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indexmap

build statuscrates.iodocsrustc

A pure-Rust hash table which preserves (in a limited sense) insertion order.

This crate implements compact map and set data-structures, where the iteration order of the keys is independent from their hash or value. It preserves insertion order (except after removals), and it allows lookup of entries by either hash table key or numerical index.

Note: this crate was originally released under the name ordermap, but it was renamed to indexmap to better reflect its features. The ordermap crate now exists as a wrapper over indexmap with stronger ordering properties.

Background

This was inspired by Python 3.6's new dict implementation (which remembers the insertion order and is fast to iterate, and is compact in memory).

Some of those features were translated to Rust, and some were not. The result was indexmap, a hash table that has following properties:

  • Order is independent of hash function and hash values of keys.
  • Fast to iterate.
  • Indexed in compact space.
  • Preserves insertion order as long as you don't call .remove(), .swap_remove(), or other methods that explicitly change order. The alternate .shift_remove() does preserve relative order.
  • Uses hashbrown for the inner table, just like Rust's libstd HashMap does.

Performance

IndexMap derives a couple of performance facts directly from how it is constructed, which is roughly:

A raw hash table of key-value indices, and a vector of key-value pairs.

  • Iteration is very fast since it is on the dense key-values.

  • Removal is fast since it moves memory areas only in the table, and uses a single swap in the vector.

  • Lookup is fast-ish because the initial 7-bit hash lookup uses SIMD, and indices are densely stored. Lookup also is slow-ish since the actual key-value pairs are stored separately. (Visible when cpu caches size is limiting.)

  • In practice, IndexMap has been tested out as the hashmap in rustc in PR45282 and the performance was roughly on par across the whole workload.

  • If you want the properties of IndexMap, or its strongest performance points fits your workload, it might be the best hash table implementation.

Recent Changes

See RELEASES.md.

About

A hash table with consistent order and fast iteration; access items by key or sequence index

docs.rs/indexmap/

Topics

hashtablerust

Resources

Readme
Activity
Custom properties

Stars

2.4k stars

Watchers

12 watching

Forks

190 forks
Report repository

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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
BranchesTags
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indexmap
build statuscrates.iodocsrustc
A pure-Rust hash table which preserves (in a limited sense) insertion order.
This crate implements compact map and set data-structures,
where the iteration order of the keys is independent from their hash or
value. It preserves insertion order (except after removals), and it
allows lookup of entries by either hash table key or numerical index.
Note: this crate was originally released under the name ordermap,
but it was renamed to indexmap to better reflect its features.
The ordermap crate now exists
as a wrapper over indexmap with stronger ordering properties.
Background
This was inspired by Python 3.6's new dict implementation (which remembers
the insertion order and is fast to iterate, and is compact in memory).
Some of those features were translated to Rust, and some were not. The result
was indexmap, a hash table that has following properties:
  • Order is independent of hash function and hash values of keys.
  • Fast to iterate.
  • Indexed in compact space.
  • Preserves insertion order as long as you don't call .remove(),
.swap_remove(), or other methods that explicitly change order.
The alternate .shift_remove() does preserve relative order.
  • Uses hashbrown for the inner table, just like Rust's libstd HashMap does.
Performance
IndexMap derives a couple of performance facts directly from how it is constructed,
which is roughly:
A raw hash table of key-value indices, and a vector of key-value pairs.
  • Iteration is very fast since it is on the dense key-values.
  • Removal is fast since it moves memory areas only in the table,
and uses a single swap in the vector.
  • Lookup is fast-ish because the initial 7-bit hash lookup uses SIMD, and indices are
densely stored. Lookup also is slow-ish since the actual key-value pairs are stored
separately. (Visible when cpu caches size is limiting.)
  • In practice, IndexMap has been tested out as the hashmap in rustc in PR45282 and
the performance was roughly on par across the whole workload.
  • If you want the properties of IndexMap, or its strongest performance points
fits your workload, it might be the best hash table implementation.
Recent Changes
See RELEASES.md.
About
A hash table with consistent order and fast iteration; access items by key or sequence index
docs.rs/indexmap/
Topics
hashtablerust
Resources
Readme
Activity
Custom properties
Stars
2.4k stars
Watchers
12 watching
Forks
190 forks
Report repository
Releases
Packages
Used by
Contributors
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
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indexmap
build statuscrates.iodocsrustc
A pure-Rust hash table which preserves (in a limited sense) insertion order.
This crate implements compact map and set data-structures,
where the iteration order of the keys is independent from their hash or
value. It preserves insertion order (except after removals), and it
allows lookup of entries by either hash table key or numerical index.
Note: this crate was originally released under the name ordermap,
but it was renamed to indexmap to better reflect its features.
The ordermap crate now exists
as a wrapper over indexmap with stronger ordering properties.
Background
This was inspired by Python 3.6's new dict implementation (which remembers
the insertion order and is fast to iterate, and is compact in memory).
Some of those features were translated to Rust, and some were not. The result
was indexmap, a hash table that has following properties:
  • Order is independent of hash function and hash values of keys.
  • Fast to iterate.
  • Indexed in compact space.
  • Preserves insertion order as long as you don't call .remove(),
.swap_remove(), or other methods that explicitly change order.
The alternate .shift_remove() does preserve relative order.
  • Uses hashbrown for the inner table, just like Rust's libstd HashMap does.
Performance
IndexMap derives a couple of performance facts directly from how it is constructed,
which is roughly:
A raw hash table of key-value indices, and a vector of key-value pairs.
  • Iteration is very fast since it is on the dense key-values.
  • Removal is fast since it moves memory areas only in the table,
and uses a single swap in the vector.
  • Lookup is fast-ish because the initial 7-bit hash lookup uses SIMD, and indices are
densely stored. Lookup also is slow-ish since the actual key-value pairs are stored
separately. (Visible when cpu caches size is limiting.)
  • In practice, IndexMap has been tested out as the hashmap in rustc in PR45282 and
the performance was roughly on par across the whole workload.
  • If you want the properties of IndexMap, or its strongest performance points
fits your workload, it might be the best hash table implementation.
Recent Changes
See RELEASES.md.
About
A hash table with consistent order and fast iteration; access items by key or sequence index
docs.rs/indexmap/
Topics
hashtablerust
Resources
Readme
Activity
Custom properties
Stars
2.4k stars
Watchers
12 watching
Forks
190 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
indexmap
build statuscrates.iodocsrustc
A pure-Rust hash table which preserves (in a limited sense) insertion order.
This crate implements compact map and set data-structures,
where the iteration order of the keys is independent from their hash or
value. It preserves insertion order (except after removals), and it
allows lookup of entries by either hash table key or numerical index.
Note: this crate was originally released under the name ordermap,
but it was renamed to indexmap to better reflect its features.
The ordermap crate now exists
as a wrapper over indexmap with stronger ordering properties.
Background
This was inspired by Python 3.6's new dict implementation (which remembers
the insertion order and is fast to iterate, and is compact in memory).
Some of those features were translated to Rust, and some were not. The result
was indexmap, a hash table that has following properties:
  • Order is independent of hash function and hash values of keys.
  • Fast to iterate.
  • Indexed in compact space.
  • Preserves insertion order as long as you don't call .remove(),
.swap_remove(), or other methods that explicitly change order.
The alternate .shift_remove() does preserve relative order.
  • Uses hashbrown for the inner table, just like Rust's libstd HashMap does.
Performance
IndexMap derives a couple of performance facts directly from how it is constructed,
which is roughly:
A raw hash table of key-value indices, and a vector of key-value pairs.
  • Iteration is very fast since it is on the dense key-values.
  • Removal is fast since it moves memory areas only in the table,
and uses a single swap in the vector.
  • Lookup is fast-ish because the initial 7-bit hash lookup uses SIMD, and indices are
densely stored. Lookup also is slow-ish since the actual key-value pairs are stored
separately. (Visible when cpu caches size is limiting.)
  • In practice, IndexMap has been tested out as the hashmap in rustc in PR45282 and
the performance was roughly on par across the whole workload.
  • If you want the properties of IndexMap, or its strongest performance points
fits your workload, it might be the best hash table implementation.
Recent Changes
See RELEASES.md.
About
A hash table with consistent order and fast iteration; access items by key or sequence index
docs.rs/indexmap/
Topics
hashtablerust
Resources
Readme
Activity
Custom properties
Stars
2.4k stars
Watchers
12 watching
Forks
190 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
BranchesTags
Repository files navigation
indexmap
build statuscrates.iodocsrustc
A pure-Rust hash table which preserves (in a limited sense) insertion order.
This crate implements compact map and set data-structures,
where the iteration order of the keys is independent from their hash or
value. It preserves insertion order (except after removals), and it
allows lookup of entries by either hash table key or numerical index.
Note: this crate was originally released under the name ordermap,
but it was renamed to indexmap to better reflect its features.
The ordermap crate now exists
as a wrapper over indexmap with stronger ordering properties.
Background
This was inspired by Python 3.6's new dict implementation (which remembers
the insertion order and is fast to iterate, and is compact in memory).
Some of those features were translated to Rust, and some were not. The result
was indexmap, a hash table that has following properties:
  • Order is independent of hash function and hash values of keys.
  • Fast to iterate.
  • Indexed in compact space.
  • Preserves insertion order as long as you don't call .remove(),
.swap_remove(), or other methods that explicitly change order.
The alternate .shift_remove() does preserve relative order.
  • Uses hashbrown for the inner table, just like Rust's libstd HashMap does.
Performance
IndexMap derives a couple of performance facts directly from how it is constructed,
which is roughly:
A raw hash table of key-value indices, and a vector of key-value pairs.
  • Iteration is very fast since it is on the dense key-values.
  • Removal is fast since it moves memory areas only in the table,
and uses a single swap in the vector.
  • Lookup is fast-ish because the initial 7-bit hash lookup uses SIMD, and indices are
densely stored. Lookup also is slow-ish since the actual key-value pairs are stored
separately. (Visible when cpu caches size is limiting.)
  • In practice, IndexMap has been tested out as the hashmap in rustc in PR45282 and
the performance was roughly on par across the whole workload.
  • If you want the properties of IndexMap, or its strongest performance points
fits your workload, it might be the best hash table implementation.
Recent Changes
See RELEASES.md.
About
A hash table with consistent order and fast iteration; access items by key or sequence index
docs.rs/indexmap/
Topics
hashtablerust
Resources
Readme
Activity
Custom properties
Stars
2.4k stars
Watchers
12 watching
Forks
190 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
indexmap
build statuscrates.iodocsrustc
A pure-Rust hash table which preserves (in a limited sense) insertion order.
This crate implements compact map and set data-structures,
where the iteration order of the keys is independent from their hash or
value. It preserves insertion order (except after removals), and it
allows lookup of entries by either hash table key or numerical index.
Note: this crate was originally released under the name ordermap,
but it was renamed to indexmap to better reflect its features.
The ordermap crate now exists
as a wrapper over indexmap with stronger ordering properties.
Background
This was inspired by Python 3.6's new dict implementation (which remembers
the insertion order and is fast to iterate, and is compact in memory).
Some of those features were translated to Rust, and some were not. The result
was indexmap, a hash table that has following properties:
  • Order is independent of hash function and hash values of keys.
  • Fast to iterate.
  • Indexed in compact space.
  • Preserves insertion order as long as you don't call .remove(),
.swap_remove(), or other methods that explicitly change order.
The alternate .shift_remove() does preserve relative order.
  • Uses hashbrown for the inner table, just like Rust's libstd HashMap does.
Performance
IndexMap derives a couple of performance facts directly from how it is constructed,
which is roughly:
A raw hash table of key-value indices, and a vector of key-value pairs.
  • Iteration is very fast since it is on the dense key-values.
  • Removal is fast since it moves memory areas only in the table,
and uses a single swap in the vector.
  • Lookup is fast-ish because the initial 7-bit hash lookup uses SIMD, and indices are
densely stored. Lookup also is slow-ish since the actual key-value pairs are stored
separately. (Visible when cpu caches size is limiting.)
  • In practice, IndexMap has been tested out as the hashmap in rustc in PR45282 and
the performance was roughly on par across the whole workload.
  • If you want the properties of IndexMap, or its strongest performance points
fits your workload, it might be the best hash table implementation.
Recent Changes
See RELEASES.md.
About
A hash table with consistent order and fast iteration; access items by key or sequence index
docs.rs/indexmap/
Topics
hashtablerust
Resources
Readme
Activity
Custom properties
Stars
2.4k stars
Watchers
12 watching
Forks
190 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
indexmap
build statuscrates.iodocsrustc
A pure-Rust hash table which preserves (in a limited sense) insertion order.
This crate implements compact map and set data-structures,
where the iteration order of the keys is independent from their hash or
value. It preserves insertion order (except after removals), and it
allows lookup of entries by either hash table key or numerical index.
Note: this crate was originally released under the name ordermap,
but it was renamed to indexmap to better reflect its features.
The ordermap crate now exists
as a wrapper over indexmap with stronger ordering properties.
Background
This was inspired by Python 3.6's new dict implementation (which remembers
the insertion order and is fast to iterate, and is compact in memory).
Some of those features were translated to Rust, and some were not. The result
was indexmap, a hash table that has following properties:
  • Order is independent of hash function and hash values of keys.
  • Fast to iterate.
  • Indexed in compact space.
  • Preserves insertion order as long as you don't call .remove(),
.swap_remove(), or other methods that explicitly change order.
The alternate .shift_remove() does preserve relative order.
  • Uses hashbrown for the inner table, just like Rust's libstd HashMap does.
Performance
IndexMap derives a couple of performance facts directly from how it is constructed,
which is roughly:
A raw hash table of key-value indices, and a vector of key-value pairs.
  • Iteration is very fast since it is on the dense key-values.
  • Removal is fast since it moves memory areas only in the table,
and uses a single swap in the vector.
  • Lookup is fast-ish because the initial 7-bit hash lookup uses SIMD, and indices are
densely stored. Lookup also is slow-ish since the actual key-value pairs are stored
separately. (Visible when cpu caches size is limiting.)
  • In practice, IndexMap has been tested out as the hashmap in rustc in PR45282 and
the performance was roughly on par across the whole workload.
  • If you want the properties of IndexMap, or its strongest performance points
fits your workload, it might be the best hash table implementation.
Recent Changes
See RELEASES.md.
About
A hash table with consistent order and fast iteration; access items by key or sequence index
docs.rs/indexmap/
Topics
hashtablerust
Resources
Readme
Activity
Custom properties
Stars
2.4k stars
Watchers
12 watching
Forks
190 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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indexmap
build statuscrates.iodocsrustc
A pure-Rust hash table which preserves (in a limited sense) insertion order.
This crate implements compact map and set data-structures,
where the iteration order of the keys is independent from their hash or
value. It preserves insertion order (except after removals), and it
allows lookup of entries by either hash table key or numerical index.
Note: this crate was originally released under the name ordermap,
but it was renamed to indexmap to better reflect its features.
The ordermap crate now exists
as a wrapper over indexmap with stronger ordering properties.
Background
This was inspired by Python 3.6's new dict implementation (which remembers
the insertion order and is fast to iterate, and is compact in memory).
Some of those features were translated to Rust, and some were not. The result
was indexmap, a hash table that has following properties:
  • Order is independent of hash function and hash values of keys.
  • Fast to iterate.
  • Indexed in compact space.
  • Preserves insertion order as long as you don't call .remove(),
.swap_remove(), or other methods that explicitly change order.
The alternate .shift_remove() does preserve relative order.
  • Uses hashbrown for the inner table, just like Rust's libstd HashMap does.
Performance
IndexMap derives a couple of performance facts directly from how it is constructed,
which is roughly:
A raw hash table of key-value indices, and a vector of key-value pairs.
  • Iteration is very fast since it is on the dense key-values.
  • Removal is fast since it moves memory areas only in the table,
and uses a single swap in the vector.
  • Lookup is fast-ish because the initial 7-bit hash lookup uses SIMD, and indices are
densely stored. Lookup also is slow-ish since the actual key-value pairs are stored
separately. (Visible when cpu caches size is limiting.)
  • In practice, IndexMap has been tested out as the hashmap in rustc in PR45282 and
the performance was roughly on par across the whole workload.
  • If you want the properties of IndexMap, or its strongest performance points
fits your workload, it might be the best hash table implementation.
Recent Changes
See RELEASES.md.
About
A hash table with consistent order and fast iteration; access items by key or sequence index
docs.rs/indexmap/
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