From b45e5f4de2fba1d0ed189529095bcd275da94738 Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Sun, 4 Dec 2016 16:02:56 -0500
Subject: [PATCH] Extended attrstr.c. Much more complete API now.

---
 common/attrstr.c | 150 +++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 138 insertions(+), 12 deletions(-)

diff --git a/common/attrstr.c b/common/attrstr.c
index 03a1dadc..98e8e90a 100644
--- a/common/attrstr.c
+++ b/common/attrstr.c
@@ -39,6 +39,7 @@ uiAttributedString *uiNewAttributedString(const char *initialString)
 	return s;
 }
 
+// TODO make sure that all implementations of graphemes() work fine with empty strings; in particular, the Windows one might not
 static void recomputeGraphemes(uiAttributedString *s)
 {
 	if (s->graphemes != NULL)
@@ -75,31 +76,95 @@ const char *uiAttributedStringString(uiAttributedString *s)
 	return s->s;
 }
 
+size_t uiAttributedStringLen(uiAttributedString *s)
+{
+	return s->len;
+}
+
+static void u8u16len(const char *str, size_t *n8, size_t *n16)
+{
+	uint32_t rune;
+	char buf[4];
+	uint16_t buf16[2];
+
+	*n8 = 0;
+	*n16 = 0;
+	while (*str) {
+		str = utf8DecodeRune(str, 0, &rune);
+		*n8 += utf8EncodeRune(rune, buf);
+		*n16 += utf16EncodeRune(rune, buf16);
+	}
+}
+
 void uiAttributedStringAppendUnattributed(uiAttributedString *s, const char *str)
 {
-	const char *t;
+	uiAttributedStringInsertAtUnattributed(s, str, s->len);
+}
+
+// this works (and returns true, which is what we want) at s->len too because s->s[s->len] is always going to be 0 due to us allocating s->len + 1 bytes and because uiRealloc() always zero-fills allocated memory
+static int onCodepointBoundary(uiAttributedString *s, size_t at)
+{
+	uint8_t c;
+
+	// for uiNewAttributedString()
+	if (s->s == NULL && at == 0)
+		return 1;
+	c = (uint8_t) (s->s[at]);
+	return c < 0x80 || c >= 0xC0;
+}
+
+// TODO note that at must be on a codeoint boundary
+void uiAttributedStringInsertAtUnattributed(uiAttributedString *s, const char *str, size_t at)
+{
 	uint32_t rune;
 	char buf[4];
 	uint16_t u16buf[2];
 	size_t n, n16;
-	size_t old, old;
+	size_t old, old16;
+	size_t oldlen, old16len;
+	size_t at16;
+	size_t i;
+
+	if (!onCodepointBoundary(s, at)) {
+		// TODO
+	}
+
+	at16 = s->u8tou16[at];
+
+	// do this first to reclaim memory
+	invalidateGraphemes(s);
 
 	// first figure out how much we need to grow by
 	// this includes post-validated UTF-8
-	t = str;
-	n = 0;
-	n16 = 0;
-	while (*t) {
-		t = utf8DecodeRune(t, 0, &rune);
-		n += utf8EncodeRune(rune, buf);
-		n16 += utf16EncodeRune(rune, buf16);
-	}
+	u8u16len(str, &n, &n16);
 
 	// and resize
-	old = s->len;
-	old16 = s->len16;
+	old = at;
+	old16 = at16;
+	oldlen = s->len;
+	old16len = s->u16len;
 	resize(s, s->len + n, s->u16len + n16);
 
+	// move existing characters out of the way
+	// note the use of memmove(): https://twitter.com/rob_pike/status/737797688217894912
+	memmove(
+		s->s + at + n8,
+		s->s + at,
+		(oldlen - at) * sizeof (char));
+	memmove(
+		s->u16 + at16 + n16,
+		s->u16 + at16,
+		(old16len - at16) * sizeof (uint16_t));
+	// note the + 1 for these; we want to copy the terminating null too
+	memmove(
+		s->u8tou16 + at + n8,
+		s->u8tou16 + at,
+		(oldlen - at + 1) * sizeof (size_t));
+	memmove(
+		s->u16tou8 + at16 + n16,
+		s->u16tou8 + at16,
+		(old16len - at16 + 1) * sizeof (size_t));
+
 	// and copy
 	while (*str) {
 		str = utf8DecodeRune(str, 0, &rune);
@@ -129,10 +194,71 @@ void uiAttributedStringAppendUnattributed(uiAttributedString *s, const char *str
 		old16 += n16;
 	}
 	// and have an index for the end of the string
+	// TODO is this done by the below?
 	s->u8tou16[old] = old16;
 	s->u16tou8[old16] = old;
 
+	// and finally adjust the prior values in the conversion tables
+	// use <= so the terminating 0 gets updated too
+	for (i = 0; i <= oldlen - at; i++)
+		s->u8tou16[at + n + i] += n16;
+	for (i = 0; i <= old16len - at16; i++)
+		s->u16tou8[at16 + n16 + i] += n;
+}
+
+// TODO document that end is the first index that will be maintained
+void uiAttributedStringDelete(uiAttributedString *s, size_t start, size_t end)
+{
+	size_t start16, end16;
+	size_t count, count16;
+	size_t i;
+
+	if (!onCodepointBoundary(s, start)) {
+		// TODO
+	}
+	if (!onCodepointBoundary(s, end)) {
+		// TODO
+	}
+
+	count = end - start;
+	start16 = s->u8tou16[start];
+	end16 = s->u8tou16[end];
+	count16 = end16 - start16;
+
 	invalidateGraphemes(s);
+
+	// overwrite old characters
+	memmove(
+		s->s + start,
+		s->s + end,
+		(oldlen - end) * sizeof (char));
+	memmove(
+		s->u16 + start16,
+		s->u16 + end16,
+		(old16len - end16) * sizeof (uint16_t));
+	// note the + 1 for these; we want to copy the terminating null too
+	memmove(
+		s->u8tou16 + start,
+		s->u8tou16 + end,
+		(oldlen - end + 1) * sizeof (size_t));
+	memmove(
+		s->u16tou8 + start16,
+		s->u16tou8 + end16,
+		(old16len - end16 + 1) * sizeof (size_t));
+
+	// update the conversion tables
+	// note the use of <= to include the null terminator
+	for (i = 0; i <= count; i++)
+		s->u8tou16[start + i] -= count16;
+	for (i = 0; i <= count16; i++)
+		s->u16tou8[start16 + i] -= count;
+
+	// null-terminate the string
+	s->s[start + count] = 0;
+	s->u16[start16 + count16] = 0;
+
+	// and finally resize
+	resize(s, start + count, start16 + count16);
 }
 
 // TODO figure out if we should count the grapheme past the end