Back to index

plt-scheme  4.2.1
png.c
Go to the documentation of this file.
00001 
00002 /* png.c - location for general purpose libpng functions
00003  *
00004  * libpng version 1.2.5 - October 3, 2002
00005  * Copyright (c) 1998-2002 Glenn Randers-Pehrson
00006  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
00007  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
00008  *
00009  */
00010 
00011 #define PNG_INTERNAL
00012 #define PNG_NO_EXTERN
00013 #include "png.h"
00014 
00015 /* Generate a compiler error if there is an old png.h in the search path. */
00016 typedef version_1_2_5 Your_png_h_is_not_version_1_2_5;
00017 
00018 /* Version information for C files.  This had better match the version
00019  * string defined in png.h.  */
00020 
00021 #ifdef PNG_USE_GLOBAL_ARRAYS
00022 /* png_libpng_ver was changed to a function in version 1.0.5c */
00023 const char png_libpng_ver[18] = "1.2.5";
00024 
00025 /* png_sig was changed to a function in version 1.0.5c */
00026 /* Place to hold the signature string for a PNG file. */
00027 const png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
00028 
00029 /* Invoke global declarations for constant strings for known chunk types */
00030 PNG_IHDR;
00031 PNG_IDAT;
00032 PNG_IEND;
00033 PNG_PLTE;
00034 PNG_bKGD;
00035 PNG_cHRM;
00036 PNG_gAMA;
00037 PNG_hIST;
00038 PNG_iCCP;
00039 PNG_iTXt;
00040 PNG_oFFs;
00041 PNG_pCAL;
00042 PNG_sCAL;
00043 PNG_pHYs;
00044 PNG_sBIT;
00045 PNG_sPLT;
00046 PNG_sRGB;
00047 PNG_tEXt;
00048 PNG_tIME;
00049 PNG_tRNS;
00050 PNG_zTXt;
00051 
00052 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
00053 
00054 /* start of interlace block */
00055 const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
00056 
00057 /* offset to next interlace block */
00058 const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
00059 
00060 /* start of interlace block in the y direction */
00061 const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
00062 
00063 /* offset to next interlace block in the y direction */
00064 const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
00065 
00066 /* width of interlace block (used in assembler routines only) */
00067 #ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
00068 const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
00069 #endif
00070 
00071 /* Height of interlace block.  This is not currently used - if you need
00072  * it, uncomment it here and in png.h
00073 const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
00074 */
00075 
00076 /* Mask to determine which pixels are valid in a pass */
00077 const int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
00078 
00079 /* Mask to determine which pixels to overwrite while displaying */
00080 const int FARDATA png_pass_dsp_mask[]
00081    = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
00082 
00083 #endif
00084 
00085 /* Tells libpng that we have already handled the first "num_bytes" bytes
00086  * of the PNG file signature.  If the PNG data is embedded into another
00087  * stream we can set num_bytes = 8 so that libpng will not attempt to read
00088  * or write any of the magic bytes before it starts on the IHDR.
00089  */
00090 
00091 void PNGAPI
00092 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
00093 {
00094    png_debug(1, "in png_set_sig_bytes\n");
00095    if (num_bytes > 8)
00096       png_error(png_ptr, "Too many bytes for PNG signature.");
00097 
00098    png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
00099 }
00100 
00101 /* Checks whether the supplied bytes match the PNG signature.  We allow
00102  * checking less than the full 8-byte signature so that those apps that
00103  * already read the first few bytes of a file to determine the file type
00104  * can simply check the remaining bytes for extra assurance.  Returns
00105  * an integer less than, equal to, or greater than zero if sig is found,
00106  * respectively, to be less than, to match, or be greater than the correct
00107  * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
00108  */
00109 int PNGAPI
00110 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
00111 {
00112    png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
00113    if (num_to_check > 8)
00114       num_to_check = 8;
00115    else if (num_to_check < 1)
00116       return (0);
00117 
00118    if (start > 7)
00119       return (0);
00120 
00121    if (start + num_to_check > 8)
00122       num_to_check = 8 - start;
00123 
00124    return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
00125 }
00126 
00127 /* (Obsolete) function to check signature bytes.  It does not allow one
00128  * to check a partial signature.  This function might be removed in the
00129  * future - use png_sig_cmp().  Returns true (nonzero) if the file is a PNG.
00130  */
00131 int PNGAPI
00132 png_check_sig(png_bytep sig, int num)
00133 {
00134   return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
00135 }
00136 
00137 /* Function to allocate memory for zlib and clear it to 0. */
00138 #ifdef PNG_1_0_X
00139 voidpf PNGAPI
00140 #else
00141 voidpf /* private */
00142 #endif
00143 png_zalloc(voidpf png_ptr, uInt items, uInt size)
00144 {
00145    png_uint_32 num_bytes = (png_uint_32)items * size;
00146    png_voidp ptr;
00147    png_structp p=png_ptr;
00148    png_uint_32 save_flags=p->flags;
00149 
00150    p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
00151    ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
00152    p->flags=save_flags;
00153 
00154 #ifndef PNG_NO_ZALLOC_ZERO
00155    if (ptr == NULL)
00156        return ((voidpf)ptr);
00157 
00158    if (num_bytes > (png_uint_32)0x8000L)
00159    {
00160       png_memset(ptr, 0, (png_size_t)0x8000L);
00161       png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
00162          (png_size_t)(num_bytes - (png_uint_32)0x8000L));
00163    }
00164    else
00165    {
00166       png_memset(ptr, 0, (png_size_t)num_bytes);
00167    }
00168 #endif
00169    return ((voidpf)ptr);
00170 }
00171 
00172 /* function to free memory for zlib */
00173 #ifdef PNG_1_0_X
00174 void PNGAPI
00175 #else
00176 void /* private */
00177 #endif
00178 png_zfree(voidpf png_ptr, voidpf ptr)
00179 {
00180    png_free((png_structp)png_ptr, (png_voidp)ptr);
00181 }
00182 
00183 /* Reset the CRC variable to 32 bits of 1's.  Care must be taken
00184  * in case CRC is > 32 bits to leave the top bits 0.
00185  */
00186 void /* PRIVATE */
00187 png_reset_crc(png_structp png_ptr)
00188 {
00189    png_ptr->crc = crc32(0, Z_NULL, 0);
00190 }
00191 
00192 /* Calculate the CRC over a section of data.  We can only pass as
00193  * much data to this routine as the largest single buffer size.  We
00194  * also check that this data will actually be used before going to the
00195  * trouble of calculating it.
00196  */
00197 void /* PRIVATE */
00198 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
00199 {
00200    int need_crc = 1;
00201 
00202    if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
00203    {
00204       if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
00205           (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
00206          need_crc = 0;
00207    }
00208    else                                                    /* critical */
00209    {
00210       if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
00211          need_crc = 0;
00212    }
00213 
00214    if (need_crc)
00215       png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
00216 }
00217 
00218 /* Allocate the memory for an info_struct for the application.  We don't
00219  * really need the png_ptr, but it could potentially be useful in the
00220  * future.  This should be used in favour of malloc(sizeof(png_info))
00221  * and png_info_init() so that applications that want to use a shared
00222  * libpng don't have to be recompiled if png_info changes size.
00223  */
00224 png_infop PNGAPI
00225 png_create_info_struct(png_structp png_ptr)
00226 {
00227    png_infop info_ptr;
00228 
00229    png_debug(1, "in png_create_info_struct\n");
00230    if(png_ptr == NULL) return (NULL);
00231 #ifdef PNG_USER_MEM_SUPPORTED
00232    info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
00233       png_ptr->malloc_fn, png_ptr->mem_ptr);
00234 #else
00235    info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
00236 #endif
00237    if (info_ptr != NULL)
00238       png_info_init_3(&info_ptr, sizeof(png_info));
00239 
00240    return (info_ptr);
00241 }
00242 
00243 /* This function frees the memory associated with a single info struct.
00244  * Normally, one would use either png_destroy_read_struct() or
00245  * png_destroy_write_struct() to free an info struct, but this may be
00246  * useful for some applications.
00247  */
00248 void PNGAPI
00249 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
00250 {
00251    png_infop info_ptr = NULL;
00252 
00253    png_debug(1, "in png_destroy_info_struct\n");
00254    if (info_ptr_ptr != NULL)
00255       info_ptr = *info_ptr_ptr;
00256 
00257    if (info_ptr != NULL)
00258    {
00259       png_info_destroy(png_ptr, info_ptr);
00260 
00261 #ifdef PNG_USER_MEM_SUPPORTED
00262       png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
00263           png_ptr->mem_ptr);
00264 #else
00265       png_destroy_struct((png_voidp)info_ptr);
00266 #endif
00267       *info_ptr_ptr = NULL;
00268    }
00269 }
00270 
00271 /* Initialize the info structure.  This is now an internal function (0.89)
00272  * and applications using it are urged to use png_create_info_struct()
00273  * instead.
00274  */
00275 #undef png_info_init
00276 void PNGAPI
00277 png_info_init(png_infop info_ptr)
00278 {
00279    /* We only come here via pre-1.0.12-compiled applications */
00280    png_info_init_3(&info_ptr, 0);
00281 }
00282 
00283 void PNGAPI
00284 png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
00285 {
00286    png_infop info_ptr = *ptr_ptr;
00287 
00288    png_debug(1, "in png_info_init_3\n");
00289 
00290    if(sizeof(png_info) > png_info_struct_size)
00291      {
00292        png_destroy_struct(info_ptr);
00293        info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
00294        *ptr_ptr = info_ptr;
00295      }
00296 
00297    /* set everything to 0 */
00298    png_memset(info_ptr, 0, sizeof (png_info));
00299 }
00300 
00301 #ifdef PNG_FREE_ME_SUPPORTED
00302 void PNGAPI
00303 png_data_freer(png_structp png_ptr, png_infop info_ptr,
00304    int freer, png_uint_32 mask)
00305 {
00306    png_debug(1, "in png_data_freer\n");
00307    if (png_ptr == NULL || info_ptr == NULL)
00308       return;
00309    if(freer == PNG_DESTROY_WILL_FREE_DATA)
00310       info_ptr->free_me |= mask;
00311    else if(freer == PNG_USER_WILL_FREE_DATA)
00312       info_ptr->free_me &= ~mask;
00313    else
00314       png_warning(png_ptr,
00315          "Unknown freer parameter in png_data_freer.");
00316 }
00317 #endif
00318 
00319 void PNGAPI
00320 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
00321    int num)
00322 {
00323    png_debug(1, "in png_free_data\n");
00324    if (png_ptr == NULL || info_ptr == NULL)
00325       return;
00326 
00327 #if defined(PNG_TEXT_SUPPORTED)
00328 /* free text item num or (if num == -1) all text items */
00329 #ifdef PNG_FREE_ME_SUPPORTED
00330 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
00331 #else
00332 if (mask & PNG_FREE_TEXT)
00333 #endif
00334 {
00335    if (num != -1)
00336    {
00337      if (info_ptr->text && info_ptr->text[num].key)
00338      {
00339          png_free(png_ptr, info_ptr->text[num].key);
00340          info_ptr->text[num].key = NULL;
00341      }
00342    }
00343    else
00344    {
00345        int i;
00346        for (i = 0; i < info_ptr->num_text; i++)
00347            png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
00348        png_free(png_ptr, info_ptr->text);
00349        info_ptr->text = NULL;
00350        info_ptr->num_text=0;
00351    }
00352 }
00353 #endif
00354 
00355 #if defined(PNG_tRNS_SUPPORTED)
00356 /* free any tRNS entry */
00357 #ifdef PNG_FREE_ME_SUPPORTED
00358 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
00359 #else
00360 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
00361 #endif
00362 {
00363     png_free(png_ptr, info_ptr->trans);
00364     info_ptr->valid &= ~PNG_INFO_tRNS;
00365 #ifndef PNG_FREE_ME_SUPPORTED
00366     png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
00367 #endif
00368     info_ptr->trans = NULL;
00369 }
00370 #endif
00371 
00372 #if defined(PNG_sCAL_SUPPORTED)
00373 /* free any sCAL entry */
00374 #ifdef PNG_FREE_ME_SUPPORTED
00375 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
00376 #else
00377 if (mask & PNG_FREE_SCAL)
00378 #endif
00379 {
00380 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
00381     png_free(png_ptr, info_ptr->scal_s_width);
00382     png_free(png_ptr, info_ptr->scal_s_height);
00383     info_ptr->scal_s_width = NULL;
00384     info_ptr->scal_s_height = NULL;
00385 #endif
00386     info_ptr->valid &= ~PNG_INFO_sCAL;
00387 }
00388 #endif
00389 
00390 #if defined(PNG_pCAL_SUPPORTED)
00391 /* free any pCAL entry */
00392 #ifdef PNG_FREE_ME_SUPPORTED
00393 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
00394 #else
00395 if (mask & PNG_FREE_PCAL)
00396 #endif
00397 {
00398     png_free(png_ptr, info_ptr->pcal_purpose);
00399     png_free(png_ptr, info_ptr->pcal_units);
00400     info_ptr->pcal_purpose = NULL;
00401     info_ptr->pcal_units = NULL;
00402     if (info_ptr->pcal_params != NULL)
00403     {
00404         int i;
00405         for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
00406         {
00407           png_free(png_ptr, info_ptr->pcal_params[i]);
00408           info_ptr->pcal_params[i]=NULL;
00409         }
00410         png_free(png_ptr, info_ptr->pcal_params);
00411         info_ptr->pcal_params = NULL;
00412     }
00413     info_ptr->valid &= ~PNG_INFO_pCAL;
00414 }
00415 #endif
00416 
00417 #if defined(PNG_iCCP_SUPPORTED)
00418 /* free any iCCP entry */
00419 #ifdef PNG_FREE_ME_SUPPORTED
00420 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
00421 #else
00422 if (mask & PNG_FREE_ICCP)
00423 #endif
00424 {
00425     png_free(png_ptr, info_ptr->iccp_name);
00426     png_free(png_ptr, info_ptr->iccp_profile);
00427     info_ptr->iccp_name = NULL;
00428     info_ptr->iccp_profile = NULL;
00429     info_ptr->valid &= ~PNG_INFO_iCCP;
00430 }
00431 #endif
00432 
00433 #if defined(PNG_sPLT_SUPPORTED)
00434 /* free a given sPLT entry, or (if num == -1) all sPLT entries */
00435 #ifdef PNG_FREE_ME_SUPPORTED
00436 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
00437 #else
00438 if (mask & PNG_FREE_SPLT)
00439 #endif
00440 {
00441    if (num != -1)
00442    {
00443       if(info_ptr->splt_palettes)
00444       {
00445           png_free(png_ptr, info_ptr->splt_palettes[num].name);
00446           png_free(png_ptr, info_ptr->splt_palettes[num].entries);
00447           info_ptr->splt_palettes[num].name = NULL;
00448           info_ptr->splt_palettes[num].entries = NULL;
00449       }
00450    }
00451    else
00452    {
00453        if(info_ptr->splt_palettes_num)
00454        {
00455          int i;
00456          for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
00457             png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
00458 
00459          png_free(png_ptr, info_ptr->splt_palettes);
00460          info_ptr->splt_palettes = NULL;
00461          info_ptr->splt_palettes_num = 0;
00462        }
00463        info_ptr->valid &= ~PNG_INFO_sPLT;
00464    }
00465 }
00466 #endif
00467 
00468 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
00469 #ifdef PNG_FREE_ME_SUPPORTED
00470 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
00471 #else
00472 if (mask & PNG_FREE_UNKN)
00473 #endif
00474 {
00475    if (num != -1)
00476    {
00477        if(info_ptr->unknown_chunks)
00478        {
00479           png_free(png_ptr, info_ptr->unknown_chunks[num].data);
00480           info_ptr->unknown_chunks[num].data = NULL;
00481        }
00482    }
00483    else
00484    {
00485        int i;
00486 
00487        if(info_ptr->unknown_chunks_num)
00488        {
00489          for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
00490             png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
00491 
00492          png_free(png_ptr, info_ptr->unknown_chunks);
00493          info_ptr->unknown_chunks = NULL;
00494          info_ptr->unknown_chunks_num = 0;
00495        }
00496    }
00497 }
00498 #endif
00499 
00500 #if defined(PNG_hIST_SUPPORTED)
00501 /* free any hIST entry */
00502 #ifdef PNG_FREE_ME_SUPPORTED
00503 if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
00504 #else
00505 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
00506 #endif
00507 {
00508     png_free(png_ptr, info_ptr->hist);
00509     info_ptr->hist = NULL;
00510     info_ptr->valid &= ~PNG_INFO_hIST;
00511 #ifndef PNG_FREE_ME_SUPPORTED
00512     png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
00513 #endif
00514 }
00515 #endif
00516 
00517 /* free any PLTE entry that was internally allocated */
00518 #ifdef PNG_FREE_ME_SUPPORTED
00519 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
00520 #else
00521 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
00522 #endif
00523 {
00524     png_zfree(png_ptr, info_ptr->palette);
00525     info_ptr->palette = NULL;
00526     info_ptr->valid &= ~PNG_INFO_PLTE;
00527 #ifndef PNG_FREE_ME_SUPPORTED
00528     png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
00529 #endif
00530     info_ptr->num_palette = 0;
00531 }
00532 
00533 #if defined(PNG_INFO_IMAGE_SUPPORTED)
00534 /* free any image bits attached to the info structure */
00535 #ifdef PNG_FREE_ME_SUPPORTED
00536 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
00537 #else
00538 if (mask & PNG_FREE_ROWS)
00539 #endif
00540 {
00541     if(info_ptr->row_pointers)
00542     {
00543        int row;
00544        for (row = 0; row < (int)info_ptr->height; row++)
00545        {
00546           png_free(png_ptr, info_ptr->row_pointers[row]);
00547           info_ptr->row_pointers[row]=NULL;
00548        }
00549        png_free(png_ptr, info_ptr->row_pointers);
00550        info_ptr->row_pointers=NULL;
00551     }
00552     info_ptr->valid &= ~PNG_INFO_IDAT;
00553 }
00554 #endif
00555 
00556 #ifdef PNG_FREE_ME_SUPPORTED
00557    if(num == -1)
00558      info_ptr->free_me &= ~mask;
00559    else
00560      info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
00561 #endif
00562 }
00563 
00564 /* This is an internal routine to free any memory that the info struct is
00565  * pointing to before re-using it or freeing the struct itself.  Recall
00566  * that png_free() checks for NULL pointers for us.
00567  */
00568 void /* PRIVATE */
00569 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
00570 {
00571    png_debug(1, "in png_info_destroy\n");
00572 
00573    png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
00574 
00575 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
00576    if (png_ptr->num_chunk_list)
00577    {
00578        png_free(png_ptr, png_ptr->chunk_list);
00579        png_ptr->chunk_list=NULL;
00580        png_ptr->num_chunk_list=0;
00581    }
00582 #endif
00583 
00584    png_info_init_3(&info_ptr, sizeof(png_info));
00585 }
00586 
00587 /* This function returns a pointer to the io_ptr associated with the user
00588  * functions.  The application should free any memory associated with this
00589  * pointer before png_write_destroy() or png_read_destroy() are called.
00590  */
00591 png_voidp PNGAPI
00592 png_get_io_ptr(png_structp png_ptr)
00593 {
00594    return (png_ptr->io_ptr);
00595 }
00596 
00597 #if !defined(PNG_NO_STDIO)
00598 /* Initialize the default input/output functions for the PNG file.  If you
00599  * use your own read or write routines, you can call either png_set_read_fn()
00600  * or png_set_write_fn() instead of png_init_io().  If you have defined
00601  * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
00602  * necessarily available.
00603  */
00604 void PNGAPI
00605 png_init_io(png_structp png_ptr, png_FILE_p fp)
00606 {
00607    png_debug(1, "in png_init_io\n");
00608    png_ptr->io_ptr = (png_voidp)fp;
00609 }
00610 #endif
00611 
00612 #if defined(PNG_TIME_RFC1123_SUPPORTED)
00613 /* Convert the supplied time into an RFC 1123 string suitable for use in
00614  * a "Creation Time" or other text-based time string.
00615  */
00616 png_charp PNGAPI
00617 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
00618 {
00619    static PNG_CONST char short_months[12][4] =
00620         {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
00621          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
00622 
00623    if (png_ptr->time_buffer == NULL)
00624    {
00625       png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
00626          sizeof(char)));
00627    }
00628 
00629 #if defined(_WIN32_WCE)
00630    {
00631       wchar_t time_buf[29];
00632       wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
00633           ptime->day % 32, short_months[(ptime->month - 1) % 12],
00634         ptime->year, ptime->hour % 24, ptime->minute % 60,
00635           ptime->second % 61);
00636       WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
00637           NULL, NULL);
00638    }
00639 #else
00640 #ifdef USE_FAR_KEYWORD
00641    {
00642       char near_time_buf[29];
00643       sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
00644           ptime->day % 32, short_months[(ptime->month - 1) % 12],
00645           ptime->year, ptime->hour % 24, ptime->minute % 60,
00646           ptime->second % 61);
00647       png_memcpy(png_ptr->time_buffer, near_time_buf,
00648           29*sizeof(char));
00649    }
00650 #else
00651    sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
00652        ptime->day % 32, short_months[(ptime->month - 1) % 12],
00653        ptime->year, ptime->hour % 24, ptime->minute % 60,
00654        ptime->second % 61);
00655 #endif
00656 #endif /* _WIN32_WCE */
00657    return ((png_charp)png_ptr->time_buffer);
00658 }
00659 #endif /* PNG_TIME_RFC1123_SUPPORTED */
00660 
00661 #if 0
00662 /* Signature string for a PNG file. */
00663 png_bytep PNGAPI
00664 png_sig_bytes(void)
00665 {
00666    return ((png_bytep)"\211\120\116\107\015\012\032\012");
00667 }
00668 #endif
00669 
00670 png_charp PNGAPI
00671 png_get_copyright(png_structp png_ptr)
00672 {
00673    if (png_ptr != NULL || png_ptr == NULL)  /* silence compiler warning */
00674    return ((png_charp) "\n libpng version 1.2.5 - October 3, 2002\n\
00675    Copyright (c) 1998-2002 Glenn Randers-Pehrson\n\
00676    Copyright (c) 1996-1997 Andreas Dilger\n\
00677    Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
00678    return ((png_charp) "");
00679 }
00680 
00681 /* The following return the library version as a short string in the
00682  * format 1.0.0 through 99.99.99zz.  To get the version of *.h files used
00683  * with your application, print out PNG_LIBPNG_VER_STRING, which is defined
00684  * in png.h.
00685  */
00686 
00687 png_charp PNGAPI
00688 png_get_libpng_ver(png_structp png_ptr)
00689 {
00690    /* Version of *.c files used when building libpng */
00691    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
00692       return((png_charp) "1.2.5");
00693    return((png_charp) "1.2.5");
00694 }
00695 
00696 png_charp PNGAPI
00697 png_get_header_ver(png_structp png_ptr)
00698 {
00699    /* Version of *.h files used when building libpng */
00700    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
00701       return((png_charp) PNG_LIBPNG_VER_STRING);
00702    return((png_charp) PNG_LIBPNG_VER_STRING);
00703 }
00704 
00705 png_charp PNGAPI
00706 png_get_header_version(png_structp png_ptr)
00707 {
00708    /* Returns longer string containing both version and date */
00709    if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
00710       return((png_charp) PNG_HEADER_VERSION_STRING);
00711    return((png_charp) PNG_HEADER_VERSION_STRING);
00712 }
00713 
00714 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
00715 int PNGAPI
00716 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
00717 {
00718    /* check chunk_name and return "keep" value if it's on the list, else 0 */
00719    int i;
00720    png_bytep p;
00721    if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
00722       return 0;
00723    p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
00724    for (i = png_ptr->num_chunk_list; i; i--, p-=5)
00725       if (!png_memcmp(chunk_name, p, 4))
00726         return ((int)*(p+4));
00727    return 0;
00728 }
00729 #endif
00730 
00731 /* This function, added to libpng-1.0.6g, is untested. */
00732 int PNGAPI
00733 png_reset_zstream(png_structp png_ptr)
00734 {
00735    return (inflateReset(&png_ptr->zstream));
00736 }
00737 
00738 /* This function was added to libpng-1.0.7 */
00739 png_uint_32 PNGAPI
00740 png_access_version_number(void)
00741 {
00742    /* Version of *.c files used when building libpng */
00743    return((png_uint_32) 10205L);
00744 }
00745 
00746 
00747 #if !defined(PNG_1_0_X)
00748 #if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
00749     /* GRR:  could add this:   && defined(PNG_MMX_CODE_SUPPORTED) */
00750 /* this INTERNAL function was added to libpng 1.2.0 */
00751 void /* PRIVATE */
00752 png_init_mmx_flags (png_structp png_ptr)
00753 {
00754     png_ptr->mmx_rowbytes_threshold = 0;
00755     png_ptr->mmx_bitdepth_threshold = 0;
00756 
00757 #  if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
00758 
00759     png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
00760 
00761     if (png_mmx_support() > 0) {
00762         png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
00763 #    ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
00764                               | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
00765 #    endif
00766 #    ifdef PNG_HAVE_ASSEMBLER_READ_INTERLACE
00767                               | PNG_ASM_FLAG_MMX_READ_INTERLACE
00768 #    endif
00769 #    ifndef PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
00770                               ;
00771 #    else
00772                               | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
00773                               | PNG_ASM_FLAG_MMX_READ_FILTER_UP
00774                               | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
00775                               | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
00776 
00777         png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
00778         png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
00779 #    endif
00780     } else {
00781         png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
00782                                | PNG_MMX_READ_FLAGS
00783                                | PNG_MMX_WRITE_FLAGS );
00784     }
00785 
00786 #  else /* !((PNGVCRD || PNGGCCRD) && PNG_ASSEMBLER_CODE_SUPPORTED)) */
00787 
00788     /* clear all MMX flags; no support is compiled in */
00789     png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
00790 
00791 #  endif /* ?(PNGVCRD || PNGGCCRD) */
00792 }
00793 
00794 #endif /* !(PNG_ASSEMBLER_CODE_SUPPORTED) */
00795 
00796 /* this function was added to libpng 1.2.0 */
00797 #if !defined(PNG_USE_PNGGCCRD) && \
00798     !(defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
00799 int PNGAPI
00800 png_mmx_support(void)
00801 {
00802     return -1;
00803 }
00804 #endif
00805 #endif /* PNG_1_0_X */