/*
 * ZoneMinder JPEG memory encoding/decoding, $Date$, $Revision$
 * Copyright (C) 2001-2008 Philip Coombes
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "zm_jpeg.h"

#include "zm_logger.h"

/* Overridden error handlers, mostly for decompression */
extern "C" {

#define MAX_JPEG_ERRS 25
#define MAX_JPEG_ERR_MULT 10   /* ratio of acceptable frame errors without a fatal error */

  static int jpeg_err_count = 0;

  void zm_jpeg_error_silent(j_common_ptr cinfo) {
    zm_error_ptr zmerr = (zm_error_ptr)cinfo->err;
    longjmp(zmerr->setjmp_buffer, 1);
  }

  void zm_jpeg_emit_silence(j_common_ptr cinfo, int msg_level) {
  }

  void zm_jpeg_error_exit(j_common_ptr cinfo) {
    zm_error_ptr zmerr = (zm_error_ptr) cinfo->err;

    char buffer[JMSG_LENGTH_MAX];
    zmerr->pub.format_message(cinfo, buffer);

    Error("%s", buffer);

    jpeg_err_count += MAX_JPEG_ERR_MULT;
    if (jpeg_err_count >= ( MAX_JPEG_ERRS * MAX_JPEG_ERR_MULT )) {
      Fatal("Maximum number (%d) of JPEG errors reached, exiting", jpeg_err_count / MAX_JPEG_ERR_MULT);
    }

    longjmp(zmerr->setjmp_buffer, 1);
  }

  void zm_jpeg_emit_message(j_common_ptr cinfo, int msg_level) {
    char buffer[JMSG_LENGTH_MAX];
    zm_error_ptr zmerr = (zm_error_ptr) cinfo->err;

    if (msg_level < 0) {
      /* It's a warning message.  Since corrupt files may generate many warnings,
       * the policy implemented here is to show only the first warning,
       * unless trace_level >= 3.
       */
      if (zmerr->pub.num_warnings == 0 || zmerr->pub.trace_level >= 3) {
        zmerr->pub.format_message(cinfo, buffer);
        if (!strstr(buffer, "Corrupt JPEG data:"))
          Warning("%s", buffer);
      }
      /* Always count warnings in num_warnings. */
      zmerr->pub.num_warnings++;
    } else {
      /* It's a trace message.  Show it if trace_level >= msg_level. */
      if (zmerr->pub.trace_level >= msg_level) {
        zmerr->pub.format_message(cinfo, buffer);
        Debug(msg_level, "%s", buffer);
      }
    }
  }

  /* Expanded data destination object for memory */

  typedef struct {
    struct jpeg_destination_mgr pub; /* public fields */

    JOCTET *outbuffer;    /* target buffer */
    size_t   *outbuffer_size;
    JOCTET *buffer;    /* start of buffer */
  } mem_destination_mgr;

  typedef mem_destination_mgr * mem_dest_ptr;

#define OUTPUT_BUF_SIZE  4096  /* choose an efficiently fwrite'able size */

  /*
   * Initialize destination --- called by jpeg_start_compress
   * before any data is actually written.
   */

  static void init_destination (j_compress_ptr cinfo) {
    mem_dest_ptr dest = (mem_dest_ptr) cinfo->dest;

    /* Allocate the output buffer --- it will be released when done with image */
    dest->buffer = (JOCTET *)(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, OUTPUT_BUF_SIZE * SIZEOF(JOCTET));

    dest->pub.next_output_byte = dest->buffer;
    dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;

    *(dest->outbuffer_size) = 0;
  }

  /*
   * Empty the output buffer --- called whenever buffer fills up.
   *
   * In typical applications, this should write the entire output buffer
   * (ignoring the current state of next_output_byte & free_in_buffer),
   * reset the pointer & count to the start of the buffer, and return TRUE
   * indicating that the buffer has been dumped.
   *
   * In applications that need to be able to suspend compression due to output
   * overrun, a FALSE return indicates that the buffer cannot be emptied now.
   * In this situation, the compressor will return to its caller (possibly with
   * an indication that it has not accepted all the supplied scanlines).  The
   * application should resume compression after it has made more room in the
   * output buffer.  Note that there are substantial restrictions on the use of
   * suspension --- see the documentation.
   *
   * When suspending, the compressor will back up to a convenient restart point
   * (typically the start of the current MCU). next_output_byte & free_in_buffer
   * indicate where the restart point will be if the current call returns FALSE.
   * Data beyond this point will be regenerated after resumption, so do not
   * write it out when emptying the buffer externally.
   */

  static boolean empty_output_buffer(j_compress_ptr cinfo) {
    mem_dest_ptr dest = (mem_dest_ptr) cinfo->dest;

    memcpy(dest->outbuffer+*(dest->outbuffer_size), dest->buffer, OUTPUT_BUF_SIZE);
    *(dest->outbuffer_size) += OUTPUT_BUF_SIZE;

    dest->pub.next_output_byte = dest->buffer;
    dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;

    return TRUE;
  }

  /*
   * Terminate destination --- called by jpeg_finish_compress
   * after all data has been written.  Usually needs to flush buffer.
   *
   * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
   * application must deal with any cleanup that should happen even
   * for error exit.
   */

  static void term_destination(j_compress_ptr cinfo) {
    mem_dest_ptr dest = (mem_dest_ptr) cinfo->dest;
    size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;

    if ( datacount > 0 ) {
      memcpy(dest->outbuffer+*(dest->outbuffer_size), dest->buffer, datacount);
      *(dest->outbuffer_size) += datacount;
    }
  }


  /*
   * Prepare for output to a stdio stream.
   * The caller must have already opened the stream, and is responsible
   * for closing it after finishing compression.
   */

  void zm_jpeg_mem_dest(j_compress_ptr cinfo, JOCTET *outbuffer, size_t *outbuffer_size) {
    mem_dest_ptr dest;

    /* The destination object is made permanent so that multiple JPEG images
     * can be written to the same file without re-executing jpeg_stdio_dest.
     * This makes it dangerous to use this manager and a different destination
     * manager serially with the same JPEG object, because their private object
     * sizes may be different.  Caveat programmer.
     */
    if ( cinfo->dest == nullptr ) {
      /* first time for this JPEG object? */
      cinfo->dest = (struct jpeg_destination_mgr *)(*cinfo->mem->alloc_small)
                    ((j_common_ptr) cinfo, JPOOL_PERMANENT, SIZEOF(mem_destination_mgr));
    }

    dest = (mem_dest_ptr) cinfo->dest;
    dest->pub.init_destination = init_destination;
    dest->pub.empty_output_buffer = empty_output_buffer;
    dest->pub.term_destination = term_destination;
    dest->outbuffer = outbuffer;
    dest->outbuffer_size = outbuffer_size;
  }

  /* Expanded data source object for memory input */

  typedef struct {
    struct jpeg_source_mgr pub;  /* public fields */

    JOCTET * inbuffer;    /* source stream */
    int  inbuffer_size;
    int  inbuffer_size_hwm; /* High water mark */

    JOCTET * buffer;    /* start of buffer */
    boolean start_of_data;  /* have we gotten any data yet? */
  } mem_source_mgr;

  typedef mem_source_mgr * mem_src_ptr;

#define INPUT_BUF_SIZE  4096  /* choose an efficiently fread'able size */

  /*
   * Initialize source --- called by jpeg_read_header
   * before any data is actually read.
   */

  static void init_source (j_decompress_ptr cinfo) {
    mem_src_ptr src = (mem_src_ptr) cinfo->src;

    /* We reset the empty-input-file flag for each image,
     * but we don't clear the input buffer.
     * This is correct behavior for reading a series of images from one source.
     */
    src->start_of_data = TRUE;
    src->pub.bytes_in_buffer = 0;
  }


  /*
   * Fill the input buffer --- called whenever buffer is emptied.
   *
   * In typical applications, this should read fresh data into the buffer
   * (ignoring the current state of next_input_byte & bytes_in_buffer),
   * reset the pointer & count to the start of the buffer, and return TRUE
   * indicating that the buffer has been reloaded.  It is not necessary to
   * fill the buffer entirely, only to obtain at least one more byte.
   *
   * There is no such thing as an EOF return.  If the end of the file has been
   * reached, the routine has a choice of ERREXIT() or inserting fake data into
   * the buffer.  In most cases, generating a warning message and inserting a
   * fake EOI marker is the best course of action --- this will allow the
   * decompressor to output however much of the image is there.  However,
   * the resulting error message is misleading if the real problem is an empty
   * input file, so we handle that case specially.
   *
   * In applications that need to be able to suspend compression due to input
   * not being available yet, a FALSE return indicates that no more data can be
   * obtained right now, but more may be forthcoming later.  In this situation,
   * the decompressor will return to its caller (with an indication of the
   * number of scanlines it has read, if any).  The application should resume
   * decompression after it has loaded more data into the input buffer.  Note
   * that there are substantial restrictions on the use of suspension --- see
   * the documentation.
   *
   * When suspending, the decompressor will back up to a convenient restart point
   * (typically the start of the current MCU). next_input_byte & bytes_in_buffer
   * indicate where the restart point will be if the current call returns FALSE.
   * Data beyond this point must be rescanned after resumption, so move it to
   * the front of the buffer rather than discarding it.
   */

  static boolean fill_input_buffer (j_decompress_ptr cinfo) {
    mem_src_ptr src = (mem_src_ptr) cinfo->src;
    size_t nbytes;

    memcpy(src->buffer, src->inbuffer, (size_t) src->inbuffer_size);
    nbytes = src->inbuffer_size;

    if ( nbytes == 0 ) {
      if ( src->start_of_data )  /* Treat empty input file as fatal error */
        ERREXIT(cinfo, JERR_INPUT_EMPTY);
      WARNMS(cinfo, JWRN_JPEG_EOF);
      /* Insert a fake EOI marker */
      src->buffer[0] = (JOCTET) 0xFF;
      src->buffer[1] = (JOCTET) JPEG_EOI;
      nbytes = 2;
    }

    src->pub.next_input_byte = src->buffer;
    src->pub.bytes_in_buffer = nbytes;
    src->start_of_data = FALSE;

    return TRUE;
  }

  /*
   * Skip data --- used to skip over a potentially large amount of
   * uninteresting data (such as an APPn marker).
   *
   * Writers of suspendable-input applications must note that skip_input_data
   * is not granted the right to give a suspension return.  If the skip extends
   * beyond the data currently in the buffer, the buffer can be marked empty so
   * that the next read will cause a fill_input_buffer call that can suspend.
   * Arranging for additional bytes to be discarded before reloading the input
   * buffer is the application writer's problem.
   */

  static void skip_input_data(j_decompress_ptr cinfo, long num_bytes) {
    mem_src_ptr src = (mem_src_ptr) cinfo->src;

    /* Just a dumb implementation for now.  Could use fseek() except
     * it doesn't work on pipes.  Not clear that being smart is worth
     * any trouble anyway --- large skips are infrequent.
     */
    if ( num_bytes > 0 ) {
      while ( num_bytes > (long) src->pub.bytes_in_buffer ) {
        num_bytes -= (long) src->pub.bytes_in_buffer;
        (void) fill_input_buffer(cinfo);
        /* note we assume that fill_input_buffer will never return FALSE,
         * so suspension need not be handled.
         */
      }
      src->pub.next_input_byte += (size_t) num_bytes;
      src->pub.bytes_in_buffer -= (size_t) num_bytes;
    }
  }

  /*
   * Terminate source --- called by jpeg_finish_decompress
   * after all data has been read.  Often a no-op.
   *
   * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
   * application must deal with any cleanup that should happen even
   * for error exit.
   */

  static void term_source(j_decompress_ptr cinfo) {
    /* no work necessary here */
  }

  /*
   * Prepare for input from a memory stream.
   * The caller must have already opened the stream, and is responsible
   * for closing it after finishing decompression.
   */

  void zm_jpeg_mem_src(j_decompress_ptr cinfo, const JOCTET *inbuffer, size_t inbuffer_size) {
    mem_src_ptr src;

    /* The source object and input buffer are made permanent so that a series
     * of JPEG images can be read from the same file by calling zm_jpeg_mem_src
     * only before the first one.  (If we discarded the buffer at the end of
     * one image, we'd likely lose the start of the next one.)
     * This makes it unsafe to use this manager and a different source
     * manager serially with the same JPEG object.  Caveat programmer.
     */
    if ( cinfo->src == nullptr ) {
      /* first time for this JPEG object? */
      cinfo->src = (struct jpeg_source_mgr *)(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, SIZEOF(mem_source_mgr));
      src = (mem_src_ptr) cinfo->src;
      src->buffer = (JOCTET *)(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, inbuffer_size * SIZEOF(JOCTET));
      src->inbuffer_size_hwm = inbuffer_size;
    } else {
      src = (mem_src_ptr) cinfo->src;
      if ( static_cast<size_t>(src->inbuffer_size_hwm) < inbuffer_size ) {
        src->buffer = (JOCTET *)(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, inbuffer_size * SIZEOF(JOCTET));
        src->inbuffer_size_hwm = inbuffer_size;
      }
    }

    src = (mem_src_ptr) cinfo->src;
    src->pub.init_source = init_source;
    src->pub.fill_input_buffer = fill_input_buffer;
    src->pub.skip_input_data = skip_input_data;
    src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */
    src->pub.term_source = term_source;
    src->inbuffer = (JOCTET *)inbuffer;
    src->inbuffer_size = inbuffer_size;
    src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
    src->pub.next_input_byte = nullptr; /* until buffer loaded */

    /* Decrement the error count slowly when processing ok otherwise occasional frame errors build up to a zmc exit */
    if (jpeg_err_count > 0) jpeg_err_count--; else jpeg_err_count = 0;
  }

  void zm_use_std_huff_tables(j_decompress_ptr cinfo) {
    /* JPEG standard Huffman tables (cf. JPEG standard section K.3) */
    /* IMPORTANT: these are only valid for 8-bit data precision! */
    static const JHUFF_TBL dclumin = {
      { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 },
      { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 },
      FALSE
    };
    static const JHUFF_TBL dcchrome = {
      { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 },
      { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 },
      FALSE
    };
    static const JHUFF_TBL aclumin = {
      { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d },
      {
        0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
        0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
        0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
        0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
        0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
        0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
        0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
        0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
        0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
        0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
        0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
        0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
        0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
        0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
        0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
        0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
        0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
        0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
        0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
        0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
        0xf9, 0xfa
      },
      FALSE
    };
    static const JHUFF_TBL acchrome = {
      { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 },
      {
        0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
        0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
        0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
        0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
        0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
        0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
        0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
        0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
        0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
        0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
        0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
        0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
        0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
        0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
        0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
        0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
        0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
        0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
        0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
        0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
        0xf9, 0xfa
      },
      FALSE
    };

    cinfo->dc_huff_tbl_ptrs[0] = (JHUFF_TBL*)&dclumin;
    cinfo->dc_huff_tbl_ptrs[1] = (JHUFF_TBL*)&dcchrome;
    cinfo->ac_huff_tbl_ptrs[0] = (JHUFF_TBL*)&aclumin;
    cinfo->ac_huff_tbl_ptrs[1] = (JHUFF_TBL*)&acchrome;
  }

}
