iccjpeg library

third_party/iccjpeg/iccjpeg.c

+/*
+ * iccprofile.c
+ *
+ * This file provides code to read and write International Color Consortium
+ * (ICC) device profiles embedded in JFIF JPEG image files.  The ICC has
+ * defined a standard format for including such data in JPEG "APP2" markers.
+ * The code given here does not know anything about the internal structure
+ * of the ICC profile data; it just knows how to put the profile data into
+ * a JPEG file being written, or get it back out when reading.
+ *
+ * This code depends on new features added to the IJG JPEG library as of
+ * IJG release 6b; it will not compile or work with older IJG versions.
+ *
+ * NOTE: this code would need surgery to work on 16-bit-int machines
+ * with ICC profiles exceeding 64K bytes in size.  If you need to do that,
+ * change all the "unsigned int" variables to "INT32".  You'll also need
+ * to find a malloc() replacement that can allocate more than 64K.
+ */
+
+#include "iccjpeg.h"
+#include <stdlib.h>                     /* define malloc() */
+
+
+/*
+ * Since an ICC profile can be larger than the maximum size of a JPEG marker
+ * (64K), we need provisions to split it into multiple markers.  The format
+ * defined by the ICC specifies one or more APP2 markers containing the
+ * following data:
+ *      Identifying string      ASCII "ICC_PROFILE\0"  (12 bytes)
+ *      Marker sequence number  1 for first APP2, 2 for next, etc (1 byte)
+ *      Number of markers       Total number of APP2's used (1 byte)
+ *      Profile data            (remainder of APP2 data)
+ * Decoders should use the marker sequence numbers to reassemble the profile,
+ * rather than assuming that the APP2 markers appear in the correct sequence.
+ */
+
+#define ICC_MARKER  (JPEG_APP0 + 2)     /* JPEG marker code for ICC */
+#define ICC_OVERHEAD_LEN  14            /* size of non-profile data in APP2 */
+#define MAX_BYTES_IN_MARKER  65533      /* maximum data len of a JPEG marker */
+#define MAX_DATA_BYTES_IN_MARKER  (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)
+
+
+/*
+ * This routine writes the given ICC profile data into a JPEG file.
+ * It *must* be called AFTER calling jpeg_start_compress() and BEFORE
+ * the first call to jpeg_write_scanlines().
+ * (This ordering ensures that the APP2 marker(s) will appear after the
+ * SOI and JFIF or Adobe markers, but before all else.)
+ */
+
+void
+write_icc_profile (j_compress_ptr cinfo,
+                   const JOCTET *icc_data_ptr,
+                   unsigned int icc_data_len)
+{
+  unsigned int num_markers;     /* total number of markers we'll write */
+  int cur_marker = 1;           /* per spec, counting starts at 1 */
+  unsigned int length;          /* number of bytes to write in this marker */
+
+  /* Calculate the number of markers we'll need, rounding up of course */
+  num_markers = icc_data_len / MAX_DATA_BYTES_IN_MARKER;
+  if (num_markers * MAX_DATA_BYTES_IN_MARKER != icc_data_len)
+    num_markers++;
+
+  while (icc_data_len > 0) {
+    /* length of profile to put in this marker */
+    length = icc_data_len;
+    if (length > MAX_DATA_BYTES_IN_MARKER)
+      length = MAX_DATA_BYTES_IN_MARKER;
+    icc_data_len -= length;
+
+    /* Write the JPEG marker header (APP2 code and marker length) */
+    jpeg_write_m_header(cinfo, ICC_MARKER,
+                        (unsigned int) (length + ICC_OVERHEAD_LEN));
+
+    /* Write the marker identifying string "ICC_PROFILE" (null-terminated).
+     * We code it in this less-than-transparent way so that the code works
+     * even if the local character set is not ASCII.
+     */
+    jpeg_write_m_byte(cinfo, 0x49);
+    jpeg_write_m_byte(cinfo, 0x43);
+    jpeg_write_m_byte(cinfo, 0x43);
+    jpeg_write_m_byte(cinfo, 0x5F);
+    jpeg_write_m_byte(cinfo, 0x50);
+    jpeg_write_m_byte(cinfo, 0x52);
+    jpeg_write_m_byte(cinfo, 0x4F);
+    jpeg_write_m_byte(cinfo, 0x46);
+    jpeg_write_m_byte(cinfo, 0x49);
+    jpeg_write_m_byte(cinfo, 0x4C);
+    jpeg_write_m_byte(cinfo, 0x45);
+    jpeg_write_m_byte(cinfo, 0x0);
+
+    /* Add the sequencing info */
+    jpeg_write_m_byte(cinfo, cur_marker);
+    jpeg_write_m_byte(cinfo, (int) num_markers);
+
+    /* Add the profile data */
+    while (length--) {
+      jpeg_write_m_byte(cinfo, *icc_data_ptr);
+      icc_data_ptr++;
+    }
+    cur_marker++;
+  }
+}
+
+
+/*
+ * Prepare for reading an ICC profile
+ */
+
+void
+setup_read_icc_profile (j_decompress_ptr cinfo)
+{
+  /* Tell the library to keep any APP2 data it may find */
+  jpeg_save_markers(cinfo, ICC_MARKER, 0xFFFF);
+}
+
+
+/*
+ * Handy subroutine to test whether a saved marker is an ICC profile marker.
+ */
+
+static boolean
+marker_is_icc (jpeg_saved_marker_ptr marker)
+{
+  return
+    marker->marker == ICC_MARKER &&
+    marker->data_length >= ICC_OVERHEAD_LEN &&
+    /* verify the identifying string */
+    GETJOCTET(marker->data[0]) == 0x49 &&
+    GETJOCTET(marker->data[1]) == 0x43 &&
+    GETJOCTET(marker->data[2]) == 0x43 &&
+    GETJOCTET(marker->data[3]) == 0x5F &&
+    GETJOCTET(marker->data[4]) == 0x50 &&
+    GETJOCTET(marker->data[5]) == 0x52 &&
+    GETJOCTET(marker->data[6]) == 0x4F &&
+    GETJOCTET(marker->data[7]) == 0x46 &&
+    GETJOCTET(marker->data[8]) == 0x49 &&
+    GETJOCTET(marker->data[9]) == 0x4C &&
+    GETJOCTET(marker->data[10]) == 0x45 &&
+    GETJOCTET(marker->data[11]) == 0x0;
+}
+
+
+/*
+ * See if there was an ICC profile in the JPEG file being read;
+ * if so, reassemble and return the profile data.
+ *
+ * TRUE is returned if an ICC profile was found, FALSE if not.
+ * If TRUE is returned, *icc_data_ptr is set to point to the
+ * returned data, and *icc_data_len is set to its length.
+ *
+ * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
+ * and must be freed by the caller with free() when the caller no longer
+ * needs it.  (Alternatively, we could write this routine to use the
+ * IJG library's memory allocator, so that the data would be freed implicitly
+ * at jpeg_finish_decompress() time.  But it seems likely that many apps
+ * will prefer to have the data stick around after decompression finishes.)
+ *
+ * NOTE: if the file contains invalid ICC APP2 markers, we just silently
+ * return FALSE.  You might want to issue an error message instead.
+ */
+
+boolean
+read_icc_profile (j_decompress_ptr cinfo,
+                  JOCTET **icc_data_ptr,
+                  unsigned int *icc_data_len)
+{
+  jpeg_saved_marker_ptr marker;
+  int num_markers = 0;
+  int seq_no;
+  JOCTET *icc_data;
+  unsigned int total_length;
+#define MAX_SEQ_NO  255         /* sufficient since marker numbers are bytes */
+  char marker_present[MAX_SEQ_NO+1];      /* 1 if marker found */
+  unsigned int data_length[MAX_SEQ_NO+1]; /* size of profile data in marker */
+  unsigned int data_offset[MAX_SEQ_NO+1]; /* offset for data in marker */
+
+  *icc_data_ptr = NULL;         /* avoid confusion if FALSE return */
+  *icc_data_len = 0;
+
+  /* This first pass over the saved markers discovers whether there are
+   * any ICC markers and verifies the consistency of the marker numbering.
+   */
+
+  for (seq_no = 1; seq_no <= MAX_SEQ_NO; seq_no++)
+    marker_present[seq_no] = 0;
+
+  for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
+    if (marker_is_icc(marker)) {
+      if (num_markers == 0)
+        num_markers = GETJOCTET(marker->data[13]);
+      else if (num_markers != GETJOCTET(marker->data[13]))
+        return FALSE;           /* inconsistent num_markers fields */
+      seq_no = GETJOCTET(marker->data[12]);
+      if (seq_no <= 0 || seq_no > num_markers)
+        return FALSE;           /* bogus sequence number */
+      if (marker_present[seq_no])
+        return FALSE;           /* duplicate sequence numbers */
+      marker_present[seq_no] = 1;
+      data_length[seq_no] = marker->data_length - ICC_OVERHEAD_LEN;
+    }
+  }
+
+  if (num_markers == 0)
+    return FALSE;
+
+  /* Check for missing markers, count total space needed,
+   * compute offset of each marker's part of the data.
+   */
+
+  total_length = 0;
+  for (seq_no = 1; seq_no <= num_markers; seq_no++) {
+    if (marker_present[seq_no] == 0)
+      return FALSE;             /* missing sequence number */
+    data_offset[seq_no] = total_length;
+    total_length += data_length[seq_no];
+  }
+
+  if (total_length <= 0)
+    return FALSE;               /* found only empty markers? */
+
+  /* Allocate space for assembled data */
+  icc_data = (JOCTET *) malloc(total_length * sizeof(JOCTET));
+  if (icc_data == NULL)
+    return FALSE;               /* oops, out of memory */
+
+  /* and fill it in */
+  for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
+    if (marker_is_icc(marker)) {
+      JOCTET FAR *src_ptr;
+      JOCTET *dst_ptr;
+      unsigned int length;
+      seq_no = GETJOCTET(marker->data[12]);
+      dst_ptr = icc_data + data_offset[seq_no];
+      src_ptr = marker->data + ICC_OVERHEAD_LEN;
+      length = data_length[seq_no];
+      while (length--) {
+        *dst_ptr++ = *src_ptr++;
+      }
+    }
+  }
+
+  *icc_data_ptr = icc_data;
+  *icc_data_len = total_length;
+
+  return TRUE;
+}