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mal/wasm/string.wam
Joel Martin 0a19c2f1c7 wasm: update to 2019 wat syntax, use .wat extension
wasm: update to wat syntax as of Jan 2019.

Examples:
- get_local -> local.get
- i32.wrap/i64 -> i32.warp_i64
- etc

The distinction between wat and wast has been clarified:
- wat: textual format for web assembly modules
- wast: superset of wat used in the specification to define tests.
2019-01-16 00:13:51 -06:00

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(module $string
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Copy len bytes from src to dst
;; Returns len
(func $memmove (param $dst i32 $src i32 $len i32)
(LET $idx 0)
(loop $copy
(i32.store8 (i32.add $idx $dst)
(i32.load8_u (i32.add $idx $src)))
(local.set $idx (i32.add 1 $idx))
(br_if $copy (i32.lt_u $idx $len))
)
)
(func $strlen (param $str i32) (result i32)
(LET $cur $str)
(loop $count
(if (i32.ne 0 (i32.load8_u $cur))
(then
(local.set $cur (i32.add $cur 1))
(br $count)))
)
(i32.sub $cur $str)
)
;; Based on https://stackoverflow.com/a/25705264/471795
;; This could be made much more efficient
(func $strstr (param $haystack i32 $needle i32) (result i32)
(LET $i 0
$needle_len ($strlen $needle)
$len ($strlen $haystack))
(if (i32.eq $needle_len 0) (return $haystack))
(local.set $i 0)
(block $done
(loop $loop
(if (i32.gt_s $i (i32.sub $len $needle_len)) (br $done))
(if (AND (i32.eq (i32.load8_u $haystack)
(i32.load8_u $needle))
(i32.eqz ($strncmp $haystack $needle $needle_len)))
(return $haystack))
(local.set $haystack (i32.add $haystack 1))
(local.set $i (i32.add $i 1))
(br $loop)
)
)
0
)
(func $atoi (param $str i32) (result i32)
(LET $acc 0
$i 0
$neg 0
$ch 0)
(block $done
(loop $loop
(local.set $ch (i32.load8_u (i32.add $str $i)))
(if (AND (i32.ne $ch (CHR "-"))
(OR (i32.lt_u $ch (CHR "0"))
(i32.gt_u $ch (CHR "9"))))
(br $done))
(local.set $i (i32.add $i 1))
(if (i32.eq $ch (CHR "-"))
(then
(local.set $neg 1))
(else
(local.set $acc (i32.add (i32.mul $acc 10)
(i32.sub $ch (CHR "0"))))))
(br $loop)
)
)
(if (result i32) $neg
(then (i32.sub 0 $acc))
(else $acc))
)
(func $strcmp (param $s1 i32 $s2 i32) (result i32)
(block $done
(loop $loop
(if (OR (i32.eqz (i32.load8_u $s1)) (i32.eqz (i32.load8_u $s2)))
(br $done))
(if (i32.ne (i32.load8_u $s1) (i32.load8_u $s2))
(br $done))
(local.set $s1 (i32.add $s1 1))
(local.set $s2 (i32.add $s2 1))
(br $loop)
)
)
(if (result i32) (i32.eq (i32.load8_u $s1) (i32.load8_u $s2))
(then 0)
(else
(if (result i32) (i32.lt_u (i32.load8_u $s1) (i32.load8_u $s2))
(then -1)
(else 1))))
)
(func $strncmp (param $s1 i32 $s2 i32 $len i32) (result i32)
(LET $i 0)
(if (i32.eq $len 0) (return 0))
(block $done
(loop $loop
(if (i32.ge_u $i $len) (br $done))
(if (i32.eqz (i32.load8_u (i32.add $i $s1))) (br $done))
(if (i32.ne (i32.load8_u (i32.add $i $s1))
(i32.load8_u (i32.add $i $s2))) (br $done))
(local.set $i (i32.add $i 1))
(br $loop)
)
)
(if (OR (i32.eq $i $len)
(i32.eq (i32.load8_u (i32.add $i $s1))
(i32.load8_u (i32.add $i $s2))))
(return 0))
(if (result i32) (i32.lt_u (i32.load8_u (i32.add $i $s1))
(i32.load8_u (i32.add $i $s2)))
(then -1)
(else 1))
)
;; Writes new string to grass with all needles in haystack replaced.
;; If the length of replace is equal to of less than needle then
;; grass can be NULL.
;; Returns length of grass.
(func $REPLACE3 (param $grass i32 $haystack i32
$needle0 i32 $replace0 i32
$needle1 i32 $replace1 i32
$needle2 i32 $replace2 i32) (result i32)
(LET $haystack_len ($strlen $haystack)
$src_str $haystack
$dst_str $grass
$s 0 $found_tmp 0 $found 0
$needle 0 $replace 0 $needle_len 0 $replace_len 0
$replace_s 0 $replace_len_s 0 $needle_len_s 0)
;; in-place
(if (i32.eqz $grass)
(then
;; check that we aren't expanding in place
(local.set $s 0)
(block $done
(loop $loop
(if (i32.ge_u $s 3) (br $done))
(local.set $needle (if (result i32) (i32.eq $s 0) $needle0
(if (result i32) (i32.eq $s 1) $needle1
$needle2)))
(local.set $replace (if (result i32) (i32.eq $s 0) $replace0
(if (result i32) (i32.eq $s 1) $replace1
$replace2)))
(local.set $needle_len ($strlen $needle))
(local.set $replace_len ($strlen $replace))
(if (i32.gt_u $replace_len $needle_len)
($fatal 7 "REPLACE: invalid expanding in-place call\n"))
(local.set $s (i32.add $s 1))
(br $loop)
)
)
(local.set $grass $haystack)
(local.set $dst_str $grass)))
(block $done1
(loop $loop1
(if (i32.ge_s (i32.sub $src_str $haystack) $haystack_len)
(br $done1))
;; Find the earliest match
(local.set $found 0)
(local.set $s 0)
(block $done2
(loop $loop2
(if (i32.ge_u $s 3) (br $done2))
(local.set $needle (if (result i32) (i32.eq $s 0) $needle0
(if (result i32) (i32.eq $s 1) $needle1
$needle2)))
(local.set $replace (if (result i32) (i32.eq $s 0) $replace0
(if (result i32) (i32.eq $s 1) $replace1
$replace2)))
(local.set $s (i32.add $s 1))
(local.set $found_tmp ($strstr $src_str $needle))
(if (i32.eqz $found_tmp) (br $loop2))
(if (OR (i32.eqz $found) (i32.lt_s $found_tmp $found))
(then
(local.set $found $found_tmp)
(local.set $needle_len_s ($strlen $needle))
(local.set $replace_s $replace)
(local.set $replace_len_s ($strlen $replace))))
(br $loop2)
)
)
(if (i32.eqz $found) (br $done1))
;; copy before the match
($memmove $dst_str $src_str (i32.add (i32.sub $found $src_str) 1))
(local.set $dst_str (i32.add $dst_str (i32.sub $found $src_str)))
;; add the replace string
($memmove $dst_str $replace_s (i32.add $replace_len_s 1))
(local.set $dst_str (i32.add $dst_str $replace_len_s))
;; Move to after the match
(local.set $src_str (i32.add $found $needle_len_s))
(br $loop1)
)
)
;; Copy the left-over
($memmove $dst_str $src_str ($strlen $src_str))
(local.set $dst_str (i32.add $dst_str ($strlen $src_str)))
(i32.store8 $dst_str (CHR "\x00"))
(i32.sub $dst_str $grass)
)
)