buffer.c

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#include "user_config.h"
#include "fatfs.h"
#include "posix.h"
#include "buffer.h"


    
buffer_t *buffer_read_open(char *name, uint8_t *buf, int size)
{
    static buffer_t _buff;
    buffer_t *p = (buffer_t *) &_buff;

    memset(p,0,(int) sizeof(buffer_t));

    p->buf  = buf;

    p->fp = fopen(name,"rb");
    if(p->fp == NULL)
    {
        printf("buffer_read_open: Can not open:[%s]\n", name);
        buffer_read_close(p);
        return(0);
    }

    p->size = size;
    p->ind = 0;
    p->len = 0;
    p->ungetf = 0;
    p->ungetc = 0;
    return(p);
}


void buffer_read_close(buffer_t *p)
{
    if(p->fp)
        fclose(p->fp);
    p->size = 0;
    p->len = 0;
    p->ind = 0;
    p->ungetf = 0;
    p->ungetc = 0;
}

void buffer_ungetc(buffer_t *p, int c)
{
    p->ungetf = 1;
    p->ungetc = c;
}

    
int buffer_getc(buffer_t *p)
{
    int size;
    int c;

    if(p->ungetf)
    {
        p->ungetf = 0;
        return(p->ungetc);
    }
    // Read a new block
    if(p->len < 1)
    {
        p->ind = 0;
        size = fread(p->buf, 1, p->size, p->fp);
        if(size <= 0)
        {
            p->len = 0;
            return(EOF);
        }
        p->len = size;
    }
    c = p->buf[p->ind];
    p->len--;
    p->ind++;
    return( c );
}


uint8_t *buffer_gets(uint8_t *str, int size, buffer_t *p)
{
    int c;
    int next;
    int ind = 0;

    // leave room for EOS
    while(ind < size)
    {
        c = buffer_getc(p);
        if(c == EOF)
        {
            if(ind == 0)
            {
                str[ind] = 0;
                return(NULL);
            }
            break;
        }
        // CR NL is end of line
        if(c == '\r')
        {
            next = buffer_getc(p);
            if(next == '\n')
                break;
            buffer_ungetc(p,next);
            break;
        }
        // NL is end of line
        if(c == '\n')
            break;
        str[ind++] = c;
    }
    str[ind] = 0;
    return(str);
}