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| author | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2020-10-22 15:54:46 -0300 |
|---|---|---|
| committer | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2020-10-22 15:54:46 -0300 |
| commit | d742a193e57029d973aff0a5eb04d8ddd03fa0ff (patch) | |
| tree | f0850c8f60997909952cbb1db3f499f066fb1188 /ltable.c | |
| parent | e4a38eb0e828e9589c391171e2e1904a3b9698e7 (diff) | |
| download | lua-d742a193e57029d973aff0a5eb04d8ddd03fa0ff.tar.gz lua-d742a193e57029d973aff0a5eb04d8ddd03fa0ff.tar.bz2 lua-d742a193e57029d973aff0a5eb04d8ddd03fa0ff.zip | |
Comments
Diffstat (limited to 'ltable.c')
| -rw-r--r-- | ltable.c | 27 |
1 files changed, 17 insertions, 10 deletions
| @@ -166,17 +166,24 @@ static Node *mainpositionTV (const Table *t, const TValue *key) { | |||
| 166 | 166 | ||
| 167 | 167 | ||
| 168 | /* | 168 | /* |
| 169 | ** Check whether key 'k1' is equal to the key in node 'n2'. | 169 | ** Check whether key 'k1' is equal to the key in node 'n2'. This |
| 170 | ** This equality is raw, so there are no metamethods. Floats | 170 | ** equality is raw, so there are no metamethods. Floats with integer |
| 171 | ** with integer values have been normalized, so integers cannot | 171 | ** values have been normalized, so integers cannot be equal to |
| 172 | ** be equal to floats. It is assumed that 'eqshrstr' is simply | 172 | ** floats. It is assumed that 'eqshrstr' is simply pointer equality, so |
| 173 | ** pointer equality, so that short strings are handled in the | 173 | ** that short strings are handled in the default case. |
| 174 | ** default case. | ||
| 175 | ** A true 'deadok' means to accept dead keys as equal to their original | 174 | ** A true 'deadok' means to accept dead keys as equal to their original |
| 176 | ** values, which can only happen if the original key was collectable. | 175 | ** values. All dead keys are compared in the default case, by pointer |
| 177 | ** All dead values are compared in the default case, by pointer | 176 | ** identity. (Only collectable objects can produce dead keys.) Note that |
| 178 | ** identity. (Note that dead long strings are also compared by | 177 | ** dead long strings are also compared by identity. |
| 179 | ** identity). | 178 | ** Once a key is dead, its corresponding value may be collected, and |
| 179 | ** then another value can be created with the same address. If this | ||
| 180 | ** other value is given to 'next', 'equalkey' will signal a false | ||
| 181 | ** positive. In a regular traversal, this situation should never happen, | ||
| 182 | ** as all keys given to 'next' came from the table itself, and therefore | ||
| 183 | ** could not have been collected. Outside a regular traversal, we | ||
| 184 | ** have garbage in, garbage out. What is relevant is that this false | ||
| 185 | ** positive does not break anything. (In particular, 'next' will return | ||
| 186 | ** some other valid item on the table or nil.) | ||
| 180 | */ | 187 | */ |
| 181 | static int equalkey (const TValue *k1, const Node *n2, int deadok) { | 188 | static int equalkey (const TValue *k1, const Node *n2, int deadok) { |
| 182 | if ((rawtt(k1) != keytt(n2)) && /* not the same variants? */ | 189 | if ((rawtt(k1) != keytt(n2)) && /* not the same variants? */ |