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| author | git perforce import user <a@b> | 2016-10-25 12:29:14 -0600 |
|---|---|---|
| committer | Sheikh Dawood Abdul Ajees <Sheikh Dawood Abdul Ajees> | 2016-10-25 18:56:37 -0500 |
| commit | 3dfe2108cfab31ba3ee5527e217d0d8e99a51162 (patch) | |
| tree | fa6485c169e50d7415a651bf838f5bcd0fd3bfbd /KaplaDemo/samples/sampleViewer3/IJGWin32/jdhuff.cpp | |
| download | physx-3.4-3dfe2108cfab31ba3ee5527e217d0d8e99a51162.tar.xz physx-3.4-3dfe2108cfab31ba3ee5527e217d0d8e99a51162.zip | |
Initial commit:
PhysX 3.4.0 Update @ 21294896
APEX 1.4.0 Update @ 21275617
[CL 21300167]
Diffstat (limited to 'KaplaDemo/samples/sampleViewer3/IJGWin32/jdhuff.cpp')
| -rw-r--r-- | KaplaDemo/samples/sampleViewer3/IJGWin32/jdhuff.cpp | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/KaplaDemo/samples/sampleViewer3/IJGWin32/jdhuff.cpp b/KaplaDemo/samples/sampleViewer3/IJGWin32/jdhuff.cpp new file mode 100644 index 00000000..43c9fe74 --- /dev/null +++ b/KaplaDemo/samples/sampleViewer3/IJGWin32/jdhuff.cpp @@ -0,0 +1,316 @@ +/* + * jdhuff.c + * + * Copyright (C) 1991-1998, 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 Huffman entropy decoding routines which are shared + * by the sequential, progressive and lossless decoders. + */ +#include "stdafx.h" + +#define JPEG_INTERNALS +//#include "jinclude.h" +//#include "jpeglib.h" +//#include "jlossy.h" /* Private declarations for lossy codec */ +//#include "jlossls.h" /* Private declarations for lossless codec */ +//#include "jdhuff.h" /* Declarations shared with jd*huff.c */ + + +/* + * Compute the derived values for a Huffman table. + * This routine also performs some validation checks on the table. + */ + +GLOBAL(void) +jpeg_make_d_derived_tbl (j_decompress_ptr cinfo, boolean isDC, int tblno, + d_derived_tbl ** pdtbl) +{ + JHUFF_TBL *htbl; + d_derived_tbl *dtbl; + int p, i, l, si, numsymbols; + int lookbits, ctr; + char huffsize[257]; + unsigned int huffcode[257]; + unsigned int code; + + /* Note that huffsize[] and huffcode[] are filled in code-length order, + * paralleling the order of the symbols themselves in htbl->huffval[]. + */ + + /* Find the input Huffman table */ + if (tblno < 0 || tblno >= NUM_HUFF_TBLS) + ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); + htbl = + isDC ? cinfo->dc_huff_tbl_ptrs[tblno] : cinfo->ac_huff_tbl_ptrs[tblno]; + if (htbl == NULL) + ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); + + /* Allocate a workspace if we haven't already done so. */ + if (*pdtbl == NULL) + *pdtbl = (d_derived_tbl *) + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, + SIZEOF(d_derived_tbl)); + dtbl = *pdtbl; + dtbl->pub = htbl; /* fill in back link */ + + /* Figure C.1: make table of Huffman code length for each symbol */ + + p = 0; + for (l = 1; l <= 16; l++) { + i = (int) htbl->bits[l]; + if (i < 0 || p + i > 256) /* protect against table overrun */ + ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); + while (i--) + huffsize[p++] = (char) l; + } + huffsize[p] = 0; + numsymbols = p; + + /* Figure C.2: generate the codes themselves */ + /* We also validate that the counts represent a legal Huffman code tree. */ + + code = 0; + si = huffsize[0]; + p = 0; + while (huffsize[p]) { + while (((int) huffsize[p]) == si) { + huffcode[p++] = code; + code++; + } + /* code is now 1 more than the last code used for codelength si; but + * it must still fit in si bits, since no code is allowed to be all ones. + */ + if (((INT32) code) >= (((INT32) 1) << si)) + ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); + code <<= 1; + si++; + } + + /* Figure F.15: generate decoding tables for bit-sequential decoding */ + + p = 0; + for (l = 1; l <= 16; l++) { + if (htbl->bits[l]) { + /* valoffset[l] = huffval[] index of 1st symbol of code length l, + * minus the minimum code of length l + */ + dtbl->valoffset[l] = (INT32) p - (INT32) huffcode[p]; + p += htbl->bits[l]; + dtbl->maxcode[l] = huffcode[p-1]; /* maximum code of length l */ + } else { + dtbl->maxcode[l] = -1; /* -1 if no codes of this length */ + } + } + dtbl->maxcode[17] = 0xFFFFFL; /* ensures jpeg_huff_decode terminates */ + + /* Compute lookahead tables to speed up decoding. + * First we set all the table entries to 0, indicating "too long"; + * then we iterate through the Huffman codes that are short enough and + * fill in all the entries that correspond to bit sequences starting + * with that code. + */ + + MEMZERO(dtbl->look_nbits, SIZEOF(dtbl->look_nbits)); + + p = 0; + for (l = 1; l <= HUFF_LOOKAHEAD; l++) { + for (i = 1; i <= (int) htbl->bits[l]; i++, p++) { + /* l = current code's length, p = its index in huffcode[] & huffval[]. */ + /* Generate left-justified code followed by all possible bit sequences */ + lookbits = huffcode[p] << (HUFF_LOOKAHEAD-l); + for (ctr = 1 << (HUFF_LOOKAHEAD-l); ctr > 0; ctr--) { + dtbl->look_nbits[lookbits] = l; + dtbl->look_sym[lookbits] = htbl->huffval[p]; + lookbits++; + } + } + } + + /* Validate symbols as being reasonable. + * For AC tables, we make no check, but accept all byte values 0..255. + * For DC tables, we require the symbols to be in range 0..16. + * (Tighter bounds could be applied depending on the data depth and mode, + * but this is sufficient to ensure safe decoding.) + */ + if (isDC) { + for (i = 0; i < numsymbols; i++) { + int sym = htbl->huffval[i]; + if (sym < 0 || sym > 16) + ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); + } + } +} + + +/* + * Out-of-line code for bit fetching. + * See jdhuff.h for info about usage. + * Note: current values of get_buffer and bits_left are passed as parameters, + * but are returned in the corresponding fields of the state struct. + * + * On most machines MIN_GET_BITS should be 25 to allow the full 32-bit width + * of get_buffer to be used. (On machines with wider words, an even larger + * buffer could be used.) However, on some machines 32-bit shifts are + * quite slow and take time proportional to the number of places shifted. + * (This is true with most PC compilers, for instance.) In this case it may + * be a win to set MIN_GET_BITS to the minimum value of 15. This reduces the + * average shift distance at the cost of more calls to jpeg_fill_bit_buffer. + */ + +#ifdef SLOW_SHIFT_32 +#define MIN_GET_BITS 15 /* minimum allowable value */ +#else +#define MIN_GET_BITS (BIT_BUF_SIZE-7) +#endif + + +GLOBAL(boolean) +jpeg_fill_bit_buffer (bitread_working_state * state, + register bit_buf_type get_buffer, register int bits_left, + int nbits) +/* Load up the bit buffer to a depth of at least nbits */ +{ + /* Copy heavily used state fields into locals (hopefully registers) */ + register const JOCTET * next_input_byte = state->next_input_byte; + register size_t bytes_in_buffer = state->bytes_in_buffer; + j_decompress_ptr cinfo = state->cinfo; + + /* Attempt to load at least MIN_GET_BITS bits into get_buffer. */ + /* (It is assumed that no request will be for more than that many bits.) */ + /* We fail to do so only if we hit a marker or are forced to suspend. */ + + if (cinfo->unread_marker == 0) { /* cannot advance past a marker */ + while (bits_left < MIN_GET_BITS) { + register int c; + + /* Attempt to read a byte */ + if (bytes_in_buffer == 0) { + if (! (*cinfo->src->fill_input_buffer) (cinfo)) + return FALSE; + next_input_byte = cinfo->src->next_input_byte; + bytes_in_buffer = cinfo->src->bytes_in_buffer; + } + bytes_in_buffer--; + c = GETJOCTET(*next_input_byte++); + + /* If it's 0xFF, check and discard stuffed zero byte */ + if (c == 0xFF) { + /* Loop here to discard any padding FF's on terminating marker, + * so that we can save a valid unread_marker value. NOTE: we will + * accept multiple FF's followed by a 0 as meaning a single FF data + * byte. This data pattern is not valid according to the standard. + */ + do { + if (bytes_in_buffer == 0) { + if (! (*cinfo->src->fill_input_buffer) (cinfo)) + return FALSE; + next_input_byte = cinfo->src->next_input_byte; + bytes_in_buffer = cinfo->src->bytes_in_buffer; + } + bytes_in_buffer--; + c = GETJOCTET(*next_input_byte++); + } while (c == 0xFF); + + if (c == 0) { + /* Found FF/00, which represents an FF data byte */ + c = 0xFF; + } else { + /* Oops, it's actually a marker indicating end of compressed data. + * Save the marker code for later use. + * Fine point: it might appear that we should save the marker into + * bitread working state, not straight into permanent state. But + * once we have hit a marker, we cannot need to suspend within the + * current MCU, because we will read no more bytes from the data + * source. So it is OK to update permanent state right away. + */ + cinfo->unread_marker = c; + /* See if we need to insert some fake zero bits. */ + goto no_more_bytes; + } + } + + /* OK, load c into get_buffer */ + get_buffer = (get_buffer << 8) | c; + bits_left += 8; + } /* end while */ + } else { + no_more_bytes: + /* We get here if we've read the marker that terminates the compressed + * data segment. There should be enough bits in the buffer register + * to satisfy the request; if so, no problem. + */ + if (nbits > bits_left) { + /* Uh-oh. Report corrupted data to user and stuff zeroes into + * the data stream, so that we can produce some kind of image. + * We use a nonvolatile flag to ensure that only one warning message + * appears per data segment. + */ + huffd_common_ptr huffd; + if (cinfo->process == JPROC_LOSSLESS) + huffd = (huffd_common_ptr) ((j_lossless_d_ptr) cinfo->codec)->entropy_private; + else + huffd = (huffd_common_ptr) ((j_lossy_d_ptr) cinfo->codec)->entropy_private; + if (! huffd->insufficient_data) { + WARNMS(cinfo, JWRN_HIT_MARKER); + huffd->insufficient_data = TRUE; + } + /* Fill the buffer with zero bits */ + get_buffer <<= MIN_GET_BITS - bits_left; + bits_left = MIN_GET_BITS; + } + } + + /* Unload the local registers */ + state->next_input_byte = next_input_byte; + state->bytes_in_buffer = bytes_in_buffer; + state->get_buffer = get_buffer; + state->bits_left = bits_left; + + return TRUE; +} + + +/* + * Out-of-line code for Huffman code decoding. + * See jdhuff.h for info about usage. + */ + +GLOBAL(int) +jpeg_huff_decode (bitread_working_state * state, + register bit_buf_type get_buffer, register int bits_left, + d_derived_tbl * htbl, int min_bits) +{ + register int l = min_bits; + register INT32 code; + + /* HUFF_DECODE has determined that the code is at least min_bits */ + /* bits long, so fetch that many bits in one swoop. */ + + CHECK_BIT_BUFFER(*state, l, return -1); + code = GET_BITS(l); + + /* Collect the rest of the Huffman code one bit at a time. */ + /* This is per Figure F.16 in the JPEG spec. */ + + while (code > htbl->maxcode[l]) { + code <<= 1; + CHECK_BIT_BUFFER(*state, 1, return -1); + code |= GET_BITS(1); + l++; + } + + /* Unload the local registers */ + state->get_buffer = get_buffer; + state->bits_left = bits_left; + + /* With garbage input we may reach the sentinel value l = 17. */ + + if (l > 16) { + WARNMS(state->cinfo, JWRN_HUFF_BAD_CODE); + return 0; /* fake a zero as the safest result */ + } + + return htbl->pub->huffval[ (int) (code + htbl->valoffset[l]) ]; +} |