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| author | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2019-10-01 17:24:37 -0300 |
|---|---|---|
| committer | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2019-10-01 17:24:37 -0300 |
| commit | b2a580bdb1982e45bb37f95b78c2dafec6efa7a6 (patch) | |
| tree | 76de58214adff838a26346514a8a6fba459bde9b /ltable.c | |
| parent | 89f6a85f034b2535e43e421991098fa05a92cd60 (diff) | |
| download | lua-b2a580bdb1982e45bb37f95b78c2dafec6efa7a6.tar.gz lua-b2a580bdb1982e45bb37f95b78c2dafec6efa7a6.tar.bz2 lua-b2a580bdb1982e45bb37f95b78c2dafec6efa7a6.zip | |
Janitorial work
- Several details in 'lcode.c'
- A few more tests for code generation
- Bug in assert in 'lcode.c' ("=" x "==")
- Comments in 'lopcodes.h' and 'ltable.c'
Diffstat (limited to 'ltable.c')
| -rw-r--r-- | ltable.c | 44 |
1 files changed, 24 insertions, 20 deletions
| @@ -833,39 +833,41 @@ static unsigned int binsearch (const TValue *array, unsigned int i, | |||
| 833 | ** and 'maxinteger' if t[maxinteger] is present.) | 833 | ** and 'maxinteger' if t[maxinteger] is present.) |
| 834 | ** (In the next explanation, we use Lua indices, that is, with base 1. | 834 | ** (In the next explanation, we use Lua indices, that is, with base 1. |
| 835 | ** The code itself uses base 0 when indexing the array part of the table.) | 835 | ** The code itself uses base 0 when indexing the array part of the table.) |
| 836 | ** The code starts with 'limit', a position in the array part that may | 836 | ** The code starts with 'limit = t->alimit', a position in the array |
| 837 | ** be a boundary. | 837 | ** part that may be a boundary. |
| 838 | ** | ||
| 838 | ** (1) If 't[limit]' is empty, there must be a boundary before it. | 839 | ** (1) If 't[limit]' is empty, there must be a boundary before it. |
| 839 | ** As a common case (e.g., after 't[#t]=nil'), check whether 'hint-1' | 840 | ** As a common case (e.g., after 't[#t]=nil'), check whether 'limit-1' |
| 840 | ** is present. If so, it is a boundary. Otherwise, do a binary search | 841 | ** is present. If so, it is a boundary. Otherwise, do a binary search |
| 841 | ** between 0 and limit to find a boundary. In both cases, try to | 842 | ** between 0 and limit to find a boundary. In both cases, try to |
| 842 | ** use this boundary as the new 'limit', as a hint for the next call. | 843 | ** use this boundary as the new 'alimit', as a hint for the next call. |
| 844 | ** | ||
| 843 | ** (2) If 't[limit]' is not empty and the array has more elements | 845 | ** (2) If 't[limit]' is not empty and the array has more elements |
| 844 | ** after 'limit', try to find a boundary there. Again, try first | 846 | ** after 'limit', try to find a boundary there. Again, try first |
| 845 | ** the special case (which should be quite frequent) where 'limit+1' | 847 | ** the special case (which should be quite frequent) where 'limit+1' |
| 846 | ** is empty, so that 'limit' is a boundary. Otherwise, check the | 848 | ** is empty, so that 'limit' is a boundary. Otherwise, check the |
| 847 | ** last element of the array part (set it as a new limit). If it is empty, | 849 | ** last element of the array part. If it is empty, there must be a |
| 848 | ** there must be a boundary between the old limit (present) and the new | 850 | ** boundary between the old limit (present) and the last element |
| 849 | ** limit (absent), which is found with a binary search. (This boundary | 851 | ** (absent), which is found with a binary search. (This boundary always |
| 850 | ** always can be a new limit.) | 852 | ** can be a new limit.) |
| 853 | ** | ||
| 851 | ** (3) The last case is when there are no elements in the array part | 854 | ** (3) The last case is when there are no elements in the array part |
| 852 | ** (limit == 0) or its last element (the new limit) is present. | 855 | ** (limit == 0) or its last element (the new limit) is present. |
| 853 | ** In this case, must check the hash part. If there is no hash part, | 856 | ** In this case, must check the hash part. If there is no hash part |
| 854 | ** the boundary is 0. Otherwise, if 'limit+1' is absent, 'limit' is | 857 | ** or 'limit+1' is absent, 'limit' is a boundary. Otherwise, call |
| 855 | ** a boundary. Finally, if 'limit+1' is present, call 'hash_search' | 858 | ** 'hash_search' to find a boundary in the hash part of the table. |
| 856 | ** to find a boundary in the hash part of the table. (In those | 859 | ** (In those cases, the boundary is not inside the array part, and |
| 857 | ** cases, the boundary is not inside the array part, and therefore | 860 | ** therefore cannot be used as a new limit.) |
| 858 | ** cannot be used as a new limit.) | ||
| 859 | */ | 861 | */ |
| 860 | lua_Unsigned luaH_getn (Table *t) { | 862 | lua_Unsigned luaH_getn (Table *t) { |
| 861 | unsigned int limit = t->alimit; | 863 | unsigned int limit = t->alimit; |
| 862 | if (limit > 0 && isempty(&t->array[limit - 1])) { | 864 | if (limit > 0 && isempty(&t->array[limit - 1])) { /* (1)? */ |
| 863 | /* (1) there must be a boundary before 'limit' */ | 865 | /* there must be a boundary before 'limit' */ |
| 864 | if (limit >= 2 && !isempty(&t->array[limit - 2])) { | 866 | if (limit >= 2 && !isempty(&t->array[limit - 2])) { |
| 865 | /* 'limit - 1' is a boundary; can it be a new limit? */ | 867 | /* 'limit - 1' is a boundary; can it be a new limit? */ |
| 866 | if (ispow2realasize(t) && !ispow2(limit - 1)) { | 868 | if (ispow2realasize(t) && !ispow2(limit - 1)) { |
| 867 | t->alimit = limit - 1; | 869 | t->alimit = limit - 1; |
| 868 | setnorealasize(t); | 870 | setnorealasize(t); /* now 'alimit' is not the real size */ |
| 869 | } | 871 | } |
| 870 | return limit - 1; | 872 | return limit - 1; |
| 871 | } | 873 | } |
| @@ -880,8 +882,8 @@ lua_Unsigned luaH_getn (Table *t) { | |||
| 880 | } | 882 | } |
| 881 | } | 883 | } |
| 882 | /* 'limit' is zero or present in table */ | 884 | /* 'limit' is zero or present in table */ |
| 883 | if (!limitequalsasize(t)) { | 885 | if (!limitequalsasize(t)) { /* (2)? */ |
| 884 | /* (2) 'limit' > 0 and array has more elements after 'limit' */ | 886 | /* 'limit' > 0 and array has more elements after 'limit' */ |
| 885 | if (isempty(&t->array[limit])) /* 'limit + 1' is empty? */ | 887 | if (isempty(&t->array[limit])) /* 'limit + 1' is empty? */ |
| 886 | return limit; /* this is the boundary */ | 888 | return limit; /* this is the boundary */ |
| 887 | /* else, try last element in the array */ | 889 | /* else, try last element in the array */ |
| @@ -899,7 +901,7 @@ lua_Unsigned luaH_getn (Table *t) { | |||
| 899 | lua_assert(limit == luaH_realasize(t) && | 901 | lua_assert(limit == luaH_realasize(t) && |
| 900 | (limit == 0 || !isempty(&t->array[limit - 1]))); | 902 | (limit == 0 || !isempty(&t->array[limit - 1]))); |
| 901 | if (isdummy(t) || isempty(luaH_getint(t, cast(lua_Integer, limit + 1)))) | 903 | if (isdummy(t) || isempty(luaH_getint(t, cast(lua_Integer, limit + 1)))) |
| 902 | return limit; /* 'limit + 1' is absent... */ | 904 | return limit; /* 'limit + 1' is absent */ |
| 903 | else /* 'limit + 1' is also present */ | 905 | else /* 'limit + 1' is also present */ |
| 904 | return hash_search(t, limit); | 906 | return hash_search(t, limit); |
| 905 | } | 907 | } |
| @@ -908,6 +910,8 @@ lua_Unsigned luaH_getn (Table *t) { | |||
| 908 | 910 | ||
| 909 | #if defined(LUA_DEBUG) | 911 | #if defined(LUA_DEBUG) |
| 910 | 912 | ||
| 913 | /* export these functions for the test library */ | ||
| 914 | |||
| 911 | Node *luaH_mainposition (const Table *t, const TValue *key) { | 915 | Node *luaH_mainposition (const Table *t, const TValue *key) { |
| 912 | return mainpositionTV(t, key); | 916 | return mainpositionTV(t, key); |
| 913 | } | 917 | } |