; pngwio.asm - functions for data output
; Last changed in libpng 1.6.24 [August 4, 2016]
; Copyright (c) 1998-2002,2004,2006-2014,2016 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.inc
; 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
; use different output methods. Note that you shouldn't change these
; functions, but rather write replacement functions and then change
; them at run time with png_set_write_fn(...).
; 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.
;void (png_structrp png_ptr, bytep data, png_size_t length)
align 4
proc png_write_data uses edi, png_ptr:dword, p2data:dword, length:dword
; NOTE: write_data_fn must not change the buffer!
mov edi,[png_ptr]
cmp dword[edi+png_struct.write_data_fn],0
je @f ;if (..!=0)
stdcall dword[edi+png_struct.write_data_fn], edi, [p2data], [length]
jmp .end_f
@@: ;else
png_error edi, 'Call to NULL write function'
.end_f:
ret
endp
; 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.
;void (png_structp png_ptr, bytep data, png_size_t length)
align 4
proc png_default_write_data uses eax edi, png_ptr:dword, p2data:dword, length:dword
; png_size_t check;
mov edi,[png_ptr]
cmp edi,0
je .end_f ;if (..==0) return
; check = fwrite(p2data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
; if (check != length)
; png_error(png_ptr, "Write Error");
.end_f:
ret
endp
; 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.
;void (png_structrp png_ptr)
align 4
proc png_flush uses edi, png_ptr:dword
mov edi,[png_ptr]
cmp dword[edi+png_struct.output_flush_fn],0
je @f ;if (..!=..)
stdcall dword[edi+png_struct.output_flush_fn],edi
@@:
ret
endp
;void (png_structp png_ptr)
align 4
proc png_default_flush uses eax edi, png_ptr:dword
mov edi,[png_ptr]
cmp edi,0
je @f ;if (..==0) return
;;; stdcall fflush, [edi+png_struct.io_ptr]
@@:
ret
endp
; 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. 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 output, 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 (png_structrp png_ptr, voidp io_ptr,
; png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
align 4
proc png_set_write_fn uses eax edi, png_ptr:dword, io_ptr:dword, write_data_fn:dword, output_flush_fn:dword
mov edi,[png_ptr]
cmp edi,0
je .end_f ;if (..==0) return
mov eax,[io_ptr]
mov [edi+png_struct.io_ptr],eax
if PNG_STDIO_SUPPORTED eq 1
mov eax,png_default_write_data ;else
cmp dword[write_data_fn],0
je @f ;if (..!=0)
mov eax,[write_data_fn]
@@:
else
mov eax,[write_data_fn]
end if
mov [edi+png_struct.write_data_fn],eax
if PNG_WRITE_FLUSH_SUPPORTED eq 1
if PNG_STDIO_SUPPORTED eq 1
mov eax,[png_default_flush] ;else
cmp dword[output_flush_fn],0
je @f ;if (..!=0)
mov eax,[output_flush_fn]
@@:
else
mov eax,[output_flush_fn]
end if
mov [edi+png_struct.output_flush_fn],eax
end if ;WRITE_FLUSH
if PNG_READ_SUPPORTED eq 1
; It is an error to read while writing a png file
cmp dword[edi+png_struct.read_data_fn],0
je @f ;if (..!=0)
mov dword[edi+png_struct.read_data_fn], 0
png_warning edi, <'Can',39,'t set both read_data_fn and write_data_fn in the same structure'>
@@:
end if
.end_f:
ret
endp