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authorDavid Robillard <d@drobilla.net>2011-01-22 19:25:40 +0000
committerDavid Robillard <d@drobilla.net>2011-01-22 19:25:40 +0000
commit88a315b8ecf1534a92466bdc1ad37fe6a1bd6031 (patch)
treed1ad453c208f2c8efd248d8e57fc32485f239e2a
parent752051a76a46c5d3c19c65ac8a8f24019a81df35 (diff)
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Pass context (current graph, subject, predicate) as a struct to functions that need it.
Allows for proper support for graphs (i.e. TriG), among other things... git-svn-id: http://svn.drobilla.net/serd/trunk@37 490d8e77-9747-427b-9fa3-0b8f29cee8a0
-rw-r--r--src/reader.c108
1 files changed, 59 insertions, 49 deletions
diff --git a/src/reader.c b/src/reader.c
index 9aa0d12a..0566617b 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -50,7 +50,6 @@ typedef uint32_t uchar;
typedef size_t Ref;
-
typedef struct {
SerdNodeType type;
Ref value;
@@ -58,6 +57,12 @@ typedef struct {
Ref lang;
} Node;
+typedef struct {
+ const Node* graph;
+ const Node* subject;
+ const Node* predicate;
+} Context;
+
static const Node SERD_NODE_NULL = {0,0,0,0};
struct SerdReaderImpl {
@@ -295,8 +300,8 @@ emit_statement(SerdReader reader,
deref(reader, o->datatype), deref(reader, o->lang));
}
-static bool read_collection(SerdReader reader, Node* dest);
-static bool read_predicateObjectList(SerdReader reader, const Node* subject);
+static bool read_collection(SerdReader reader, Context ctx, Node* dest);
+static bool read_predicateObjectList(SerdReader reader, Context ctx);
// [40] hex ::= [#x30-#x39] | [#x41-#x46]
static inline uint8_t
@@ -986,7 +991,7 @@ blank_id(SerdReader reader)
// Spec: [21] blank ::= nodeID | '[]' | '[' predicateObjectList ']' | collection
// Actual: [21] blank ::= nodeID | '[ ws* ]' | '[' ws* predicateObjectList ws* ']' | collection
static bool
-read_blank(SerdReader reader, Node* dest)
+read_blank(SerdReader reader, Context ctx, Node* dest)
{
switch (peek_byte(reader)) {
case '_':
@@ -1001,18 +1006,17 @@ read_blank(SerdReader reader, Node* dest)
return true;
} else {
*dest = make_node(BLANK, blank_id(reader), 0, 0);
- read_predicateObjectList(reader, dest);
+ ctx.subject = dest;
+ read_predicateObjectList(reader, ctx);
read_ws_star(reader);
eat_byte(reader, ']');
return true;
}
case '(':
- return read_collection(reader, dest);
+ return read_collection(reader, ctx, dest);
default:
- error(reader, "illegal blank node\n");
+ return error(reader, "illegal blank node\n");
}
- // TODO: collections
- return false;
}
inline static bool
@@ -1029,12 +1033,14 @@ is_object_end(const uint8_t c)
// [13] object ::= resource | blank | literal
// Recurses, calling statement_sink for every statement encountered.
+// Leaves stack in original calling state (i.e. pops everything it pushes).
static bool
-read_object(SerdReader reader, const Node* subject, const Node* predicate)
+read_object(SerdReader reader, Context ctx)
{
static const char* const XSD_BOOLEAN = "http://www.w3.org/2001/XMLSchema#boolean";
static const size_t XSD_BOOLEAN_LEN = 40;
+ uint8_t pre[6];
bool ret = false;
Node o = SERD_NODE_NULL;
const uint8_t c = peek_byte(reader);
@@ -1042,7 +1048,7 @@ read_object(SerdReader reader, const Node* subject, const Node* predicate)
case ')':
return false;
case '[': case '(': case '_':
- TRY_THROW(ret = read_blank(reader, &o));
+ TRY_THROW(ret = read_blank(reader, ctx, &o));
break;
case '<': case ':':
TRY_THROW(ret = read_resource(reader, &o));
@@ -1054,23 +1060,19 @@ read_object(SerdReader reader, const Node* subject, const Node* predicate)
break;
case '.':
TRY_THROW(ret = read_literal(reader, &o));
- default: break;
- }
-
- if (!ret) {
- assert(o.value == 0);
+ break;
+ default:
/* Either a boolean literal, or a qname.
- Unfortunately there is no way to distinbuish these without a lot of readahead,
- since `true' or `false' could be the start of a qname.
+ Unfortunately there is no way to distinguish these without
+ readahead, since `true' or `false' could be the start of a qname.
*/
- uint8_t pre[6];
readahead(reader, pre, 6);
- if (!strncmp((char*)pre, "true", 4) && is_object_end(pre[4])) {
+ if (!memcmp(pre, "true", 4) && is_object_end(pre[4])) {
eat_string(reader, "true", 4);
const Ref value = push_string(reader, "true", 5);
const Ref datatype = push_string(reader, XSD_BOOLEAN, XSD_BOOLEAN_LEN + 1);
o = make_node(LITERAL, value, datatype, 0);
- } else if (!strncmp((char*)pre, "false", 5) && is_object_end(pre[5])) {
+ } else if (!memcmp(pre, "false", 5) && is_object_end(pre[5])) {
eat_string(reader, "false", 5);
const Ref value = push_string(reader, "false", 6);
const Ref datatype = push_string(reader, XSD_BOOLEAN, XSD_BOOLEAN_LEN + 1);
@@ -1078,33 +1080,32 @@ read_object(SerdReader reader, const Node* subject, const Node* predicate)
} else if (!is_object_end(c)) {
o = make_node(QNAME, read_qname(reader), 0, 0);
}
+ ret = o.value;
}
- if (o.value != 0) {
- emit_statement(reader, NULL, subject, predicate, &o);
- pop_string(reader, o.lang);
- pop_string(reader, o.datatype);
- pop_string(reader, o.value);
- return true;
+ if (ret) {
+ assert(o.value);
+ emit_statement(reader, ctx.graph, ctx.subject, ctx.predicate, &o);
}
+
except:
pop_string(reader, o.lang);
pop_string(reader, o.datatype);
pop_string(reader, o.value);
- return false;
+ return ret;
}
// Spec: [8] objectList ::= object ( ',' object )*
// Actual: [8] objectList ::= object ( ws* ',' ws* object )*
static bool
-read_objectList(SerdReader reader, const Node* subject, const Node* predicate)
+read_objectList(SerdReader reader, Context ctx)
{
- TRY_RET(read_object(reader, subject, predicate));
+ TRY_RET(read_object(reader, ctx));
read_ws_star(reader);
while (peek_byte(reader) == ',') {
eat_byte(reader, ',');
read_ws_star(reader);
- TRY_RET(read_object(reader, subject, predicate));
+ TRY_RET(read_object(reader, ctx));
read_ws_star(reader);
}
return true;
@@ -1113,7 +1114,7 @@ read_objectList(SerdReader reader, const Node* subject, const Node* predicate)
// Spec: [7] predicateObjectList ::= verb objectList ( ';' verb objectList )* ( ';' )?
// Actual: [7] predicateObjectList ::= verb ws+ objectList ( ws* ';' ws* verb ws+ objectList )* ( ';' )?
static bool
-read_predicateObjectList(SerdReader reader, const Node* subject)
+read_predicateObjectList(SerdReader reader, Context ctx)
{
if (reader->eof) {
return false;
@@ -1121,7 +1122,8 @@ read_predicateObjectList(SerdReader reader, const Node* subject)
Node predicate = SERD_NODE_NULL;
TRY_RET(read_verb(reader, &predicate));
TRY_THROW(read_ws_plus(reader));
- TRY_THROW(read_objectList(reader, subject, &predicate));
+ ctx.predicate = &predicate;
+ TRY_THROW(read_objectList(reader, ctx));
pop_string(reader, predicate.value);
predicate.value = 0;
read_ws_star(reader);
@@ -1133,8 +1135,9 @@ read_predicateObjectList(SerdReader reader, const Node* subject)
return true;
default:
TRY_THROW(read_verb(reader, &predicate));
+ ctx.predicate = &predicate;
TRY_THROW(read_ws_plus(reader));
- TRY_THROW(read_objectList(reader, subject, &predicate));
+ TRY_THROW(read_objectList(reader, ctx));
pop_string(reader, predicate.value);
predicate.value = 0;
read_ws_star(reader);
@@ -1148,18 +1151,20 @@ except:
/** Recursive helper for read_collection. */
static bool
-read_collection_rec(SerdReader reader, const Node* head)
+read_collection_rec(SerdReader reader, Context ctx)
{
read_ws_star(reader);
if (peek_byte(reader) == ')') {
eat_byte(reader, ')');
- emit_statement(reader, NULL, head, &reader->rdf_rest, &reader->rdf_nil);
+ emit_statement(reader, NULL, ctx.subject, &reader->rdf_rest, &reader->rdf_nil);
return false;
} else {
const Node rest = make_node(BLANK, blank_id(reader), 0, 0);
- emit_statement(reader, NULL, head, &reader->rdf_rest, &rest);
- if (read_object(reader, &rest, &reader->rdf_first)) {
- read_collection_rec(reader, &rest);
+ emit_statement(reader, ctx.graph, ctx.subject, &reader->rdf_rest, &rest);
+ ctx.subject = &rest;
+ ctx.predicate = &reader->rdf_first;
+ if (read_object(reader, ctx)) {
+ read_collection_rec(reader, ctx);
pop_string(reader, rest.value);
return true;
} else {
@@ -1172,7 +1177,7 @@ read_collection_rec(SerdReader reader, const Node* head)
// [22] itemList ::= object+
// [23] collection ::= '(' itemList? ')'
static bool
-read_collection(SerdReader reader, Node* dest)
+read_collection(SerdReader reader, Context ctx, Node* dest)
{
TRY_RET(eat_byte(reader, '('));
read_ws_star(reader);
@@ -1183,22 +1188,25 @@ read_collection(SerdReader reader, Node* dest)
}
*dest = make_node(BLANK, blank_id(reader), 0, 0);
- if (!read_object(reader, dest, &reader->rdf_first)) {
+ ctx.subject = dest;
+ ctx.predicate = &reader->rdf_first;
+ if (!read_object(reader, ctx)) {
pop_string(reader, dest->value);
return error(reader, "unexpected end of collection\n");
}
- return read_collection_rec(reader, dest);
+ ctx.subject = dest;
+ return read_collection_rec(reader, ctx);
}
// [11] subject ::= resource | blank
static Node
-read_subject(SerdReader reader)
+read_subject(SerdReader reader, Context ctx)
{
- Node subject = SERD_NODE_NULL;
+ Node subject = SERD_NODE_NULL;
switch (peek_byte(reader)) {
case '[': case '(': case '_':
- read_blank(reader, &subject);
+ read_blank(reader, ctx, &subject);
break;
default:
read_resource(reader, &subject);
@@ -1209,12 +1217,13 @@ read_subject(SerdReader reader)
// Spec: [6] triples ::= subject predicateObjectList
// Actual: [6] triples ::= subject ws+ predicateObjectList
static bool
-read_triples(SerdReader reader)
+read_triples(SerdReader reader, Context ctx)
{
- const Node subject = read_subject(reader);
+ const Node subject = read_subject(reader, ctx);
if (subject.value != 0) {
+ ctx.subject = &subject;
TRY_RET(read_ws_plus(reader));
- const bool ret = read_predicateObjectList(reader, &subject);
+ const bool ret = read_predicateObjectList(reader, ctx);
pop_string(reader, subject.value);
return ret;
}
@@ -1281,6 +1290,7 @@ read_directive(SerdReader reader)
static bool
read_statement(SerdReader reader)
{
+ Context ctx = { 0, 0, 0 };
read_ws_star(reader);
if (reader->eof) {
return true;
@@ -1290,7 +1300,7 @@ read_statement(SerdReader reader)
TRY_RET(read_directive(reader));
break;
default:
- TRY_RET(read_triples(reader));
+ TRY_RET(read_triples(reader, ctx));
break;
}
read_ws_star(reader);