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fixes #799 - lookup table is created on first wcwidth call for char > 127

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This commit is contained in:
Jörg Breitbart
2017-07-17 19:07:02 +02:00
parent 6ed5c9e64d
commit 598a729fc0
1 changed files with 26 additions and 20 deletions
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src/InputHandler.ts
+26 -20
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@@ -1600,21 +1600,26 @@ export const wcwidth = (function(opts) {
}
return 1;
}
// lookup table for BMP
const CODEPOINTS = 65536; // BMP holds 65536 codepoints
const BITWIDTH = 2; // a codepoint can have a width of 0, 1 or 2
const ITEMSIZE = 32; // using uint32_t
const CONTAINERSIZE = CODEPOINTS * BITWIDTH / ITEMSIZE;
const CODEPOINTS_PER_ITEM = ITEMSIZE / BITWIDTH;
const table = (typeof Uint32Array === 'undefined')
? new Array(CONTAINERSIZE)
: new Uint32Array(CONTAINERSIZE);
for (let i = 0; i < CONTAINERSIZE; ++i) {
let num = 0;
let pos = CODEPOINTS_PER_ITEM;
while (pos--)
num = (num << 2) | wcwidthBMP(CODEPOINTS_PER_ITEM * i + pos);
table[i] = num;
const control = opts.control | 0;
let table = null;
function init_table() {
// lookup table for BMP
const CODEPOINTS = 65536; // BMP holds 65536 codepoints
const BITWIDTH = 2; // a codepoint can have a width of 0, 1 or 2
const ITEMSIZE = 32; // using uint32_t
const CONTAINERSIZE = CODEPOINTS * BITWIDTH / ITEMSIZE;
const CODEPOINTS_PER_ITEM = ITEMSIZE / BITWIDTH;
table = (typeof Uint32Array === 'undefined')
? new Array(CONTAINERSIZE)
: new Uint32Array(CONTAINERSIZE);
for (let i = 0; i < CONTAINERSIZE; ++i) {
let num = 0;
let pos = CODEPOINTS_PER_ITEM;
while (pos--)
num = (num << 2) | wcwidthBMP(CODEPOINTS_PER_ITEM * i + pos);
table[i] = num;
}
return table;
}
// get width from lookup table
// position in container : num / CODEPOINTS_PER_ITEM
@@ -1631,12 +1636,13 @@ export const wcwidth = (function(opts) {
return function (num) {
num = num | 0; // get asm.js like optimization under V8
if (num < 32)
return opts.control;
else if (num < 127)
return control | 0;
if (num < 127)
return 1;
else if (num < 65536)
return table[num >> 4] >> ((num & 15) << 1) & 3;
let t = table || init_table();
if (num < 65536)
return t[num >> 4] >> ((num & 15) << 1) & 3;
// do a full search for high codepoints
else return wcwidthHigh(num);
return wcwidthHigh(num);
};
})({nul: 0, control: 0}); // configurable options