mirror of
https://github.com/michaelrsweet/pdfio.git
synced 2024-12-26 13:28:22 +01:00
581 lines
13 KiB
C
581 lines
13 KiB
C
//
|
||
// PDF file functions for pdfio.
|
||
//
|
||
// Copyright © 2021 by Michael R Sweet.
|
||
//
|
||
// Licensed under Apache License v2.0. See the file "LICENSE" for more
|
||
// information.
|
||
//
|
||
|
||
//
|
||
// Include necessary headers...
|
||
//
|
||
|
||
#include "pdfio-private.h"
|
||
#ifndef O_BINARY
|
||
# define O_BINARY 0
|
||
#endif // !O_BINARY
|
||
|
||
|
||
//
|
||
// Local functions...
|
||
//
|
||
|
||
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);
|
||
|
||
|
||
//
|
||
// 'pdfioFileClose()' - Close a PDF file and free all memory used for it.
|
||
//
|
||
|
||
bool // O - `true` on success and `false` on failure
|
||
pdfioFileClose(pdfio_file_t *pdf) // I - PDF file
|
||
{
|
||
bool ret = true; // Return value
|
||
size_t i; // Looping var
|
||
|
||
|
||
// Range check input
|
||
if (!pdf)
|
||
return (false);
|
||
|
||
// Close the file itself...
|
||
if (pdf->mode == _PDFIO_MODE_WRITE)
|
||
ret = write_trailer(pdf);
|
||
|
||
if (close(pdf->fd) < 0)
|
||
ret = false;
|
||
|
||
// Free all data...
|
||
free(pdf->filename);
|
||
free(pdf->version);
|
||
|
||
for (i = 0; i < pdf->num_arrays; i ++)
|
||
_pdfioArrayDelete(pdf->arrays[i]);
|
||
free(pdf->arrays);
|
||
|
||
for (i = 0; i < pdf->num_dicts; i ++)
|
||
_pdfioDictDelete(pdf->dicts[i]);
|
||
free(pdf->dicts);
|
||
|
||
for (i = 0; i < pdf->num_objs; i ++)
|
||
_pdfioObjDelete(pdf->objs[i]);
|
||
free(pdf->objs);
|
||
|
||
free(pdf->pages);
|
||
|
||
for (i = 0; i < pdf->num_strings; i ++)
|
||
free(pdf->strings[i]);
|
||
free(pdf->strings);
|
||
|
||
free(pdf);
|
||
|
||
return (ret);
|
||
}
|
||
|
||
|
||
//
|
||
// 'pdfioFileCreate()' - Create a PDF file.
|
||
//
|
||
|
||
pdfio_file_t * // O - PDF file or `NULL` on error
|
||
pdfioFileCreate(
|
||
const char *filename, // I - Filename
|
||
const char *version, // I - PDF version number or `NULL` for default (2.0)
|
||
pdfio_error_cb_t error_cb, // I - Error callback or `NULL` for default
|
||
void *error_data) // I - Error callback data, if any
|
||
{
|
||
pdfio_file_t *pdf; // PDF file
|
||
|
||
|
||
// Range check input...
|
||
if (!filename)
|
||
return (NULL);
|
||
|
||
if (!version)
|
||
version = "2.0";
|
||
|
||
if (!error_cb)
|
||
{
|
||
error_cb = _pdfioFileDefaultError;
|
||
error_data = NULL;
|
||
}
|
||
|
||
// Allocate a PDF file structure...
|
||
if ((pdf = (pdfio_file_t *)calloc(1, sizeof(pdfio_file_t))) == NULL)
|
||
{
|
||
pdfio_file_t temp; // Dummy file
|
||
char message[8192]; // Message string
|
||
|
||
temp.filename = (char *)filename;
|
||
snprintf(message, sizeof(message), "Unable to allocate memory for PDF file - %s", strerror(errno));
|
||
(error_cb)(&temp, message, error_data);
|
||
return (NULL);
|
||
}
|
||
|
||
pdf->filename = strdup(filename);
|
||
pdf->version = strdup(version);
|
||
pdf->mode = _PDFIO_MODE_WRITE;
|
||
pdf->error_cb = error_cb;
|
||
pdf->error_data = error_data;
|
||
|
||
// Create the file...
|
||
if ((pdf->fd = open(filename, O_WRONLY | O_BINARY | O_CREAT | O_TRUNC, 0666)) < 0)
|
||
{
|
||
_pdfioFileError(pdf, "Unable to create file - %s", strerror(errno));
|
||
free(pdf->filename);
|
||
free(pdf->version);
|
||
free(pdf);
|
||
return (NULL);
|
||
}
|
||
|
||
// Write a standard PDF header...
|
||
if (!_pdfioFilePrintf(pdf, "%%PDF-%s\n%%\342\343\317\323\n", version))
|
||
{
|
||
pdfioFileClose(pdf);
|
||
unlink(filename);
|
||
return (NULL);
|
||
}
|
||
|
||
return (pdf);
|
||
}
|
||
|
||
|
||
//
|
||
// 'pdfioFileCreateObject()' - Create a new object in a PDF file.
|
||
//
|
||
|
||
pdfio_obj_t * // O - New object
|
||
pdfioFileCreateObject(
|
||
pdfio_file_t *pdf, // I - PDF file
|
||
pdfio_dict_t *dict) // I - Object dictionary
|
||
{
|
||
pdfio_obj_t *obj; // New object
|
||
|
||
|
||
// Range check input...
|
||
if (!pdf || !dict)
|
||
{
|
||
if (pdf)
|
||
_pdfioFileError(pdf, "Missing object dictionary.");
|
||
|
||
return (NULL);
|
||
}
|
||
|
||
if (pdf->mode != _PDFIO_MODE_WRITE)
|
||
return (NULL);
|
||
|
||
if (dict->pdf != pdf)
|
||
dict = pdfioDictCopy(pdf, dict); // Copy dictionary to new PDF
|
||
|
||
// Allocate memory for the object...
|
||
if ((obj = (pdfio_obj_t *)calloc(1, sizeof(pdfio_obj_t))) == NULL)
|
||
{
|
||
_pdfioFileError(pdf, "Unable to allocate memory for object - %s", strerror(errno));
|
||
return (NULL);
|
||
}
|
||
|
||
// Expand the objects array as needed
|
||
if (pdf->num_objs >= pdf->alloc_objs)
|
||
{
|
||
pdfio_obj_t **temp = (pdfio_obj_t **)realloc(pdf->objs, (pdf->alloc_objs + 32) * sizeof(pdfio_obj_t *));
|
||
|
||
if (!temp)
|
||
{
|
||
_pdfioFileError(pdf, "Unable to allocate memory for object - %s", strerror(errno));
|
||
free(obj);
|
||
return (NULL);
|
||
}
|
||
|
||
pdf->objs = temp;
|
||
pdf->alloc_objs += 32;
|
||
}
|
||
|
||
pdf->objs[pdf->num_objs ++] = obj;
|
||
|
||
// Initialize the object...
|
||
obj->pdf = pdf;
|
||
obj->number = pdf->num_objs;
|
||
obj->dict = dict;
|
||
obj->offset = _pdfioFileTell(pdf);
|
||
|
||
// Don't write anything just yet...
|
||
return (obj);
|
||
}
|
||
|
||
|
||
//
|
||
// 'pdfioFileCreatePage()' - Create a page in a PDF file.
|
||
//
|
||
|
||
pdfio_obj_t * // O - New object
|
||
pdfioFileCreatePage(pdfio_file_t *pdf, // I - PDF file
|
||
pdfio_dict_t *dict) // I - Page dictionary
|
||
{
|
||
// TODO: Implement me
|
||
(void)pdf;
|
||
(void)dict;
|
||
return (NULL);
|
||
}
|
||
|
||
|
||
//
|
||
// '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.
|
||
//
|
||
|
||
const char * // O - Filename
|
||
pdfioFileGetName(pdfio_file_t *pdf) // I - PDF file
|
||
{
|
||
return (pdf ? pdf->filename : NULL);
|
||
}
|
||
|
||
|
||
//
|
||
// 'pdfioFileGetNumObjects()' - Get the number of objects in a PDF file.
|
||
//
|
||
|
||
size_t // O - Number of objects
|
||
pdfioFileGetNumObjects(
|
||
pdfio_file_t *pdf) // I - PDF file
|
||
{
|
||
return (pdf ? pdf->num_objs : 0);
|
||
}
|
||
|
||
|
||
//
|
||
// 'pdfioFileGetNumPages()' - Get the number of pages in a PDF file.
|
||
//
|
||
|
||
size_t // O - Number of pages
|
||
pdfioFileGetNumPages(pdfio_file_t *pdf) // I - PDF file
|
||
{
|
||
return (pdf ? pdf->num_pages : 0);
|
||
}
|
||
|
||
|
||
//
|
||
// 'pdfioFileGetObject()' - Get an object from a PDF file.
|
||
//
|
||
|
||
pdfio_obj_t * // O - Object
|
||
pdfioFileGetObject(pdfio_file_t *pdf, // I - PDF file
|
||
size_t number) // I - Object number (starting at 1)
|
||
{
|
||
if (!pdf || number < 1 || number > pdf->num_objs)
|
||
return (NULL);
|
||
else
|
||
return (pdf->objs[number - 1]);
|
||
}
|
||
|
||
|
||
//
|
||
// 'pdfioFileGetPage()' - Get a page object from a PDF file.
|
||
//
|
||
|
||
pdfio_obj_t * // O - Object
|
||
pdfioFileGetPage(pdfio_file_t *pdf, // I - PDF file
|
||
size_t number) // I - Page number (starting at 1)
|
||
{
|
||
if (!pdf || number < 1 || number > pdf->num_pages)
|
||
return (NULL);
|
||
else
|
||
return (pdf->pages[number - 1]);
|
||
}
|
||
|
||
|
||
//
|
||
// 'pdfioFileGetVersion()' - Get the PDF version number for a PDF file.
|
||
//
|
||
|
||
const char * // O - Version number or `NULL`
|
||
pdfioFileGetVersion(
|
||
pdfio_file_t *pdf) // I - PDF file
|
||
{
|
||
return (pdf ? pdf->version : NULL);
|
||
}
|
||
|
||
|
||
//
|
||
// 'pdfioFileOpen()' - Open a PDF file for reading.
|
||
//
|
||
|
||
pdfio_file_t * // O - PDF file
|
||
pdfioFileOpen(
|
||
const char *filename, // I - Filename
|
||
pdfio_error_cb_t error_cb, // I - Error callback or `NULL` for default
|
||
void *error_data) // I - Error callback data, if any
|
||
{
|
||
pdfio_file_t *pdf; // PDF file
|
||
char line[1024], // Line from file
|
||
*ptr; // Pointer into line
|
||
off_t xref_offset; // Offset to xref table
|
||
|
||
|
||
// Range check input...
|
||
if (!filename)
|
||
return (NULL);
|
||
|
||
if (!error_cb)
|
||
{
|
||
error_cb = _pdfioFileDefaultError;
|
||
error_data = NULL;
|
||
}
|
||
|
||
// Allocate a PDF file structure...
|
||
if ((pdf = (pdfio_file_t *)calloc(1, sizeof(pdfio_file_t))) == NULL)
|
||
{
|
||
pdfio_file_t temp; // Dummy file
|
||
char message[8192]; // Message string
|
||
|
||
temp.filename = (char *)filename;
|
||
snprintf(message, sizeof(message), "Unable to allocate memory for PDF file - %s", strerror(errno));
|
||
(error_cb)(&temp, message, error_data);
|
||
return (NULL);
|
||
}
|
||
|
||
pdf->filename = strdup(filename);
|
||
pdf->mode = _PDFIO_MODE_READ;
|
||
pdf->error_cb = error_cb;
|
||
pdf->error_data = error_data;
|
||
|
||
// Open the file...
|
||
if ((pdf->fd = open(filename, O_RDONLY | O_BINARY)) < 0)
|
||
{
|
||
_pdfioFileError(pdf, "Unable to open file - %s", strerror(errno));
|
||
free(pdf->filename);
|
||
free(pdf);
|
||
return (NULL);
|
||
}
|
||
|
||
// Read the header from the first line...
|
||
if (!_pdfioFileGets(pdf, line, sizeof(line)))
|
||
goto error;
|
||
|
||
if ((strncmp(line, "%PDF-1.", 7) && strncmp(line, "%PDF-2.", 7)) || !isdigit(line[7] & 255))
|
||
{
|
||
// Bad header
|
||
_pdfioFileError(pdf, "Bad header '%s'.", line);
|
||
goto error;
|
||
}
|
||
|
||
// Copy the version number...
|
||
pdf->version = strdup(line + 5);
|
||
|
||
// Grab the last 32 characters of the file to find the start of the xref table...
|
||
_pdfioFileSeek(pdf, -32, SEEK_END);
|
||
if (_pdfioFileRead(pdf, line, 32) < 32)
|
||
{
|
||
_pdfioFileError(pdf, "Unable to read startxref data.");
|
||
goto error;
|
||
}
|
||
line[32] = '\0';
|
||
|
||
if ((ptr = strstr(line, "startxref")) == NULL)
|
||
{
|
||
_pdfioFileError(pdf, "Unable to find start of xref table.");
|
||
goto error;
|
||
}
|
||
|
||
xref_offset = (off_t)strtol(ptr + 9, NULL, 10);
|
||
|
||
if (!load_xref(pdf, xref_offset))
|
||
goto error;
|
||
|
||
return (pdf);
|
||
|
||
|
||
// If we get here we had a fatal read error...
|
||
error:
|
||
|
||
pdfioFileClose(pdf);
|
||
|
||
return (NULL);
|
||
}
|
||
|
||
|
||
//
|
||
// 'add_object()' - Add an object to a PDF file.
|
||
//
|
||
|
||
static pdfio_obj_t * // O - New object
|
||
add_object(pdfio_file_t *pdf) // I - PDF file
|
||
{
|
||
pdfio_obj_t *obj; // New object
|
||
|
||
|
||
// Allocate memory for the object...
|
||
if ((obj = (pdfio_obj_t *)calloc(1, sizeof(pdfio_obj_t))) == NULL)
|
||
{
|
||
_pdfioFileError(pdf, "Unable to allocate memory for object - %s", strerror(errno));
|
||
return (NULL);
|
||
}
|
||
|
||
// Expand the objects array as needed
|
||
if (pdf->num_objs >= pdf->alloc_objs)
|
||
{
|
||
pdfio_obj_t **temp = (pdfio_obj_t **)realloc(pdf->objs, (pdf->alloc_objs + 32) * sizeof(pdfio_obj_t *));
|
||
|
||
if (!temp)
|
||
{
|
||
_pdfioFileError(pdf, "Unable to allocate memory for object - %s", strerror(errno));
|
||
free(obj);
|
||
return (NULL);
|
||
}
|
||
|
||
pdf->objs = temp;
|
||
pdf->alloc_objs += 32;
|
||
}
|
||
|
||
pdf->objs[pdf->num_objs ++] = obj;
|
||
|
||
return (obj);
|
||
}
|
||
|
||
|
||
//
|
||
// '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.
|
||
//
|
||
|
||
static bool // O - `true` on success, `false` on failure
|
||
write_trailer(pdfio_file_t *pdf) // I - PDF file
|
||
{
|
||
// TODO: Write trailer
|
||
(void)pdf;
|
||
|
||
return (false);
|
||
}
|