/*
	stringq
	
	 process char buffer as queue like pipe

	by Yoshioka Tsuneo(QWF00133@niftyserve.or.jp)
	This File is Copy,Edit,Re-Distribute,etc.. FREE!
	Welcome any e-mail!!
*/
#include "stringq.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>

STRINGQ *STRINGQ_open(char *buf,int size)
{
	STRINGQ *b;

	b = malloc(sizeof(STRINGQ));
	if(!b)return NULL;
	memset(b,0,sizeof(STRINGQ));
	if(buf==NULL){
		b->buf = malloc(size);
		if(! b->buf){free(b);return NULL;}
	}else{
		b->buf_by_user = 1;
		b->buf=buf;
	}
	memset(b->buf ,0,size);
	b->bufsize = size;
	return b;
}
int STRINGQ_getc(STRINGQ *b)
{
	int c;

	if(b->len==0){
		if(b->exist_eof){return EOF;}else{return -2;}
	}
	c = b->buf[b->start_ptr];
	b->start_ptr++;
	if(b->start_ptr == b->bufsize){b->start_ptr = 0;}
	b->len--;
	return c;
}
int STRINGQ_ungetc(int c,STRINGQ *b)
{
	b->start_ptr--;
	if(b->start_ptr <0){b->start_ptr = b->bufsize -1;}
	b->buf[b->start_ptr] = c;
	b->len++;
	return c;
}
int STRINGQ_putc(int c,STRINGQ *b)
{
	if(b->len==b->bufsize){return -2;}
	
	b->buf[b->end_ptr] = c;
	b->end_ptr ++;
	if(b->end_ptr == b->bufsize){b->end_ptr = 0;}
	b->len++;
	return c;
}
void STRINGQ_puteof(STRINGQ *b)
{
	b->exist_eof = 1;
}
void STRINGQ_close(STRINGQ *b)
{
	if(!b->buf_by_user)free(b->buf);
	free(b);
}
int STRINGQ_write(STRINGQ *b,const char *buff,int len)
{
	int len2;
	int save_len;

	if(b->len >= b->bufsize){
		return -2;
	}else if((len + b->len) > b->bufsize){
		len = b->bufsize - b->len;
	}
	/*if(len + b->len > b->bufsize){return -2;}*/

	save_len = len;
	len2=MIN(len,b->bufsize - b->start_ptr);
	memcpy(b->buf + b->end_ptr,buff,len2);
	len -= len2;
	b->len += len2;
	b->end_ptr += len2;
	if(b->end_ptr == b->bufsize){b->end_ptr = 0;}

	if(len>0){
		memcpy(b->buf,buff+len2,len);
		b->len += len;
		b->end_ptr += len;
	}
	return save_len;
}
int STRINGQ_read(STRINGQ *b,char *buff,int len)
{
	int readlen;
	int len2;

	if(len > b->len){
		if(b->exist_eof){
			readlen = b->len;
		}else{
			return -2;
		}
	}else{
		readlen = len;
	}
	/*len = readlen;*/
	len2 = MIN(len,b->bufsize - b->start_ptr);
	memcpy(buff,b->buf + b->start_ptr,len2);
	len -= len2;
	b->len -= len2;
	b->start_ptr += len2;
	if(b->start_ptr == b->bufsize){b->start_ptr =0;}
	if(len>0){
		/* b->end_ptr == 0*/
		memcpy(buff+len2,b->buf,len);
		b->len -=len;
		b->start_ptr +=len;
	}
	return readlen;
}
int STRINGQ_puts(const char *str,STRINGQ *b)
{
	return STRINGQ_write(b,str,strlen(str));
}
int STRINGQ_printf(STRINGQ *b,const char *format,...)
{
	va_list vp;
	int ret;
	char line[10000];

	va_start(vp,format);
	vsprintf(line,format,vp);
	ret = STRINGQ_puts(line,b);
	va_end(vp);
	return ret;
}

/* may be contain bug */
char *STRINGQ_gets(char *str,int n,STRINGQ *b)
{
	int c;
	char *str2 = str;

	c = STRINGQ_getc(b);
	if(c==EOF){return NULL;}
	*str2++=c;
	while(c!=EOF && c!='\n' && c!='\0' && --n>0){
		c = STRINGQ_getc(b);
		*str2++ = c;
	}
	*str2 = '\0';
	return str;
}