adrido/minetest-mapper-cpp
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Abstract & improve some stream operations, and make them idempotent.

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<stream>.eof() may require the stream to be read (peeked) before giving the
correct result. But it can't be peeked if already at EOF - see below.

<stream>.peek() is not idempotent:
If the stream is at EOF, but not known to be, it sets eofbit.
However, if the stream is known to be at EOF, it sets the failbit :-(
This commit is contained in:
Rogier 2015-12-26 11:04:48 +01:00
parent 8f6c9d7557
commit 2ec0988e32
1 changed files with 34 additions and 14 deletions
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48
mapper.cpp
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@ -72,6 +72,26 @@ const FuzzyBool FuzzyBool::Yes = 1;
const FuzzyBool FuzzyBool::Maybe = 0;
const FuzzyBool FuzzyBool::No = -1;
static inline bool validStreamAtWsOrEof(std::istream &is)
{
// May need to peek before knowing it's EOF.
// However, peeking twice results in fail()...
return !is.fail() && (is.eof() || is.peek() == ' ' || is.eof() || is.peek() == '\t');
}
static inline bool validStreamAtEof(std::istream &is)
{
// May need to peek before knowing it's EOF.
// However, peeking twice at eof results in fail()...
return !is.fail() && (is.eof() || (is.peek(), is.eof()));
}
static inline int safePeekStream(std::istream &is)
{
// Don't peek at EOF, else stream fails...
return is.eof() ? EOF : is.peek();
}
void usage()
{
const char *options_text = "[options]\n"
@ -279,7 +299,7 @@ static bool parseNodeCoordinate(istream &is, int &coord, bool &isBlockCoord, int
int i;
char s;
s = c = is.peek();
s = c = safePeekStream(is);
if (c == '*') {
if (wildcard) {
i = wildcard;
@ -303,18 +323,18 @@ static bool parseNodeCoordinate(istream &is, int &coord, bool &isBlockCoord, int
return false;
coord = i;
isBlockCoord = false;
if (is.eof())
if (validStreamAtEof(is))
return true;
// Check if this is a block number, and so: if it has a node number.
c = is.peek();
c = safePeekStream(is);
if (c == '#' || c == '.') {
// coordinate read was a block number
is.ignore(1);
if (wildcard) {
return false; // wildcards are generic
}
else if (isdigit(is.peek())) {
else if (isdigit(safePeekStream(is))) {
// has a node number / offset
is >> i;
if (!is.fail()) {
@ -446,19 +466,19 @@ static bool parseGeometry(istream &is, NodeCoord &coord1, NodeCoord &coord2, Nod
if (expectDimensions >= FuzzyBool::Maybe && parseCoordinates(is, dimensions, n, 0, 'x')) {
convertBlockToNodeCoordinates(dimensions, 0, n);
// <w>x<h>[+<x>+<y>]
if (is.eof()) {
if (validStreamAtEof(is)) {
centered = true;
for (int i = 0; i < n; i++) {
coord1.dimension[i] = 0;
coord1.isBlock[i] = false;
}
return (is.eof() || is.peek() == ' ' || is.peek() == '\t');
return validStreamAtWsOrEof(is);
}
else {
centered = false;
if (parseCoordinates(is, coord1, n, 0, '\0')) {
convertBlockToNodeCoordinates(coord1, 0, n);
return (is.eof() || is.peek() == ' ' || is.peek() == '\t');
return validStreamAtWsOrEof(is);
}
else
return false;
@ -471,23 +491,23 @@ static bool parseGeometry(istream &is, NodeCoord &coord1, NodeCoord &coord2, Nod
coord1.x() = coord1.y() = coord1.z() = 0;
}
if (parseCoordinates(is, coord1, n, wildcard, ',')) {
if (expectDimensions == FuzzyBool::No || (expectDimensions == FuzzyBool::Maybe && (is.eof() || is.peek() == ' ' || is.peek() == '\t'))) {
if (expectDimensions == FuzzyBool::No || (expectDimensions == FuzzyBool::Maybe && validStreamAtWsOrEof(is))) {
// Just coordinates were specified
centered = false;
return (is.eof() || is.peek() == ' ' || is.peek() == '\t');
return validStreamAtWsOrEof(is);
}
else if (wildcard && (coord1.x() == wildcard || coord1.y() == wildcard || coord1.z() == wildcard)) {
// wildcards are only allowed for plain coordinates (i.e. no dimensions)
return false;
}
else if (is.peek() == ':') {
else if (safePeekStream(is) == ':') {
is.ignore(1);
pos = is.tellg();
if (parseCoordinates(is, coord2, n, 0, ',')) {
// <x1>,<y1>:<x2>,<y2>
centered = false;
convertBlockToNodeCoordinates(coord1, coord2, n);
return (is.eof() || is.peek() == ' ' || is.peek() == '\t');
return validStreamAtWsOrEof(is);
}
is.clear();
is.seekg(pos);
@ -497,7 +517,7 @@ static bool parseGeometry(istream &is, NodeCoord &coord1, NodeCoord &coord2, Nod
centered = true;
convertBlockToNodeCoordinates(coord1, 8, n);
convertBlockToNodeCoordinates(dimensions, 0, n);
return (is.eof() || is.peek() == ' ' || is.peek() == '\t');
return validStreamAtWsOrEof(is);
}
else {
return false;
@ -509,7 +529,7 @@ static bool parseGeometry(istream &is, NodeCoord &coord1, NodeCoord &coord2, Nod
if (parseCoordinates(is, dimensions, n, 0, '\0')) {
convertBlockToNodeCoordinates(coord1, 0, n);
convertBlockToNodeCoordinates(dimensions, 0, n);
return (is.eof() || is.peek() == ' ' || is.peek() == '\t');
return validStreamAtWsOrEof(is);
}
else {
return false;
@ -526,7 +546,7 @@ static bool parseGeometry(istream &is, NodeCoord &coord1, NodeCoord &coord2, Nod
if (parseCoordinates(is, dimensions, n, 0, '\0')) {
convertBlockToNodeCoordinates(coord1, 0, n);
convertBlockToNodeCoordinates(dimensions, 0, n);
return (is.eof() || is.peek() == ' ' || is.peek() == '\t');
return validStreamAtWsOrEof(is);
}
return false;
}