diff options
Diffstat (limited to 'code/jpeg-6/jdmarker.c')
| -rwxr-xr-x | code/jpeg-6/jdmarker.c | 1052 |
1 files changed, 1052 insertions, 0 deletions
diff --git a/code/jpeg-6/jdmarker.c b/code/jpeg-6/jdmarker.c new file mode 100755 index 0000000..6c3c519 --- /dev/null +++ b/code/jpeg-6/jdmarker.c @@ -0,0 +1,1052 @@ +/*
+ * jdmarker.c
+ *
+ * Copyright (C) 1991-1995, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains routines to decode JPEG datastream markers.
+ * Most of the complexity arises from our desire to support input
+ * suspension: if not all of the data for a marker is available,
+ * we must exit back to the application. On resumption, we reprocess
+ * the marker.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+typedef enum { /* JPEG marker codes */
+ M_SOF0 = 0xc0,
+ M_SOF1 = 0xc1,
+ M_SOF2 = 0xc2,
+ M_SOF3 = 0xc3,
+
+ M_SOF5 = 0xc5,
+ M_SOF6 = 0xc6,
+ M_SOF7 = 0xc7,
+
+ M_JPG = 0xc8,
+ M_SOF9 = 0xc9,
+ M_SOF10 = 0xca,
+ M_SOF11 = 0xcb,
+
+ M_SOF13 = 0xcd,
+ M_SOF14 = 0xce,
+ M_SOF15 = 0xcf,
+
+ M_DHT = 0xc4,
+
+ M_DAC = 0xcc,
+
+ M_RST0 = 0xd0,
+ M_RST1 = 0xd1,
+ M_RST2 = 0xd2,
+ M_RST3 = 0xd3,
+ M_RST4 = 0xd4,
+ M_RST5 = 0xd5,
+ M_RST6 = 0xd6,
+ M_RST7 = 0xd7,
+
+ M_SOI = 0xd8,
+ M_EOI = 0xd9,
+ M_SOS = 0xda,
+ M_DQT = 0xdb,
+ M_DNL = 0xdc,
+ M_DRI = 0xdd,
+ M_DHP = 0xde,
+ M_EXP = 0xdf,
+
+ M_APP0 = 0xe0,
+ M_APP1 = 0xe1,
+ M_APP2 = 0xe2,
+ M_APP3 = 0xe3,
+ M_APP4 = 0xe4,
+ M_APP5 = 0xe5,
+ M_APP6 = 0xe6,
+ M_APP7 = 0xe7,
+ M_APP8 = 0xe8,
+ M_APP9 = 0xe9,
+ M_APP10 = 0xea,
+ M_APP11 = 0xeb,
+ M_APP12 = 0xec,
+ M_APP13 = 0xed,
+ M_APP14 = 0xee,
+ M_APP15 = 0xef,
+
+ M_JPG0 = 0xf0,
+ M_JPG13 = 0xfd,
+ M_COM = 0xfe,
+
+ M_TEM = 0x01,
+
+ M_ERROR = 0x100
+} JPEG_MARKER;
+
+
+/*
+ * Macros for fetching data from the data source module.
+ *
+ * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
+ * the current restart point; we update them only when we have reached a
+ * suitable place to restart if a suspension occurs.
+ */
+
+/* Declare and initialize local copies of input pointer/count */
+#define INPUT_VARS(cinfo) \
+ struct jpeg_source_mgr * datasrc = (cinfo)->src; \
+ const JOCTET * next_input_byte = datasrc->next_input_byte; \
+ size_t bytes_in_buffer = datasrc->bytes_in_buffer
+
+/* Unload the local copies --- do this only at a restart boundary */
+#define INPUT_SYNC(cinfo) \
+ ( datasrc->next_input_byte = next_input_byte, \
+ datasrc->bytes_in_buffer = bytes_in_buffer )
+
+/* Reload the local copies --- seldom used except in MAKE_BYTE_AVAIL */
+#define INPUT_RELOAD(cinfo) \
+ ( next_input_byte = datasrc->next_input_byte, \
+ bytes_in_buffer = datasrc->bytes_in_buffer )
+
+/* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
+ * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
+ * but we must reload the local copies after a successful fill.
+ */
+#define MAKE_BYTE_AVAIL(cinfo,action) \
+ if (bytes_in_buffer == 0) { \
+ if (! (*datasrc->fill_input_buffer) (cinfo)) \
+ { action; } \
+ INPUT_RELOAD(cinfo); \
+ } \
+ bytes_in_buffer--
+
+/* Read a byte into variable V.
+ * If must suspend, take the specified action (typically "return FALSE").
+ */
+#define INPUT_BYTE(cinfo,V,action) \
+ MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
+ V = GETJOCTET(*next_input_byte++); )
+
+/* As above, but read two bytes interpreted as an unsigned 16-bit integer.
+ * V should be declared unsigned int or perhaps INT32.
+ */
+#define INPUT_2BYTES(cinfo,V,action) \
+ MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
+ V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
+ MAKE_BYTE_AVAIL(cinfo,action); \
+ V += GETJOCTET(*next_input_byte++); )
+
+
+/*
+ * Routines to process JPEG markers.
+ *
+ * Entry condition: JPEG marker itself has been read and its code saved
+ * in cinfo->unread_marker; input restart point is just after the marker.
+ *
+ * Exit: if return TRUE, have read and processed any parameters, and have
+ * updated the restart point to point after the parameters.
+ * If return FALSE, was forced to suspend before reaching end of
+ * marker parameters; restart point has not been moved. Same routine
+ * will be called again after application supplies more input data.
+ *
+ * This approach to suspension assumes that all of a marker's parameters can
+ * fit into a single input bufferload. This should hold for "normal"
+ * markers. Some COM/APPn markers might have large parameter segments,
+ * but we use skip_input_data to get past those, and thereby put the problem
+ * on the source manager's shoulders.
+ *
+ * Note that we don't bother to avoid duplicate trace messages if a
+ * suspension occurs within marker parameters. Other side effects
+ * require more care.
+ */
+
+
+LOCAL boolean
+get_soi (j_decompress_ptr cinfo)
+/* Process an SOI marker */
+{
+ int i;
+
+ TRACEMS(cinfo, 1, JTRC_SOI);
+
+ if (cinfo->marker->saw_SOI)
+ ERREXIT(cinfo, JERR_SOI_DUPLICATE);
+
+ /* Reset all parameters that are defined to be reset by SOI */
+
+ for (i = 0; i < NUM_ARITH_TBLS; i++) {
+ cinfo->arith_dc_L[i] = 0;
+ cinfo->arith_dc_U[i] = 1;
+ cinfo->arith_ac_K[i] = 5;
+ }
+ cinfo->restart_interval = 0;
+
+ /* Set initial assumptions for colorspace etc */
+
+ cinfo->jpeg_color_space = JCS_UNKNOWN;
+ cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
+
+ cinfo->saw_JFIF_marker = FALSE;
+ cinfo->density_unit = 0; /* set default JFIF APP0 values */
+ cinfo->X_density = 1;
+ cinfo->Y_density = 1;
+ cinfo->saw_Adobe_marker = FALSE;
+ cinfo->Adobe_transform = 0;
+
+ cinfo->marker->saw_SOI = TRUE;
+
+ return TRUE;
+}
+
+
+LOCAL boolean
+get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
+/* Process a SOFn marker */
+{
+ INT32 length;
+ int c, ci;
+ jpeg_component_info * compptr;
+ INPUT_VARS(cinfo);
+
+ cinfo->progressive_mode = is_prog;
+ cinfo->arith_code = is_arith;
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+
+ INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
+ INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
+ INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
+ INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
+
+ length -= 8;
+
+ TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
+ (int) cinfo->image_width, (int) cinfo->image_height,
+ cinfo->num_components);
+
+ if (cinfo->marker->saw_SOF)
+ ERREXIT(cinfo, JERR_SOF_DUPLICATE);
+
+ /* We don't support files in which the image height is initially specified */
+ /* as 0 and is later redefined by DNL. As long as we have to check that, */
+ /* might as well have a general sanity check. */
+ if (cinfo->image_height <= 0 || cinfo->image_width <= 0
+ || cinfo->num_components <= 0)
+ ERREXIT(cinfo, JERR_EMPTY_IMAGE);
+
+ if (length != (cinfo->num_components * 3))
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ if (cinfo->comp_info == NULL) /* do only once, even if suspend */
+ cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ cinfo->num_components * SIZEOF(jpeg_component_info));
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ compptr->component_index = ci;
+ INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
+ INPUT_BYTE(cinfo, c, return FALSE);
+ compptr->h_samp_factor = (c >> 4) & 15;
+ compptr->v_samp_factor = (c ) & 15;
+ INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
+
+ TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
+ compptr->component_id, compptr->h_samp_factor,
+ compptr->v_samp_factor, compptr->quant_tbl_no);
+ }
+
+ cinfo->marker->saw_SOF = TRUE;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+LOCAL boolean
+get_sos (j_decompress_ptr cinfo)
+/* Process a SOS marker */
+{
+ INT32 length;
+ int i, ci, n, c, cc;
+ jpeg_component_info * compptr;
+ INPUT_VARS(cinfo);
+
+ if (! cinfo->marker->saw_SOF)
+ ERREXIT(cinfo, JERR_SOS_NO_SOF);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+
+ INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
+
+ if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ TRACEMS1(cinfo, 1, JTRC_SOS, n);
+
+ cinfo->comps_in_scan = n;
+
+ /* Collect the component-spec parameters */
+
+ for (i = 0; i < n; i++) {
+ INPUT_BYTE(cinfo, cc, return FALSE);
+ INPUT_BYTE(cinfo, c, return FALSE);
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ if (cc == compptr->component_id)
+ goto id_found;
+ }
+
+ ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
+
+ id_found:
+
+ cinfo->cur_comp_info[i] = compptr;
+ compptr->dc_tbl_no = (c >> 4) & 15;
+ compptr->ac_tbl_no = (c ) & 15;
+
+ TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
+ compptr->dc_tbl_no, compptr->ac_tbl_no);
+ }
+
+ /* Collect the additional scan parameters Ss, Se, Ah/Al. */
+ INPUT_BYTE(cinfo, c, return FALSE);
+ cinfo->Ss = c;
+ INPUT_BYTE(cinfo, c, return FALSE);
+ cinfo->Se = c;
+ INPUT_BYTE(cinfo, c, return FALSE);
+ cinfo->Ah = (c >> 4) & 15;
+ cinfo->Al = (c ) & 15;
+
+ TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
+ cinfo->Ah, cinfo->Al);
+
+ /* Prepare to scan data & restart markers */
+ cinfo->marker->next_restart_num = 0;
+
+ /* Count another SOS marker */
+ cinfo->input_scan_number++;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+METHODDEF boolean
+get_app0 (j_decompress_ptr cinfo)
+/* Process an APP0 marker */
+{
+#define JFIF_LEN 14
+ INT32 length;
+ UINT8 b[JFIF_LEN];
+ int buffp;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ /* See if a JFIF APP0 marker is present */
+
+ if (length >= JFIF_LEN) {
+ for (buffp = 0; buffp < JFIF_LEN; buffp++)
+ INPUT_BYTE(cinfo, b[buffp], return FALSE);
+ length -= JFIF_LEN;
+
+ if (b[0]==0x4A && b[1]==0x46 && b[2]==0x49 && b[3]==0x46 && b[4]==0) {
+ /* Found JFIF APP0 marker: check version */
+ /* Major version must be 1, anything else signals an incompatible change.
+ * We used to treat this as an error, but now it's a nonfatal warning,
+ * because some bozo at Hijaak couldn't read the spec.
+ * Minor version should be 0..2, but process anyway if newer.
+ */
+ if (b[5] != 1)
+ WARNMS2(cinfo, JWRN_JFIF_MAJOR, b[5], b[6]);
+ else if (b[6] > 2)
+ TRACEMS2(cinfo, 1, JTRC_JFIF_MINOR, b[5], b[6]);
+ /* Save info */
+ cinfo->saw_JFIF_marker = TRUE;
+ cinfo->density_unit = b[7];
+ cinfo->X_density = (b[8] << 8) + b[9];
+ cinfo->Y_density = (b[10] << 8) + b[11];
+ TRACEMS3(cinfo, 1, JTRC_JFIF,
+ cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
+ if (b[12] | b[13])
+ TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, b[12], b[13]);
+ if (length != ((INT32) b[12] * (INT32) b[13] * (INT32) 3))
+ TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) length);
+ } else {
+ /* Start of APP0 does not match "JFIF" */
+ TRACEMS1(cinfo, 1, JTRC_APP0, (int) length + JFIF_LEN);
+ }
+ } else {
+ /* Too short to be JFIF marker */
+ TRACEMS1(cinfo, 1, JTRC_APP0, (int) length);
+ }
+
+ INPUT_SYNC(cinfo);
+ if (length > 0) /* skip any remaining data -- could be lots */
+ (*cinfo->src->skip_input_data) (cinfo, (long) length);
+
+ return TRUE;
+}
+
+
+METHODDEF boolean
+get_app14 (j_decompress_ptr cinfo)
+/* Process an APP14 marker */
+{
+#define ADOBE_LEN 12
+ INT32 length;
+ UINT8 b[ADOBE_LEN];
+ int buffp;
+ unsigned int version, flags0, flags1, transform;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ /* See if an Adobe APP14 marker is present */
+
+ if (length >= ADOBE_LEN) {
+ for (buffp = 0; buffp < ADOBE_LEN; buffp++)
+ INPUT_BYTE(cinfo, b[buffp], return FALSE);
+ length -= ADOBE_LEN;
+
+ if (b[0]==0x41 && b[1]==0x64 && b[2]==0x6F && b[3]==0x62 && b[4]==0x65) {
+ /* Found Adobe APP14 marker */
+ version = (b[5] << 8) + b[6];
+ flags0 = (b[7] << 8) + b[8];
+ flags1 = (b[9] << 8) + b[10];
+ transform = b[11];
+ TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
+ cinfo->saw_Adobe_marker = TRUE;
+ cinfo->Adobe_transform = (UINT8) transform;
+ } else {
+ /* Start of APP14 does not match "Adobe" */
+ TRACEMS1(cinfo, 1, JTRC_APP14, (int) length + ADOBE_LEN);
+ }
+ } else {
+ /* Too short to be Adobe marker */
+ TRACEMS1(cinfo, 1, JTRC_APP14, (int) length);
+ }
+
+ INPUT_SYNC(cinfo);
+ if (length > 0) /* skip any remaining data -- could be lots */
+ (*cinfo->src->skip_input_data) (cinfo, (long) length);
+
+ return TRUE;
+}
+
+
+LOCAL boolean
+get_dac (j_decompress_ptr cinfo)
+/* Process a DAC marker */
+{
+ INT32 length;
+ int index, val;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ while (length > 0) {
+ INPUT_BYTE(cinfo, index, return FALSE);
+ INPUT_BYTE(cinfo, val, return FALSE);
+
+ length -= 2;
+
+ TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
+
+ if (index < 0 || index >= (2*NUM_ARITH_TBLS))
+ ERREXIT1(cinfo, JERR_DAC_INDEX, index);
+
+ if (index >= NUM_ARITH_TBLS) { /* define AC table */
+ cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
+ } else { /* define DC table */
+ cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
+ cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
+ if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
+ ERREXIT1(cinfo, JERR_DAC_VALUE, val);
+ }
+ }
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+LOCAL boolean
+get_dht (j_decompress_ptr cinfo)
+/* Process a DHT marker */
+{
+ INT32 length;
+ UINT8 bits[17];
+ UINT8 huffval[256];
+ int i, index, count;
+ JHUFF_TBL **htblptr;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ while (length > 0) {
+ INPUT_BYTE(cinfo, index, return FALSE);
+
+ TRACEMS1(cinfo, 1, JTRC_DHT, index);
+
+ bits[0] = 0;
+ count = 0;
+ for (i = 1; i <= 16; i++) {
+ INPUT_BYTE(cinfo, bits[i], return FALSE);
+ count += bits[i];
+ }
+
+ length -= 1 + 16;
+
+ TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
+ bits[1], bits[2], bits[3], bits[4],
+ bits[5], bits[6], bits[7], bits[8]);
+ TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
+ bits[9], bits[10], bits[11], bits[12],
+ bits[13], bits[14], bits[15], bits[16]);
+
+ if (count > 256 || ((INT32) count) > length)
+ ERREXIT(cinfo, JERR_DHT_COUNTS);
+
+ for (i = 0; i < count; i++)
+ INPUT_BYTE(cinfo, huffval[i], return FALSE);
+
+ length -= count;
+
+ if (index & 0x10) { /* AC table definition */
+ index -= 0x10;
+ htblptr = &cinfo->ac_huff_tbl_ptrs[index];
+ } else { /* DC table definition */
+ htblptr = &cinfo->dc_huff_tbl_ptrs[index];
+ }
+
+ if (index < 0 || index >= NUM_HUFF_TBLS)
+ ERREXIT1(cinfo, JERR_DHT_INDEX, index);
+
+ if (*htblptr == NULL)
+ *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
+
+ MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
+ MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
+ }
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+LOCAL boolean
+get_dqt (j_decompress_ptr cinfo)
+/* Process a DQT marker */
+{
+ INT32 length;
+ int n, i, prec;
+ unsigned int tmp;
+ JQUANT_TBL *quant_ptr;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ while (length > 0) {
+ INPUT_BYTE(cinfo, n, return FALSE);
+ prec = n >> 4;
+ n &= 0x0F;
+
+ TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
+
+ if (n >= NUM_QUANT_TBLS)
+ ERREXIT1(cinfo, JERR_DQT_INDEX, n);
+
+ if (cinfo->quant_tbl_ptrs[n] == NULL)
+ cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
+ quant_ptr = cinfo->quant_tbl_ptrs[n];
+
+ for (i = 0; i < DCTSIZE2; i++) {
+ if (prec)
+ INPUT_2BYTES(cinfo, tmp, return FALSE);
+ else
+ INPUT_BYTE(cinfo, tmp, return FALSE);
+ quant_ptr->quantval[i] = (UINT16) tmp;
+ }
+
+ for (i = 0; i < DCTSIZE2; i += 8) {
+ TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
+ quant_ptr->quantval[i ], quant_ptr->quantval[i+1],
+ quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
+ quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
+ quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
+ }
+
+ length -= DCTSIZE2+1;
+ if (prec) length -= DCTSIZE2;
+ }
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+LOCAL boolean
+get_dri (j_decompress_ptr cinfo)
+/* Process a DRI marker */
+{
+ INT32 length;
+ unsigned int tmp;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+
+ if (length != 4)
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ INPUT_2BYTES(cinfo, tmp, return FALSE);
+
+ TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
+
+ cinfo->restart_interval = tmp;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+METHODDEF boolean
+skip_variable (j_decompress_ptr cinfo)
+/* Skip over an unknown or uninteresting variable-length marker */
+{
+ INT32 length;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+
+ TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
+
+ INPUT_SYNC(cinfo); /* do before skip_input_data */
+ (*cinfo->src->skip_input_data) (cinfo, (long) length - 2L);
+
+ return TRUE;
+}
+
+
+/*
+ * Find the next JPEG marker, save it in cinfo->unread_marker.
+ * Returns FALSE if had to suspend before reaching a marker;
+ * in that case cinfo->unread_marker is unchanged.
+ *
+ * Note that the result might not be a valid marker code,
+ * but it will never be 0 or FF.
+ */
+
+LOCAL boolean
+next_marker (j_decompress_ptr cinfo)
+{
+ int c;
+ INPUT_VARS(cinfo);
+
+ for (;;) {
+ INPUT_BYTE(cinfo, c, return FALSE);
+ /* Skip any non-FF bytes.
+ * This may look a bit inefficient, but it will not occur in a valid file.
+ * We sync after each discarded byte so that a suspending data source
+ * can discard the byte from its buffer.
+ */
+ while (c != 0xFF) {
+ cinfo->marker->discarded_bytes++;
+ INPUT_SYNC(cinfo);
+ INPUT_BYTE(cinfo, c, return FALSE);
+ }
+ /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
+ * pad bytes, so don't count them in discarded_bytes. We assume there
+ * will not be so many consecutive FF bytes as to overflow a suspending
+ * data source's input buffer.
+ */
+ do {
+ INPUT_BYTE(cinfo, c, return FALSE);
+ } while (c == 0xFF);
+ if (c != 0)
+ break; /* found a valid marker, exit loop */
+ /* Reach here if we found a stuffed-zero data sequence (FF/00).
+ * Discard it and loop back to try again.
+ */
+ cinfo->marker->discarded_bytes += 2;
+ INPUT_SYNC(cinfo);
+ }
+
+ if (cinfo->marker->discarded_bytes != 0) {
+ WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
+ cinfo->marker->discarded_bytes = 0;
+ }
+
+ cinfo->unread_marker = c;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+LOCAL boolean
+first_marker (j_decompress_ptr cinfo)
+/* Like next_marker, but used to obtain the initial SOI marker. */
+/* For this marker, we do not allow preceding garbage or fill; otherwise,
+ * we might well scan an entire input file before realizing it ain't JPEG.
+ * If an application wants to process non-JFIF files, it must seek to the
+ * SOI before calling the JPEG library.
+ */
+{
+ int c, c2;
+ INPUT_VARS(cinfo);
+
+ INPUT_BYTE(cinfo, c, return FALSE);
+ INPUT_BYTE(cinfo, c2, return FALSE);
+ if (c != 0xFF || c2 != (int) M_SOI)
+ ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
+
+ cinfo->unread_marker = c2;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+/*
+ * Read markers until SOS or EOI.
+ *
+ * Returns same codes as are defined for jpeg_consume_input:
+ * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
+ */
+
+METHODDEF int
+read_markers (j_decompress_ptr cinfo)
+{
+ /* Outer loop repeats once for each marker. */
+ for (;;) {
+ /* Collect the marker proper, unless we already did. */
+ /* NB: first_marker() enforces the requirement that SOI appear first. */
+ if (cinfo->unread_marker == 0) {
+ if (! cinfo->marker->saw_SOI) {
+ if (! first_marker(cinfo))
+ return JPEG_SUSPENDED;
+ } else {
+ if (! next_marker(cinfo))
+ return JPEG_SUSPENDED;
+ }
+ }
+ /* At this point cinfo->unread_marker contains the marker code and the
+ * input point is just past the marker proper, but before any parameters.
+ * A suspension will cause us to return with this state still true.
+ */
+ switch (cinfo->unread_marker) {
+ case M_SOI:
+ if (! get_soi(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF0: /* Baseline */
+ case M_SOF1: /* Extended sequential, Huffman */
+ if (! get_sof(cinfo, FALSE, FALSE))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF2: /* Progressive, Huffman */
+ if (! get_sof(cinfo, TRUE, FALSE))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF9: /* Extended sequential, arithmetic */
+ if (! get_sof(cinfo, FALSE, TRUE))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF10: /* Progressive, arithmetic */
+ if (! get_sof(cinfo, TRUE, TRUE))
+ return JPEG_SUSPENDED;
+ break;
+
+ /* Currently unsupported SOFn types */
+ case M_SOF3: /* Lossless, Huffman */
+ case M_SOF5: /* Differential sequential, Huffman */
+ case M_SOF6: /* Differential progressive, Huffman */
+ case M_SOF7: /* Differential lossless, Huffman */
+ case M_JPG: /* Reserved for JPEG extensions */
+ case M_SOF11: /* Lossless, arithmetic */
+ case M_SOF13: /* Differential sequential, arithmetic */
+ case M_SOF14: /* Differential progressive, arithmetic */
+ case M_SOF15: /* Differential lossless, arithmetic */
+ ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
+ break;
+
+ case M_SOS:
+ if (! get_sos(cinfo))
+ return JPEG_SUSPENDED;
+ cinfo->unread_marker = 0; /* processed the marker */
+ return JPEG_REACHED_SOS;
+
+ case M_EOI:
+ TRACEMS(cinfo, 1, JTRC_EOI);
+ cinfo->unread_marker = 0; /* processed the marker */
+ return JPEG_REACHED_EOI;
+
+ case M_DAC:
+ if (! get_dac(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_DHT:
+ if (! get_dht(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_DQT:
+ if (! get_dqt(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_DRI:
+ if (! get_dri(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_APP0:
+ case M_APP1:
+ case M_APP2:
+ case M_APP3:
+ case M_APP4:
+ case M_APP5:
+ case M_APP6:
+ case M_APP7:
+ case M_APP8:
+ case M_APP9:
+ case M_APP10:
+ case M_APP11:
+ case M_APP12:
+ case M_APP13:
+ case M_APP14:
+ case M_APP15:
+ if (! (*cinfo->marker->process_APPn[cinfo->unread_marker - (int) M_APP0]) (cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_COM:
+ if (! (*cinfo->marker->process_COM) (cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_RST0: /* these are all parameterless */
+ case M_RST1:
+ case M_RST2:
+ case M_RST3:
+ case M_RST4:
+ case M_RST5:
+ case M_RST6:
+ case M_RST7:
+ case M_TEM:
+ TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
+ break;
+
+ case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
+ if (! skip_variable(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ default: /* must be DHP, EXP, JPGn, or RESn */
+ /* For now, we treat the reserved markers as fatal errors since they are
+ * likely to be used to signal incompatible JPEG Part 3 extensions.
+ * Once the JPEG 3 version-number marker is well defined, this code
+ * ought to change!
+ */
+ ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
+ break;
+ }
+ /* Successfully processed marker, so reset state variable */
+ cinfo->unread_marker = 0;
+ } /* end loop */
+}
+
+
+/*
+ * Read a restart marker, which is expected to appear next in the datastream;
+ * if the marker is not there, take appropriate recovery action.
+ * Returns FALSE if suspension is required.
+ *
+ * This is called by the entropy decoder after it has read an appropriate
+ * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
+ * has already read a marker from the data source. Under normal conditions
+ * cinfo->unread_marker will be reset to 0 before returning; if not reset,
+ * it holds a marker which the decoder will be unable to read past.
+ */
+
+METHODDEF boolean
+read_restart_marker (j_decompress_ptr cinfo)
+{
+ /* Obtain a marker unless we already did. */
+ /* Note that next_marker will complain if it skips any data. */
+ if (cinfo->unread_marker == 0) {
+ if (! next_marker(cinfo))
+ return FALSE;
+ }
+
+ if (cinfo->unread_marker ==
+ ((int) M_RST0 + cinfo->marker->next_restart_num)) {
+ /* Normal case --- swallow the marker and let entropy decoder continue */
+ TRACEMS1(cinfo, 2, JTRC_RST, cinfo->marker->next_restart_num);
+ cinfo->unread_marker = 0;
+ } else {
+ /* Uh-oh, the restart markers have been messed up. */
+ /* Let the data source manager determine how to resync. */
+ if (! (*cinfo->src->resync_to_restart) (cinfo,
+ cinfo->marker->next_restart_num))
+ return FALSE;
+ }
+
+ /* Update next-restart state */
+ cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
+
+ return TRUE;
+}
+
+
+/*
+ * This is the default resync_to_restart method for data source managers
+ * to use if they don't have any better approach. Some data source managers
+ * may be able to back up, or may have additional knowledge about the data
+ * which permits a more intelligent recovery strategy; such managers would
+ * presumably supply their own resync method.
+ *
+ * read_restart_marker calls resync_to_restart if it finds a marker other than
+ * the restart marker it was expecting. (This code is *not* used unless
+ * a nonzero restart interval has been declared.) cinfo->unread_marker is
+ * the marker code actually found (might be anything, except 0 or FF).
+ * The desired restart marker number (0..7) is passed as a parameter.
+ * This routine is supposed to apply whatever error recovery strategy seems
+ * appropriate in order to position the input stream to the next data segment.
+ * Note that cinfo->unread_marker is treated as a marker appearing before
+ * the current data-source input point; usually it should be reset to zero
+ * before returning.
+ * Returns FALSE if suspension is required.
+ *
+ * This implementation is substantially constrained by wanting to treat the
+ * input as a data stream; this means we can't back up. Therefore, we have
+ * only the following actions to work with:
+ * 1. Simply discard the marker and let the entropy decoder resume at next
+ * byte of file.
+ * 2. Read forward until we find another marker, discarding intervening
+ * data. (In theory we could look ahead within the current bufferload,
+ * without having to discard data if we don't find the desired marker.
+ * This idea is not implemented here, in part because it makes behavior
+ * dependent on buffer size and chance buffer-boundary positions.)
+ * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
+ * This will cause the entropy decoder to process an empty data segment,
+ * inserting dummy zeroes, and then we will reprocess the marker.
+ *
+ * #2 is appropriate if we think the desired marker lies ahead, while #3 is
+ * appropriate if the found marker is a future restart marker (indicating
+ * that we have missed the desired restart marker, probably because it got
+ * corrupted).
+ * We apply #2 or #3 if the found marker is a restart marker no more than
+ * two counts behind or ahead of the expected one. We also apply #2 if the
+ * found marker is not a legal JPEG marker code (it's certainly bogus data).
+ * If the found marker is a restart marker more than 2 counts away, we do #1
+ * (too much risk that the marker is erroneous; with luck we will be able to
+ * resync at some future point).
+ * For any valid non-restart JPEG marker, we apply #3. This keeps us from
+ * overrunning the end of a scan. An implementation limited to single-scan
+ * files might find it better to apply #2 for markers other than EOI, since
+ * any other marker would have to be bogus data in that case.
+ */
+
+GLOBAL boolean
+jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
+{
+ int marker = cinfo->unread_marker;
+ int action = 1;
+
+ /* Always put up a warning. */
+ WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
+
+ /* Outer loop handles repeated decision after scanning forward. */
+ for (;;) {
+ if (marker < (int) M_SOF0)
+ action = 2; /* invalid marker */
+ else if (marker < (int) M_RST0 || marker > (int) M_RST7)
+ action = 3; /* valid non-restart marker */
+ else {
+ if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
+ marker == ((int) M_RST0 + ((desired+2) & 7)))
+ action = 3; /* one of the next two expected restarts */
+ else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
+ marker == ((int) M_RST0 + ((desired-2) & 7)))
+ action = 2; /* a prior restart, so advance */
+ else
+ action = 1; /* desired restart or too far away */
+ }
+ TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
+ switch (action) {
+ case 1:
+ /* Discard marker and let entropy decoder resume processing. */
+ cinfo->unread_marker = 0;
+ return TRUE;
+ case 2:
+ /* Scan to the next marker, and repeat the decision loop. */
+ if (! next_marker(cinfo))
+ return FALSE;
+ marker = cinfo->unread_marker;
+ break;
+ case 3:
+ /* Return without advancing past this marker. */
+ /* Entropy decoder will be forced to process an empty segment. */
+ return TRUE;
+ }
+ } /* end loop */
+}
+
+
+/*
+ * Reset marker processing state to begin a fresh datastream.
+ */
+
+METHODDEF void
+reset_marker_reader (j_decompress_ptr cinfo)
+{
+ cinfo->comp_info = NULL; /* until allocated by get_sof */
+ cinfo->input_scan_number = 0; /* no SOS seen yet */
+ cinfo->unread_marker = 0; /* no pending marker */
+ cinfo->marker->saw_SOI = FALSE; /* set internal state too */
+ cinfo->marker->saw_SOF = FALSE;
+ cinfo->marker->discarded_bytes = 0;
+}
+
+
+/*
+ * Initialize the marker reader module.
+ * This is called only once, when the decompression object is created.
+ */
+
+GLOBAL void
+jinit_marker_reader (j_decompress_ptr cinfo)
+{
+ int i;
+
+ /* Create subobject in permanent pool */
+ cinfo->marker = (struct jpeg_marker_reader *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(struct jpeg_marker_reader));
+ /* Initialize method pointers */
+ cinfo->marker->reset_marker_reader = reset_marker_reader;
+ cinfo->marker->read_markers = read_markers;
+ cinfo->marker->read_restart_marker = read_restart_marker;
+ cinfo->marker->process_COM = skip_variable;
+ for (i = 0; i < 16; i++)
+ cinfo->marker->process_APPn[i] = skip_variable;
+ cinfo->marker->process_APPn[0] = get_app0;
+ cinfo->marker->process_APPn[14] = get_app14;
+ /* Reset marker processing state */
+ reset_marker_reader(cinfo);
+}
|