_img.c
 tlsf_helper.c
-fscanf.c
 strftime.c
 strpbrk.c
 strtoul.c
diff --git a/apps/plugins/lua/fscanf.c b/apps/plugins/lua/fscanf.c
deleted file mode 100644
index 9f5f129d3c..0000000000
--- a/apps/plugins/lua/fscanf.c
+++ /dev/null
@@ -1,291 +0,0 @@
-/***************************************************************************
- *             __________               __   ___.
- *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
- *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
- *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
- *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
- *                     \/            \/     \/    \/            \/
- * $Id$
- *
- * Copied from firmware/common/sscanf.c
- * Original author: Tomasz Malesinski
- *
- * Copyright (C) 2010 Maurus Cuelenaere
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
- * KIND, either express or implied.
- *
- ****************************************************************************/
-
-#include "rocklibc.h"
-
-static int parse_dec(int (*peek)(void *userp),
-                     void (*pop)(void *userp),
-                     void *userp,
-                     long *vp)
-{
-    long v = 0;
-    int n = 0;
-    int minus = 0;
-    char ch;
-
-    if ((*peek)(userp) == '-')
-    {
-        (*pop)(userp);
-        n++;
-        minus = 1;
-    }
-
-    ch = (*peek)(userp);
-    if (!isdigit(ch))
-        return -1;
-
-    do
-    {
-        v = v * 10 + ch - '0';
-        (*pop)(userp);
-        n++;
-        ch = (*peek)(userp);
-    } while (isdigit(ch));
-
-    *vp = minus ? -v : v;
-    return n;
-}
-
-static int parse_chars(int (*peek)(void *userp),
-                       void (*pop)(void *userp),
-                       void *userp,
-                       char *vp,
-                       bool fake)
-{
-    int n = 0;
-
-    char *pt=vp;
-
-    while (!isspace((*peek)(userp)))
-    {
-        if(fake==false)
-            *(pt++) = (*peek)(userp);
-
-        n++;
-        (*pop)(userp);
-    }
-
-    if(fake==false)
-        (*pt)='\0';
-
-    return n;
-}
-
-static int parse_hex(int (*peek)(void *userp),
-                     void (*pop)(void *userp),
-                     void *userp,
-                     unsigned long *vp)
-{
-    unsigned long v = 0;
-    int n = 0;
-    char ch;
-
-    ch = (*peek)(userp);
-    if (!isxdigit(ch))
-        return -1;
-
-    do
-    {
-        if (ch >= 'a')
-            ch = ch - 'a' + 10;
-        else if (ch >= 'A')
-            ch = ch - 'A' + 10;
-        else
-            ch = ch - '0';
-        v = v * 16 + ch;
-        (*pop)(userp);
-        n++;
-        ch = (*peek)(userp);
-    } while (isxdigit(ch));
-
-    *vp = v;
-    return n;
-}
-
-static int skip_spaces(int (*peek)(void *userp),
-                       void (*pop)(void *userp),
-                       void *userp)
-{
-    int n = 0;
-    while (isspace((*peek)(userp))) {
-        n++;
-        (*pop)(userp);
-    }
-    return n;
-}
-
-static int scan(int (*peek)(void *userp),
-                void (*pop)(void *userp),
-                void *userp,
-                const char *fmt,
-                va_list ap)
-{
-    char ch;
-    int n = 0;
-    int n_chars = 0;
-    int r;
-    long lval;
-    bool skip=false;
-    unsigned long ulval;
-
-    while ((ch = *fmt++) != '\0')
-    {
-        bool literal = false;
-
-        if (ch == '%')
-        {
-            ch = *fmt++;
-
-            if(ch== '*')  /* We should process this, but not store it in an argument */
-            {
-                ch=*fmt++;
-                skip=true;
-            }
-            else
-            {
-                skip=false;
-            }
-
-            switch (ch)
-            {
-                case 'x':
-                    n_chars += skip_spaces(peek, pop, userp);
-                    if ((r = parse_hex(peek, pop, userp, &ulval)) >= 0)
-                    {
-                        if(skip==false)
-                        {
-                            *(va_arg(ap, unsigned int *)) = ulval;
-                            n++;
-                        }
-                        n_chars += r;
-                    }
-                    else
-                        return n;
-                    break;
-                case 'd':
-                    n_chars += skip_spaces(peek, pop, userp);
-                    if ((r = parse_dec(peek, pop, userp, &lval)) >= 0)
-                    {
-                        if(skip==false)
-                        {
-                            *(va_arg(ap, int *)) = lval;
-                            n++;
-                        }
-                        n_chars += r;
-                    }
-                    else
-                        return n;
-                    break;
-                case 'n':
-                    if(skip==false)
-                    {
-                        *(va_arg(ap, int *)) = n_chars;
-                        n++;
-                    }
-                    break;
-                case 'l':
-                    n_chars += skip_spaces(peek, pop, userp);
-                    ch = *fmt++;
-                    switch (ch)
-                    {
-                        case 'x':
-                            if ((r = parse_hex(peek, pop, userp, &ulval)) >= 0)
-                            {
-                                if(skip==false)
-                                {
-                                    *(va_arg(ap, unsigned long *)) = ulval;
-                                    n++;
-                                }
-                                n_chars += r;
-                            }
-                            else
-                                return n;
-                            break;
-                        case 'd':
-                            if ((r = parse_dec(peek, pop, userp, &lval)) >= 0)
-                            {
-                                if(skip==false)
-                                {
-                                    *(va_arg(ap, long *)) = lval;
-                                    n++;
-                                }
-                                n_chars += r;
-                            }
-                            else
-                                return n;
-                            break;
-                        case '\0':
-                            return n;
-                        default:
-                            literal = true;
-                            break;
-                    }
-                    break;
-                case 's':
-                    n_chars += skip_spaces(peek, pop, userp);
-                    n_chars += parse_chars(peek,pop, userp,skip?0:va_arg(ap, char *), skip );
-                    if(skip==false)
-                    {
-                        n++;
-                    }
-                    break;
-                case '\0':
-                    return n;
-                default:
-                    literal = true;
-                    break;
-            }
-        } else
-            literal = true;
-
-        if (literal)
-        {
-            n_chars += skip_spaces(peek, pop, userp);
-            if ((*peek)(userp) != ch)
-                continue;
-            else
-            {
-                (*pop)(userp);
-                n_chars++;
-            }
-        }
-    }
-    return n;
-}
-
-static int fspeek(void *userp)
-{
-    int fd = *((int*) userp);
-    char buf = 0;
-    if(rb->read(fd, &buf, 1) == 1)
-        rb->lseek(fd, -1, SEEK_CUR);
-    return buf;
-}
-
-static void fspop(void *userp)
-{
-    int fd = *((int*) userp);
-    rb->lseek(fd, 1, SEEK_CUR);
-}
-
-int PREFIX(fscanf)(int fd, const char *fmt, ...)
-{
-    int r;
-    va_list ap;
-
-    va_start(ap, fmt);
-    r = scan(fspeek, fspop, &fd, fmt, ap);
-    va_end(ap);
-    return r;
-}
diff --git a/apps/plugins/lua/liolib.c b/apps/plugins/lua/liolib.c
index 970543d4d5..6744efedd5 100644
--- a/apps/plugins/lua/liolib.c
+++ b/apps/plugins/lua/liolib.c
@@ -17,6 +17,7 @@
 #include "lauxlib.h"
 #include "lualib.h"
 #include "rocklibc.h"
+#include "rocklib.h"
 
 #include "llimits.h"
 
@@ -247,7 +248,7 @@ static int io_lines (lua_State *L) {
 
 static int read_number (lua_State *L, int *f) {
   lua_Number d;
-  if (PREFIX(fscanf)(*f, LUA_NUMBER_SCAN, &d) == 1) {
+  if (filetol(*f, &d) == 1) { /* was fscanf(f, LUA_NUMBER_SCAN, &d)*/
     lua_pushnumber(L, d);
     return 1;
   }
diff --git a/apps/plugins/lua/rockaux.c b/apps/plugins/lua/rockaux.c
index ba3a37343b..562d1654a7 100644
--- a/apps/plugins/lua/rockaux.c
+++ b/apps/plugins/lua/rockaux.c
@@ -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;
+}
+
diff --git a/apps/plugins/lua/rocklib.h b/apps/plugins/lua/rocklib.h
index b650207e67..4714dec36d 100644
--- a/apps/plugins/lua/rocklib.h
+++ b/apps/plugins/lua/rocklib.h
@@ -47,6 +47,7 @@ struct lua_str_reg {
 
 LUALIB_API int (luaopen_rock) (lua_State *L);
 int get_current_path(lua_State *L, int level);
+int filetol(int fd, long *num);
 
 #endif /* _ROCKLIB_H_ */
 
diff --git a/apps/plugins/lua/rocklibc.h b/apps/plugins/lua/rocklibc.h
index 44f916fded..fde50ae4f5 100644
--- a/apps/plugins/lua/rocklibc.h
+++ b/apps/plugins/lua/rocklibc.h
@@ -43,7 +43,5 @@ extern int errno;
 #define memcmp rb->memcmp
 #define strlen rb->strlen
 
-extern int PREFIX(fscanf)(int fd, const char *fmt, ...);
-
 #endif /* _ROCKLIBC_H_ */