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https://github.com/michaelrsweet/pdfio.git
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Implement JPEG image object support.
This commit is contained in:
Michael R Sweet
parent
eb4477ce9b
commit
128d5f0d42
241
pdfio-content.c
241
pdfio-content.c
@ -12,14 +12,25 @@
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//
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#include "pdfio-content.h"
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#include "pdfio-private.h"
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#include <math.h>
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//
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// Local types...
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//
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typedef pdfio_obj_t *(*image_func_t)(pdfio_dict_t *dict, int fd);
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//
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// Local functions...
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//
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static bool write_string(pdfio_stream_t *st, const char *s);
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static pdfio_obj_t *copy_gif(pdfio_dict_t *dict, int fd);
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static pdfio_obj_t *copy_jpeg(pdfio_dict_t *dict, int fd);
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static pdfio_obj_t *copy_png(pdfio_dict_t *dict, int fd);
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static bool write_string(pdfio_stream_t *st, const char *s);
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//
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@ -859,6 +870,8 @@ pdfioFileCreateICCProfileObject(
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//
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// 'pdfioFileCreateImageObject()' - Add an image object to a PDF file.
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//
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// Currently only GIF, JPEG, and PNG files are supported.
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//
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pdfio_obj_t * // O - Object
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pdfioFileCreateImageObject(
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@ -866,10 +879,230 @@ pdfioFileCreateImageObject(
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const char *filename, // I - Filename
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bool interpolate) // I - Interpolate image data?
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{
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(void)pdf;
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(void)filename;
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(void)interpolate;
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pdfio_dict_t *dict; // Image dictionary
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pdfio_obj_t *obj; // Image object
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int fd; // File
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unsigned char buffer[32]; // Read buffer
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image_func_t copy_func = NULL; // Image copy function
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// Range check input...
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if (!pdf || !filename)
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return (NULL);
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// Try opening the file...
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if ((fd = open(filename, O_RDONLY | O_BINARY)) < 0)
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{
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_pdfioFileError(pdf, "Unable to open image file '%s': %s", filename, strerror(errno));
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return (NULL);
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}
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// Read the file header to determine the file format...
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if (read(fd, buffer, sizeof(buffer)) < (ssize_t)sizeof(buffer))
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{
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_pdfioFileError(pdf, "Unable to read header from image file '%s'.", filename);
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close(fd);
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return (NULL);
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}
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lseek(fd, 0, SEEK_SET);
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if (!memcmp(buffer, "\211PNG\015\012\032\012\000\000\000\015IHDR", 16))
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{
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// PNG image...
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copy_func = copy_png;
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}
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else if (!memcmp(buffer, "GIF87a", 6) || !memcmp(buffer, "GIF89a", 6))
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{
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// GIF image...
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copy_func = copy_gif;
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}
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else if (!memcmp(buffer, "\377\330\377", 3))
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{
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// JPEG image...
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copy_func = copy_jpeg;
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}
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else
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{
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// Something else that isn't supported...
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_pdfioFileError(pdf, "Unsupported image file '%s'.", filename);
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close(fd);
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return (NULL);
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}
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// Create the base image dictionary the copy the file into an object...
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if ((dict = pdfioDictCreate(pdf)) == NULL)
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{
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close(fd);
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return (NULL);
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}
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pdfioDictSetName(dict, "Type", "XObject");
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pdfioDictSetName(dict, "SubType", "Image");
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pdfioDictSetBoolean(dict, "Interpolate", interpolate);
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obj = (copy_func)(dict, fd);
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// Close the file and return the object...
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close(fd);
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return (obj);
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}
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//
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// 'copy_gif()' - Copy a GIF image.
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//
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static pdfio_obj_t * // O - Object or `NULL` on error
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copy_gif(pdfio_dict_t *dict, // I - Dictionary
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int fd) // I - File descriptor
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{
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// TODO: Implement copy_gif
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(void)dict;
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(void)fd;
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return (NULL);
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}
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//
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// 'copy_jpeg()' - Copy a JPEG image.
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//
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static pdfio_obj_t * // O - Object or `NULL` on error
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copy_jpeg(pdfio_dict_t *dict, // I - Dictionary
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int fd) // I - File descriptor
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{
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pdfio_obj_t *obj; // Object
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pdfio_stream_t *st; // Stream for JPEG data
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ssize_t bytes; // Bytes read
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unsigned char buffer[16384], // Read buffer
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*bufptr, // Pointer into buffer
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*bufend; // End of buffer
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size_t length; // Length of chunk
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unsigned width = 0, // Width in columns
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height = 0, // Height in lines
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num_colors = 0; // Number of colors
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// Scan the file for a SOFn marker, then we can get the dimensions...
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bytes = read(fd, buffer, sizeof(buffer));
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for (bufptr = buffer + 2, bufend = buffer + bytes; bufptr < bufend;)
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{
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if (*bufptr == 0xff)
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{
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bufptr ++;
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if (bufptr >= bufend)
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{
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/*
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* If we are at the end of the current buffer, re-fill and continue...
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*/
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if ((bytes = read(fd, buffer, sizeof(buffer))) <= 0)
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break;
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bufptr = buffer;
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bufend = buffer + bytes;
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}
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if (*bufptr == 0xff)
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continue;
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if ((bufptr + 16) >= bufend)
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{
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/*
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* Read more of the marker...
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*/
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bytes = bufend - bufptr;
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memmove(buffer, bufptr, (size_t)bytes);
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bufptr = buffer;
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bufend = buffer + bytes;
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if ((bytes = read(fd, bufend, sizeof(buffer) - (size_t)bytes)) <= 0)
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break;
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bufend += bytes;
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}
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length = (size_t)((bufptr[1] << 8) | bufptr[2]);
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PDFIO_DEBUG("copy_jpeg: JPEG X'FF%02X' (length %u)\n", *bufptr, (unsigned)length);
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if ((*bufptr >= 0xc0 && *bufptr <= 0xc3) || (*bufptr >= 0xc5 && *bufptr <= 0xc7) || (*bufptr >= 0xc9 && *bufptr <= 0xcb) || (*bufptr >= 0xcd && *bufptr <= 0xcf))
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{
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// SOFn marker, look for dimensions...
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width = (unsigned)((bufptr[6] << 8) | bufptr[7]);
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height = (unsigned)((bufptr[4] << 8) | bufptr[5]);
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num_colors = bufptr[8];
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break;
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}
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// Skip past this marker...
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bufptr ++;
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bytes = bufend - bufptr;
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while (length >= (size_t)bytes)
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{
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length -= (size_t)bytes;
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if ((bytes = read(fd, buffer, sizeof(buffer))) <= 0)
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break;
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bufptr = buffer;
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bufend = buffer + bytes;
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}
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if (length > (size_t)bytes)
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break;
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bufptr += length;
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}
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}
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if (width == 0 || height == 0 || (num_colors != 1 && num_colors != 3))
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return (NULL);
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// Create the image object...
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pdfioDictSetNumber(dict, "Width", width);
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pdfioDictSetNumber(dict, "Height", height);
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pdfioDictSetNumber(dict, "BitsPerComponent", 8);
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pdfioDictSetName(dict, "ColorSpace", num_colors == 3 ? "CalRGB" : "CalGray");
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pdfioDictSetName(dict, "Filter", "DCTDecode");
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obj = pdfioFileCreateObject(dict->pdf, dict);
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st = pdfioObjCreateStream(obj, PDFIO_FILTER_NONE);
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// Copy the file to a stream...
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lseek(fd, 0, SEEK_SET);
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while ((bytes = read(fd, buffer, sizeof(buffer))) > 0)
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{
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if (!pdfioStreamWrite(st, buffer, (size_t)bytes))
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return (NULL);
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}
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if (!pdfioStreamClose(st))
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return (NULL);
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return (obj);
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}
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//
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// 'copy_png()' - Copy a PNG image.
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//
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static pdfio_obj_t * // O - Object or `NULL` on error
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copy_png(pdfio_dict_t *dict, // I - Dictionary
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int fd) // I - File descriptor
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{
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// TODO: Implement copy_png
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(void)dict;
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(void)fd;
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return (NULL);
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}
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@ -18,8 +18,51 @@
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# include <stdarg.h>
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# include <errno.h>
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# include <inttypes.h>
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# include <fcntl.h>
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# include <unistd.h>
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# ifdef _WIN32
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# include <io.h>
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# include <direct.h>
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/*
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* Microsoft renames the POSIX functions to _name, and introduces
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* a broken compatibility layer using the original names. As a result,
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* random crashes can occur when, for example, strdup() allocates memory
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* from a different heap than used by malloc() and free().
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*
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* To avoid moronic problems like this, we #define the POSIX function
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* names to the corresponding non-standard Microsoft names.
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*/
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# define access _access
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# define close _close
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# define fileno _fileno
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# define lseek _lseek
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# define mkdir(d,p) _mkdir(d)
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# define open _open
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# define read _read
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# define rmdir _rmdir
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# define snprintf _snprintf
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# define strdup _strdup
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# define unlink _unlink
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# define vsnprintf _vsnprintf
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# define write _write
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/*
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* Map various parameters for POSIX...
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*/
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# define F_OK 00
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# define W_OK 02
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# define R_OK 04
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# define O_RDONLY _O_RDONLY
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# define O_WRONLY _O_WRONLY
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# define O_CREAT _O_CREAT
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# define O_TRUNC _O_TRUNC
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# define O_BINARY _O_BINARY
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# else // !_WIN32
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# include <fcntl.h>
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# include <unistd.h>
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# define O_BINARY 0
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# endif // _WIN32
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# include <string.h>
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# include <ctype.h>
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# include <zlib.h>
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