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libpsyc/src/parser.c
2011-04-17 12:05:14 +02:00

390 lines
10 KiB
C

#include <stdint.h>
#include <stdlib.h>
#ifdef DEBUG
#include <stdio.h>
#endif
#include <psyc/parser.h>
/** @brief isGlyph
*
* @todo: document this function
*/
inline char isGlyph(uint8_t g)
{
switch(g)
{
case ':':
case '-':
case '+':
case '=':
return 1;
default:
return 0;
}
}
inline char isNumeric(uint8_t c)
{
return c >= '0' && c <= '9' ;
}
inline char isAlphaNumeric(uint8_t c)
{
return
(( c >= 'a' && c <= 'z' )||
( c >= 'A' && c <= 'Z' )||
isNumeric(c))
;
}
/** @brief generalized linebased parser */
inline int PSYC_parse(
PSYC_State* state,
PSYC_Array* name, PSYC_Array* value,
uint8_t* modifier, unsigned long* expectedBytes)
{
/* first we test if we can access the first char */
if(state->buffer.length<=state->cursor) // cursor is not inside the length
return PSYC_INSUFFICIENT; // return insufficient data.
// in case we return insufficent, we rewind to the start.
unsigned int startc=state->cursor;
/* each line of the header starts with a glyph.
* iE :_name, -_name +_name etc, so just test if
* the first char is a glyph. */
if(1==state->inHeader)
{
if(!isGlyph(state->buffer.ptr[state->cursor])) // is the first char not a glyph?
{
if(isNumeric(state->buffer.ptr[state->cursor]))
{
if(state->buffer.length<=++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
while(isNumeric(state->buffer.ptr[state->cursor]));
{
state->length = 10 * state->length + state->buffer.ptr[state->cursor] - '0';
if(state->buffer.length<=++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
}
// a NL follows the length
if (state->buffer.ptr[state->cursor] != '\n')
{
}
}
// the only other possibility now is that the packet
// is complete(empty packet) or that the method started.
if(isAlphaNumeric(state->buffer.ptr[state->cursor]))
{
state->inHeader = 0;
return 2; // return header finished
}
if(state->buffer.ptr[state->cursor] == '|')
{
if(state->buffer.length<=++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
if(state->buffer.ptr[state->cursor]=='\n')
{
++(state->cursor);
return 3; // return packet finished
}
}
return -6; // report error
}
else // it is a glyph, so a variable name starts here
{
*modifier = *(state->buffer.ptr+state->cursor);
if (state->buffer.length <= ++(state->cursor))
{
state->cursor = startc; // rewind to start of line
return PSYC_INSUFFICIENT; // return insufficient
}
name->ptr = state->buffer.ptr + state->cursor;
name->length = 0;
}
}
char method=0;
/* in the body, the same applies, only that the
* method does not start with a glyph.*/
if(0==state->inHeader && !isGlyph(state->buffer.ptr[state->cursor]))
{
if(!isAlphaNumeric(state->buffer.ptr[state->cursor]) && state->buffer.ptr[state->cursor] != '_')
{
// the body rule is optional, which means
// that now also just |\n can follow.
if(state->buffer.ptr[state->cursor] == '|')
{
if(state->buffer.length<=++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
if(state->buffer.ptr[state->cursor]=='\n')
{
++(state->cursor);
return 3; // return packet finished
}
}
return -5; // report error
}
else
{
name->ptr = state->buffer.ptr+state->cursor;
name->length=1;
method=1;
}
}
else
{
*modifier = *(state->buffer.ptr+state->cursor);
if (state->buffer.length <= ++(state->cursor))
{
state->cursor = startc; // rewind
return PSYC_INSUFFICIENT; // return insufficient
}
name->ptr = state->buffer.ptr+state->cursor;
name->length=1;
}
/* validate the incremented cursor */
if(state->buffer.length <= ++(state->cursor))
{
state->cursor=startc;
return PSYC_INSUFFICIENT;
}
/* what follows is the name. At least one char.
* allowed is alphanumeric and _ */
// first char must exist.
if(!isAlphaNumeric(state->buffer.ptr[state->cursor]) // is it not alphanum
&& state->buffer.ptr[state->cursor] != '_') // AND not '_'. must be invalid then
return -1; // return parser error.
name->length+=1;
/* now checking how long the name of the variable is. */
unsigned int i=0;
while(1)
{
if(state->buffer.length<= ++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
// same as bevore
if(!isAlphaNumeric(state->buffer.ptr[state->cursor]) &&
state->buffer.ptr[state->cursor] != '_')
break; // not valid? then stop the loop right here
++(name->length); // was a valid char, increase length
}
/* we now parsed the variable name successfully
* after the name either a \n or a \t follows.
*
* for the method, the data starts after an \n
* so checking for \n too here
* We dont check if cursor inside length, because
* the last loop iteration did that already.
*/
if(state->buffer.ptr[state->cursor] == '\t' || state->buffer.ptr[state->cursor] == '\n') // && method==1))
{
/* after the \t the data follows, which is
* anything but \n. data can be of length 0
*
* for the method: after the \n data follows,
* which is anything but \n|\n
*
* but data is optional, so we first check
* here if data follows at all.
*
* arg-data=value. we set value here so it
* points to a valid range and so we point
* to the first potential arg-data byte.
* If there is no arg-data, we still have
* the length attribute on 0. */
if((method == 0 && state->buffer.ptr[state->cursor] == '\n') /* emptyvar */ ||
(method == 1 && state->cursor+2 < state->buffer.length &&
state->buffer.ptr[state->cursor+1] == '|' &&
state->buffer.ptr[state->cursor+2] == '\n') /*no data */ )
{
value->ptr=state->buffer.ptr+state->cursor;
value->length=0;
}
else
{
value->ptr=state->buffer.ptr+state->cursor+1;
if (0 != state->length) // we know the length of the packet
{
// is the packet in the buffer?
if (value->ptr + state->length + 3 > state->buffer.ptr + state->buffer.length)
{ // no
value->length = state->buffer.length - state->cursor;
*expectedBytes = state->length - value->length;
}
else // yes, the packet is complete in the buffer.
{
value->length= state->buffer.length - state->cursor -3;
*expectedBytes = 0;
}
}
else // else search for the terminator
{
value->length=0;
while (1)
{
if(state->buffer.length<=++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT ; // return insufficient
}
if(0 == method && state->buffer.ptr[state->cursor] == '\n')
break;
if(1 == method && state->buffer.ptr[state->cursor] == '\n')
{
if(state->buffer.length<=(state->cursor)+2) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
if(state->buffer.ptr[state->cursor+1] == '|')
if(state->buffer.ptr[state->cursor+2] == '\n')
{
/* packet finishes here */
state->cursor+=3;
return 3;
}
}
++(value->length);
}
}
}
}
else if(state->inHeader == 0 && method==0 && state->buffer.ptr[state->cursor] == ' ') // oi, its a binary var!
{ // after SP the length follows.
unsigned int binLength= 0;
if(state->buffer.length<=++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
while(isNumeric(state->buffer.ptr[state->cursor]));
{
binLength = 10 * binLength + state->buffer.ptr[state->cursor] - '0';
if(state->buffer.length<=++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
}
// after the length a TAB follows
if (state->buffer.ptr[state->cursor] != '\t')
return -8;
// is the length still in this buffer?
if(state->buffer.length <= state->cursor+binLength+1 )
{
state->cursor=startc;
return PSYC_INSUFFICIENT;
}
value->ptr = state->buffer.ptr + state->cursor+1;
value->length=binLength;
state->cursor += binLength+1;
}
else
return -8;
/* if there was a \t, then we parsed up until the
* \n char from the simple-arg rule ( \t arg-state->buffer.ptr \n )
*
* Now, if there would be no \t, we still would be at
* the point where a \n must follow.
*
* So, just checking \n here will cover both cases of
* the alternative ( simple-arg / \n ) from rule
* routing-modifier
*
* again, the loop has already validated the cursors
* position*/
if(state->buffer.ptr[state->cursor] != '\n')
return -2; // return parser error.
/* if a \n follows now, the an body is attached.
* if not, a |\n must follow */
if(state->buffer.length<=++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
if(1 == state->inHeader && state->buffer.ptr[state->cursor] == '\n')
{
state->cursor+=1;
state->inHeader = 0;
return 2; // line is complete, but body starts now.
}
if(state->buffer.ptr[state->cursor] != '|') // no pipe, then only line complete, not the packet.
{
if (state->inHeader == 1)
return PSYC_ROUTING;
else
return PSYC_ENTITY;
}
if(state->buffer.length<=++(state->cursor)) // incremented cursor inside lenght?
{
state->cursor=startc; // set to start value
return PSYC_INSUFFICIENT; // return insufficient
}
if(state->buffer.ptr[state->cursor] != '\n')
return -4;
state->cursor+=1;
return 3; // packet is complete
}