// This file is a part of Framsticks SDK.  http://www.framsticks.com/
// Copyright (C) 1999-2015  Maciej Komosinski and Szymon Ulatowski.
// See LICENSE.txt for details.

#include "sstring.h"
#include <common/nonstd.h> //to be sure the vsnprintf-related stuff gets included

#ifdef SSTRING_SIMPLE

// simple sstring implementation using direct character arrays
// - duplicate = copy all characters
// - no mutex needed

#include "sstring-simple.cpp"

#else
///////////////////////////////////////////////////////////////////////////
// old sstring implementation using SBuf references
// - duplicate = copy buffer pointer
// - mutex required to be thread safe

#include <common/nonstd_stl.h>
#include "extvalue.h"
#include <assert.h>

#ifdef MULTITHREADED
#include <pthread.h>
static pthread_mutex_t sstring_ref_lock = PTHREAD_MUTEX_INITIALIZER;
#define REF_LOCK pthread_mutex_lock(&sstring_ref_lock);
#define REF_UNLOCK pthread_mutex_unlock(&sstring_ref_lock)
#else
#define REF_LOCK 
#define REF_UNLOCK 
#endif

static int guessMemSize(int request)
{
	return request + min(request / 2, 10000) + 8;
}

SBuf::SBuf()
{
	txt = (char*)"";
	size = used = 0;
	refcount = 1;
}

SBuf::SBuf(int initsize)
{
	size = guessMemSize(initsize);
	if (size > 0)	{ txt = (char*)malloc(size + 1); txt[0] = 0; }
	else	txt = (char*)"";
	used = 0;
	refcount = 1;
}

SBuf::~SBuf()
{
	freeBuf();
}

void SBuf::initEmpty()
{
	txt = (char*)"";
	used = size = 0;
	refcount = 1;
}

void SBuf::freeBuf()
{
	if (!size) return;
	free(txt); used = 0;
}

void SBuf::copyFrom(const char *ch, int chlen)
{
	if (chlen == -1) chlen = strlen(ch);
	if (chlen > 0)
	{
		if (chlen < size)
		{
			memmove(txt, ch, chlen);
		}
		else
		{
			size = guessMemSize(chlen);
			char *newtxt = (char*)malloc(size + 1);
			memcpy(newtxt, ch, chlen);
			free(txt);
			txt = newtxt;
		}
	}
	txt[chlen] = 0;
	used = chlen;
}

void SBuf::append(const char *ch, int chlen)
{ // doesn't check anything!
	memmove(txt + used, ch, chlen);
	used += chlen;
	txt[used] = 0;
}

void SBuf::ensureSize(int needed)
{
	if (size >= needed) return;
	needed = guessMemSize(needed);
	txt = (char*)realloc(txt, needed + 1);
	size = needed;
}

/////////////////////////////////////////////

SString::SString()
{
	initEmpty();
}

SString::~SString()
{
	REF_LOCK;
	detach();
	REF_UNLOCK;
}

SString::SString(int x)
{
	buf = new SBuf(x);
}

SString::SString(const char *t, int t_len)
{
	initEmpty();
	if (!t) return;
	copyFrom(t, t_len);
}

SString::SString(SString&& from)
{
	buf = from.buf;
	from.buf = &SBuf::empty();
}

SString::SString(const SString &from)
{
	if (from.buf == &SBuf::empty())
		buf = &SBuf::empty();
	else
	{
		REF_LOCK;
		buf = from.buf;
		if (buf->size)
			buf->refcount++;
		REF_UNLOCK;
	}
}

void SString::initEmpty()
{
	buf = &SBuf::empty();
}

void SString::memoryHint(int howbig)
{
	detachCopy(howbig);
}

void SString::detachEmpty(int ensuresize)
{
	if (buf == &SBuf::empty()) { buf = new SBuf(ensuresize); return; }
	if (buf->refcount < 2) buf->ensureSize(ensuresize);
	else
	{
		buf->refcount--;
		buf = new SBuf(ensuresize);
	}
}

void SString::detach()
{
	if (buf == &SBuf::empty()) return;
	if (!--buf->refcount) delete buf;
}

void SString::detachCopy(int ensuresize)
{
	if (buf == &SBuf::empty()) { buf = new SBuf(ensuresize); return; }
	if (buf->refcount < 2)
	{
		buf->ensureSize(ensuresize);
		return;
	}
	buf->refcount--;
	SBuf *newbuf = new SBuf(ensuresize);
	newbuf->copyFrom(buf->txt, min(ensuresize, buf->used));
	buf = newbuf;
}

char *SString::directWrite(int ensuresize)
{
	if (ensuresize < 0) ensuresize = len();
	REF_LOCK;
	detachCopy(ensuresize);
	REF_UNLOCK;
	appending = buf->used;
	return buf->txt;
}

/*
char *SString::directWrite()
{
return directWrite(buf->used);
}
*/
char *SString::directAppend(int maxappend)
{
	REF_LOCK;
	detachCopy(buf->used + maxappend);
	REF_UNLOCK;
	appending = buf->used;
	return buf->txt + appending;
}

void SString::endWrite(int newlength)
{
	if (newlength < 0) newlength = strlen(buf->txt);
	else buf->txt[newlength] = 0;
	buf->used = newlength;
}

void SString::endAppend(int newappend)
{
	if (newappend < 0) newappend = strlen(buf->txt + appending);
	else buf->txt[appending + newappend] = 0;
	buf->used = appending + newappend;
}

////////////// append /////////////////

void SString::operator+=(const char *s)
{
	if (!s) return;
	int x = strlen(s);
	if (!x) return;
	append(s, x);
}

void SString::append(const char *txt, int count)
{
	if (!count) return;
	REF_LOCK;
	detachCopy(buf->used + count);
	REF_UNLOCK;
	buf->append(txt, count);
}

void SString::operator+=(const SString&s)
{
	append(s.c_str(), s.len());
}

SString SString::operator+(const SString& s) const
{
	SString ret(*this);
	ret += s;
	return ret;
}

/////////////////////////////

void SString::copyFrom(const char *ch, int chlen)
{
	if (!ch) chlen = 0;
	else if (chlen < 0) chlen = strlen(ch);
	REF_LOCK;
	detachEmpty(chlen);
	REF_UNLOCK;
	memmove(buf->txt, ch, chlen);
	buf->txt[chlen] = 0; buf->used = chlen;
}

void SString::operator=(const char *ch)
{
	copyFrom(ch);
}

void SString::operator=(const SString&s)
{
	if (s.buf == buf) return;
	REF_LOCK;
	detach();
	buf = s.buf;
	if (buf->size) buf->refcount++;
	REF_UNLOCK;
}
///////////////////////////////////////

SString SString::substr(int begin, int length) const
{
	if (begin < 0) { length += begin; begin = 0; }
	if (length >= (len() - begin)) length = len() - begin;
	if (length <= 0) return SString();
	if (length == len()) return *this;
	return SString((*this)(begin), length);
}

///////////////////////////////////////

bool SString::equals(const SString& s) const
{
	if (s.buf == buf) return true;
	return strcmp(buf->txt, s.buf->txt) == 0;
}

///////////////////////////////////////

int SString::indexOf(int character, int start) const
{
	const char *found = strchr(buf->txt + start, character);
	return found ? found - buf->txt : -1;
}

int SString::indexOf(const char *substring, int start) const
{
	char *found = strstr(buf->txt + start, substring);
	return found ? found - buf->txt : -1;
}

int SString::indexOf(const SString & substring, int start) const
{
	char *found = strstr(buf->txt + start, substring.c_str());
	return found ? found - buf->txt : -1;
}

bool SString::getNextToken(int& pos, SString &token, char separator) const
{
	if (pos >= len()) { token = 0; return false; }
	int p1 = pos, p2;
	const char *t1 = buf->txt + pos;
	const char *t2 = strchr(t1, separator);
	if (t2) pos = (p2 = (t2 - buf->txt)) + 1; else p2 = pos = len();
	strncpy(token.directWrite(p2 - p1), t1, p2 - p1);
	token.endWrite(p2 - p1);
	return true;
}

bool SString::startsWith(const char *pattern) const
{
	const char *t = this->c_str();
	for (; *pattern; pattern++, t++)
		if (*t != *pattern) return false;
	return true;
}

SString SString::valueOf(int i)
{
	return SString::sprintf("%d", i);
}
SString SString::valueOf(long i)
{
	return SString::sprintf("%d", i);
}
SString SString::valueOf(double d)
{
	SString tmp = SString::sprintf("%.15g", d);
	if ((!strchr(tmp.c_str(), '.')) && (!strchr(tmp.c_str(), 'e'))) tmp += ".0";
	return tmp;
}
SString SString::valueOf(const SString& s)
{
	return s;
}

#if 0 //testing _vscprintf
#define USE_VSCPRINTF
int _vscprintf(const char *format, va_list argptr)
{
	return vsnprintf("", 0, format, argptr);
}
#endif

SString SString::sprintf(const char* format, ...)
{
	int n, size = 30;
	va_list ap;

	SString ret;

#ifdef USE_VSCPRINTF
	va_start(ap, format);
	size = _vscprintf(format, ap);
	va_end(ap);
#endif

	while (1)
	{
		char* p = ret.directWrite(size);
		assert(p != NULL);
		size = ret.directMaxLen() + 1;
		/* Try to print in the allocated space. */
		va_start(ap, format);
		n = vsnprintf(p, size, format, ap);
		va_end(ap);
		/* If that worked, return the string. */
		if (n > -1 && n < size)
		{
			ret.endWrite(n);
			return ret;
		}
		/* Else try again with more space. */
#ifdef VSNPRINTF_RETURNS_REQUIRED_SIZE
		if (n > -1)    /* glibc 2.1 */
			size = n; /* precisely what is needed */
		else           /* glibc 2.0 */
#endif
			size *= 2;  /* twice the old size */
	}
}

SString &SString::empty()
{
	static SString empty;
	return empty;
}

SBuf &SBuf::empty()
{
	static SBuf empty;
	return empty;
}

#endif //#ifdef SSTRING_SIMPLE

//////////////////////////////////////////////////
// to be moved somewhere else?
// public domain source: http://isthe.com/chongo/src/fnv
typedef uint32_t Fnv32_t;

#define FNV_32_PRIME ((Fnv32_t)0x01000193)
#define FNV1_32_INIT ((Fnv32_t)0x811c9dc5)
#define FNV1_32A_INIT FNV1_32_INIT

Fnv32_t fnv_32a_buf(void *buf, size_t len, Fnv32_t hval)
{
	unsigned char *bp = (unsigned char *)buf;	/* start of buffer */
	unsigned char *be = bp + len;		/* beyond end of buffer */

	while (bp < be) {

		/* xor the bottom with the current octet */
		hval ^= (Fnv32_t)*bp++;

		/* multiply by the 32 bit FNV magic prime mod 2^32 */
#if defined(NO_FNV_GCC_OPTIMIZATION)
		hval *= FNV_32_PRIME;
#else
		hval += (hval << 1) + (hval << 4) + (hval << 7) + (hval << 8) + (hval << 24);
#endif

	}

	/* return our new hash value */
	return hval;
}
//////////////////////////////////////////////////

#ifdef SSTRING_SIMPLE
uint32_t SString::hash() const
{
	return fnv_32a_buf(txt, used, FNV1_32A_INIT);
}
#else
uint32_t SBuf::hash() const
{
	return fnv_32a_buf(txt, used, FNV1_32A_INIT);
}
#endif