diff --git a/src/builtin.c b/src/builtin.c index 9aebd1f2d2..204d3f6feb 100644 --- a/src/builtin.c +++ b/src/builtin.c @@ -780,6 +780,38 @@ static jv f_sort_by_impl(jq_state *jq, jv input, jv keys) { } } +/* Assuming the input array is sorted, bsearch/1 returns */ +/* the index of the target if the target is in the input array; and otherwise */ +/* (-1 - ix), where ix is the insertion point that would leave the array sorted. */ +/* If the input is not sorted, bsearch will terminate but with irrelevant results. */ +static jv f_bsearch(jq_state *jq, jv input, jv target) { + if (jv_get_kind(input) != JV_KIND_ARRAY) { + jv_free(target); + return type_error(input, "cannot be searched from"); + } + int start = 0; + int end = jv_array_length(jv_copy(input)); + jv answer = jv_invalid(); + while (start < end) { + int mid = start + (end - start) / 2; + int result = jv_cmp(jv_copy(target), jv_array_get(jv_copy(input), mid)); + if (result == 0) { + answer = jv_number(mid); + break; + } else if (result < 0) { + end = mid; + } else { + start = mid + 1; + } + } + if (!jv_is_valid(answer)) { + answer = jv_number(-1 - start); + } + jv_free(input); + jv_free(target); + return answer; +} + static jv f_group_by_impl(jq_state *jq, jv input, jv keys) { if (jv_get_kind(input) == JV_KIND_ARRAY && jv_get_kind(keys) == JV_KIND_ARRAY && @@ -1718,6 +1750,7 @@ BINOPS {f_sort, "sort", 1}, {f_sort_by_impl, "_sort_by_impl", 2}, {f_group_by_impl, "_group_by_impl", 2}, + {f_bsearch, "bsearch", 2}, {f_min, "min", 1}, {f_max, "max", 1}, {f_min_by_impl, "_min_by_impl", 2}, diff --git a/src/builtin.jq b/src/builtin.jq index 802595bafd..946d7a6ec6 100644 --- a/src/builtin.jq +++ b/src/builtin.jq @@ -215,37 +215,6 @@ def tostream: getpath($p) | reduce path(.[]?) as $q ([$p, .]; [$p+$q]); -# Assuming the input array is sorted, bsearch/1 returns -# the index of the target if the target is in the input array; and otherwise -# (-1 - ix), where ix is the insertion point that would leave the array sorted. -# If the input is not sorted, bsearch will terminate but with irrelevant results. -def bsearch($target): - if length == 0 then -1 - elif length == 1 then - if $target == .[0] then 0 elif $target < .[0] then -1 else -2 end - else . as $in - # state variable: [start, end, answer] - # where start and end are the upper and lower offsets to use. - | [0, length-1, null] - | until( .[0] > .[1] ; - if .[2] != null then (.[1] = -1) # i.e. break - else - ( ( (.[1] + .[0]) / 2 ) | floor ) as $mid - | $in[$mid] as $monkey - | if $monkey == $target then (.[2] = $mid) # success - elif .[0] == .[1] then (.[1] = -1) # failure - elif $monkey < $target then (.[0] = ($mid + 1)) - else (.[1] = ($mid - 1)) - end - end ) - | if .[2] == null then # compute the insertion point - if $in[ .[0] ] < $target then (-2 -.[0]) - else (-1 -.[0]) - end - else .[2] - end - end; - # Apply f to composite entities recursively, and to atoms def walk(f): def w: diff --git a/tests/jq.test b/tests/jq.test index b94f29d245..8991e27d3a 100644 --- a/tests/jq.test +++ b/tests/jq.test @@ -1547,12 +1547,22 @@ ascii_upcase "useful but not for é" "USEFUL BUT NOT FOR é" -bsearch(0,2,4) +bsearch(0,1,2,3,4) [1,2,3] -1 +0 1 +2 -4 +bsearch({x:1}) +[{ "x": 0 },{ "x": 1 },{ "x": 2 }] +1 + +try ["OK", bsearch(0)] catch ["KO",.] +"aa" +["KO","string (\"aa\") cannot be searched from"] + # strptime tests are in optional.test strftime("%Y-%m-%dT%H:%M:%SZ")