diff options
Diffstat (limited to 'pngwio.c')
| -rw-r--r-- | pngwio.c | 111 |
1 files changed, 68 insertions, 43 deletions
@@ -1,12 +1,15 @@ /* pngwio.c - functions for data output * - * Last changed in libpng 1.2.35 [February 14, 2009] - * For conditions of distribution and use, see copyright notice in png.h + * Last changed in libpng 1.2.37 [June 4, 2009] * Copyright (c) 1998-2009 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * * This file provides a location for all output. Users who need * special handling are expected to write functions that have the same * arguments as these and perform similar functions, but that possibly @@ -20,10 +23,11 @@ #ifdef PNG_WRITE_SUPPORTED /* Write the data to whatever output you are using. The default routine - writes to a file pointer. Note that this routine sometimes gets called - with very small lengths, so you should implement some kind of simple - buffering if you are using unbuffered writes. This should never be asked - to write more than 64K on a 16 bit machine. */ + * writes to a file pointer. Note that this routine sometimes gets called + * with very small lengths, so you should implement some kind of simple + * buffering if you are using unbuffered writes. This should never be asked + * to write more than 64K on a 16 bit machine. + */ void /* PRIVATE */ png_write_data(png_structp png_ptr, png_bytep data, png_size_t length) @@ -36,16 +40,18 @@ png_write_data(png_structp png_ptr, png_bytep data, png_size_t length) #if !defined(PNG_NO_STDIO) /* This is the function that does the actual writing of data. If you are - not writing to a standard C stream, you should create a replacement - write_data function and use it at run time with png_set_write_fn(), rather - than changing the library. */ + * not writing to a standard C stream, you should create a replacement + * write_data function and use it at run time with png_set_write_fn(), rather + * than changing the library. + */ #ifndef USE_FAR_KEYWORD void PNGAPI png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length) { png_uint_32 check; - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; #if defined(_WIN32_WCE) if ( !WriteFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) ) check = 0; @@ -56,10 +62,10 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length) png_error(png_ptr, "Write Error"); } #else -/* this is the model-independent version. Since the standard I/O library - can't handle far buffers in the medium and small models, we have to copy - the data. -*/ +/* This is the model-independent version. Since the standard I/O library + * can't handle far buffers in the medium and small models, we have to copy + * the data. + */ #define NEAR_BUF_SIZE 1024 #define MIN(a,b) (a <= b ? a : b) @@ -71,7 +77,8 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length) png_byte *near_data; /* Needs to be "png_byte *" instead of "png_bytep" */ png_FILE_p io_ptr; - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; /* Check if data really is near. If so, use usual code. */ near_data = (png_byte *)CVT_PTR_NOCHECK(data); io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr); @@ -93,7 +100,7 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length) do { written = MIN(NEAR_BUF_SIZE, remaining); - png_memcpy(buf, data, written); /* copy far buffer to near buffer */ + png_memcpy(buf, data, written); /* Copy far buffer to near buffer */ #if defined(_WIN32_WCE) if ( !WriteFile(io_ptr, buf, written, &err, NULL) ) err = 0; @@ -102,8 +109,10 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length) #endif if (err != written) break; + else check += err; + data += written; remaining -= written; } @@ -117,8 +126,9 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length) #endif /* This function is called to output any data pending writing (normally - to disk). After png_flush is called, there should be no data pending - writing in any buffers. */ + * to disk). After png_flush is called, there should be no data pending + * writing in any buffers. + */ #if defined(PNG_WRITE_FLUSH_SUPPORTED) void /* PRIVATE */ png_flush(png_structp png_ptr) @@ -134,48 +144,58 @@ png_default_flush(png_structp png_ptr) #if !defined(_WIN32_WCE) png_FILE_p io_ptr; #endif - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; #if !defined(_WIN32_WCE) io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr)); - if (io_ptr != NULL && fileno(io_ptr) != -1) - fflush(io_ptr); + fflush(io_ptr); #endif } #endif #endif /* This function allows the application to supply new output functions for - libpng if standard C streams aren't being used. - - This function takes as its arguments: - png_ptr - pointer to a png output data structure - io_ptr - pointer to user supplied structure containing info about - the output functions. May be NULL. - write_data_fn - pointer to a new output function that takes as its - arguments a pointer to a png_struct, a pointer to - data to be written, and a 32-bit unsigned int that is - the number of bytes to be written. The new write - function should call png_error(png_ptr, "Error msg") - to exit and output any fatal error messages. - flush_data_fn - pointer to a new flush function that takes as its - arguments a pointer to a png_struct. After a call to - the flush function, there should be no data in any buffers - or pending transmission. If the output method doesn't do - any buffering of ouput, a function prototype must still be - supplied although it doesn't have to do anything. If - PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile - time, output_flush_fn will be ignored, although it must be - supplied for compatibility. */ + * libpng if standard C streams aren't being used. + * + * This function takes as its arguments: + * png_ptr - pointer to a png output data structure + * io_ptr - pointer to user supplied structure containing info about + * the output functions. May be NULL. + * write_data_fn - pointer to a new output function that takes as its + * arguments a pointer to a png_struct, a pointer to + * data to be written, and a 32-bit unsigned int that is + * the number of bytes to be written. The new write + * function should call png_error(png_ptr, "Error msg") + * to exit and output any fatal error messages. May be + * NULL, in which case libpng's default function will + * be used. + * flush_data_fn - pointer to a new flush function that takes as its + * arguments a pointer to a png_struct. After a call to + * the flush function, there should be no data in any buffers + * or pending transmission. If the output method doesn't do + * any buffering of ouput, a function prototype must still be + * supplied although it doesn't have to do anything. If + * PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile + * time, output_flush_fn will be ignored, although it must be + * supplied for compatibility. May be NULL, in which case + * libpng's default function will be used, if + * PNG_WRITE_FLUSH_SUPPORTED is defined. This is not + * a good idea if io_ptr does not point to a standard + * *FILE structure. + */ void PNGAPI png_set_write_fn(png_structp png_ptr, png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn) { - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; + png_ptr->io_ptr = io_ptr; #if !defined(PNG_NO_STDIO) if (write_data_fn != NULL) png_ptr->write_data_fn = write_data_fn; + else png_ptr->write_data_fn = png_default_write_data; #else @@ -186,6 +206,7 @@ png_set_write_fn(png_structp png_ptr, png_voidp io_ptr, #if !defined(PNG_NO_STDIO) if (output_flush_fn != NULL) png_ptr->output_flush_fn = output_flush_fn; + else png_ptr->output_flush_fn = png_default_flush; #else @@ -212,9 +233,11 @@ void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check) void FAR *far_ptr; FP_OFF(near_ptr) = FP_OFF(ptr); far_ptr = (void FAR *)near_ptr; + if (check != 0) if (FP_SEG(ptr) != FP_SEG(far_ptr)) png_error(png_ptr, "segment lost in conversion"); + return(near_ptr); } # else @@ -224,9 +247,11 @@ void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check) void FAR *far_ptr; near_ptr = (void FAR *)ptr; far_ptr = (void FAR *)near_ptr; + if (check != 0) if (far_ptr != ptr) png_error(png_ptr, "segment lost in conversion"); + return(near_ptr); } # endif |