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/* buffers.c */
#include "or.h"
int buf_new(char **buf, size_t *buflen, size_t *buf_datalen) {
assert(buf && buflen && buf_datalen);
*buf = (char *)malloc(MAX_BUF_SIZE);
if(!*buf)
return -1;
memset(*buf,0,MAX_BUF_SIZE);
*buflen = MAX_BUF_SIZE;
*buf_datalen = 0;
return 0;
}
void buf_free(char *buf) {
free(buf);
}
int read_to_buf(int s, char **buf, size_t *buflen, size_t *buf_datalen, int *reached_eof) {
/* grab from s, put onto buf, return how many bytes read */
int read_result;
assert(buf && *buf && buflen && buf_datalen && reached_eof && (s>=0));
/* this is the point where you would grow the buffer, if you want to */
read_result = read(s, *buf+*buf_datalen, *buflen - *buf_datalen);
if (read_result < 0) {
if(errno!=EAGAIN) { /* it's a real error */
return -1;
}
return 0;
} else if (read_result == 0) {
log(LOG_DEBUG,"read_to_buf(): Encountered eof");
*reached_eof = 1;
return 0;
} else { /* we read some bytes */
*buf_datalen += read_result;
log(LOG_DEBUG,"read_to_buf(): Read %d bytes. %d on inbuf.",read_result, *buf_datalen);
return read_result;
}
}
int flush_buf(int s, char **buf, size_t *buflen, size_t *buf_datalen) {
/* push from buf onto s
* then memmove to front of buf
* return -1 or how many bytes remain on the buf */
int write_result;
assert(buf && *buf && buflen && buf_datalen && (s>=0));
if(*buf_datalen == 0) /* nothing to flush */
return 0;
/* this is the point where you would grow the buffer, if you want to */
write_result = write(s, buf, *buf_datalen);
if (write_result < 0) {
if(errno!=EAGAIN) { /* it's a real error */
return -1;
}
log(LOG_DEBUG,"flush_buf(): write() would block, returning.");
return 0;
} else {
*buf_datalen -= write_result;
memmove(*buf, *buf+write_result, *buf_datalen);
log(LOG_DEBUG,"flush_buf(): flushed %d bytes, %d remain.",write_result,*buf_datalen);
return *buf_datalen;
}
}
int write_to_buf(char *string, size_t string_len,
char **buf, size_t *buflen, size_t *buf_datalen) {
/* append string to buf (growing as needed, return -1 if "too big")
* return total number of bytes on the buf
*/
assert(string && buf && *buf && buflen && buf_datalen);
/* this is the point where you would grow the buffer, if you want to */
if (string_len + *buf_datalen > *buflen) { /* we're out of luck */
log(LOG_DEBUG, "write_to_buf(): buflen too small. Time to implement growing dynamic bufs.");
return -1;
}
memcpy(*buf+*buf_datalen, string, string_len);
*buf_datalen += string_len;
log(LOG_DEBUG,"write_to_buf(): added %d bytes to buf (now %d total).",string_len, *buf_datalen);
return *buf_datalen;
}
int fetch_from_buf(char *string, size_t string_len,
char **buf, size_t *buflen, size_t *buf_datalen) {
/* if there is string_len bytes in buf, write them onto string,
* then memmove buf back (that is, remove them from buf) */
assert(string && buf && *buf && buflen && buf_datalen);
/* this is the point where you would grow the buffer, if you want to */
if(string_len > *buf_datalen) /* we want too much. sorry. */
return -1;
memcpy(string,*buf,string_len);
*buf_datalen -= string_len;
memmove(*buf, *buf+string_len, *buf_datalen);
return *buf_datalen;
}
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