diff options
Diffstat (limited to 'contrib/ltree/ltree.h')
| -rw-r--r-- | contrib/ltree/ltree.h | 41 |
1 files changed, 31 insertions, 10 deletions
diff --git a/contrib/ltree/ltree.h b/contrib/ltree/ltree.h index 2c483045dbb..e5f2710c90e 100644 --- a/contrib/ltree/ltree.h +++ b/contrib/ltree/ltree.h @@ -7,9 +7,19 @@ #include "tsearch/ts_locale.h" #include "utils/memutils.h" + +/* ltree */ + +/* + * We want the maximum length of a label to be encoding-independent, so + * set it somewhat arbitrarily at 255 characters (not bytes), while using + * uint16 fields to hold the byte length. + */ +#define LTREE_LABEL_MAX_CHARS 255 + typedef struct { - uint16 len; + uint16 len; /* label string length in bytes */ char name[FLEXIBLE_ARRAY_MEMBER]; } ltree_level; @@ -19,7 +29,8 @@ typedef struct typedef struct { int32 vl_len_; /* varlena header (do not touch directly!) */ - uint16 numlevel; + uint16 numlevel; /* number of labels */ + /* Array of maxalign'd ltree_level structs follows: */ char data[FLEXIBLE_ARRAY_MEMBER]; } ltree; @@ -30,25 +41,35 @@ typedef struct /* lquery */ +/* lquery_variant: one branch of some OR'ed alternatives */ typedef struct { - int32 val; - uint16 len; + int32 val; /* CRC of label string */ + uint16 len; /* label string length in bytes */ uint8 flag; /* see LVAR_xxx flags below */ char name[FLEXIBLE_ARRAY_MEMBER]; } lquery_variant; +/* + * Note: these macros contain too many MAXALIGN calls and so will sometimes + * overestimate the space needed for an lquery_variant. However, we can't + * change it without breaking on-disk compatibility for lquery. + */ #define LVAR_HDRSIZE MAXALIGN(offsetof(lquery_variant, name)) #define LVAR_NEXT(x) ( (lquery_variant*)( ((char*)(x)) + MAXALIGN(((lquery_variant*)(x))->len) + LVAR_HDRSIZE ) ) -#define LVAR_ANYEND 0x01 -#define LVAR_INCASE 0x02 -#define LVAR_SUBLEXEME 0x04 +#define LVAR_ANYEND 0x01 /* '*' flag: prefix match */ +#define LVAR_INCASE 0x02 /* '@' flag: case-insensitive match */ +#define LVAR_SUBLEXEME 0x04 /* '%' flag: word-wise match */ +/* + * In an lquery_level, "flag" contains the union of the variants' flags + * along with possible LQL_xxx flags; so those bit sets can't overlap. + */ typedef struct { uint16 totallen; /* total length of this level, in bytes */ - uint16 flag; /* see LQL_xxx flags below */ + uint16 flag; /* see LQL_xxx and LVAR_xxx flags */ uint16 numvar; /* number of variants; 0 means '*' */ uint16 low; /* minimum repeat count for '*' */ uint16 high; /* maximum repeat count for '*' */ @@ -60,7 +81,7 @@ typedef struct #define LQL_NEXT(x) ( (lquery_level*)( ((char*)(x)) + MAXALIGN(((lquery_level*)(x))->totallen) ) ) #define LQL_FIRST(x) ( (lquery_variant*)( ((char*)(x))+LQL_HDRSIZE ) ) -#define LQL_NOT 0x10 +#define LQL_NOT 0x10 /* level has '!' (NOT) prefix */ #ifdef LOWER_NODE #define FLG_CANLOOKSIGN(x) ( ( (x) & ( LQL_NOT | LVAR_ANYEND | LVAR_SUBLEXEME ) ) == 0 ) @@ -73,7 +94,7 @@ typedef struct { int32 vl_len_; /* varlena header (do not touch directly!) */ uint16 numlevel; /* number of lquery_levels */ - uint16 firstgood; + uint16 firstgood; /* number of leading simple-match levels */ uint16 flag; /* see LQUERY_xxx flags below */ /* Array of maxalign'd lquery_level structs follows: */ char data[FLEXIBLE_ARRAY_MEMBER]; |