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core: Add binary_search and binary_search_elem methods to slices.

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These are like the existing bsearch methods but if the search fails,
it returns the next insertion point.

The new `binary_search` returns a `BinarySearchResult` that is either
`Found` or `NotFound`. For convenience, the `found` and `not_found`
methods convert to `Option`, ala `Result`.

Deprecate bsearch and bsearch_elem.
This commit is contained in:
Brian Anderson
2014-08-06 20:48:25 -07:00
parent 76d46af6d4
commit a4b354ca02
8 changed files with 186 additions and 47 deletions
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46
src/etc/unicode.py
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@@ -293,13 +293,12 @@ def emit_bsearch_range_table(f):
f.write("""
fn bsearch_range_table(c: char, r: &'static [(char,char)]) -> bool {
use core::cmp::{Equal, Less, Greater};
use core::slice::ImmutableVector;
use core::option::None;
r.bsearch(|&(lo,hi)| {
use core::slice::ImmutableSlice;
r.binary_search(|&(lo,hi)| {
if lo <= c && c <= hi { Equal }
else if hi < c { Less }
else { Greater }
}) != None
}).found().is_some()
}\n
""")
@@ -352,9 +351,10 @@ def emit_conversions_module(f, lowerupper, upperlower):
f.write("pub mod conversions {")
f.write("""
use core::cmp::{Equal, Less, Greater};
use core::slice::ImmutableVector;
use core::slice::ImmutableSlice;
use core::tuple::Tuple2;
use core::option::{Option, Some, None};
use core::slice;
pub fn to_lower(c: char) -> char {
match bsearch_case_table(c, LuLl_table) {
@@ -371,11 +371,14 @@ def emit_conversions_module(f, lowerupper, upperlower):
}
fn bsearch_case_table(c: char, table: &'static [(char, char)]) -> Option<uint> {
table.bsearch(|&(key, _)| {
match table.binary_search(|&(key, _)| {
if c == key { Equal }
else if key < c { Less }
else { Greater }
})
}) {
slice::Found(i) => Some(i),
slice::NotFound(_) => None,
}
}
""")
@@ -387,8 +390,8 @@ def emit_conversions_module(f, lowerupper, upperlower):
def emit_grapheme_module(f, grapheme_table, grapheme_cats):
f.write("""pub mod grapheme {
use core::option::{Some, None};
use core::slice::ImmutableVector;
use core::slice::ImmutableSlice;
use core::slice;
#[allow(non_camel_case_types)]
#[deriving(Clone)]
@@ -400,16 +403,16 @@ def emit_grapheme_module(f, grapheme_table, grapheme_cats):
fn bsearch_range_value_table(c: char, r: &'static [(char, char, GraphemeCat)]) -> GraphemeCat {
use core::cmp::{Equal, Less, Greater};
match r.bsearch(|&(lo, hi, _)| {
match r.binary_search(|&(lo, hi, _)| {
if lo <= c && c <= hi { Equal }
else if hi < c { Less }
else { Greater }
}) {
Some(idx) => {
slice::Found(idx) => {
let (_, _, cat) = r[idx];
cat
}
None => GC_Any
slice::NotFound(_) => GC_Any
}
}
@@ -427,20 +430,21 @@ def emit_grapheme_module(f, grapheme_table, grapheme_cats):
def emit_charwidth_module(f, width_table):
f.write("pub mod charwidth {\n")
f.write(" use core::option::{Option, Some, None};\n")
f.write(" use core::slice::ImmutableVector;\n")
f.write(" use core::slice::ImmutableSlice;\n")
f.write(" use core::slice;\n")
f.write("""
fn bsearch_range_value_table(c: char, is_cjk: bool, r: &'static [(char, char, u8, u8)]) -> u8 {
use core::cmp::{Equal, Less, Greater};
match r.bsearch(|&(lo, hi, _, _)| {
match r.binary_search(|&(lo, hi, _, _)| {
if lo <= c && c <= hi { Equal }
else if hi < c { Less }
else { Greater }
}) {
Some(idx) => {
slice::Found(idx) => {
let (_, _, r_ncjk, r_cjk) = r[idx];
if is_cjk { r_cjk } else { r_ncjk }
}
None => 1
slice::NotFound(_) => 1
}
}
""")
@@ -525,19 +529,19 @@ def emit_norm_module(f, canon, compat, combine, norm_props):
f.write("""
fn bsearch_range_value_table(c: char, r: &'static [(char, char, u8)]) -> u8 {
use core::option::{Some, None};
use core::cmp::{Equal, Less, Greater};
use core::slice::ImmutableVector;
match r.bsearch(|&(lo, hi, _)| {
use core::slice::ImmutableSlice;
use core::slice;
match r.binary_search(|&(lo, hi, _)| {
if lo <= c && c <= hi { Equal }
else if hi < c { Less }
else { Greater }
}) {
Some(idx) => {
slice::Found(idx) => {
let (_, _, result) = r[idx];
result
}
None => 0
slice::NotFound(_) => 0
}
}\n
""")