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C++: throw exceptions in overflow cases

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This commit is contained in:
Brandon Liu
2022-12-22 21:55:05 +08:00
parent f9cc6a20ac
commit 58d47196c7
2 changed files with 49 additions and 9 deletions
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21
cpp/pmtiles.hpp
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@@ -311,14 +311,14 @@ void rotate(int64_t n, int64_t &x, int64_t &y, int64_t rx, int64_t ry) {
} }
zxy t_on_level(uint8_t z, uint64_t pos) { zxy t_on_level(uint8_t z, uint64_t pos) {
int64_t n = 1 << z; int64_t n = 1LL << z;
int64_t rx, ry, s, t = pos; int64_t rx, ry, s, t = pos;
int64_t tx = 0; int64_t tx = 0;
int64_t ty = 0; int64_t ty = 0;
for (s = 1; s < n; s *= 2) { for (s = 1; s < n; s *= 2) {
rx = 1 & (t / 2); rx = 1LL & (t / 2);
ry = 1 & (t ^ rx); ry = 1LL & (t ^ rx);
rotate(s, tx, ty, rx, ry); rotate(s, tx, ty, rx, ry);
tx += s * rx; tx += s * rx;
ty += s * ry; ty += s * ry;
@@ -385,28 +385,33 @@ entryv3 find_tile(const std::vector<entryv3> &entries, uint64_t tile_id) {
inline zxy tileid_to_zxy(uint64_t tileid) { inline zxy tileid_to_zxy(uint64_t tileid) {
uint64_t acc = 0; uint64_t acc = 0;
uint8_t t_z = 0; for (uint8_t t_z = 0; t_z < 32; t_z++) {
while (true) {
uint64_t num_tiles = (1LL << t_z) * (1LL << t_z); uint64_t num_tiles = (1LL << t_z) * (1LL << t_z);
if (acc + num_tiles > tileid) { if (acc + num_tiles > tileid) {
return t_on_level(t_z, tileid - acc); return t_on_level(t_z, tileid - acc);
} }
acc += num_tiles; acc += num_tiles;
t_z++;
} }
throw std::overflow_error("tile zoom exceeds 64-bit limit");
} }
inline uint64_t zxy_to_tileid(uint8_t z, uint32_t x, uint32_t y) { inline uint64_t zxy_to_tileid(uint8_t z, uint32_t x, uint32_t y) {
if (z > 31) {
throw std::overflow_error("tile zoom exceeds 64-bit limit");
}
if (x > (1 << z) - 1 || y > (1 << z) - 1) {
throw std::overflow_error("tile x/y outside zoom level bounds");
}
uint64_t acc = 0; uint64_t acc = 0;
for (uint8_t t_z = 0; t_z < z; t_z++) acc += (1LL << t_z) * (1LL << t_z); for (uint8_t t_z = 0; t_z < z; t_z++) acc += (1LL << t_z) * (1LL << t_z);
int64_t n = 1 << z; int64_t n = 1LL << z;
int64_t rx, ry, s, d = 0; int64_t rx, ry, s, d = 0;
int64_t tx = x; int64_t tx = x;
int64_t ty = y; int64_t ty = y;
for (s = n / 2; s > 0; s /= 2) { for (s = n / 2; s > 0; s /= 2) {
rx = (tx & s) > 0; rx = (tx & s) > 0;
ry = (ty & s) > 0; ry = (ty & s) > 0;
d += s * s * ((3 * rx) ^ ry); d += s * s * ((3LL * rx) ^ ry);
rotate(s, tx, ty, rx, ry); rotate(s, tx, ty, rx, ry);
} }
return acc + d; return acc + d;

37
cpp/test.cpp
View File

@@ -46,7 +46,7 @@ MU_TEST(test_zxy_to_tileid) {
} }
MU_TEST(test_roundtrip) { MU_TEST(test_roundtrip) {
for (int z = 0; z < 25; z++) { for (int z = 0; z < 32; z++) {
uint64_t dim = (1 << z) - 1; uint64_t dim = (1 << z) - 1;
auto tl = tileid_to_zxy(zxy_to_tileid(z, 0, 0)); auto tl = tileid_to_zxy(zxy_to_tileid(z, 0, 0));
mu_check(tl.z == z); mu_check(tl.z == z);
@@ -65,6 +65,41 @@ MU_TEST(test_roundtrip) {
mu_check(br.x == dim); mu_check(br.x == dim);
mu_check(br.y == dim); mu_check(br.y == dim);
} }
bool caught = false;
try {
tileid_to_zxy(18446744073709551615ULL);
} catch (const std::runtime_error &e) {
caught = true;
}
mu_check(caught);
caught = false;
try {
zxy_to_tileid(32, 0, 0);
} catch (const std::runtime_error &e) {
caught = true;
}
mu_check(caught);
caught = false;
try {
zxy_to_tileid(0, 1, 1);
} catch (const std::runtime_error &e) {
caught = true;
}
mu_check(caught);
caught = false;
try {
zxy_to_tileid(31, 2147483647ULL + 1, 2147483647ULL + 1);
} catch (const std::runtime_error &e) {
caught = true;
}
mu_check(caught);
} }
MU_TEST(test_serialize_directory) { MU_TEST(test_serialize_directory) {