Add String#lastIndexOf and improve tests (#163)

std/assembly/index.d.ts

@@ -431,7 +431,8 @@ declare class String {
   charCodeAt(index: u32): u16;
   concat(other: string): string;
   endsWith(other: string): bool;
-  indexOf(other: string): u32;
+  indexOf(other: string, fromIndex?: i32): u32;
+  lastIndexOf(other: string, fromIndex?: i32): i32;
   includes(other: string): bool;
   startsWith(other: string): bool;
   substr(start: u32, length?: u32): string;

std/assembly/internal/string.ts

@@ -15,6 +15,11 @@ export const MAX_LENGTH = (<i32>MAX_SIZE_32 - HEADER_SIZE) >>> 1;
 /** Singleton empty String. */
 export const EMPTY = changetype<String>(""); // TODO: is this a bad idea with '===' in place?
 
+@inline
+export function clamp<T>(val: T, lo: T, hi: T): T {
+  return max<T>(min<T>(val, hi), lo);
+}
+
 /** Allocates a raw String with uninitialized contents. */
 export function allocate(length: i32): String {
   assert(length > 0 && length <= MAX_LENGTH);

std/assembly/string.ts

@@ -2,6 +2,7 @@ import {
   HEADER_SIZE,
   MAX_LENGTH,
   EMPTY,
+  clamp,
   allocate,
   isWhiteSpaceOrLineTerminator,
   CharCode,
@@ -97,7 +98,7 @@ export class String {
   endsWith(searchString: String, endPosition: i32 = MAX_LENGTH): bool {
     assert(this !== null);
     if (searchString === null) return false;
-    var end: isize = <isize>min(max(endPosition, 0), this.length);
+    var end = clamp<isize>(endPosition, 0, this.length);
     var searchLength: isize = searchString.length;
     var start: isize = end - searchLength;
     if (start < 0) return false;
@@ -206,21 +207,44 @@ export class String {
     return this.indexOf(searchString, position) != -1;
   }
 
-  indexOf(searchString: String, position: i32 = 0): i32 {
+  indexOf(searchString: String, fromIndex: i32 = 0): i32 {
     assert(this !== null);
     if (searchString === null) searchString = changetype<String>("null");
-    var pos: isize = position;
+    var searchLen: isize = searchString.length;
+    if (!searchLen) return 0;
     var len: isize = this.length;
-    var start: isize = min<isize>(max<isize>(pos, 0), len);
-    var searchLen: isize = <isize>searchString.length;
-
-    // TODO: two-way, multiple char codes
-    for (let k: usize = start; <isize>k + searchLen <= len; ++k) {
+    if (!len) return -1;
+    var start = clamp<isize>(fromIndex, 0, len);
+    len -= searchLen;
+    // TODO: multiple char codes
+    for (let k: isize = start; k <= len; ++k) {
       if (!compare_memory(
         changetype<usize>(this) + HEADER_SIZE + (k << 1),
         changetype<usize>(searchString) + HEADER_SIZE,
-        searchLen << 1)
-      ) {
+        searchLen << 1
+      )) {
+        return <i32>k;
+      }
+    }
+    return -1;
+  }
+
+  lastIndexOf(searchString: String, fromIndex: i32 = 0): i32 {
+    assert(this !== null);
+    if (searchString === null) searchString = changetype<String>("null");
+    var len: isize = this.length;
+    var searchLen: isize = searchString.length;
+    if (!searchLen) return len;
+    if (!len) return -1;
+    var start = clamp<isize>(fromIndex - searchLen, 0, len);
+
+    // TODO: multiple char codes
+    for (let k: isize = len - 1; k >= start; --k) {
+      if (!compare_memory(
+        changetype<usize>(this) + HEADER_SIZE + (k << 1),
+        changetype<usize>(searchString) + HEADER_SIZE,
+        searchLen << 1
+      )) {
         return <i32>k;
       }
     }
@@ -233,8 +257,8 @@ export class String {
 
     var pos: isize = position;
     var len: isize = this.length;
-    var start: isize = min<isize>(max<isize>(pos, 0), len);
-    var searchLength: isize = <isize>searchString.length;
+    var start = clamp<isize>(pos, 0, len);
+    var searchLength: isize = searchString.length;
     if (searchLength + start > len) {
       return false;
     }
@@ -253,7 +277,7 @@ export class String {
     if (intStart < 0) {
       intStart = max<isize>(size + intStart, 0);
     }
-    var resultLength: isize = min<isize>(max<isize>(end, 0), size - intStart);
+    var resultLength = clamp<isize>(end, 0, size - intStart);
     if (resultLength <= 0) {
       return EMPTY;
     }
@@ -269,8 +293,8 @@ export class String {
   substring(start: i32, end: i32 = i32.MAX_VALUE): String {
     assert(this !== null);
     var len = this.length;
-    var finalStart = min<i32>(max<i32>(start, 0), len);
-    var finalEnd = min<i32>(max<i32>(end, 0), len);
+    var finalStart = clamp<isize>(start, 0, len);
+    var finalEnd = clamp<isize>(end, 0, len);
     var from = min<i32>(finalStart, finalEnd);
     var to = max<i32>(finalStart, finalEnd);
     len = to - from;

std/portable/index.d.ts

@@ -280,14 +280,14 @@ declare class String {
 
   private constructor();
 
-  indexOf(subject: string, position?: i32): i32;
+  indexOf(other: string, fromIndex?: i32): i32;
+  lastIndexOf(other: string, fromIndex?: i32): i32;
   includes(other: string): bool;
-  lastIndexOf(subject: string, position?: i32): i32;
   charAt(index: i32): string;
   charCodeAt(index: i32): i32;
   substring(from: i32, to?: i32): string;
-  startsWith(subject: string): bool;
-  endsWith(subject: string): bool;
+  startsWith(other: string): bool;
+  endsWith(other: string): bool;
   replace(search: string, replacement: string): string;
   repeat(count?: i32): string;
   toString(): string;

tests/compiler/std/array-access.optimized.wat

@@ -132,7 +132,7 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 12)
-     (i32.const 231)
+     (i32.const 255)
      (i32.const 4)
     )
     (unreachable)
@@ -154,31 +154,31 @@
        (get_local $1)
       )
      )
-     (tee_local $3
+     (tee_local $2
       (select
-       (tee_local $3
+       (tee_local $2
         (select
          (get_local $2)
-         (i32.const 0)
-         (i32.gt_s
+         (tee_local $3
+          (i32.load
+           (get_local $0)
+          )
+         )
+         (i32.lt_s
           (get_local $2)
-          (i32.const 0)
+          (get_local $3)
          )
         )
        )
-       (tee_local $2
-        (i32.load
-         (get_local $0)
-        )
-       )
-       (i32.lt_s
-        (get_local $3)
+       (i32.const 0)
+       (i32.gt_s
         (get_local $2)
+        (i32.const 0)
        )
       )
      )
     )
-    (get_local $2)
+    (get_local $3)
    )
    (return
     (i32.const 0)
@@ -192,7 +192,7 @@
       (i32.const 4)
      )
      (i32.shl
-      (get_local $3)
+      (get_local $2)
       (i32.const 1)
      )
     )

tests/compiler/std/array-access.untouched.wat

@@ -201,6 +201,7 @@
   (local $6 i32)
   (local $7 i32)
   (local $8 i32)
+  (local $9 i32)
   (if
    (i32.eqz
     (i32.ne
@@ -212,7 +213,7 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 12)
-     (i32.const 231)
+     (i32.const 255)
      (i32.const 4)
     )
     (unreachable)
@@ -235,32 +236,37 @@
     (get_local $0)
    )
   )
-  (set_local $7
-   (select
-    (tee_local $5
-     (select
-      (tee_local $5
-       (get_local $3)
-      )
-      (tee_local $6
-       (i32.const 0)
-      )
-      (i32.gt_s
-       (get_local $5)
-       (get_local $6)
+  (set_local $8
+   (block $~lib/internal/string/clamp<isize>|inlined.0 (result i32)
+    (set_local $5
+     (i32.const 0)
+    )
+    (select
+     (tee_local $6
+      (select
+       (tee_local $6
+        (get_local $3)
+       )
+       (tee_local $7
+        (get_local $4)
+       )
+       (i32.lt_s
+        (get_local $6)
+        (get_local $7)
+       )
       )
      )
-    )
-    (tee_local $6
-     (get_local $4)
-    )
-    (i32.lt_s
-     (get_local $5)
-     (get_local $6)
+     (tee_local $7
+      (get_local $5)
+     )
+     (i32.gt_s
+      (get_local $6)
+      (get_local $7)
+     )
     )
    )
   )
-  (set_local $8
+  (set_local $9
    (i32.load
     (get_local $1)
    )
@@ -268,8 +274,8 @@
   (if
    (i32.gt_s
     (i32.add
+     (get_local $9)
      (get_local $8)
-     (get_local $7)
     )
     (get_local $4)
    )
@@ -285,7 +291,7 @@
       (i32.const 4)
      )
      (i32.shl
-      (get_local $7)
+      (get_local $8)
       (i32.const 1)
      )
     )
@@ -294,7 +300,7 @@
      (i32.const 4)
     )
     (i32.shl
-     (get_local $8)
+     (get_local $9)
      (i32.const 1)
     )
    )

tests/compiler/std/array.optimized.wat

@@ -5823,7 +5823,7 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 728)
-     (i32.const 20)
+     (i32.const 25)
      (i32.const 2)
     )
     (unreachable)
@@ -5855,7 +5855,7 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 696)
-     (i32.const 18)
+     (i32.const 19)
      (i32.const 4)
     )
     (unreachable)
@@ -5903,7 +5903,7 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 696)
-     (i32.const 74)
+     (i32.const 75)
      (i32.const 4)
     )
     (unreachable)

tests/compiler/std/array.untouched.wat

@@ -8611,7 +8611,7 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 728)
-     (i32.const 20)
+     (i32.const 25)
      (i32.const 2)
     )
     (unreachable)
@@ -8647,7 +8647,7 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 696)
-     (i32.const 18)
+     (i32.const 19)
      (i32.const 4)
     )
     (unreachable)
@@ -8699,7 +8699,7 @@
     (call $~lib/env/abort
      (i32.const 0)
      (i32.const 696)
-     (i32.const 74)
+     (i32.const 75)
      (i32.const 4)
     )
     (unreachable)

tests/compiler/std/string.ts

@@ -13,8 +13,24 @@ assert(str.charCodeAt(0) == 0x68);
 assert(str.startsWith("hi"));
 assert(str.endsWith("string"));
 assert(str.includes("I'm"));
+
+assert("".indexOf("") == 0);
+assert("".indexOf("hi") == -1);
+assert(str.indexOf("") == 0);
 assert(str.indexOf(",") == 2);
 assert(str.indexOf("x") == -1);
+assert(str.indexOf(",", 2) == 2);
+assert(str.indexOf(",", 3) == -1);
+assert(str.indexOf(", I", -1) == 2);
+
+assert("".lastIndexOf("") == 0);
+assert("".lastIndexOf("hi") == -1);
+assert(str.lastIndexOf("") == str.length);
+assert(str.lastIndexOf(",") == 2);
+assert(str.lastIndexOf("x") == -1);
+assert(str.lastIndexOf(",", 2) == 2);
+assert(str.lastIndexOf(",", 3) == 2);
+assert(str.lastIndexOf(", I", -1) == 2);
 
 export function getString(): string {
   return str;