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cppcheck/CheckOther.cpp

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//---------------------------------------------------------------------------
#include "CheckOther.h"
#include "tokenize.h"
#include "CommonCheck.h"
#include <list>
#include <map>
#include <sstream>
#include <stdlib.h> // <- atoi
#include <cstring>
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Warning on C-Style casts.. p = (kalle *)foo;
//---------------------------------------------------------------------------
void WarningOldStylePointerCast()
{
for (const TOKEN *tok = tokens; tok; tok = tok->next)
{
// Old style pointer casting..
if (!Match(tok, "( %type% * ) %var%"))
continue;
// Is "type" a class?
const char *pattern[] = {"class","",NULL};
pattern[1] = getstr(tok, 1);
if (!findtoken(tokens, pattern))
continue;
std::ostringstream ostr;
ostr << FileLine(tok) << ": C-style pointer casting";
ReportErr(ostr.str());
}
}
//---------------------------------------------------------------------------
// Use standard function "isdigit" instead
//---------------------------------------------------------------------------
void WarningIsDigit()
{
for (const TOKEN *tok = tokens; tok; tok = tok->next)
{
bool err = false;
err |= Match(tok, "%var% >= '0' && %var% <= '9'");
err |= Match(tok, "* %var% >= '0' && * %var% <= '9'");
err |= Match(tok, "( %var% >= '0' ) && ( %var% <= '9' )");
err |= Match(tok, "( * %var% >= '0' ) && ( * %var% <= '9' )");
if (err)
{
std::ostringstream ostr;
ostr << FileLine(tok) << ": The condition can be simplified; use 'isdigit'";
ReportErr(ostr.str());
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Use standard function "isalpha" instead
//---------------------------------------------------------------------------
void WarningIsAlpha()
{
for (const TOKEN *tok = tokens; tok; tok = tok->next)
{
bool err = false;
if ( tok->str[0] != '(' )
continue;
err |= Match(tok, "( %var% >= 'A' && %var% <= 'Z' ) || ( %var% >= 'a' && %var% <= 'z' )");
err |= Match(tok, "( %var% >= 'a' && %var% <= 'z' ) || ( %var% >= 'A' && %var% <= 'Z' )");
err |= Match(tok, "( * %var% >= 'A' && * %var% <= 'Z' ) || ( * %var% >= 'a' && * %var% <= 'z' )");
err |= Match(tok, "( * %var% >= 'a' && * %var% <= 'z' ) || ( * %var% >= 'A' && * %var% <= 'Z' )");
err |= Match(tok, "( ( %var% >= 'A' ) && ( %var% <= 'Z' ) ) || ( ( %var% >= 'a' ) && ( %var% <= 'z' ) )");
err |= Match(tok, "( ( %var% >= 'a' ) && ( %var% <= 'z' ) ) || ( ( %var% >= 'A' ) && ( %var% <= 'Z' ) )");
err |= Match(tok, "( ( * %var% >= 'A' ) && ( * %var% <= 'Z' ) ) || ( ( * var >= 'a' ) && ( * %var% <= 'z' ) )");
err |= Match(tok, "( ( * %var% >= 'a' ) && ( * %var% <= 'z' ) ) || ( ( * var >= 'A' ) && ( * %var% <= 'Z' ) )");
if (err)
{
std::ostringstream ostr;
ostr << FileLine(tok) << ": The condition can be simplified; use 'isalpha'";
ReportErr(ostr.str());
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Redundant code..
//---------------------------------------------------------------------------
void WarningRedundantCode()
{
// if (p) delete p
for (const TOKEN *tok = tokens; tok; tok = tok->next)
{
if (strcmp(tok->str,"if"))
continue;
const char *varname1 = NULL;
const TOKEN *tok2 = NULL;
if (Match(tok,"if ( %var% )"))
{
varname1 = getstr(tok, 2);
tok2 = gettok(tok, 4);
}
else if (Match(tok,"if ( %var% != NULL )"))
{
varname1 = getstr(tok, 2);
tok2 = gettok(tok, 6);
}
if (varname1==NULL || tok2==NULL)
continue;
if ( tok2->str[0] == '{' )
tok2 = tok2->next;
bool err = false;
if (Match(tok2,"delete %var% ;"))
err = (strcmp(getstr(tok2,1),varname1)==0);
else if (Match(tok2,"delete [ ] %var% ;"))
err = (strcmp(getstr(tok2,1),varname1)==0);
else if (Match(tok2,"free ( %var% )"))
err = (strcmp(getstr(tok2,2),varname1)==0);
else if (Match(tok2,"kfree ( %var% )"))
err = (strcmp(getstr(tok2,2),varname1)==0);
if (err)
{
std::ostringstream ostr;
ostr << FileLine(tok) << ": Redundant condition. It is safe to deallocate a NULL pointer";
ReportErr(ostr.str());
}
}
// TODO: Redundant condition
// if (haystack.find(needle) != haystack.end())
// haystack.remove(needle);
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// if (condition) ....
//---------------------------------------------------------------------------
void WarningIf()
{
// Search for 'if (condition);'
for (const TOKEN *tok = tokens; tok; tok = tok->next)
{
if (strcmp(tok->str,"if")==0)
{
int parlevel = 0;
for (const TOKEN *tok2 = tok->next; tok2; tok2 = tok2->next)
{
if (tok2->str[0]=='(')
parlevel++;
else if (tok2->str[0]==')')
{
parlevel--;
if (parlevel<=0)
{
if (strcmp(getstr(tok2,1), ";") == 0 &&
strcmp(getstr(tok2,2), "else") != 0)
{
std::ostringstream ostr;
ostr << FileLine(tok) << ": Found \"if (condition);\"";
ReportErr(ostr.str());
}
break;
}
}
}
}
}
// Search for 'a=b; if (a==b)'
for (const TOKEN *tok = tokens; tok; tok = tok->next)
{
// Begin statement?
if ( ! strchr(";{}", tok->str[0]) )
continue;
tok = tok->next;
if ( ! tok )
break;
if (!Match(tok,"%var% = %var% ; if ( %var%"))
continue;
if ( strcmp(getstr(tok, 9), ")") != 0 )
continue;
// var1 = var2 ; if ( var3 cond var4 )
const char *var1 = tok->str;
const char *var2 = getstr(tok, 2);
const char *var3 = getstr(tok, 6);
const char *cond = getstr(tok, 7);
const char *var4 = getstr(tok, 8);
// Check that var3 is equal with either var1 or var2
if (strcmp(var1,var3) && strcmp(var2,var3))
continue;
// Check that var4 is equal with either var1 or var2
if (strcmp(var1,var4) && strcmp(var2,var4))
continue;
// Check that there is a condition..
const char *p[6] = {"==","<=",">=","!=","<",">"};
bool iscond = false;
for (int i = 0; i < 6; i++)
iscond |= (strcmp(cond, p[i]) == 0);
if (!iscond)
break;
// we found the error. Report.
std::ostringstream ostr;
ostr << FileLine(gettok(tok,4)) << ": The condition is always ";
for (int i = 0; i < 6; i++)
{
if (strcmp(cond, p[i]) == 0)
ostr << (i < 3 ? "True" : "False");
}
ReportErr(ostr.str());
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// strtol(str, 0, radix) <- radix must be 0 or 2-36
//---------------------------------------------------------------------------
void InvalidFunctionUsage()
{
for ( const TOKEN *tok = tokens; tok; tok = tok->next )
{
if ( strcmp(tok->str, "strtol") && strcmp(tok->str, "strtoul") )
continue;
// Locate the third parameter of the function call..
int parlevel = 0;
int param = 1;
for ( const TOKEN *tok2 = tok->next; tok2; tok2 = tok2->next )
{
if ( tok2->str[0] == '(' )
parlevel++;
else if (tok2->str[0] == ')')
parlevel--;
else if (parlevel == 1 && tok2->str[0] == ',')
{
param++;
if (param==3)
{
if ( Match(tok2, ", %num% )") )
{
int radix = atoi(tok2->next->str);
if (!(radix==0 || (radix>=2 && radix<=36)))
{
std::ostringstream ostr;
ostr << FileLine(tok2) << ": Invalid radix in call to strtol or strtoul. Must be 0 or 2-36";
ReportErr(ostr.str());
}
}
break;
}
}
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Assignment in condition
//---------------------------------------------------------------------------
void CheckIfAssignment()
{
for (const TOKEN *tok = tokens; tok; tok = tok->next)
{
if (Match(tok, "if ( %var% = %num% )") ||
Match(tok, "if ( %var% = %str% )") ||
Match(tok, "if ( %var% = %var% )") )
{
std::ostringstream ostr;
ostr << FileLine(tok) << ": Possible bug. Should it be '==' instead of '='?";
ReportErr(ostr.str());
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Check for unsigned divisions
//---------------------------------------------------------------------------
void CheckUnsignedDivision()
{
// Check for "ivar / uvar" and "uvar / ivar"
std::map<std::string, char> varsign;
for ( TOKEN *tok = tokens; tok; tok = tok->next )
{
if ( Match(tok, "[{};(,] %type% %var% [;=,)]") )
{
const char *type = getstr(tok, 1);
if (strcmp(type,"char")==0 || strcmp(type,"short")==0 || strcmp(type,"int")==0)
varsign[getstr(tok,2)] = 's';
}
else if ( Match(tok, "[{};(,] unsigned %type% %var% [;=,)]") )
varsign[getstr(tok,3)] = 'u';
else if (!Match(tok,"[).]") && Match(tok->next, "%var% / %var%"))
{
const char *varname1 = getstr(tok,1);
const char *varname2 = getstr(tok,3);
char sign1 = varsign[varname1];
char sign2 = varsign[varname2];
if ( sign1 && sign2 && sign1 != sign2 )
{
// One of the operands are signed, the other is unsigned..
std::ostringstream ostr;
ostr << FileLine(tok->next) << ": Warning: Division with signed and unsigned operators";
ReportErr(ostr.str());
}
}
else if (!Match(tok,"[).]") && Match(tok->next, "%var% / - %num%"))
{
const char *varname1 = getstr(tok,1);
char sign1 = varsign[varname1];
if ( sign1 == 'u' )
{
std::ostringstream ostr;
ostr << FileLine(tok->next) << ": Unsigned division. The result will be wrong.";
ReportErr(ostr.str());
}
}
else if (Match(tok, "[([=*/+-] - %num% / %var%"))
{
const char *varname2 = getstr(tok,4);
char sign2 = varsign[varname2];
if ( sign2 == 'u' )
{
std::ostringstream ostr;
ostr << FileLine(tok->next) << ": Unsigned division. The result will be wrong.";
ReportErr(ostr.str());
}
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Check scope of variables..
//---------------------------------------------------------------------------
static void CheckVariableScope_LookupVar( const TOKEN *tok1, const char varname[] );
void CheckVariableScope()
{
// Walk through all tokens..
bool func = false;
int indentlevel = 0;
for ( const TOKEN *tok = tokens; tok; tok = tok->next )
{
// Skip class and struct declarations..
if ( strcmp(tok->str, "class") == 0 || strcmp(tok->str, "struct") == 0 )
{
for (const TOKEN *tok2 = tok; tok2; tok2 = tok2->next)
{
if ( tok2->str[0] == '{' )
{
int _indentlevel = 0;
tok = tok2;
for (tok = tok2; tok; tok = tok->next)
{
if ( tok->str[0] == '{' )
{
_indentlevel++;
}
if ( tok->str[0] == '}' )
{
_indentlevel--;
if ( _indentlevel <= 0 )
{
tok = tok->next;
break;
}
}
}
break;
}
if (strchr(",);", tok2->str[0]))
{
break;
}
}
if ( ! tok )
break;
}
if ( tok->str[0] == '{' )
{
indentlevel++;
}
if ( tok->str[0] == '}' )
{
indentlevel--;
if ( indentlevel == 0 )
func = false;
}
if ( indentlevel == 0 && Match(tok, ") {") )
{
func = true;
}
if ( indentlevel > 0 && func && strchr("{};", tok->str[0]) )
{
// First token of statement..
const TOKEN *tok1 = tok->next;
if ( ! tok1 )
continue;
if (strcmp(tok1->str,"return")==0 ||
strcmp(tok1->str,"delete")==0 ||
strcmp(tok1->str,"goto")==0 ||
strcmp(tok1->str,"else")==0)
continue;
// Variable declaration?
if (Match(tok1, "%var% %var% ;") ||
Match(tok1, "%var% %var% =") )
{
CheckVariableScope_LookupVar( tok1, getstr(tok1, 1) );
}
}
}
}
//---------------------------------------------------------------------------
static void CheckVariableScope_LookupVar( const TOKEN *tok1, const char varname[] )
{
const TOKEN *tok = tok1;
// Skip the variable declaration..
while ( tok->str[0] != ';' )
tok = tok->next;
// Check if the variable is used in this indentlevel..
bool used = false, used1 = false;
int indentlevel = 0;
int parlevel = 0;
bool for_or_while = false;
while ( indentlevel >= 0 && tok )
{
if ( tok->str[0] == '{' )
{
indentlevel++;
}
else if ( tok->str[0] == '}' )
{
indentlevel--;
if ( indentlevel == 0 )
{
if ( for_or_while && used )
return;
used1 = used;
used = false;
}
}
else if ( tok->str[0] == '(' )
{
parlevel++;
}
else if ( tok->str[0] == ')' )
{
parlevel--;
}
else if ( strcmp(tok->str, varname) == 0 )
{
if ( indentlevel == 0 || used1 )
return;
used = true;
}
else if ( indentlevel==0 )
{
if ( strcmp(tok->str,"for")==0 || strcmp(tok->str,"while")==0 )
for_or_while = true;
if ( parlevel == 0 && tok->str[0] == ';' )
for_or_while = false;
}
tok = tok->next;
}
// Warning if "used" is true
std::ostringstream errmsg;
errmsg << FileLine(tok1) << " The scope of the variable '" << varname << "' can be limited";
ReportErr( errmsg.str() );
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Check for constant function parameters
//---------------------------------------------------------------------------
void CheckConstantFunctionParameter()
{
for (const TOKEN *tok = tokens; tok; tok = tok->next)
{
if ( Match(tok,"[,(] const std :: %type% %var% [,)]") )
{
std::ostringstream errmsg;
errmsg << FileLine(tok) << " " << getstr(tok,5) << " is passed by value, it could be passed by reference/pointer instead";
ReportErr( errmsg.str() );
}
else if ( Match(tok,"[,(] const %type% %var% [,)]") )
{
// Check if type is a struct or class.
const char *pattern[3] = {"class","type",0};
pattern[1] = getstr(tok, 2);
if ( findtoken(tokens, pattern) )
{
std::ostringstream errmsg;
errmsg << FileLine(tok) << " " << getstr(tok,3) << " is passed by value, it could be passed by reference/pointer instead";
ReportErr( errmsg.str() );
}
pattern[0] = "struct";
if ( findtoken(tokens, pattern) )
{
std::ostringstream errmsg;
errmsg << FileLine(tok) << " " << getstr(tok,3) << " is passed by value, it could be passed by reference/pointer instead";
ReportErr( errmsg.str() );
}
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Check that all struct members are used
//---------------------------------------------------------------------------
void CheckStructMemberUsage()
{
const char *structname = 0;
for ( const TOKEN *tok = tokens; tok; tok = tok->next )
{
if ( tok->FileIndex != 0 )
continue;
if ( tok->str[0] == '}' )
structname = 0;
if ( Match(tok, "struct %type% {") )
structname = getstr(tok, 1);
if (structname && Match(tok, "[{;]"))
{
const char *varname = 0;
if (Match(tok->next, "%type% %var% [;[]"))
varname = getstr( tok, 2 );
else if (Match(tok->next, "%type% %type% %var% [;[]"))
varname = getstr( tok, 2 );
else if (Match(tok->next, "%type% * %var% [;[]"))
varname = getstr( tok, 3 );
else if (Match(tok->next, "%type% %type% * %var% [;[]"))
varname = getstr( tok, 4 );
else
continue;
const char *varnames[2];
varnames[0] = varname;
varnames[1] = 0;
bool used = false;
for ( const TOKEN *tok2 = tokens; tok2; tok2 = tok2->next )
{
if ( tok->FileIndex != 0 )
continue;
if (Match(tok2, ". %var%", varnames))
{
if ( strcmp("=", getstr(tok2,2)) == 0 )
continue;
used = true;
break;
}
}
if ( ! used )
{
std::ostringstream errmsg;
errmsg << FileLine(tok) << ": struct member '" << structname << "::" << varname << "' is never read";
ReportErr(errmsg.str());
}
}
}
}
//---------------------------------------------------------------------------
// Check usage of char variables..
//---------------------------------------------------------------------------
void CheckCharVariable()
{
for (const TOKEN *tok = tokens; tok; tok = tok->next)
{
// Declaring the variable..
if ( Match(tok, "[{};(,] char %var% [;=,)]") )
{
const char *varname[2] = {0};
varname[0] = getstr(tok, 2);
// Check usage of char variable..
int indentlevel = 0;
for ( const TOKEN *tok2 = tok->next; tok2; tok2 = tok2->next )
{
if ( tok2->str[0] == '{' )
++indentlevel;
else if ( tok2->str[0] == '}' )
{
--indentlevel;
if ( indentlevel <= 0 )
break;
}
else if ( Match(tok2, "%var% [ %var1% ]", varname) )
{
std::ostringstream errmsg;
errmsg << FileLine(tok2) << ": Warning - using char variable as array index";
ReportErr(errmsg.str());
break;
}
else if ( Match(tok2, "[&|] %var1%", varname) || Match(tok2, "%var1% [&|]", varname) )
{
std::ostringstream errmsg;
errmsg << FileLine(tok2) << ": Warning - using char variable in bit operation";
ReportErr(errmsg.str());
break;
}
}
}
}
}
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
// Incomplete statement..
//---------------------------------------------------------------------------
void CheckIncompleteStatement()
{
int parlevel = 0;
for ( const TOKEN *tok = tokens; tok; tok = tok->next )
{
if ( tok->str[0] == '(' )
++parlevel;
else if ( tok->str[0] == ')' )
--parlevel;
if ( parlevel != 0 )
continue;
if ( !Match(tok,"#") && Match(tok->next,"; %str%") && !Match(gettok(tok,3), ",") )
{
std::ostringstream errmsg;
errmsg << FileLine(tok->next) << ": Redundant code: Found a statement that begins with string constant";
ReportErr(errmsg.str());
}
if ( !Match(tok,"#") && Match(tok->next,"; %num%") && !Match(gettok(tok,3), ",") )
{
std::ostringstream errmsg;
errmsg << FileLine(tok->next) << ": Redundant code: Found a statement that begins with numeric constant";
ReportErr(errmsg.str());
}
}
}
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