clean up error handling and start decoding of indirect objects

6 files changed, 191 insertions, 94 deletions

diff --git a/src/cos_decode.c b/src/cos_decode.c
index 3936e05..730c771 100644
--- a/src/cos_decode.c
+++ b/src/cos_decode.c
@@ -10,9 +10,13 @@
 #include "cos_object.h"
 #include "pdf_doc.h"
 
+/** increments in which cos string allocations are extended */
 #define COS_STRING_ALLOC 32
 
-nspdferror
+/** Maximum length of cos name */
+#define NAME_MAX_LENGTH 127
+
+static nspdferror
 cos_string_append(struct cos_string *s, uint8_t c)
 {
     //printf("appending 0x%x to %p len %d alloc %d\n", c, s->data, s->length, s->alloc);
@@ -29,7 +33,7 @@ cos_string_append(struct cos_string *s, uint8_t c)
     return NSPDFERROR_OK;
 }
 
-uint8_t xtoi(uint8_t x)
+static uint8_t xtoi(uint8_t x)
 {
     if (x >= '0' && x <= '9') {
         x = x - '0';
@@ -41,7 +45,8 @@ uint8_t xtoi(uint8_t x)
     return x;
 }
 
-int cos_decode_number(struct pdf_doc *doc,
+static nspdferror
+cos_decode_number(struct pdf_doc *doc,
                       uint64_t *offset_out,
                       struct cos_object **cosobj_out)
 {
@@ -60,7 +65,8 @@ int cos_decode_number(struct pdf_doc *doc,
             uint64_t tens;
 
             if (len == 0) {
-                return -2; /* parse error no decimals in input */
+                 /* parse error no decimals in input */
+                return NSPDFERROR_SYNTAX;
             }
             /* sum value from each place */
             for (tens = 1; len > 0; tens = tens * 10, len--) {
@@ -71,7 +77,7 @@ int cos_decode_number(struct pdf_doc *doc,
 
             cosobj = calloc(1, sizeof(struct cos_object));
             if (cosobj == NULL) {
-                return -1; /* memory error */
+                return NSPDFERROR_NOMEM;
             }
 
             cosobj->type = COS_TYPE_INT;
@@ -81,20 +87,20 @@ int cos_decode_number(struct pdf_doc *doc,
 
             *offset_out = offset;
 
-            return 0;
+            return NSPDFERROR_OK;
         }
         num[len] = c - '0';
         offset++;
     }
-    return -1; /* number too long */
+    return NSPDFERROR_RANGE; /* number too long */
 }
 
 
 /**
- * literal string processing
+ * decode literal string
  *
  */
-nspdferror
+static nspdferror
 cos_decode_string(struct pdf_doc *doc,
                   uint64_t *offset_out,
                   struct cos_object **cosobj_out)
@@ -220,8 +226,10 @@ cos_decode_string(struct pdf_doc *doc,
     return NSPDFERROR_OK;
 }
 
-
-nspdferror
+/**
+ * decode hex encoded string
+ */
+static nspdferror
 cos_decode_hex_string(struct pdf_doc *doc,
                       uint64_t *offset_out,
                       struct cos_object **cosobj_out)
@@ -281,8 +289,11 @@ cos_decode_hex_string(struct pdf_doc *doc,
     return NSPDFERROR_SYNTAX;
 }
 
-
-int cos_decode_dictionary(struct pdf_doc *doc,
+/**
+ * decode a dictionary object
+ */
+static nspdferror
+cos_decode_dictionary(struct pdf_doc *doc,
                       uint64_t *offset_out,
                       struct cos_object **cosobj_out)
 {
@@ -302,7 +313,7 @@ int cos_decode_dictionary(struct pdf_doc *doc,
     offset += 2;
     doc_skip_ws(doc, &offset);
 
-    printf("found a dictionary\n");
+    //printf("found a dictionary\n");
 
     cosobj = calloc(1, sizeof(struct cos_object));
     if (cosobj == NULL) {
@@ -314,7 +325,7 @@ int cos_decode_dictionary(struct pdf_doc *doc,
            (DOC_BYTE(doc, offset + 1) != '>')) {
 
         res = cos_decode_object(doc, &offset, &key);
-        if (res != 0) {
+        if (res != NSPDFERROR_OK) {
             /* todo free up any dictionary entries already created */
             printf("key object decode failed\n");
             return res;
@@ -322,12 +333,12 @@ int cos_decode_dictionary(struct pdf_doc *doc,
         if (key->type != COS_TYPE_NAME) {
             /* key value pairs without a name */
             printf("key was %d not a name %d\n", key->type, COS_TYPE_NAME);
-            return -1; /* syntax error */
+            return NSPDFERROR_SYNTAX;
         }
-        printf("key: %s\n", key->u.n);
+        //printf("key: %s\n", key->u.n);
 
         res = cos_decode_object(doc, &offset, &value);
-        if (res != 0) {
+        if (res != NSPDFERROR_OK) {
             printf("Unable to decode value object in dictionary\n");
             /* todo free up any dictionary entries already created */
             return res;
@@ -337,7 +348,7 @@ int cos_decode_dictionary(struct pdf_doc *doc,
         entry = calloc(1, sizeof(struct cos_dictionary_entry));
         if (entry == NULL) {
             /* todo free up any dictionary entries already created */
-            return -1; /* memory error */
+            return NSPDFERROR_NOMEM;
         }
 
         entry->key = key;
@@ -353,11 +364,13 @@ int cos_decode_dictionary(struct pdf_doc *doc,
     *cosobj_out = cosobj;
     *offset_out = offset;
 
-    return 0;
+    return NSPDFERROR_OK;
 }
 
-
-nspdferror
+/**
+ * decode a list
+ */
+static nspdferror
 cos_decode_list(struct pdf_doc *doc,
                 uint64_t *offset_out,
                 struct cos_object **cosobj_out)
@@ -419,19 +432,19 @@ cos_decode_list(struct pdf_doc *doc,
     *cosobj_out = cosobj;
     *offset_out = offset;
 
-    return 0;
+    return NSPDFERROR_OK;
 }
 
-#define NAME_MAX_LENGTH 127
 
 /**
  * decode a name object
  *
  * \todo deal with # symbols on pdf versions 1.2 and later
  */
-int cos_decode_name(struct pdf_doc *doc,
-                      uint64_t *offset_out,
-                      struct cos_object **cosobj_out)
+static nspdferror
+cos_decode_name(struct pdf_doc *doc,
+                uint64_t *offset_out,
+                struct cos_object **cosobj_out)
 {
     uint64_t offset;
     struct cos_object *cosobj;
@@ -445,7 +458,7 @@ int cos_decode_name(struct pdf_doc *doc,
     if (c != '/') {
         return -1; /* names must be prefixed with a / */
     }
-    printf("found a name\n");
+    //printf("found a name\n");
 
     c = DOC_BYTE(doc, offset);
     while ((idx <= NAME_MAX_LENGTH) &&
@@ -468,7 +481,7 @@ int cos_decode_name(struct pdf_doc *doc,
 
     cosobj = calloc(1, sizeof(struct cos_object));
     if (cosobj == NULL) {
-        return -1; /* memory error */
+        return NSPDFERROR_NOMEM; /* memory error */
     }
 
     cosobj->type = COS_TYPE_NAME;
@@ -478,13 +491,16 @@ int cos_decode_name(struct pdf_doc *doc,
 
     *offset_out = offset;
 
-    return 0;
+    return NSPDFERROR_OK;
 }
 
-
-int cos_decode_boolean(struct pdf_doc *doc,
-                      uint64_t *offset_out,
-                      struct cos_object **cosobj_out)
+/**
+ * decode a cos boolean object
+ */
+static int
+cos_decode_boolean(struct pdf_doc *doc,
+                   uint64_t *offset_out,
+                   struct cos_object **cosobj_out)
 {
     uint64_t offset;
     struct cos_object *cosobj;
@@ -541,7 +557,7 @@ int cos_decode_boolean(struct pdf_doc *doc,
 
     cosobj = calloc(1, sizeof(struct cos_object));
     if (cosobj == NULL) {
-        return -1; /* memory error */
+        return NSPDFERROR_NOMEM; /* memory error */
     }
 
     cosobj->type = COS_TYPE_BOOL;
@@ -551,13 +567,16 @@ int cos_decode_boolean(struct pdf_doc *doc,
 
     *offset_out = offset;
 
-    return 0;
-
+    return NSPDFERROR_OK;
 }
 
-int cos_decode_null(struct pdf_doc *doc,
-                      uint64_t *offset_out,
-                      struct cos_object **cosobj_out)
+/**
+ * decode the null object.
+ */
+static nspdferror
+cos_decode_null(struct pdf_doc *doc,
+                uint64_t *offset_out,
+                struct cos_object **cosobj_out)
 {
     uint64_t offset;
     struct cos_object *cosobj;
@@ -569,14 +588,17 @@ int cos_decode_null(struct pdf_doc *doc,
     if ((c != 'n') && (c != 'N')) {
         return -1; /* syntax error */
     }
+
     c = DOC_BYTE(doc, offset++);
     if ((c != 'u') && (c != 'U')) {
         return -1; /* syntax error */
     }
+
     c = DOC_BYTE(doc, offset++);
     if ((c != 'l') && (c != 'L')) {
         return -1; /* syntax error */
     }
+
     c = DOC_BYTE(doc, offset++);
     if ((c != 'l') && (c != 'L')) {
         return -1; /* syntax error */
@@ -586,15 +608,16 @@ int cos_decode_null(struct pdf_doc *doc,
 
     cosobj = calloc(1, sizeof(struct cos_object));
     if (cosobj == NULL) {
-        return -1; /* memory error */
+        return NSPDFERROR_NOMEM;
     }
 
     cosobj->type = COS_TYPE_NULL;
     *offset_out = offset;
 
-    return 0;
+    return NSPDFERROR_OK;
 }
 
+
 /**
  * attempt to decode the stream into a reference
  *
@@ -607,9 +630,10 @@ int cos_decode_null(struct pdf_doc *doc,
  * \param cosobj_out the object to return into, on input contains the first
  * integer
  */
-int cos_attempt_decode_reference(struct pdf_doc *doc,
-                      uint64_t *offset_out,
-                      struct cos_object **cosobj_out)
+static nspdferror
+cos_attempt_decode_reference(struct pdf_doc *doc,
+                             uint64_t *offset_out,
+                             struct cos_object **cosobj_out)
 {
     uint64_t offset;
     struct cos_object *cosobj; /* possible generation object */
@@ -621,13 +645,14 @@ int cos_attempt_decode_reference(struct pdf_doc *doc,
 
     res = cos_decode_number(doc, &offset, &cosobj);
     if (res != 0) {
-        return 0; /* no error if object could not be decoded */
+        /* no error if next token could not be decoded as a number */
+        return NSPDFERROR_OK;
     }
 
     if (cosobj->type != COS_TYPE_INT) {
         /* next object was not an integer so not a reference */
         cos_free_object(cosobj);
-        return 0;
+        return NSPDFERROR_OK;
     }
 
     if (cosobj->u.i < 0) {
@@ -635,8 +660,7 @@ int cos_attempt_decode_reference(struct pdf_doc *doc,
          * non-negative
          */
         cos_free_object(cosobj);
-        return 0;
-
+        return NSPDFERROR_OK;
     }
 
     /* two int in a row, look for the R */
@@ -644,18 +668,18 @@ int cos_attempt_decode_reference(struct pdf_doc *doc,
     if (c != 'R') {
         /* no R so not a reference */
         cos_free_object(cosobj);
-        return 0;
+        return NSPDFERROR_OK;
     }
 
     /* found reference */
 
-    printf("found reference\n");
+    //printf("found reference\n");
     doc_skip_ws(doc, &offset);
 
     nref = calloc(1, sizeof(struct cos_reference));
     if (nref == NULL) {
-        /* todo free objects */
-        return -1; /* memory error */
+        /** \todo free objects */
+        return NSPDFERROR_NOMEM; /* memory error */
     }
 
     nref->id = (*cosobj_out)->u.i;
@@ -670,10 +694,11 @@ int cos_attempt_decode_reference(struct pdf_doc *doc,
 
     *offset_out = offset;
 
-    return 0;
+    return NSPDFERROR_OK;
 }
 
-/**
+
+/*
  * Decode input stream into an object
  *
  * lex and parse a byte stream to generate COS objects
@@ -704,7 +729,8 @@ int cos_attempt_decode_reference(struct pdf_doc *doc,
  *   TOK_STRING |
  *   list |
  *   dictionary |
- *   object_reference;
+ *   object_reference |
+ *   indirect_object;
  *
  * list:
  *   '[' listargs ']';
@@ -717,13 +743,20 @@ int cos_attempt_decode_reference(struct pdf_doc *doc,
  *
  * object_reference:
  *   TOK_UINT TOK_UINT 'R';
+ *
+ * indirect_object:
+ *   TOK_UINT TOK_UINT 'obj' cos_object 'endobj'
+ *   |
+ *  TOK_UINT TOK_UINT 'obj' dictionary 'stream' streamdata 'endstream' 'endobj'
+ *   ;
  */
-int cos_decode_object(struct pdf_doc *doc,
-                      uint64_t *offset_out,
-                      struct cos_object **cosobj_out)
+nspdferror
+cos_decode_object(struct pdf_doc *doc,
+                  uint64_t *offset_out,
+                  struct cos_object **cosobj_out)
 {
     uint64_t offset;
-    int res;
+    nspdferror res;
     struct cos_object *cosobj;
 
     offset = *offset_out;
@@ -786,11 +819,10 @@ int cos_decode_object(struct pdf_doc *doc,
         break;
 
     default:
-        res = -1; /* syntax error */
+        res = NSPDFERROR_SYNTAX; /* syntax error */
     }
 
-
-    if (res == 0) {
+    if (res == NSPDFERROR_OK) {
         *cosobj_out = cosobj;
         *offset_out = offset;
     }
diff --git a/src/cos_object.c b/src/cos_object.c
index 96c669e..f4cd4fd 100644
--- a/src/cos_object.c
+++ b/src/cos_object.c
@@ -7,6 +7,7 @@
 
 #include "nspdferror.h"
 #include "cos_object.h"
+#include "pdf_doc.h"
 
 
 nspdferror cos_free_object(struct cos_object *cos_obj)
@@ -115,25 +116,38 @@ cos_dictionary_extract_value(struct cos_object *dict,
     return NSPDFERROR_NOTFOUND;
 }
 
-nspdferror cos_get_int(struct cos_object *cobj, int64_t *value_out)
+nspdferror
+cos_get_int(struct pdf_doc *doc,
+            struct cos_object *cobj,
+            int64_t *value_out)
 {
-    if (cobj->type != COS_TYPE_INT) {
-        return NSPDFERROR_TYPE;
+    nspdferror res;
+
+    res = xref_get_referenced(doc, &cobj);
+    if (res == NSPDFERROR_OK) {
+        if (cobj->type != COS_TYPE_INT) {
+            res = NSPDFERROR_TYPE;
+        } else {
+            *value_out = cobj->u.i;
+        }
     }
-    *value_out = cobj->u.i;
-    return NSPDFERROR_OK;
+    return res;
 }
 
 nspdferror
-cos_get_dictionary(struct cos_object *cobj,
+cos_get_dictionary(struct pdf_doc *doc,
+                   struct cos_object *cobj,
                    struct cos_object **value_out)
 {
-    if (cobj->type == COS_TYPE_REFERENCE) {
-        
-    }
-    if (cobj->type != COS_TYPE_DICTIONARY) {
-        return NSPDFERROR_TYPE;
+    nspdferror res;
+
+    res = xref_get_referenced(doc, &cobj);
+    if (res == NSPDFERROR_OK) {
+        if (cobj->type != COS_TYPE_DICTIONARY) {
+            res = NSPDFERROR_TYPE;
+        } else {
+            *value_out = cobj;
+        }
     }
-    *value_out = cobj;
-    return NSPDFERROR_OK;
+    return res;
 }
diff --git a/src/cos_object.h b/src/cos_object.h
index 65b3ed5..8d1449d 100644
--- a/src/cos_object.h
+++ b/src/cos_object.h
@@ -83,7 +83,12 @@ struct cos_object {
     } u;
 };
 
-int cos_decode_object(struct pdf_doc *doc, uint64_t *offset_out, struct cos_object **cosobj_out);
+/**
+ * Decode input stream into an object
+ *
+ * lex and parse a byte stream to generate a COS object.
+ */
+nspdferror cos_decode_object(struct pdf_doc *doc, uint64_t *offset_out, struct cos_object **cosobj_out);
 
 nspdferror cos_free_object(struct cos_object *cos_obj);
 
@@ -91,8 +96,9 @@ nspdferror cos_dictionary_get_value(struct cos_object *dict, const char *key, st
 
 nspdferror cos_dictionary_extract_value(struct cos_object *dict, const char *key, struct cos_object **value_out);
 
-nspdferror cos_get_int(struct cos_object *cobj, int64_t *value_out);
 
-nspdferror cos_get_dictionary(struct cos_object *cobj, struct cos_object **value_out);
+nspdferror cos_get_int(struct pdf_doc *doc, struct cos_object *cobj, int64_t *value_out);
+
+nspdferror cos_get_dictionary(struct pdf_doc *doc, struct cos_object *cobj, struct cos_object **value_out);
 
 
diff --git a/src/pdf_doc.c b/src/pdf_doc.c
index 9b92bd0..dd31b72 100644
--- a/src/pdf_doc.c
+++ b/src/pdf_doc.c
@@ -1,4 +1,3 @@
-
 #include <stdint.h>
 #include <stddef.h>
 #include <stdbool.h>
@@ -11,7 +10,7 @@
 /**
  * move offset to next non whitespace byte
  */
-int doc_skip_ws(struct pdf_doc *doc, uint64_t *offset)
+nspdferror doc_skip_ws(struct pdf_doc *doc, uint64_t *offset)
 {
     uint8_t c;
     /* TODO sort out keeping offset in range */
@@ -28,13 +27,13 @@ int doc_skip_ws(struct pdf_doc *doc, uint64_t *offset)
         }
         c = DOC_BYTE(doc, *offset);
     }
-    return 0;
+    return NSPDFERROR_OK;
 }
 
 /**
  * move offset to next non eol byte
  */
-int doc_skip_eol(struct pdf_doc *doc, uint64_t *offset)
+nspdferror doc_skip_eol(struct pdf_doc *doc, uint64_t *offset)
 {
     uint8_t c;
     /* TODO sort out keeping offset in range */
@@ -43,5 +42,53 @@ int doc_skip_eol(struct pdf_doc *doc, uint64_t *offset)
         (*offset)++;
         c = DOC_BYTE(doc, *offset);
     }
-    return 0;
+    return NSPDFERROR_OK;
+}
+
+static struct cos_object cos_null_obj = {
+    .type = COS_TYPE_NULL,
+};
+
+nspdferror
+xref_get_referenced(struct pdf_doc *doc, struct cos_object **cobj_out)
+{
+    nspdferror res;
+    struct cos_object *cobj;
+    struct cos_object *indirect;
+    uint64_t offset;
+    struct xref_table_entry *entry;
+
+    cobj = *cobj_out;
+
+    if (cobj->type != COS_TYPE_REFERENCE) {
+        /* not passed a reference object so just return what was passed */
+        return NSPDFERROR_OK;
+    }
+
+    entry = doc->xref_table + cobj->u.reference->id;
+
+    /* check if referenced object is in range and exists. return null object if
+     * not
+     */
+    if ((cobj->u.reference->id >= doc->xref_size) ||
+        (cobj->u.reference->id == 0) ||
+        (entry->ref.id == 0)) {
+        *cobj_out = &cos_null_obj;
+        return NSPDFERROR_OK;
+    }
+
+    if (entry->object == NULL) {
+        /* indirect object has never been decoded */
+        offset = entry->offset;
+        res = cos_decode_object(doc, &offset, &indirect);
+        if (res != NSPDFERROR_OK) {
+            return res;
+        }
+
+        entry->object = indirect;
+    }
+
+    cobj = entry->object;
+
+    return NSPDFERROR_OK;
 }
diff --git a/src/pdf_doc.h b/src/pdf_doc.h
index 696c121..b37e3b2 100644
--- a/src/pdf_doc.h
+++ b/src/pdf_doc.h
@@ -7,7 +7,7 @@ struct xref_table_entry {
     uint64_t offset;
 
     /* indirect object if already decoded */
-    struct cos_object *o;
+    struct cos_object *object;
 };
 
 
@@ -38,5 +38,7 @@ struct pdf_doc {
 /* byte data acessory, allows for more complex buffer handling in future */
 #define DOC_BYTE(doc, offset) (doc->start[(offset)])
 
-int doc_skip_ws(struct pdf_doc *doc, uint64_t *offset);
-int doc_skip_eol(struct pdf_doc *doc, uint64_t *offset);
+nspdferror doc_skip_ws(struct pdf_doc *doc, uint64_t *offset);
+nspdferror doc_skip_eol(struct pdf_doc *doc, uint64_t *offset);
+
+nspdferror xref_get_referenced(struct pdf_doc *doc, struct cos_object **cobj_out);
diff --git a/src/xref.c b/src/xref.c
index 5e5ac8b..b1748be 100644
--- a/src/xref.c
+++ b/src/xref.c
@@ -225,10 +225,6 @@ int check_header(struct pdf_doc *doc)
 }
 
 
-
-
-
-
 nspdferror
 decode_trailer(struct pdf_doc *doc,
                uint64_t *offset_out,
@@ -407,7 +403,7 @@ nspdferror decode_xref_trailer(struct pdf_doc *doc, uint64_t xref_offset)
             goto decode_xref_trailer_failed;
         }
 
-        res = cos_get_int(cobj_size, &size);
+        res = cos_get_int(doc, cobj_size, &size);
         if (res != NSPDFERROR_OK) {
             printf("trailer Size not int\n");
             goto decode_xref_trailer_failed;
@@ -446,7 +442,7 @@ nspdferror decode_xref_trailer(struct pdf_doc *doc, uint64_t xref_offset)
     /* check for prev ID key in trailer and recurse call if present */
     res = cos_dictionary_get_value(trailer, "Prev", &cobj_prev);
     if (res == NSPDFERROR_OK) {
-        res = cos_get_int(cobj_prev, &prev);
+        res = cos_get_int(doc, cobj_prev, &prev);
         if (res != NSPDFERROR_OK) {
             printf("trailer Prev not int\n");
             goto decode_xref_trailer_failed;
@@ -522,7 +518,7 @@ nspdferror decode_catalog(struct pdf_doc *doc)
     nspdferror res;
     struct cos_object *catalog;
 
-    res = cos_get_dictionary(doc->root, &catalog);
+    res = cos_get_dictionary(doc, doc->root, &catalog);
     
     return res;
 }