Changes to many headers. midi.c has fewer deps. Prepare for merge.

[cantaveria.git] / util.c

/*
   Cantaveria - action adventure platform game
   Copyright (C) 2009 2010 Evan Rinehart

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; either version 2
   of the License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to

   The Free Software Foundation, Inc.
   51 Franklin Street, Fifth Floor
   Boston, MA  02110-1301, USA
*/


#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

#include <rng.h>
#include <util.h>

/* error reporting */
void report_verror(const char* format, va_list ap){
        vprintf(format, ap);
}

void fatal_error(const char* format, ...){
        va_list ap;
        va_start(ap, format);
        report_verror(format, ap);
        va_end(ap);
        exit(-1);
}

void boot_msg(const char* format, ...){
        va_list ap;
        va_start(ap, format);
        vprintf(format, ap);
        va_end(ap);
}

void error_msg(const char* format, ...){
        va_list ap;
        va_start(ap, format);
        report_verror(format, ap);
        va_end(ap);
}

void out_of_memory(const char* prefix){
        error_msg("%s: *out of memory*\n", prefix);
        exit(-2);
}

/* 'safe' functions */
void* xmalloc(size_t size){
        void* v = malloc(size);
        if(!v){
                /* On Linux malloc by default does not return NULL
                even if there is no more memory. So this function
                isn't really 'safe' on that system. */
                out_of_memory("xmalloc");
        }
        return v;
}

char* strxcpy(const char* str){
        char* cpy = xmalloc(strlen(str)+1);
        strcpy(cpy, str);
        return cpy;
}

void strmcat(char* dst, const char* src, size_t n){
        strncat(dst, src, n - strlen(src) - 1);
}




/*
   decodes utf8 encoded string str and places the
   next character in u.
   returns the number of bytes of str consumed.
*/
int unicode_getc(char* str, utf32* u){
        /*unsigned char b[4] = {str[0], str[1], str[2], str[3]};*/
        unsigned char b[4];
        unsigned char a[4] = {0,0,0,0};
        int N;

        memcpy(b, str, 4);

        /* 1111 0xf
           1110 0xe
           1100 0xc
           1000 0x8 */

        if((b[0] & 0x80) == 0){ /*one byte sequence*/
                a[3] = b[0];
                N = 1;
        }

        else if(
                ((b[0]&0xe0)==0xc0) &&
                ((b[1]&0xc0)==0x80)
        ){
                /*two byte sequence*/
                a[3] = ((b[0]&0x03)<<6)|(b[1]&0x3f);
                a[2] = (b[0]&0x1c)>>2;
                N = 2;
        }

        else if(
                ((b[0]&0xf0)==0xe0) &&
                ((b[1]&0xc0)==0x80) &&
                ((b[2]&0xc0)==0x80)
        ){
                /*three byte sequence*/
                a[3] = ((b[1]&0x03)<<6)|(b[2]&0x3f);
                a[2] = ((b[0]&0x0f)<<4)|((b[1]&0x3c)>>2);
                N = 3;
        }

        else if(
                ((b[0]&0xf8)==0xf0) &&
                ((b[1]&0xc0)==0x80) &&
                ((b[2]&0xc0)==0x80) &&
                ((b[3]&0xc0)==0x80)
        ){
                /*four byte sequence*/
                a[3] = ((b[2]&0x03)<<6)|(b[3]&0x3f);
                a[2] = ((b[1]&0x0f)<<4)|((b[2]&0x3c)>>2);
                a[1] = ((b[0]&0x03)<<2)|((b[1]&0x30)>>4);
                N = 4;
        }

        else {
                a[3] = '?';
                N = 4;/*FIXME find next valid byte*/
        }

        *u = (a[0]<<24) | (a[1]<<16) | (a[2]<<8) | a[3];
        return N;
}



void tree_insert(
        struct treenode* root,
        int (*compare)(void* k1, void* k2),
        void* key, void* value)
{

        struct treenode* node = xmalloc(sizeof(struct treenode));
        struct treenode* ptr;
        node->key = key;
        node->value = value;
        node->l = NULL;
        node->r = NULL;

        ptr = root;
        while(1){
                if( compare(ptr->key, key) < 0 ){
                        if(ptr->l){ptr = ptr->l;}
                        else{ptr->l = node; break;}
                }
                else if( compare(ptr->key, key) > 0){
                        if(ptr->r){ptr = ptr->r;}
                        else{ptr->r = node; break;}
                }
                else{ /* key already exists */
                        error_msg("tree_insert: key already exists\n");
                        break;
                }
        }
}

void* tree_search(
        struct treenode* root,
        int (*compare)(void* k1, void* k2),
        void* key)
{
        if(root==NULL){
                return NULL;
        }
        else if(compare(root->key, key)>0){
                return tree_search(root->r, compare, key);
        }
        else if(compare(root->key, key)<0){
                return tree_search(root->l, compare, key);
        }
        else{
                return root->value;
        }
}



/* rng utility functions */
void rand_reset(unsigned s){
        zsrand(s);
}

int randi(int a, int b){
        int L = b-a;
        int P = 1;
        int x;

        while(P < L){
                P <<= 1;
        }

        do{
                x = zrand() & (P-1);
        } while(x > L);

        return x+a;
}

double randf(){
        double D = UINT_MAX;
        unsigned x = zrand();
        return x / D;
}


/* Copyright 300BC Euclid */
int gcd(int a, int b){
        while(b){
                int t = b;
                b = a % b;
                a = t;
        }
        return a;
}