From 4f93f935dc7a981ca073a322425c3f5929ffb644 Mon Sep 17 00:00:00 2001 From: Thomas Voss Date: Sun, 21 Jan 2024 03:03:58 +0100 Subject: Support line- & column-based match locations --- vendor/librune/lib/utf8/u8prev.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 vendor/librune/lib/utf8/u8prev.c (limited to 'vendor/librune/lib/utf8/u8prev.c') diff --git a/vendor/librune/lib/utf8/u8prev.c b/vendor/librune/lib/utf8/u8prev.c new file mode 100644 index 0000000..fac0fc7 --- /dev/null +++ b/vendor/librune/lib/utf8/u8prev.c @@ -0,0 +1,37 @@ +#include "rune.h" +#include "utf8.h" + +#include "internal/common.h" + +const char8_t * +u8prev(rune *ch, const char8_t **p, const char8_t *start) +{ + int off; + bool match = true; + const char8_t *s = *p; + ptrdiff_t d = s - start; + + if (d <= 0) { + return nullptr; + } else if (U1(s[-1])) { + *ch = s[-1]; + off = 1; + } else if (d > 1 && UC(s[-1]) && U2(s[-2])) { + *ch = ((s[-2] & 0x1F) << 6) | (s[-1] & 0x3F); + off = 2; + } else if (d > 2 && UC(s[-1]) && UC(s[-2]) && U3(s[-3])) { + *ch = ((s[-3] & 0x0F) << 12) | ((s[-2] & 0x3F) << 6) | (s[-1] & 0x3F); + off = 3; + } else if (d > 3 && UC(s[-1]) && UC(s[-2]) && UC(s[-3]) && U4(s[-4])) { + *ch = ((s[-4] & 0x07) << 18) | ((s[-3] & 0x3F) << 12) + | ((s[-2] & 0x3F) << 6) | (s[-1] & 0x3F); + off = 4; + } else + match = false; + + if (match && u8chkr(*ch)) + return *p -= off; + + *ch = RUNE_ERROR; + return *p--; +} -- cgit v1.2.3