407 lines
12 KiB
Forth
407 lines
12 KiB
Forth
# Helpers for Unicode.
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#
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# The basic unit for rendering Unicode is the code point.
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# https://en.wikipedia.org/wiki/Code_point
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# The glyph a non-cursive font displays may represent multiple code points.
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#
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# In addition to raw code points (just integers assigned special meaning), Mu
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# provides a common encoding as a convenience: code-point-utf8.
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fn test-unicode-serialization-and-deserialization {
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var i/ebx: int <- copy 0
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var init?/esi: boolean <- copy 1/true
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{
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compare i, 0x10000 # 32 bits of utf-8 are sufficient for https://en.wikipedia.org/wiki/Plane_(Unicode)#Basic_Multilingual_Plane
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# but not emoji
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break-if->=
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var c/eax: code-point <- copy i
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var _g/eax: code-point-utf8 <- to-utf8 c
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var g/ecx: code-point-utf8 <- copy _g
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var c2/eax: code-point <- to-code-point g
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compare i, c2
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{
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break-if-=
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{
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compare init?, 0/false
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break-if-=
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draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "F - test-unicode-serialization-and-deserialization: ", 3/fg 0/bg
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}
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init? <- copy 0/false
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draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, i, 3/fg 0/bg
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draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "/", 3/fg 0/bg
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{
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var x/eax: int <- copy g
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draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, x, 3/fg 0/bg
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}
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draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "/", 3/fg 0/bg
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{
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var x2/eax: int <- copy c2
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draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, x2, 3/fg 0/bg
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}
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draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, " ", 3/fg 0/bg
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}
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i <- add 0xf # to speed things up; ensure increment is not a power of 2
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loop
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}
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}
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# transliterated from tb_utf8_char_to_unicode in https://github.com/nsf/termbox
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fn to-code-point in: code-point-utf8 -> _/eax: code-point {
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var g/ebx: int <- copy in
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# if single byte, just return it
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{
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compare g, 0xff
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break-if->
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var result/eax: code-point <- copy g
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return result
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}
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#
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var len/edx: int <- utf8-length in
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# extract bits from first byte
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var b/eax: byte <- copy-byte g
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var result/edi: code-point <- copy b
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{
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compare len, 2
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break-if-!=
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result <- and 0x1f
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}
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{
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compare len, 3
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break-if-!=
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result <- and 0x0f
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}
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{
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compare len, 4
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break-if-!=
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result <- and 0x07
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}
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# extract bits from remaining bytes
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g <- shift-right 8
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var i/ecx: int <- copy 1
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{
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compare i, len
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break-if->=
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var b/eax: byte <- copy-byte g
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b <- and 0x3f
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result <- shift-left 6
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result <- or b
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g <- shift-right 8
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i <- increment
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loop
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}
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return result
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}
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# transliterated from tb_utf8_unicode_to_char in https://github.com/nsf/termbox
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# https://wiki.tcl-lang.org/page/UTF%2D8+bit+by+bit explains the algorithm
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fn to-utf8 in: code-point -> _/eax: code-point-utf8 {
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var c/eax: int <- copy in
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var num-trailers/ecx: int <- copy 0
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var first/edx: int <- copy 0
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$to-utf8:compute-length: {
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# single byte: just return it
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compare c, 0x7f
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{
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break-if->
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var g/eax: code-point-utf8 <- copy c
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return g
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}
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# 2 bytes
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compare c, 0x7ff
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{
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break-if->
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num-trailers <- copy 1
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first <- copy 0xc0
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break $to-utf8:compute-length
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}
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# 3 bytes
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compare c, 0xffff
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{
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break-if->
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num-trailers <- copy 2
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first <- copy 0xe0
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break $to-utf8:compute-length
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}
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# 4 bytes
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compare c, 0x1fffff
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{
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break-if->
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num-trailers <- copy 3
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first <- copy 0xf0
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break $to-utf8:compute-length
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}
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# more than 4 bytes: unsupported
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compare c, 0x1fffff
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{
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break-if->
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abort "unsupported code point"
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return 0
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}
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}
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# emit trailer bytes, 6 bits from 'in', first two bits '10'
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var result/edi: code-point-utf8 <- copy 0
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{
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compare num-trailers, 0
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break-if-<=
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var tmp/esi: int <- copy c
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tmp <- and 0x3f
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tmp <- or 0x80
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result <- shift-left 8
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result <- or tmp
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# update loop state
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c <- shift-right 6
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num-trailers <- decrement
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loop
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}
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# emit engine
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result <- shift-left 8
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result <- or c
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result <- or first
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#
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return result
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}
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# single-byte code point have identical code-point-utf8s
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fn test-to-utf8-single-byte {
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var in-int/ecx: int <- copy 0
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{
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compare in-int, 0x7f
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break-if->
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var in/eax: code-point <- copy in-int
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var out/eax: code-point-utf8 <- to-utf8 in
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var out-int/eax: int <- copy out
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check-ints-equal out-int, in-int, "F - test-to-utf8-single-byte"
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in-int <- increment
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loop
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}
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}
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# byte | byte | byte | byte
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# smallest 2-byte utf-8
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fn test-to-utf8-two-bytes-min {
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var in/eax: code-point <- copy 0x80 # 10 00-0000
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var out/eax: code-point-utf8 <- to-utf8 in
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var out-int/eax: int <- copy out
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check-ints-equal out-int, 0x80c2, "F - to-utf8/2a" # 110 0-0010 10 00-0000
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}
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# largest 2-byte utf-8
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fn test-to-utf8-two-bytes-max {
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var in/eax: code-point <- copy 0x7ff # 1-1111 11-1111
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var out/eax: code-point-utf8 <- to-utf8 in
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var out-int/eax: int <- copy out
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check-ints-equal out-int, 0xbfdf, "F - to-utf8/2b" # 110 1-1111 10 11-1111
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}
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# smallest 3-byte utf-8
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fn test-to-utf8-three-bytes-min {
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var in/eax: code-point <- copy 0x800 # 10-0000 00-0000
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var out/eax: code-point-utf8 <- to-utf8 in
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var out-int/eax: int <- copy out
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check-ints-equal out-int, 0x80a0e0, "F - to-utf8/3a" # 1110 0000 10 10-0000 10 00-0000
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}
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# largest 3-byte utf-8
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fn test-to-utf8-three-bytes-max {
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var in/eax: code-point <- copy 0xffff # 1111 11-1111 11-1111
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var out/eax: code-point-utf8 <- to-utf8 in
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var out-int/eax: int <- copy out
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check-ints-equal out-int, 0xbfbfef, "F - to-utf8/3b" # 1110 1111 10 11-1111 10 11-1111
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}
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# smallest 4-byte utf-8
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fn test-to-utf8-four-bytes-min {
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var in/eax: code-point <- copy 0x10000 # 1-0000 00-0000 00-0000
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var out/eax: code-point-utf8 <- to-utf8 in
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var out-int/eax: int <- copy out
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check-ints-equal out-int, 0x808090f0, "F - to-utf8/4a" # 1111-0 000 10 01-0000 10 00-0000 10 00-0000
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}
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# largest 4-byte utf-8
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fn test-to-utf8-four-bytes-max {
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var in/eax: code-point <- copy 0x1fffff # 111 11-1111 11-1111 11-1111
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var out/eax: code-point-utf8 <- to-utf8 in
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var out-int/eax: int <- copy out
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check-ints-equal out-int, 0xbfbfbff7, "F - to-utf8/4b" # 1111-0 111 10 11-1111 10 11-1111 10 11-1111
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}
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# read the next code-point-utf8 from a stream of bytes
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fn read-code-point-utf8 in: (addr stream byte) -> _/eax: code-point-utf8 {
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# if at eof, return EOF
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{
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var eof?/eax: boolean <- stream-empty? in
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compare eof?, 0/false
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break-if-=
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return 0xffffffff
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}
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var c/eax: byte <- read-byte in
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var num-trailers/ecx: int <- copy 0
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$read-code-point-utf8:compute-length: {
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# single byte: just return it
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compare c, 0xc0
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{
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break-if->=
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var g/eax: code-point-utf8 <- copy c
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return g
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}
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compare c, 0xfe
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{
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break-if-<
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var g/eax: code-point-utf8 <- copy c
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return g
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}
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# 2 bytes
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compare c, 0xe0
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{
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break-if->=
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num-trailers <- copy 1
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break $read-code-point-utf8:compute-length
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}
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# 3 bytes
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compare c, 0xf0
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{
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break-if->=
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num-trailers <- copy 2
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break $read-code-point-utf8:compute-length
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}
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# 4 bytes
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compare c, 0xf8
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{
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break-if->=
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num-trailers <- copy 3
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break $read-code-point-utf8:compute-length
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}
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abort "utf-8 encodings larger than 4 bytes are not yet supported"
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return 0
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}
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# prepend trailer bytes
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var result/edi: code-point-utf8 <- copy c
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var num-byte-shifts/edx: int <- copy 1
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{
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compare num-trailers, 0
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break-if-<=
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var tmp/eax: byte <- read-byte in
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var tmp2/eax: int <- copy tmp
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tmp2 <- shift-left-bytes tmp2, num-byte-shifts
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result <- or tmp2
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# update loop state
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num-byte-shifts <- increment
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num-trailers <- decrement
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loop
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}
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return result
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}
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fn test-read-code-point-utf8 {
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var s: (stream byte 0x30)
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var s2/ecx: (addr stream byte) <- address s
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write s2, "aΒc世d界e"
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var c/eax: code-point-utf8 <- read-code-point-utf8 s2
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var n/eax: int <- copy c
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check-ints-equal n, 0x61, "F - test code-point-utf8/0"
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var c/eax: code-point-utf8 <- read-code-point-utf8 s2
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var n/eax: int <- copy c
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check-ints-equal n, 0x92ce/greek-capital-letter-beta, "F - test code-point-utf8/1"
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var c/eax: code-point-utf8 <- read-code-point-utf8 s2
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var n/eax: int <- copy c
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check-ints-equal n, 0x63, "F - test code-point-utf8/2"
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var c/eax: code-point-utf8 <- read-code-point-utf8 s2
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var n/eax: int <- copy c
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check-ints-equal n, 0x96b8e4, "F - test code-point-utf8/3"
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var c/eax: code-point-utf8 <- read-code-point-utf8 s2
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var n/eax: int <- copy c
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check-ints-equal n, 0x64, "F - test code-point-utf8/4"
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var c/eax: code-point-utf8 <- read-code-point-utf8 s2
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var n/eax: int <- copy c
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check-ints-equal n, 0x8c95e7, "F - test code-point-utf8/5"
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var c/eax: code-point-utf8 <- read-code-point-utf8 s2
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var n/eax: int <- copy c
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check-ints-equal n, 0x65, "F - test code-point-utf8/6"
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}
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fn utf8-length g: code-point-utf8 -> _/edx: int {
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{
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compare g, 0xff
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break-if->
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return 1
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}
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{
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compare g, 0xffff
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break-if->
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return 2
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}
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{
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compare g, 0xffffff
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break-if->
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return 3
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}
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return 4
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}
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# needed because available primitives only shift by a literal/constant number of bits
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fn shift-left-bytes n: int, k: int -> _/eax: int {
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var i/ecx: int <- copy 0
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var result/eax: int <- copy n
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{
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compare i, k
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break-if->=
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compare i, 4 # only 4 bytes in 32 bits
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break-if->=
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result <- shift-left 8
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i <- increment
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loop
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}
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return result
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}
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fn test-shift-left-bytes-0 {
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var result/eax: int <- shift-left-bytes 1, 0
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check-ints-equal result, 1, "F - shift-left-bytes 0"
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}
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fn test-shift-left-bytes-1 {
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var result/eax: int <- shift-left-bytes 1, 1
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check-ints-equal result, 0x100, "F - shift-left-bytes 1"
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}
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fn test-shift-left-bytes-2 {
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var result/eax: int <- shift-left-bytes 1, 2
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check-ints-equal result, 0x10000, "F - shift-left-bytes 2"
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}
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fn test-shift-left-bytes-3 {
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var result/eax: int <- shift-left-bytes 1, 3
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check-ints-equal result, 0x1000000, "F - shift-left-bytes 3"
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}
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fn test-shift-left-bytes-4 {
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var result/eax: int <- shift-left-bytes 1, 4
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check-ints-equal result, 0, "F - shift-left-bytes 4"
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}
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fn test-shift-left-bytes-5 {
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var result/eax: int <- shift-left-bytes 1, 5
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check-ints-equal result, 0, "F - shift-left-bytes >4"
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}
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# write a code-point-utf8 to a stream of bytes
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# this is like write-to-stream, except we skip leading 0 bytes
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fn write-code-point-utf8 out: (addr stream byte), g: code-point-utf8 {
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$write-code-point-utf8:body: {
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var c/eax: int <- copy g
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append-byte out, c # first byte is always written
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c <- shift-right 8
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compare c, 0
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break-if-= $write-code-point-utf8:body
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append-byte out, c
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c <- shift-right 8
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compare c, 0
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break-if-= $write-code-point-utf8:body
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append-byte out, c
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c <- shift-right 8
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compare c, 0
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break-if-= $write-code-point-utf8:body
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append-byte out, c
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}
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}
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