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.\" ========================================================================
.\"
.IX Title "libcritnib 3"
.TH libcritnib 3 "2022-09-19" "perl v5.34.0" "critnib"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
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.nh
.SH "NAME"
libcritnib \- an ordered map data structure with lock\-free reads
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
\&\fB#include <critnib.h>\fR
.PP
Link with \fI\-lcritnib\fR.
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
.SS "Functions:"
.IX Subsection "Functions:"
.IP "\fBcritnib *critnib_new(void);\fR" 4
.IX Item "critnib *critnib_new(void);"
Creates a new empty critnib structure.
.IP "\fBvoid critnib_delete(critnib *\fR\fIc\fR\fB);\fR" 4
.IX Item "void critnib_delete(critnib *c);"
Destroys and frees the memory.  Note that removed items are reused but won't
have their memory freed until this function is called.
.IP "\fBint critnib_insert(critnib *\fR\fIc\fR\fB, uintptr_t \fR\fIkey\fR\fB, void *\fR\fIvalue\fR\fB, int \fR\fIupdate\fR\fB);\fR" 4
.IX Item "int critnib_insert(critnib *c, uintptr_t key, void *value, int update);"
Adds a key:value pair to the critnib structure.  If \fIupdate\fR is non-zero,
an already existing key has its value updated, otherwise the function returns
\&\fB\s-1EEXIST\s0\fR.  It may return \fB\s-1ENOMEM\s0\fR if we're out of memory, or 0 if all went
okay.
.IP "\fBvoid *critnib_remove(critnib *\fR\fIc\fR\fB, uintptr_t \fR\fIkey\fR\fB);\fR" 4
.IX Item "void *critnib_remove(critnib *c, uintptr_t key);"
Removes a given key from the structure.  Its associated value is returned,
or 0 (\s-1NULL\s0) if there was no such key.
.IP "\fBvoid *critnib_get(critnib *\fR\fIc\fR\fB, uintptr_t \fR\fIkey\fR\fB);\fR" 4
.IX Item "void *critnib_get(critnib *c, uintptr_t key);"
Obtains a value for a given key, or 0 (\s-1NULL\s0) if not present.
.IP "\fBvoid *critnib_find_le(critnib *\fR\fIc\fR\fB, uintptr_t \fR\fIkey\fR\fB);\fR" 4
.IX Item "void *critnib_find_le(critnib *c, uintptr_t key);"
Searches for the largest key not exceeding the argument, and returns its value.
.IP "\fBint critnib_find(critnib *\fR\fIc\fR\fB, uintptr_t \fR\fIkey\fR\fB, enum find_dir_t \fR\fIdir\fR\fB, uintptr_t *\fR\fIrkey\fR\fB, void **\fR\fIrvalue\fR\fB);\fR" 4
.IX Item "int critnib_find(critnib *c, uintptr_t key, enum find_dir_t dir, uintptr_t *rkey, void **rvalue);"
Searches for a key that's smaller (\fB\s-1FIND_L\s0\fR), smaller-or-equal (\fB\s-1FIND_LE\s0\fR),
equal (\fB\s-1FIND_EQ\s0\fR), greater-or-equal (\fB\s-1FIND_GE\s0\fR), or greater (\fB\s-1FIND_G\s0\fR) than
the argument.  If found, the key and value are assigned to \fI*rkey\fR and \fI*rvalue\fR
(which may be null to skip assignment), and 1 is returned.
.IP "\fBvoid critnib_iter(critnib *\fR\fIc\fR\fB, uintptr_t \fR\fImin\fR\fB, uintptr_t \fR\fImax\fR\fB, \fR\fIfunc\fR\fB, void *\fR\fIprivdata\fR\fB);\fR" 4
.IX Item "void critnib_iter(critnib *c, uintptr_t min, uintptr_t max, func, void *privdata);"
Walks the structure, visiting all entries whose keys are at least \fImin\fR but
no larger than \fImax\fR (give \fB\-1\fR for no max), calling \fIfunc\fR for every
entry found.  If the \fIfunc\fR returns a non-zero value, the walk is aborted.
.Sp
The prototype for \fIfunc\fR should be:
\&\fBint (*\fR\fIfunc\fR\fB)(uintptr_t \fR\fIkey\fR\fB, void *\fR\fIvalue\fR\fB, void *\fR\fIprivdata\fR\fB);\fR
where \fIprivdata\fR is an optional value passed to the iterator.
.Sp
\&\fB\s-1NB.\s0 This version of the library implements the iterator in a crude
blocking way, stalling any concurrent writers and iterators.  This
limitation will be lifted in the future.\fR