diff options
Diffstat (limited to 'src/jpeg-6/jdmarker.c')
| -rw-r--r-- | src/jpeg-6/jdmarker.c | 1052 |
1 files changed, 1052 insertions, 0 deletions
diff --git a/src/jpeg-6/jdmarker.c b/src/jpeg-6/jdmarker.c new file mode 100644 index 00000000..80e5f783 --- /dev/null +++ b/src/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); +} |