terom@8: 
terom@8: #include "line_proto.h"
terom@8: 
terom@8: #include <string.h>
terom@8: #include <stdlib.h>
terom@8: #include <assert.h>
terom@8: 
terom@8: /*
terom@8:  * Our state
terom@8:  */
terom@8: struct line_proto {
terom@8:     /* The sock_stream we read/write with */
terom@8:     struct sock_stream *sock;
terom@8: 
terom@8:     /* Offset of trailing data in buf */
terom@8:     size_t tail_offset;
terom@8: 
terom@8:     /* Length of trailing data in buf, if any */
terom@8:     size_t tail_len;
terom@8: 
terom@8:     /* Last error */
terom@8:     struct error_info err;
terom@8: };
terom@8: 
terom@8: err_t line_proto_create (struct line_proto **lp_ptr, struct sock_stream *sock, struct error_info *err)
terom@8: {
terom@8:     struct line_proto *lp;
terom@8: 
terom@8:     // allocate
terom@8:     if ((lp = calloc(1, sizeof(*lp))) == NULL)
terom@8:         return SET_ERROR(err, ERR_CALLOC);
terom@8: 
terom@8:     // store
terom@8:     lp->sock = sock;
terom@8: 
terom@8:     // return
terom@8:     *lp_ptr = lp;
terom@8: 
terom@8:     return SUCCESS;
terom@8: }
terom@8: 
terom@8: /*
terom@8:  * This looks for a full '\r\n' terminated line at the beginning of the given buffer. If found, the \r\n will be
terom@8:  * replaced with a '\0', and the offset to the beginning of the next line returned. If not found, zero is returned
terom@8:  * (which is never a valid next-line offset).
terom@8:  *
terom@8:  * The given \a hint is an hint as to the offset at which to start scanning, used for incremental invocations of this
terom@8:  * on the same buffer.
terom@8:  *
terom@8:  */
terom@8: int _parse_line (char *buf, size_t len, size_t *hint) {
terom@8:     int i;
terom@8: 
terom@8:     // empty buffer -> nothing
terom@8:     if (len == 0)
terom@8:         return 0;
terom@8: 
terom@8:     // look for terminating '\r\n' sequence
terom@8:     for (i = *hint; i < len - 1; i++) {
terom@8:         // match this + next char
terom@8:         if (buf[i] == '\r' && buf[i + 1] == '\n')
terom@8:             break;
terom@8:     }
terom@8: 
terom@8:     // incomplete?
terom@8:     if (i >= len - 1) {
terom@8:         *hint = len - 1;
terom@8:         return 0;
terom@8:     }
terom@8: 
terom@8:     // mangle the newline off
terom@8:     buf[i] = '\0';
terom@8: 
terom@8:     // return offset to next line
terom@8:     return i + 2;
terom@8: }
terom@8: 
terom@8: err_t line_proto_read (struct line_proto *lp, char *buf, size_t len)
terom@8: {
terom@8:     // offset to recv() new data into, offset to _parse_line hint, offset to next line from _parse_line
terom@8:     size_t recv_offset = 0, peek_offset = 0, next_offset = 0;
terom@8:     int ret;
terom@8: 
terom@8:     // adjust offset from previous data
terom@8:     recv_offset = lp->tail_len;
terom@8: 
terom@8:     // move trailing data from previous line to front of buffer
terom@8:     if (lp->tail_offset) {
terom@8:         // move to front
terom@8:         memmove(buf, buf + lp->tail_offset, lp->tail_len);
terom@8: 
terom@8:         // reset
terom@8:         lp->tail_offset = 0;
terom@8:         lp->tail_len = 0;
terom@8:     }
terom@8: 
terom@8:     // readline loop
terom@8:     do {
terom@8:         // parse any line at the beginning of the buffer
terom@8:         if ((next_offset = _parse_line(buf, recv_offset, &peek_offset)) > 0)
terom@8:             break;
terom@8: 
terom@8:         // ensure there's enough space for it
terom@8:         assert(recv_offset < len);
terom@8:         
terom@8:         // otherwise, read more data
terom@8:         if ((ret = sock_stream_read(lp->sock, buf + recv_offset, len - recv_offset)) < 0)
terom@8:             RETURN_SET_ERROR_INFO(&lp->err, sock_stream_error(lp->sock));
terom@8: 
terom@8:         // EOF?
terom@8:         if (ret == 0)
terom@8:             return SET_ERROR(&lp->err, ERR_READ_EOF);
terom@8:         
terom@8:         // update recv_offset
terom@8:         recv_offset += ret;
terom@8: 
terom@8:     } while (1);
terom@8: 
terom@8:     // update state for next call
terom@8:     lp->tail_offset = next_offset;
terom@8:     lp->tail_len = recv_offset - next_offset;
terom@8: 
terom@8:     // ok
terom@8:     return SUCCESS;
terom@8: }
terom@8: 
terom@8: const struct error_info* line_proto_error (struct line_proto *lp)
terom@8: {
terom@8:     // return pointer
terom@8:     return &lp->err;
terom@8: }