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Work on token parsing.

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This commit is contained in:
Michael R Sweet
2021-05-01 17:50:52 -04:00
parent f5f0e190b5
commit e107b94c83
9 changed files with 338 additions and 110 deletions
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232
pdfio-file.c
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@@ -22,6 +22,7 @@
//
static pdfio_obj_t *add_object(pdfio_file_t *pdf);
static bool load_xref(pdfio_file_t *pdf, off_t xref_offset);
static bool write_trailer(pdfio_file_t *pdf);
@@ -220,6 +221,17 @@ pdfioFileCreatePage(pdfio_file_t *pdf, // I - PDF file
}
//
// 'pdfioFileGetID()' - Get the PDF file's ID strings.
//
pdfio_array_t * // O - Array with binary strings
pdfioFileGetID(pdfio_file_t *pdf) // I - PDF file
{
return (pdf ? pdfioDictGetArray(pdf->trailer, "ID") : NULL);
}
//
// 'pdfioFileGetName()' - Get a PDF's filename.
//
@@ -285,7 +297,7 @@ pdfioFileGetPage(pdfio_file_t *pdf, // I - PDF file
//
// '()' - Get the PDF version number for a PDF file.
// 'pdfioFileGetVersion()' - Get the PDF version number for a PDF file.
//
const char * // O - Version number or `NULL`
@@ -379,104 +391,9 @@ pdfioFileOpen(
xref_offset = (off_t)strtol(ptr + 9, NULL, 10);
if (_pdfioFileSeek(pdf, xref_offset, SEEK_SET) != xref_offset)
{
_pdfioFileError(pdf, "Unable to seek to start of xref table.");
if (!load_xref(pdf, xref_offset))
goto error;
}
if (!_pdfioFileGets(pdf, line, sizeof(line)))
{
_pdfioFileError(pdf, "Unable to read start of xref table.");
goto error;
}
if (strcmp(line, "xref"))
{
_pdfioFileError(pdf, "Bad xref table header '%s'.", line);
goto error;
}
// Read the xref tables
while (_pdfioFileGets(pdf, line, sizeof(line)))
{
intmax_t number, // Object number
num_objects; // Number of objects
if (!strcmp(line, "trailer"))
break;
if (sscanf(line, "%jd%jd", &number, &num_objects) != 2)
{
_pdfioFileError(pdf, "Malformed xref table section '%s'.", line);
goto error;
}
// Read this group of objects...
for (; num_objects > 0; num_objects --, number ++)
{
intmax_t offset; // Offset in file
int generation; // Generation number
pdfio_obj_t *obj; // Object
// Read a line from the file and validate it...
if (_pdfioFileRead(pdf, line, 20) != 20)
goto error;
line[20] = '\0';
if (strcmp(line + 18, "\r\n") && strcmp(line + 18, " \n") && strcmp(line + 18, " \r"))
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
goto error;
}
line[18] = '\0';
// Parse the line
if ((offset = strtoimax(line, &ptr, 10)) < 0)
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
goto error;
}
if ((generation = (int)strtol(ptr, &ptr, 10)) < 0 || generation > 65535)
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
goto error;
}
if (*ptr != ' ')
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
goto error;
}
ptr ++;
if (*ptr != 'f' && *ptr != 'n')
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
goto error;
}
if (*ptr == 'f')
continue; // Don't care about free objects...
// Create a placeholder for the object in memory...
if ((obj = add_object(pdf)) == NULL)
goto error;
obj->number = (size_t)number;
obj->generation = (unsigned short)generation;
obj->offset = offset;
}
}
if (strcmp(line, "trailer"))
{
_pdfioFileError(pdf, "Missing trailer.");
goto error;
}
// TODO: Read trailer dict...
return (pdf);
@@ -528,6 +445,127 @@ add_object(pdfio_file_t *pdf) // I - PDF file
}
//
// 'load_xref()' - Load an XREF table...
//
static bool // O - `true` on success, `false` on failure
load_xref(pdfio_file_t *pdf, // I - PDF file
off_t xref_offset) // I - Offset to xref
{
bool done = false; // Are we done?
char line[1024], // Line from file
*ptr; // Pointer into line
while (!done)
{
if (_pdfioFileSeek(pdf, xref_offset, SEEK_SET) != xref_offset)
{
_pdfioFileError(pdf, "Unable to seek to start of xref table.");
return (false);
}
if (!_pdfioFileGets(pdf, line, sizeof(line)))
{
_pdfioFileError(pdf, "Unable to read start of xref table.");
return (false);
}
if (strcmp(line, "xref"))
{
_pdfioFileError(pdf, "Bad xref table header '%s'.", line);
return (false);
}
// Read the xref tables
while (_pdfioFileGets(pdf, line, sizeof(line)))
{
intmax_t number, // Object number
num_objects; // Number of objects
if (!strcmp(line, "trailer"))
break;
if (sscanf(line, "%jd%jd", &number, &num_objects) != 2)
{
_pdfioFileError(pdf, "Malformed xref table section '%s'.", line);
return (false);
}
// Read this group of objects...
for (; num_objects > 0; num_objects --, number ++)
{
intmax_t offset; // Offset in file
int generation; // Generation number
pdfio_obj_t *obj; // Object
// Read a line from the file and validate it...
if (_pdfioFileRead(pdf, line, 20) != 20)
return (false);
line[20] = '\0';
if (strcmp(line + 18, "\r\n") && strcmp(line + 18, " \n") && strcmp(line + 18, " \r"))
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
return (false);
}
line[18] = '\0';
// Parse the line
if ((offset = strtoimax(line, &ptr, 10)) < 0)
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
return (false);
}
if ((generation = (int)strtol(ptr, &ptr, 10)) < 0 || generation > 65535)
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
return (false);
}
if (*ptr != ' ')
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
return (false);
}
ptr ++;
if (*ptr != 'f' && *ptr != 'n')
{
_pdfioFileError(pdf, "Malformed xref table entry '%s'.", line);
return (false);
}
if (*ptr == 'f')
continue; // Don't care about free objects...
// Create a placeholder for the object in memory...
if ((obj = add_object(pdf)) == NULL)
return (false);
obj->number = (size_t)number;
obj->generation = (unsigned short)generation;
obj->offset = offset;
}
}
if (strcmp(line, "trailer"))
{
_pdfioFileError(pdf, "Missing trailer.");
return (false);
}
// TODO: Read trailer dict...
done = true;
}
return (true);
}
//
// 'write_trailer()' - Write the PDF catalog object, xref table, and trailer.
//