/** \file util.c
	Generic utilities library.

	Contains datastructures such as automatically growing array lists, priority queues, etc.
*/

#include "config.h"


#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include <math.h>
#include <sys/time.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <wctype.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
#include <assert.h>

#include "fallback.h"
#include "util.h"

#include "common.h"
#include "wutil.h"

/**
   Minimum allocated size for data structures. Used to avoid excessive
   memory allocations for lists, hash tables, etc, which are nearly
   empty.
*/
#define MIN_SIZE 32

/**
   Maximum number of characters that can be inserted using a single
   call to sb_printf. This is needed since vswprintf doesn't tell us
   what went wrong. We don't know if we ran out of space or something
   else went wrong. We assume that any error is an out of memory-error
   and try again until we reach this size.  After this size has been
   reached, it is instead assumed that something was wrong with the
   format string.
*/
#define SB_MAX_SIZE (128*1024*1024)

/**
   Handle oom condition. Default action is to print a stack trace and
   exit, but an alternative action can be specified.
 */
#define oom_handler( p )						\
	{											\
		if( oom_handler_internal == util_die_on_oom )	\
		{												\
			DIE_MEM();									\
		}												\
		oom_handler_internal( p );						\
	}													\
		


void util_die_on_oom( void * p);

void (*oom_handler_internal)(void *) = &util_die_on_oom;

void (*util_set_oom_handler( void (*h)(void *) ))(void *)
{
	void (*old)(void *) = oom_handler_internal;
	
	if( h )
		oom_handler_internal = h;
	else
		oom_handler_internal = &util_die_on_oom;

	return old;
}

void util_die_on_oom( void *p )
{
}

int mini( int a,
		  int b )
{
	return a<b?a:b;
}


int maxi( int a,
		  int b )
{
	return a>b?a:b;
}

int wcsfilecmp( const wchar_t *a, const wchar_t *b )
{
	CHECK( a, 0 );
	CHECK( b, 0 );
	
	if( *a==0 )
	{
		if( *b==0)
			return 0;
		return -1;
	}
	if( *b==0 )
	{
		return 1;
	}

	int secondary_diff=0;
	if( iswdigit( *a ) && iswdigit( *b ) )
	{
		wchar_t *aend, *bend;
		long al;
		long bl;
		int diff;

		errno = 0;		
		al = wcstol( a, &aend, 10 );
		bl = wcstol( b, &bend, 10 );

		if( errno )
		{
			/*
			  Huuuuuuuuge numbers - fall back to regular string comparison
			*/
			return wcscmp( a, b );
		}
		
		diff = al - bl;
		if( diff )
			return diff>0?2:-2;

		secondary_diff = (aend-a) - (bend-b);

		a=aend-1;
		b=bend-1;
	}
	else
	{
		int diff = towlower(*a) - towlower(*b);
		if( diff != 0 )
			return (diff>0)?2:-2;

		secondary_diff = *a-*b;
	}

	int res = wcsfilecmp( a+1, b+1 );

	if( abs(res) < 2 )
	{
		/*
		  No primary difference in rest of string.
		  Use secondary difference on this element if found.
		*/
		if( secondary_diff )
		{
			return secondary_diff>0?1:-1;
		}
	}
	
	return res;
	
}

void sb_init( string_buffer_t * b)
{
	wchar_t c=0;

	CHECK( b, );

	if( !b )
	{
		return;
	}

	memset( b, 0, sizeof(string_buffer_t) );	
	b_append( b, &c, sizeof( wchar_t));
	b->used -= sizeof(wchar_t);
}

string_buffer_t *sb_new()
{
	string_buffer_t *res = (string_buffer_t *)malloc( sizeof( string_buffer_t ) );

	if( !res )
	{
		oom_handler( 0 );
		return 0;
	}
	
	sb_init( res );
	return res;
}

void sb_append_substring( string_buffer_t *b, const wchar_t *s, size_t l )
{
	wchar_t tmp=0;

	CHECK( b, );
	CHECK( s, );

	b_append( b, s, sizeof(wchar_t)*l );
	b_append( b, &tmp, sizeof(wchar_t) );
	b->used -= sizeof(wchar_t);
}


void sb_append_char( string_buffer_t *b, wchar_t c )
{
	wchar_t tmp=0;

	CHECK( b, );

	b_append( b, &c, sizeof(wchar_t) );
	b_append( b, &tmp, sizeof(wchar_t) );
	b->used -= sizeof(wchar_t);
}

void sb_append_internal( string_buffer_t *b, ... )
{
	va_list va;
	wchar_t *arg;

	CHECK( b, );
	
	va_start( va, b );
	while( (arg=va_arg(va, wchar_t *) )!= 0 )
	{
		b_append( b, arg, sizeof(wchar_t)*(wcslen(arg)+1) );
		b->used -= sizeof(wchar_t);
	}
	va_end( va );
}

int sb_printf( string_buffer_t *buffer, const wchar_t *format, ... )
{
	va_list va;
	int res;
	
	CHECK( buffer, -1 );
	CHECK( format, -1 );
	
	va_start( va, format );
	res = sb_vprintf( buffer, format, va );	
	va_end( va );
	
	return res;	
}

int sb_vprintf( string_buffer_t *buffer, const wchar_t *format, va_list va_orig )
{
	int res;
	
	CHECK( buffer, -1 );
	CHECK( format, -1 );

	if( !buffer->length )
	{
		buffer->length = MIN_SIZE;
		buffer->buff = (char *)malloc( MIN_SIZE );
		if( !buffer->buff )
		{
			oom_handler( buffer );
			return -1;
		}
	}	

	while( 1 )
	{
		va_list va;
		va_copy( va, va_orig );
		
		res = vswprintf( (wchar_t *)((char *)buffer->buff+buffer->used), 
						 (buffer->length-buffer->used)/sizeof(wchar_t), 
						 format,
						 va );
		

		va_end( va );		
		if( res >= 0 )
		{
			buffer->used+= res*sizeof(wchar_t);
			break;
		}

		/*
		  As far as I know, there is no way to check if a
		  vswprintf-call failed because of a badly formated string
		  option or because the supplied destination string was to
		  small. In GLIBC, errno seems to be set to EINVAL either way. 

		  Because of this, sb_printf will on failiure try to
		  increase the buffer size until the free space is
		  larger than SB_MAX_SIZE, at which point it will
		  conclude that the error was probably due to a badly
		  formated string option, and return an error. Make
		  sure to null terminate string before that, though.
		*/
	
		if( buffer->length - buffer->used > SB_MAX_SIZE )
		{
			wchar_t tmp=0;
			b_append( buffer, &tmp, sizeof(wchar_t) );
			buffer->used -= sizeof(wchar_t);
			break;
		}
		
		buffer->buff = (char *)realloc( buffer->buff, 2*buffer->length );

		if( !buffer->buff )
		{
			oom_handler( buffer );
			return -1;
		}
		
		buffer->length *= 2;				
	}
	return res;	
}




void sb_destroy( string_buffer_t * b )
{
	CHECK( b, );
	
	free( b->buff );
}

void sb_clear( string_buffer_t * b )
{
	sb_truncate( b, 0 );
	assert( !wcslen( (wchar_t *)b->buff) );
}

void sb_truncate( string_buffer_t *b, int chars_left )
{
	wchar_t *arr;
	
	CHECK( b, );

	b->used = (chars_left)*sizeof( wchar_t);
	arr = (wchar_t *)b->buff;
	arr[chars_left] = 0;
	
}

ssize_t sb_length( string_buffer_t *b )
{
	CHECK( b, -1 );
	return (b->used-1)/sizeof( wchar_t);
	
}




void b_init( buffer_t *b)
{
	CHECK( b, );
	memset( b,0,sizeof(buffer_t));
}



void b_destroy( buffer_t *b )
{
	CHECK( b, );
	free( b->buff );
}


int b_append( buffer_t *b, const void *d, ssize_t len )
{
	if( len<=0 )
		return 0;

	CHECK( b, -1 );	

	if( !b )
	{
		return 0;
	}

	if( !d )
	{
		return 0;
	}

	if( b->length <= (b->used + len) )
	{
		size_t l = maxi( b->length*2,
						 b->used+len+MIN_SIZE );
		
		void *d = realloc( b->buff, l );
		if( !d )
		{
			oom_handler( b );
			return -1;			
		}
		b->buff=(char *)d;
		b->length = l;
	}
	memcpy( ((char*)b->buff)+b->used,
			d,
			len );

//	fwprintf( stderr, L"Copy %s, new value %s\n", d, b->buff );
	b->used+=len;

	return 1;
}

long long get_time()
{
	struct timeval time_struct;
	gettimeofday( &time_struct, 0 );
	return 1000000ll*time_struct.tv_sec+time_struct.tv_usec;
}