12 files changed, 80 insertions, 8 deletions
diff --git a/examples/arc_containers.c b/examples/arc_containers.c
index f9c14123..0ee2cbeb 100644
--- a/examples/arc_containers.c
+++ b/examples/arc_containers.c
@@ -1,5 +1,6 @@
 // Create a stack and a list of shared pointers to maps,
 // and demonstrate sharing and cloning of maps.
+#include <stc/cstr.h>
 #define i_type Map
 #define i_key_str // strings
 #define i_val int
diff --git a/examples/books.c b/examples/books.c
index b891388d..eb644ba7 100644
--- a/examples/books.c
+++ b/examples/books.c
@@ -1,5 +1,6 @@
 // https://doc.rust-lang.org/std/collections/struct.HashMap.html
 
+#include <stc/cstr.h>
 #define i_key_str
 #define i_val_str
 #include <stc/cmap.h>
diff --git a/examples/hashmap.c b/examples/hashmap.c
index f39a3904..9ff019e6 100644
--- a/examples/hashmap.c
+++ b/examples/hashmap.c
@@ -1,5 +1,6 @@
 // https://doc.rust-lang.org/rust-by-example/std/hash.html
 
+#include <stc/cstr.h>
 #define i_key_str
 #define i_val_str
 #include <stdio.h>
diff --git a/examples/mapmap.c b/examples/mapmap.c
index 51a5ce59..ccf09314 100644
--- a/examples/mapmap.c
+++ b/examples/mapmap.c
@@ -1,5 +1,6 @@
 // unordered_map<string, unordered_map<string, string>>:
 
+#include <stc/cstr.h>
 #define i_type People
 #define i_key_str
 #define i_val_str
diff --git a/examples/mmap.c b/examples/mmap.c
index f8e56dc3..16b5d2df 100644
--- a/examples/mmap.c
+++ b/examples/mmap.c
@@ -2,6 +2,7 @@
 // https://en.cppreference.com/w/cpp/container/multimap/insert
 
 // Multimap entries
+#include <stc/cstr.h>
 #define i_val_str
 #include <stc/clist.h>
 
diff --git a/examples/rawptr_elements.c b/examples/rawptr_elements.c
index f31f9abd..c438727b 100644
--- a/examples/rawptr_elements.c
+++ b/examples/rawptr_elements.c
@@ -13,6 +13,7 @@ struct { double x, y; } typedef Point;
 #define i_tag pnt
 #include <stc/cset.h>
 
+#include <stc/cstr.h>
 // Map of int64 pointers: Define i_valraw as int64_t for easy emplace calls!
 typedef int64_t inttype;
 #define i_key_str
diff --git a/examples/regex1.c b/examples/regex1.c
index 23a28f08..48dfe515 100644
--- a/examples/regex1.c
+++ b/examples/regex1.c
@@ -30,3 +30,4 @@ int main(int argc, char* argv[])
 }
 
 #include "../src/cregex.c"
+#include "../src/casefold.c"
diff --git a/examples/regex2.c b/examples/regex2.c
index 750638c4..60fd707a 100644
--- a/examples/regex2.c
+++ b/examples/regex2.c
@@ -33,3 +33,4 @@ int main()
 }
 
 #include "../src/cregex.c"
+#include "../src/casefold.c"
diff --git a/examples/regex_match.c b/examples/regex_match.c
index 3747b319..5d2ff215 100644
--- a/examples/regex_match.c
+++ b/examples/regex_match.c
@@ -1,4 +1,6 @@
 #include <stdio.h>
+#define i_implement
+#include <stc/cstr.h>
 #include <stc/cregex.h>
 #include <stc/crandom.h>
 #include <stc/csview.h>
@@ -33,3 +35,4 @@ int main()
 }
 
 #include "../src/cregex.c"
+#include "../src/casefold.c"
diff --git a/examples/splitstr.c b/examples/splitstr.c
index d0aefa85..390a6c6f 100644
--- a/examples/splitstr.c
+++ b/examples/splitstr.c
@@ -1,3 +1,4 @@
+#include <stc/cstr.h>
 #define i_val_str
 #include <stc/cvec.h>
 #include <stc/csview.h>
diff --git a/examples/unordered_set.c b/examples/unordered_set.c
index 2decb88c..11ffea80 100644
--- a/examples/unordered_set.c
+++ b/examples/unordered_set.c
@@ -1,5 +1,6 @@
 // https://iq.opengenus.org/containers-cpp-stl/
 // C program to demonstrate various function of stc cset
+#include <stc/cstr.h>
 #define i_key_str
 #include <stc/cset.h>
 
diff --git a/src/cregex_utf8.c b/src/casefold.c
index 69be6315..1b0a9463 100644
--- a/src/cregex_utf8.c
+++ b/src/casefold.c
@@ -1,8 +1,6 @@
-#include <stdint.h>
-#include <stdio.h>
 #include <ctype.h>
-#include <stc/utf8.h>
-#include <stdbool.h>
+#define i_header
+#include <stc/cstr.h>
 
 static struct CaseFold { uint16_t c0, c1, m1; } casefold[] = {
     {65, 90, 122}, {181, 181, 956}, {192, 214, 246}, {216, 222, 254},
@@ -127,6 +125,52 @@ bool utf8_isalpha(uint32_t c) {
     return utf8_islower(c) || utf8_isupper(c);
 }
 
+static struct fnfold {
+    int (*conv_asc)(int);
+    uint32_t (*conv_u8)(uint32_t);
+}
+fn_tolower = {tolower, utf8_tolower},
+fn_toupper = {toupper, utf8_toupper};
+
+
+static cstr cstr_casefold(const cstr* self, struct fnfold fold) {
+    csview sv = cstr_sv(self);
+    cstr out = cstr_null;
+    char *buf = cstr_reserve(&out, sv.size*3/2);
+    uint32_t cp; size_t sz = 0;
+    utf8_decode_t d = {UTF8_OK};
+
+    for (; *sv.str; sv.str += d.size) {
+        utf8_peek(sv.str, &d);
+        switch (d.size) {
+        case 1:
+            buf[sz++] = (char)fold.conv_asc(*sv.str);
+            break;
+        default: 
+            cp = fold.conv_u8(d.codep);
+            sz += utf8_encode(buf + sz, cp);
+        }
+    }
+    _cstr_set_size(&out, sz);
+    cstr_shrink_to_fit(&out);
+    return out;
+}
+
+cstr cstr_tolower(const cstr* self) {
+    return cstr_casefold(self, fn_tolower);
+}
+
+cstr cstr_toupper(const cstr* self) {
+    return cstr_casefold(self, fn_toupper);
+}
+
+void cstr_lowercase(cstr* self) {
+    cstr_take(self, cstr_casefold(self, fn_tolower));
+}
+
+void cstr_uppercase(cstr* self) {
+    cstr_take(self, cstr_casefold(self, fn_toupper));
+}
 
 #ifdef TEST
 int main()
@@ -134,14 +178,29 @@ int main()
     for (size_t i=0; i < sizeof cfold_low/sizeof *cfold_low; ++i)
     {
         char x[3][5]={0};
+        unsigned s0, s1, s2;
         uint32_t a = casefold[i].c0;
         uint32_t b = utf8_tolower(a);
         uint32_t c = utf8_toupper(b);
 
-        utf8_encode(x[0], a);
-        utf8_encode(x[1], b);
-        utf8_encode(x[2], c);
-        printf("%s %s %s - %u %u %u\n", x[0], x[1], x[2], a, b, c);
+        s0 = utf8_encode(x[0], a);
+        s1 = utf8_encode(x[1], b);
+        s2 = utf8_encode(x[2], c);
+        printf("%s %s %s - %u %u %u (%u %u %u)\n", x[0], x[1], x[2], a, b, c, s0, s1, s2);
+    }
+    c_auto (cstr, t1)
+    {
+        t1 = cstr_new("Die preußischen Köstlichkeiten.");
+
+        cstr_buf b = cstr_buffer(&t1);
+        printf("%s, %llu %llu\n", b.data, b.size, b.cap);
+        cstr_lowercase(&t1);
+        b = cstr_buffer(&t1);
+        printf("%s, %llu %llu\n", b.data, b.size, b.cap);
+
+        cstr_uppercase(&t1);
+        b = cstr_buffer(&t1);
+        printf("%s, %llu %llu\n", b.data, b.size, b.cap);
     }
 }
 #endif