work on the native parser, in progress, uploaded to have a backup

experimental/PdfViewer/pdfparser/native/SkPdfNativeTokenizer.cpp

 
 #include "SkPdfNativeTokenizer.h"
-
-SkPdfNativeTokenizer::SkPdfNativeTokenizer() {
-    // TODO(edisonn): Auto-generated constructor stub
-
+#include "SkPdfObject.h"
+#include "SkPdfConfig.h"
+
+#include "SkPdfStreamCommonDictionary_autogen.h"
+
+unsigned char* skipPdfWhiteSpaces(unsigned char* start, unsigned char* end) {
+    while (start < end && isPdfWhiteSpace(*start)) {
+        if (*start == kComment_PdfDelimiter) {
+            // skip the comment until end of line
+            while (start < end && !isPdfEOL(*start)) {
+                *start = '\0';
+                start++;
+            }
+        } else {
+            *start = '\0';
+            start++;
+        }
+    }
+    return start;
+}
+
+// TODO(edisonn) '(' can be used, will it break the string a delimiter or space inside () ?
+unsigned char* endOfPdfToken(unsigned char* start, unsigned char* end) {
+    //int opened brackets
+    //TODO(edisonn): what out for special chars, like \n, \032
+
+    SkASSERT(!isPdfWhiteSpace(*start));
+
+    if (start < end && isPdfDelimiter(*start)) {
+        start++;
+        return start;
+    }
+
+    while (start < end && !isPdfWhiteSpaceOrPdfDelimiter(*start)) {
+        start++;
+    }
+    return start;
+}
+
+unsigned char* skipPdfComment(unsigned char* start, unsigned char* end) {
+    SkASSERT(start == end || *start == kComment_PdfDelimiter);
+    while (start < end && isPdfEOL(*start)) {
+        *start = '\0';
+        start++;
+    }
+    return start;
+}
+
+// last elem has to be ]
+unsigned char* readArray(unsigned char* start, unsigned char* end, SkPdfObject* array, SkPdfAllocator* allocator) {
+    while (start < end) {
+        // skip white spaces
+        start = skipPdfWhiteSpaces(start, end);
+
+        unsigned char* endOfToken = endOfPdfToken(start, end);
+
+        if (endOfToken == start) {
+            // TODO(edisonn): report error in pdf file (end of stream with ] for end of aray
+            return start;
+        }
+
+        if (endOfToken == start + 1 && *start == kClosedSquareBracket_PdfDelimiter) {
+            return endOfToken;
+        }
+
+        SkPdfObject* newObj = allocator->allocObject();
+        start = nextObject(start, end, newObj, allocator);
+        // TODO(edisonn): perf/memory: put the variables on the stack, and flush them on the array only when
+        // we are sure they are not references!
+        if (newObj->isKeywordReference() && array->size() >= 2 && array->objAtAIndex(array->size() - 1)->isInteger() && array->objAtAIndex(array->size() - 2)->isInteger()) {
+            SkPdfObject* gen = array->removeLastInArray();
+            SkPdfObject* id = array->removeLastInArray();
+            newObj->reset();
+            SkPdfObject::makeReference(id->intValue(), gen->intValue(), newObj);
+        }
+        array->appendInArray(newObj);
+    }
+    // TODO(edisonn): report not reached, we should never get here
+    SkASSERT(false);
+    return start;
+}
+
+// When we read strings we will rewrite the string so we will reuse the memory
+// when we start to read the string, we already consumed the opened bracket
+unsigned char* readString(unsigned char* start, unsigned char* end, SkPdfObject* str) {
+    unsigned char* out = start;
+    unsigned char* in = start;
+
+    int openRoundBrackets = 0;
+    while (in < end && (*in != kClosedRoundBracket_PdfDelimiter || openRoundBrackets > 0)) {
+        openRoundBrackets += ((*in) == kOpenedRoundBracket_PdfDelimiter);
+        openRoundBrackets -= ((*in) == kClosedRoundBracket_PdfDelimiter);
+        if (*in == kEscape_PdfSpecial) {
+            if (in + 1 < end) {
+                switch (in[1]) {
+                    case 'n':
+                        *out = kLF_PdfWhiteSpace;
+                        out++;
+                        in += 2;
+                        break;
+
+                    case 'r':
+                        *out = kCR_PdfWhiteSpace;
+                        out++;
+                        in += 2;
+                        break;
+
+                    case 't':
+                        *out = kHT_PdfWhiteSpace;
+                        out++;
+                        in += 2;
+                        break;
+
+                    case 'b':
+                        // TODO(edisonn): any special meaning to backspace?
+                        *out = kBackspace_PdfSpecial;
+                        out++;
+                        in += 2;
+                        break;
+
+                    case 'f':
+                        *out = kFF_PdfWhiteSpace;
+                        out++;
+                        in += 2;
+                        break;
+
+                    case kOpenedRoundBracket_PdfDelimiter:
+                        *out = kOpenedRoundBracket_PdfDelimiter;
+                        out++;
+                        in += 2;
+                        break;
+
+                    case kClosedRoundBracket_PdfDelimiter:
+                        *out = kClosedRoundBracket_PdfDelimiter;
+                        out++;
+                        in += 2;
+                        break;
+
+                    case kEscape_PdfSpecial:
+                        *out = kEscape_PdfSpecial;
+                        out++;
+                        in += 2;
+                        break;
+
+                    case '0':
+                    case '1':
+                    case '2':
+                    case '3':
+                    case '4':
+                    case '5':
+                    case '6':
+                    case '7': {
+                            //read octals
+                            in++;   // consume backslash
+
+                            int code = 0;
+                            int i = 0;
+                            while (in < end && *in >= '0' && *in < '8') {
+                                code = (code << 3) + ((*in) - '0');  // code * 8 + d
+                                i++;
+                                in++;
+                                if (i == 3) {
+                                    *out = code & 0xff;
+                                    out++;
+                                    i = 0;
+                                }
+                            }
+                            if (i > 0) {
+                                *out = code & 0xff;
+                                out++;
+                            }
+                        }
+                        break;
+
+                    default:
+                        // Per spec, backslash is ignored is escaped ch is unknown
+                        in++;
+                        break;
+                }
+            }
+        } else {
+            // TODO(edisonn): perf, avoid copy into itself, maybe first do a simple scan until found backslash ?
+            // we could have one look that first just inc current, and when we find the backslash
+            // we go to this loop
+            *in = *out;
+            in++;
+            out++;
+        }
+    }
+
+
+    SkPdfObject::makeString(start, out, str);
+    return in + 1;  // consume ) at the end of the string
+}
+
+unsigned char* readHexString(unsigned char* start, unsigned char* end, SkPdfObject* str) {
+    unsigned char* out = start;
+    unsigned char* in = start;
+
+    unsigned char code = 0;
+
+    while (in < end) {
+        while (in < end && isPdfWhiteSpace(*in)) {
+            in++;
+        }
+
+        if (*in == kClosedInequityBracket_PdfDelimiter) {
+            *in = '\0';
+            in++;
+            // normal exit
+            break;
+        }
+
+        if (in >= end) {
+            // end too soon
+            break;
+        }
+
+        switch (*in) {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+                code = (*in - '0') << 4;
+                break;
+
+            case 'a':
+            case 'b':
+            case 'c':
+            case 'd':
+            case 'e':
+            case 'f':
+                code = (*in - 'a' + 10) << 4;
+                break;
+
+            case 'A':
+            case 'B':
+            case 'C':
+            case 'D':
+            case 'E':
+            case 'F':
+                code = (*in - 'A' + 10) << 4;
+                break;
+
+            // TODO(edisonn): spec does not say how to handle this error
+            default:
+                break;
+        }
+
+        in++;  // advance
+
+        while (in < end && isPdfWhiteSpace(*in)) {
+            in++;
+        }
+
+        // TODO(edisonn): report error
+        if (in >= end) {
+            *out = code;
+            out++;
+            break;
+        }
+
+        if (*in == kClosedInequityBracket_PdfDelimiter) {
+            *out = code;
+            out++;
+            break;
+        }
+
+        switch (*in) {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+                code += (*in - '0');
+                break;
+
+            case 'a':
+            case 'b':
+            case 'c':
+            case 'd':
+            case 'e':
+            case 'f':
+                code += (*in - 'a' + 10);
+                break;
+
+            case 'A':
+            case 'B':
+            case 'C':
+            case 'D':
+            case 'E':
+            case 'F':
+                code += (*in - 'A' + 10);
+                break;
+
+            // TODO(edisonn): spec does not say how to handle this error
+            default:
+                break;
+        }
+
+        *out = code;
+        out++;
+        in++;
+    }
+
+    if (out < in) {
+        *out = '\0';
+    }
+
+    SkPdfObject::makeHexString(start, out, str);
+    return in;  // consume > at the end of the string
+}
+
+// TODO(edisonn): before PDF 1.2 name could not have special characters, add version parameter
+unsigned char* readName(unsigned char* start, unsigned char* end, SkPdfObject* name) {
+    unsigned char* out = start;
+    unsigned char* in = start;
+
+    unsigned char code = 0;
+
+    while (in < end) {
+        if (isPdfWhiteSpaceOrPdfDelimiter(*in)) {
+            break;
+        }
+
+        if (*in == '#' && in + 2 < end) {
+            in++;
+            switch (*in) {
+                case '0':
+                case '1':
+                case '2':
+                case '3':
+                case '4':
+                case '5':
+                case '6':
+                case '7':
+                case '8':
+                case '9':
+                    code = (*in - '0') << 4;
+                    break;
+
+                case 'a':
+                case 'b':
+                case 'c':
+                case 'd':
+                case 'e':
+                case 'f':
+                    code = (*in - 'a' + 10) << 4;
+                    break;
+
+                case 'A':
+                case 'B':
+                case 'C':
+                case 'D':
+                case 'E':
+                case 'F':
+                    code = (*in - 'A' + 10) << 4;
+                    break;
+
+                // TODO(edisonn): spec does not say how to handle this error
+                default:
+                    break;
+            }
+
+            in++;  // advance
+
+            switch (*in) {
+                case '0':
+                case '1':
+                case '2':
+                case '3':
+                case '4':
+                case '5':
+                case '6':
+                case '7':
+                case '8':
+                case '9':
+                    code += (*in - '0');
+                    break;
+
+                case 'a':
+                case 'b':
+                case 'c':
+                case 'd':
+                case 'e':
+                case 'f':
+                    code += (*in - 'a' + 10);
+                    break;
+
+                case 'A':
+                case 'B':
+                case 'C':
+                case 'D':
+                case 'E':
+                case 'F':
+                    code += (*in - 'A' + 10);
+                    break;
+
+                // TODO(edisonn): spec does not say how to handle this error
+                default:
+                    break;
+            }
+
+            *out = code;
+            out++;
+            in++;
+        } else {
+            *out = *in;
+            out++;
+            in++;
+        }
+    }
+
+    SkPdfObject::makeName(start, out, name);
+    return in;
+}
+
+// TODO(edisonn): pdf spec let Length to be an indirect object define after the stream
+// that makes for an interesting scenario, where the stream itself contains endstream, together
+// with a reference object with the length, but the real length object would be somewhere else
+// it could confuse the parser
+/*example:
+
+7 0 obj
+<< /length 8 0 R>>
+stream
+...............
+endstream
+8 0 obj #we are in stream actually, not a real object
+<< 10 >> #we are in stream actually, not a real object
+endobj
+endstream
+8 0 obj #real obj
+<< 100 >> #real obj
+endobj
+and it could get worse, with multiple object like this
+*/
+
+// right now implement the silly algorithm that assumes endstream is finishing the stream
+
+
+unsigned char* readStream(unsigned char* start, unsigned char* end, SkPdfObject* dict) {
+    start = skipPdfWhiteSpaces(start, end);
+    if (!(start[0] == 's' && start[1] == 't' && start[2] == 'r' && start[3] == 'e' && start[4] == 'a' && start[5] == 'm')) {
+        // no stream. return.
+        return start;
+    }
+
+    start += 6; // strlen("stream")
+    if (start[0] == kCR_PdfWhiteSpace && start[1] == kLF_PdfWhiteSpace) {
+        start += 2;
+    } else if (start[0] == kLF_PdfWhiteSpace) {
+        start += 1;
+    }
+
+    SkPdfStreamCommonDictionary* stream = (SkPdfStreamCommonDictionary*) dict;
+    // TODO(edisonn): load Length
+    int length = -1;
+
+    // TODO(edisonn): very basic implementation
+    if (stream->has_Length() && stream->Length(NULL) > 0) {
+        length = stream->Length(NULL);
+    }
+
+    // TODO(edisonn): laod external streams
+    // TODO(edisonn): look at the last filter, to determione how to deal with possible issue
+
+    if (length < 0) {
+        // scan the buffer, until we find first endstream
+        // TODO(edisonn): all buffers must have a 0 at the end now,
+        // TODO(edisonn): hack (mark end of content with 0)
+        unsigned char lastCh = *end;
+        *end = '\0';
+        //SkASSERT(*end == '\0');
+        unsigned char* endstream = (unsigned char*)strstr((const char*)start, "endstream");
+        *end = lastCh;
+
+        if (endstream) {
+            length = endstream - start;
+            if (*(endstream-1) == kLF_PdfWhiteSpace) length--;
+            if (*(endstream-1) == kCR_PdfWhiteSpace) length--;
+        }
+    }
+    if (length >= 0) {
+        unsigned char* endstream = start + length;
+
+        if (endstream[0] == kCR_PdfWhiteSpace && endstream[1] == kLF_PdfWhiteSpace) {
+            endstream += 2;
+        } else if (endstream[0] == kLF_PdfWhiteSpace) {
+            endstream += 1;
+        }
+
+        // TODO(edisonn): verify the next bytes are "endstream"
+
+        endstream += strlen("endstream");
+        // TODO(edisonn): Assert? report error/warning?
+        dict->addStream(start, length);
+        return endstream;
+    }
+    return start;
+}
+
+unsigned char* readDictionary(unsigned char* start, unsigned char* end, SkPdfObject* dict, SkPdfAllocator* allocator) {
+    SkPdfObject::makeEmptyDictionary(dict);
+
+    start = skipPdfWhiteSpaces(start, end);
+
+    while (start < end && *start == kNamed_PdfDelimiter) {
+        SkPdfObject key;
+        *start = '\0';
+        start++;
+        start = readName(start, end, &key);
+        start = skipPdfWhiteSpaces(start, end);
+
+        if (start < end) {
+            SkPdfObject* value = allocator->allocObject();
+            start = nextObject(start, end, value, allocator);
+
+            start = skipPdfWhiteSpaces(start, end);
+
+            if (start < end) {
+                // seems we have an indirect reference
+                if (isPdfDigit(*start)) {
+                    SkPdfObject generation;
+                    start = nextObject(start, end, &generation, allocator);
+
+                    SkPdfObject keywordR;
+                    start = nextObject(start, end, &keywordR, allocator);
+
+                    if (value->isInteger() && generation.isInteger() && keywordR.isKeywordReference()) {
+                        int64_t id = value->intValue();
+                        value->reset();
+                        SkPdfObject::makeReference(id, generation.intValue(), value);
+                        dict->set(&key, value);
+                    } else {
+                        // error, ignore
+                        dict->set(&key, value);
+                    }
+                } else {
+                    // next elem is not a digit, but it might not be / either!
+                    dict->set(&key, value);
+                }
+            } else {
+                // /key >>
+                dict->set(&key, value);
+                return end;
+            }
+            start = skipPdfWhiteSpaces(start, end);
+        } else {
+            dict->set(&key, &SkPdfObject::kNull);
+            return end;
+        }
+    }
+
+    // TODO(edisonn): options to ignore these errors
+
+    // now we should expect >>
+    start = skipPdfWhiteSpaces(start, end);
+    start = endOfPdfToken(start, end);  // >
+    start = endOfPdfToken(start, end);  // >
+
+    // TODO(edisonn): read stream ... put dict and stream in a struct, and have a pointer to struct ...
+    // or alocate 2 objects, and if there is no stream, free it to be used by someone else? or just leave it ?
+
+    start = readStream(start, end, dict);
+
+    return start;
+}
+
+unsigned char* nextObject(unsigned char* start, unsigned char* end, SkPdfObject* token, SkPdfAllocator* allocator) {
+    unsigned char* current;
+
+    // skip white spaces
+    start = skipPdfWhiteSpaces(start, end);
+
+    current = endOfPdfToken(start, end);
+
+    // no token, len would be 0
+    if (current == start) {
+        return NULL;
+    }
+
+    int tokenLen = current - start;
+
+    if (tokenLen == 1) {
+        // start array
+        switch (*start) {
+            case kOpenedSquareBracket_PdfDelimiter:
+                *start = '\0';
+                SkPdfObject::makeEmptyArray(token);
+                return readArray(current, end, token, allocator);
+
+            case kOpenedRoundBracket_PdfDelimiter:
+                *start = '\0';
+                return readString(start, end, token);
+
+            case kOpenedInequityBracket_PdfDelimiter:
+                *start = '\0';
+                if (end > start + 1 && start[1] == kOpenedInequityBracket_PdfDelimiter) {
+                    // TODO(edisonn): pass here the length somehow?
+                    return readDictionary(start + 2, end, token, allocator);  // skip <<
+                } else {
+                    return readHexString(start + 1, end, token);  // skip <
+                }
+
+            case kNamed_PdfDelimiter:
+                *start = '\0';
+                return readName(start + 1, end, token);
+
+            // TODO(edisonn): what to do curly brackets? read spec!
+            case kOpenedCurlyBracket_PdfDelimiter:
+            default:
+                break;
+        }
+
+        SkASSERT(!isPdfWhiteSpace(*start));
+        if (isPdfDelimiter(*start)) {
+            // TODO(edisonn): how stream ] } > ) will be handled?
+            // for now ignore, and it will become a keyword to be ignored
+        }
+    }
+
+    if (tokenLen == 4 && start[0] == 'n' && start[1] == 'u' && start[2] == 'l' && start[3] == 'l') {
+        SkPdfObject::makeNull(token);
+        return current;
+    }
+
+    if (tokenLen == 4 && start[0] == 't' && start[1] == 'r' && start[2] == 'u' && start[3] == 'e') {
+        SkPdfObject::makeBoolean(true, token);
+        return current;
+    }
+
+    if (tokenLen == 5 && start[0] == 'f' && start[1] == 'a' && start[2] == 'l' && start[3] == 's' && start[3] == 'e') {
+        SkPdfObject::makeBoolean(false, token);
+        return current;
+    }
+
+    if (isPdfNumeric(*start)) {
+        SkPdfObject::makeNumeric(start, current, token);
+    } else {
+        SkPdfObject::makeKeyword(start, current, token);
+    }
+    return current;
+}
+
+SkPdfObject* SkPdfAllocator::allocBlock() {
+    return new SkPdfObject[BUFFER_SIZE];
+}
+
+SkPdfAllocator::~SkPdfAllocator() {
+    for (int i = 0 ; i < fHandles.count(); i++) {
+        free(fHandles[i]);
+    }
+    for (int i = 0 ; i < fHistory.count(); i++) {
+        delete[] fHistory[i];
+    }
+    delete[] fCurrent;
+}
+
+SkPdfObject* SkPdfAllocator::allocObject() {
+    if (fCurrentUsed >= BUFFER_SIZE) {
+        fHistory.push(fCurrent);
+        fCurrent = allocBlock();
+        fCurrentUsed = 0;
+    }
+
+    fCurrentUsed++;
+    return &fCurrent[fCurrentUsed - 1];
+}
+
+// TODO(edisonn): perf: do no copy the buffers, but use them, and mark cache the result, so there is no need of a second pass
+SkPdfNativeTokenizer::SkPdfNativeTokenizer(SkPdfObject* objWithStream, const SkPdfMapper* mapper, SkPdfAllocator* allocator) : fMapper(mapper), fAllocator(allocator), fUncompressedStream(NULL), fUncompressedStreamEnd(NULL), fEmpty(false), fHasPutBack(false) {
+    unsigned char* buffer = NULL;
+    size_t len = 0;
+    objWithStream->GetFilteredStreamRef(&buffer, &len, fAllocator);
+    fUncompressedStreamStart = fUncompressedStream = (unsigned char*)fAllocator->alloc(len);
+    fUncompressedStreamEnd = fUncompressedStream + len;
+    memcpy(fUncompressedStream, buffer, len);}
+
+SkPdfNativeTokenizer::SkPdfNativeTokenizer(unsigned char* buffer, int len, const SkPdfMapper* mapper, SkPdfAllocator* allocator) : fMapper(mapper), fAllocator(allocator), fEmpty(false), fHasPutBack(false) {
+    fUncompressedStreamStart = fUncompressedStream = (unsigned char*)fAllocator->alloc(len);
+    fUncompressedStreamEnd = fUncompressedStream + len;
+    memcpy(fUncompressedStream, buffer, len);
 }
 
 SkPdfNativeTokenizer::~SkPdfNativeTokenizer() {
-    // TODO(edisonn): Auto-generated destructor stub
-}
-
+    // free the unparsed stream, we don't need it.
+    // the parsed one is locked as it contains the strings and keywords referenced in objects
+    if (fUncompressedStream) {
+        realloc(fUncompressedStreamStart, fUncompressedStream - fUncompressedStreamStart);
+    } else {
+        SkASSERT(false);
+    }
+}
+
+bool SkPdfNativeTokenizer::readTokenCore(PdfToken* token) {
+    token->fKeyword = NULL;
+    token->fObject = NULL;
+
+    fUncompressedStream = skipPdfWhiteSpaces(fUncompressedStream, fUncompressedStreamEnd);
+    if (fUncompressedStream >= fUncompressedStreamEnd) {
+        return false;
+    }
+
+    SkPdfObject obj;
+    fUncompressedStream = nextObject(fUncompressedStream, fUncompressedStreamEnd, &obj, fAllocator);
+
+    // If it is a keyword, we will only get the pointer of the string
+    if (obj.type() == SkPdfObject::kKeyword_PdfObjectType) {
+        token->fKeyword = obj.c_str();
+        token->fKeywordLength = obj.len();
+        token->fType = kKeyword_TokenType;
+    } else {
+        SkPdfObject* pobj = fAllocator->allocObject();
+        *pobj = obj;
+        token->fObject = pobj;
+        token->fType = kObject_TokenType;
+    }
+
+#ifdef PDF_TRACE
+    static int read_op = 0;
+    read_op++;
+    if (182749 == read_op) {
+        printf("break;\n");
+    }
+    printf("%i READ %s %s\n", read_op, token->fType == kKeyword_TokenType ? "Keyword" : "Object", token->fKeyword ? std::string(token->fKeyword, token->fKeywordLength).c_str() : token->fObject->toString().c_str());
+#endif
+
+    return true;
+}
+
+void SkPdfNativeTokenizer::PutBack(PdfToken token) {
+    SkASSERT(!fHasPutBack);
+    fHasPutBack = true;
+    fPutBack = token;
+#ifdef PDF_TRACE
+    printf("PUT_BACK %s %s\n", token.fType == kKeyword_TokenType ? "Keyword" : "Object", token.fKeyword ? std::string(token.fKeyword, token.fKeywordLength).c_str(): token.fObject->toString().c_str());
+#endif
+}
+
+bool SkPdfNativeTokenizer::readToken(PdfToken* token) {
+    if (fHasPutBack) {
+        *token = fPutBack;
+        fHasPutBack = false;
+#ifdef PDF_TRACE
+    printf("READ_BACK %s %s\n", token->fType == kKeyword_TokenType ? "Keyword" : "Object", token->fKeyword ? std::string(token->fKeyword, token->fKeywordLength).c_str() : token->fObject->toString().c_str());
+#endif
+        return true;
+    }
+
+    if (fEmpty) {
+#ifdef PDF_TRACE
+    printf("EMPTY TOKENIZER\n");
+#endif
+        return false;
+    }
+
+    return readTokenCore(token);
+}