/** Parse individual header field (name-value pair) */
APT_DECLARE(apt_header_field_t*) apt_header_field_parse(apt_text_stream_t *stream, apr_pool_t *pool)
{
apr_size_t folding_length = 0;
apr_array_header_t *folded_lines = NULL;
apt_header_field_t *header_field;
apt_str_t temp_line;
apt_str_t *line;
apt_pair_t pair;
/* read name-value pair */
if(apt_text_header_read(stream,&pair) == FALSE) {
return NULL;
}
/* check folding lines (value spanning multiple lines) */
while(stream->pos < stream->end) {
if(apt_text_is_wsp(*stream->pos) == FALSE) {
break;
}
stream->pos++;
/* skip further white spaces (if any) */
apt_text_white_spaces_skip(stream);
if(!folded_lines) {
folded_lines = apr_array_make(pool,1,sizeof(apt_str_t));
}
if(apt_text_line_read(stream,&temp_line) == TRUE) {
line = apr_array_push(folded_lines);
*line = temp_line;
folding_length += line->length;
}
};
header_field = apt_header_field_alloc(pool);
/* copy parsed name of the header field */
header_field->name.length = pair.name.length;
header_field->name.buf = apr_palloc(pool, pair.name.length + 1);
if(pair.name.length) {
memcpy(header_field->name.buf, pair.name.buf, pair.name.length);
}
header_field->name.buf[header_field->name.length] = '\0';
/* copy parsed value of the header field */
header_field->value.length = pair.value.length + folding_length;
header_field->value.buf = apr_palloc(pool, header_field->value.length + 1);
if(pair.value.length) {
memcpy(header_field->value.buf, pair.value.buf, pair.value.length);
}
if(folding_length) {
int i;
char *pos = header_field->value.buf + pair.value.length;
/* copy parsed folding lines */
for(i=0; i<folded_lines->nelts; i++) {
line = &APR_ARRAY_IDX(folded_lines,i,apt_str_t);
memcpy(pos,line->buf,line->length);
pos += line->length;
}
}
header_field->value.buf[header_field->value.length] = '\0';
return header_field;
}
/** To be used to navigate through the header fields (name:value pairs) of the text stream (message)
Valid header fields are:
name:value<CRLF>
name: value<CRLF>
name: value<CRLF>
name: value<LF>
name:<CRLF> (only name, no value)
<CRLF> (empty header)
Malformed header fields are:
name:value (missing end of line <CRLF>)
name<CRLF> (missing separator ':')
*/
APT_DECLARE(apt_bool_t) apt_text_header_read(apt_text_stream_t *stream, apt_pair_t *pair)
{
char *pos = stream->pos;
apt_bool_t status = FALSE;
apt_string_reset(&pair->name);
apt_string_reset(&pair->value);
/* while not end of stream */
while(pos < stream->end) {
if(*pos == APT_TOKEN_CR) {
/* end of line detected */
if(pair->value.buf) {
/* set length of the value */
pair->value.length = pos - pair->value.buf;
}
pos++;
if(pos < stream->end && *pos == APT_TOKEN_LF) {
pos++;
}
status = TRUE;
break;
}
else if(*pos == APT_TOKEN_LF) {
/* end of line detected */
if(pair->value.buf) {
/* set length of the value */
pair->value.length = pos - pair->value.buf;
}
pos++;
status = TRUE;
break;
}
else if(!pair->name.length) {
/* skip preceding white spaces (SHOULD NOT be any WSP, though) and read name */
if(!pair->name.buf && apt_text_is_wsp(*pos) == FALSE) {
pair->name.buf = pos;
}
if(*pos == ':') {
/* set length of the name */
pair->name.length = pos - pair->name.buf;
}
}
else if(!pair->value.length) {
/* skip preceding white spaces and read value */
if(!pair->value.buf && apt_text_is_wsp(*pos) == FALSE) {
pair->value.buf = pos;
}
}
pos++;
}
if(status == TRUE) {
/* advance stream pos regardless it's a valid header or not */
stream->pos = pos;
/* if length == 0 && buf => header is malformed */
if(!pair->name.length && pair->name.buf) {
status = FALSE;
}
}
else {
/* end of stream is reached, do not advance stream pos, but set is_eos flag */
stream->is_eos = TRUE;
}
return status;
}
