# Some useful helpers for dealing with strings.
recipe string-equal [
default-space:address:space <- new location:type, 30:literal
a:address:array:character <- next-ingredient
a-len:integer <- length a:address:array:character/deref
b:address:array:character <- next-ingredient
b-len:integer <- length b:address:array:character/deref
# compare lengths
{
trace [string-equal], [comparing lengths]
length-equal?:boolean <- equal a-len:integer, b-len:integer
break-if length-equal?:boolean
reply 0:literal
}
# compare each corresponding character
trace [string-equal], [comparing characters]
i:integer <- copy 0:literal
{
done?:boolean <- greater-or-equal i:integer, a-len:integer
break-if done?:boolean
a2:character <- index a:address:array:character/deref, i:integer
b2:character <- index b:address:array:character/deref, i:integer
{
chars-match?:boolean <- equal a2:character, b2:character
break-if chars-match?:boolean
reply 0:literal
}
i:integer <- add i:integer, 1:literal
loop
}
reply 1:literal
]
scenario string-equal-reflexive [
run [
default-space:address:space <- new location:type, 30:literal
x:address:array:character <- new [abc]
3:boolean/raw <- string-equal x:address:array:character, x:address:array:character
]
memory should contain [
3 <- 1 # x == x for all x
]
]
scenario string-equal-identical [
run [
default-space:address:space <- new location:type, 30:literal
x:address:array:character <- new [abc]
y:address:array:character <- new [abc]
3:boolean/raw <- string-equal x:address:array:character, y:address:array:character
]
memory should contain [
3 <- 1 # abc == abc
]
]
scenario string-equal-distinct-lengths [
run [
default-space:address:space <- new location:type, 30:literal
x:address:array:character <- new [abc]
y:address:array:character <- new [abcd]
3:boolean/raw <- string-equal x:address:array:character, y:address:array:character
]
memory should contain [
3 <- 0 # abc != abcd
]
trace should contain [
string-equal: comparing lengths
]
trace should not contain [
string-equal: comparing characters
]
]
scenario string-equal-with-empty [
run [
default-space:address:space <- new location:type, 30:literal
x:address:array:character <- new []
y:address:array:character <- new [abcd]
3:boolean/raw <- string-equal x:address:array:character, y:address:array:character
]
memory should contain [
3 <- 0 # "" != abcd
]
]
scenario string-equal-common-lengths-but-distinct [
run [
default-space:address:space <- new location:type, 30:literal
x:address:array:character <- new [abc]
y:address:array:character <- new [abd]
3:boolean/raw <- string-equal x:address:array:character, y:address:array:character
]
memory should contain [
3 <- 0 # abc != abd
]
]
# A new type to help incrementally construct strings.
container buffer [
length:integer
data:address:array:character
]
recipe init-buffer [
default-space:address:space <- new location:type, 30:literal
#? $print default-space:address:space
#? $print [
#? ]
result:address:buffer <- new buffer:type
len:address:integer <- get-address result:address:buffer/deref, length:offset
len:address:integer/deref <- copy 0:literal
s:address:address:array:character <- get-address result:address:buffer/deref, data:offset
capacity:integer <- next-ingredient
s:address:address:array:character/deref <- new character:type, capacity:integer
#? $print s:address:address:array:character/deref
#? $print [
#? ]
reply result:address:buffer
]
recipe grow-buffer [
default-space:address:space <- new location:type, 30:literal
in:address:buffer <- next-ingredient
# double buffer size
x:address:address:array:character <- get-address in:address:buffer/deref, data:offset
oldlen:integer <- length x:address:address:array:character/deref/deref
newlen:integer <- multiply oldlen:integer, 2:literal
olddata:address:array:character <- copy x:address:address:array:character/deref
x:address:address:array:character/deref <- new character:type, newlen:integer
# copy old contents
i:integer <- copy 0:literal
{
done?:boolean <- greater-or-equal i:integer, oldlen:integer
break-if done?:boolean
src:character <- index olddata:address:array:character/deref, i:integer
dest:address:character <- index-address x:address:address:array:character/deref/deref, i:integer
dest:address:character/deref <- copy src:character
i:integer <- add i:integer, 1:literal
loop
}
reply in:address:buffer
]
recipe buffer-full? [
default-space:address:space <- new location:type, 30:literal
in:address:buffer <- next-ingredient
len:integer <- get in:address:buffer/deref, length:offset
s:address:array:character <- get in:address:buffer/deref, data:offset
capacity:integer <- length s:address:array:character/deref
result:boolean <- greater-or-equal len:integer, capacity:integer
reply result:boolean
]
# in:address:buffer <- buffer-append in:address:buffer, c:character
recipe buffer-append [
default-space:address:space <- new location:type, 30:literal
in:address:buffer <- next-ingredient
c:character <- next-ingredient
{
# grow buffer if necessary
full?:boolean <- buffer-full? in:address:buffer
break-unless full?:boolean
in:address:buffer <- grow-buffer in:address:buffer
}
len:address:integer <- get-address in:address:buffer/deref, length:offset
s:address:array:character <- get in:address:buffer/deref, data:offset
dest:address:character <- index-address s:address:array:character/deref, len:address:integer/deref
dest:address:character/deref <- copy c:character
len:address:integer/deref <- add len:address:integer/deref, 1:literal
reply in:address:buffer/same-as-arg:0
]
scenario buffer-append-works [
run [
default-space:address:space <- new location:type, 30:literal
x:address:buffer <- init-buffer 3:literal
s1:address:array:character <- get x:address:buffer/deref, data:offset
x:address:buffer <- buffer-append x:address:buffer, 97:literal # 'a'
x:address:buffer <- buffer-append x:address:buffer, 98:literal # 'b'
x:address:buffer <- buffer-append x:address:buffer, 99:literal # 'c'
s2:address:array:character <- get x:address:buffer/deref, data:offset
1:boolean/raw <- equal s1:address:array:character, s2:address:array:character
#? $print s2:address:array:character
#? $print [
#? ]
#? $print 1060:integer/raw
#? $print [
#? ]
#? $print 1061:integer/raw
#? $print [
#? ]
#? $print 1062:integer/raw
#? $print [
#? ]
#? $print 1063:integer/raw
#? $print [
#? ]
#? $print 1064:integer/raw
#? $print [
#? ]
#? $print 1065:integer/raw
#? $print [
#? ]
2:array:character/raw <- copy s2:address:array:character/deref
+buffer-filled
x:address:buffer <- buffer-append x:address:buffer, 100:literal # 'd'
s3:address:array:character <- get x:address:buffer/deref, data:offset
10:boolean/raw <- equal s1:address:array:character, s3:address:array:character
11:integer/raw <- get x:address:buffer/deref, length:offset
12:array:character/raw <- copy s3:address:array:character/deref
]
memory should contain [
# before +buffer-filled
1 <- 1 # no change in data pointer
2 <- 3 # size of data
3 <- 97 # data
4 <- 98
5 <- 99
# in the end
10 <- 0 # data pointer has grown
11 <- 4 # final length
12 <- 6 # but data's capacity has doubled
13 <- 97 # data
14 <- 98
15 <- 99
16 <- 100
17 <- 0
18 <- 0
]
]