From 752d263d9c89ecc39a2c73b95dcd994f89a1fa93 Mon Sep 17 00:00:00 2001
From: mykola2312 <49044616+mykola2312@users.noreply.github.com>
Date: Tue, 17 May 2022 02:36:16 +0300
Subject: [PATCH] implement std functions for string processing & text
 converting multi-byte (UTF-8) character set to double-byte character set and
 vise-versa

---
 CMakeLists.txt |   2 +
 string.c       | 142 +++++++++++++++++++++++++++++++++++++++++++++++++
 string.h       |  27 ++++++++++
 3 files changed, 171 insertions(+)
 create mode 100644 string.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8329c05..d52ae91 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,7 @@ set(HEADERS
     bitmap.h
     endian.h
     struct.h
+    string.h
 )
 
 set(SOURCES
@@ -18,6 +19,7 @@ set(SOURCES
     bitmap.c
     endian.c
     struct.c
+    string.c
 )
 
 add_library(cutil STATIC ${SOURCES} ${HEADERS}
diff --git a/string.c b/string.c
new file mode 100644
index 0000000..3910320
--- /dev/null
+++ b/string.c
@@ -0,0 +1,142 @@
+#include "string.h"
+#include "cutil.h"
+
+size_t cu_strlen(const char* str)
+{
+    u32 len = 0;
+    while(*str++) len++;
+    return len;
+}
+
+void cu_strcpy(char* dst,const char* src)
+{
+    while((*dst++ = *src++)){}
+}
+
+void cu_strncpy(char* dst,const char* src,size_t maxLen)
+{
+    maxLen=-1;
+    while((*dst++ = *src++) && --maxLen){}
+    if(!maxLen) dst[maxLen] = '\0';
+}
+
+const char* cu_strchr(const char* src,char chr)
+{
+    while(*src)
+    {
+        if(*src == chr) return src;
+        src++;
+    }
+    return NULL;
+}
+
+const char* cu_strrchr(const char* src,char chr)
+{
+    const char* ptr;
+    
+    ptr = src+cu_strlen(src)-1;
+    while(ptr != src)
+    {
+        if(*ptr == chr) return ptr;
+        ptr--;
+    }
+    return NULL;
+}
+
+int cu_strcmp(const char* src,const char* dst)
+{
+    if(cu_strlen(src) != cu_strlen(dst)) return 1;
+    while(*src)
+        if(*src++ != *dst++) return 1;
+    return 0;
+}
+
+int cu_strncmp(const char* haystack,char* needle)
+{
+    return !!cu_memcmp(haystack,needle,cu_strlen(needle));
+}
+
+int cu_strcasecmp(const char* src,const char* dst)
+{
+    if(cu_strlen(src) != cu_strlen(dst)) return 1;
+    while(*src)
+    {
+        if(cu_tolower(*src++) != cu_tolower(*dst++))
+            return 1;
+    }
+    return 0;
+}
+
+char cu_toupper(char c)
+{
+    if(c >= 0x61 && c <= 0x7A) return c&0xDF;
+    return c;
+}
+
+char cu_tolower(char c)
+{
+    if(c >= 0x41 && c <= 0x5A) return c|(1<<5);
+    return c;
+}
+
+size_t cu_chrlen(char cchr)
+{
+    u8 chr = (u8)cchr;
+    
+    if(chr & 0b10000000)
+    {
+        if((chr>>5) == 0b110) return 2;
+        else if((chr>>4) == 0b1110) return 3;
+        else if((chr>>5) == 0b11110) return 4;
+    }
+    return 1;
+}
+
+dbcs_t cu_chr2dbcs(const char* ptr)
+{
+    const u8* chr = (u8*)ptr;
+    
+    switch(cu_chrlen(chr[0]))
+    {
+        case 1: return chr[0]&0x7F;
+        case 2: return ((chr[0]&0x1F)<<6)|(chr[1]&0x3F);
+        case 3: return ((chr[0]&0x0F)<<12)|((chr[1]&0x3F)<<6)|(chr[2]&0x3F);
+        default: return 0x003F;
+    }
+}
+
+size_t cu_dbcslen(dbcs_t chr)
+{
+    if(chr > 0x7FF) return 3;
+    else if(chr > 0x7F) return 2;
+    return 1;
+}
+
+void cu_dbcs2str(dbcs_t* dbcs,char* str,size_t maxStr)
+{
+    char* end = str + maxStr - 1;
+    dbcs_t wc;
+    
+    while((wc = *dbcs++) && str != end)
+    {
+        size_t len = cu_dbcslen(wc);
+        if((str+len) >= end) break;
+        switch(len)
+        {
+            case 1:
+                *str++ = wc&0x7F;
+                break;
+            case 2:
+                *str++ = 0b11000000|((wc>>6)&0x1F);
+                *str++ = 0b10000000|((wc)&0x3F);
+                break;
+            case 3:
+                *str++ = 0b11100000|((wc>>12)&0x0F);
+                *str++ = 0b10000000|((wc>>6)&0x3F);
+                *str++ = 0b10000000|((wc)&0x3F);
+                break;
+            default: *str++ = '?';
+        }
+    }
+    *str++ = '\0';
+}
diff --git a/string.h b/string.h
index 17fcac6..10c7058 100644
--- a/string.h
+++ b/string.h
@@ -1,4 +1,31 @@
 #ifndef __CUTIL_STRING_H
 #define __CUTIL_STRING_H
 
+#include "cutypes.h"
+
+#define DBCS2SBCS(dbcs) ((char)(dbcs&0xFF))
+
+typedef u16 dbcs_t;
+
+size_t cu_strlen(const char* str);
+
+void cu_strcpy(char* dst,const char* src);
+void cu_strncpy(char* dst,const char* src, size_t maxLen);
+
+const char* cu_strchr(const char* src,char chr);
+const char* cu_strrchr(const char* src,char chr);
+
+int cu_strcmp(const char* src,const char* dst);
+int cu_strncmp(const char* haystack,char* needle);
+int cu_strcasecmp(const char* src,const char* dst);
+
+char cu_toupper(char c);
+char cu_tolower(char c);
+
+size_t cu_chrlen(char chr);
+dbcs_t cu_chr2dbcs(const char* chr);
+
+size_t cu_dbcslen(dbcs_t chr);
+void cu_dbcs2str(dbcs_t* dbcs,char* str, size_t maxStr);
+
 #endif
\ No newline at end of file