ref: ec9b6c314dc018bbf0af4ff657fa5ff56a5bf9f7
dir: /src/psaux/psstack.c/
/****************************************************************************
*
* psstack.c
*
* Adobe's code for emulating a CFF stack (body).
*
* Copyright 2007-2013 Adobe Systems Incorporated.
*
* This software, and all works of authorship, whether in source or
* object code form as indicated by the copyright notice(s) included
* herein (collectively, the "Work") is made available, and may only be
* used, modified, and distributed under the FreeType Project License,
* LICENSE.TXT. Additionally, subject to the terms and conditions of the
* FreeType Project License, each contributor to the Work hereby grants
* to any individual or legal entity exercising permissions granted by
* the FreeType Project License and this section (hereafter, "You" or
* "Your") a perpetual, worldwide, non-exclusive, no-charge,
* royalty-free, irrevocable (except as stated in this section) patent
* license to make, have made, use, offer to sell, sell, import, and
* otherwise transfer the Work, where such license applies only to those
* patent claims licensable by such contributor that are necessarily
* infringed by their contribution(s) alone or by combination of their
* contribution(s) with the Work to which such contribution(s) was
* submitted. If You institute patent litigation against any entity
* (including a cross-claim or counterclaim in a lawsuit) alleging that
* the Work or a contribution incorporated within the Work constitutes
* direct or contributory patent infringement, then any patent licenses
* granted to You under this License for that Work shall terminate as of
* the date such litigation is filed.
*
* By using, modifying, or distributing the Work you indicate that you
* have read and understood the terms and conditions of the
* FreeType Project License as well as those provided in this section,
* and you accept them fully.
*
*/
#include "psft.h"
#include <freetype/internal/ftdebug.h>
#include "psglue.h"
#include "psfont.h"
#include "psstack.h"
#include "pserror.h"
/* Allocate and initialize an instance of CF2_Stack. */
/* Note: This function returns NULL on error (does not set */
/* `error'). */
FT_LOCAL_DEF( CF2_Stack )
cf2_stack_init( FT_Memory memory,
FT_Error* e,
FT_UInt stackSize )
{
FT_Error error = FT_Err_Ok; /* for FT_NEW */
CF2_Stack stack = NULL;
if ( FT_NEW( stack ) )
return NULL;
/* initialize the structure; FT_NEW zeroes it */
stack->memory = memory;
stack->error = e;
/* allocate the stack buffer */
if ( FT_NEW_ARRAY( stack->buffer, stackSize ) )
{
FT_FREE( stack );
return NULL;
}
stack->stackSize = stackSize;
stack->top = stack->buffer; /* empty stack */
return stack;
}
FT_LOCAL_DEF( void )
cf2_stack_free( CF2_Stack stack )
{
if ( stack )
{
FT_Memory memory = stack->memory;
/* free the buffer */
FT_FREE( stack->buffer );
/* free the main structure */
FT_FREE( stack );
}
}
FT_LOCAL_DEF( CF2_UInt )
cf2_stack_count( CF2_Stack stack )
{
return (CF2_UInt)( stack->top - stack->buffer );
}
FT_LOCAL_DEF( void )
cf2_stack_pushInt( CF2_Stack stack,
CF2_Int val )
{
if ( stack->top == stack->buffer + stack->stackSize )
{
CF2_SET_ERROR( stack->error, Stack_Overflow );
return; /* stack overflow */
}
stack->top->u.i = val;
stack->top->type = CF2_NumberInt;
stack->top++;
}
FT_LOCAL_DEF( void )
cf2_stack_pushFixed( CF2_Stack stack,
CF2_Fixed val )
{
if ( stack->top == stack->buffer + stack->stackSize )
{
CF2_SET_ERROR( stack->error, Stack_Overflow );
return; /* stack overflow */
}
stack->top->u.r = val;
stack->top->type = CF2_NumberFixed;
stack->top++;
}
/* this function is only allowed to pop an integer type */
FT_LOCAL_DEF( CF2_Int )
cf2_stack_popInt( CF2_Stack stack )
{
if ( stack->top == stack->buffer )
{
CF2_SET_ERROR( stack->error, Stack_Underflow );
return 0; /* underflow */
}
if ( stack->top[-1].type != CF2_NumberInt )
{
CF2_SET_ERROR( stack->error, Syntax_Error );
return 0; /* type mismatch */
}
stack->top--;
return stack->top->u.i;
}
/* Note: type mismatch is silently cast */
/* TODO: check this */
FT_LOCAL_DEF( CF2_Fixed )
cf2_stack_popFixed( CF2_Stack stack )
{
if ( stack->top == stack->buffer )
{
CF2_SET_ERROR( stack->error, Stack_Underflow );
return cf2_intToFixed( 0 ); /* underflow */
}
stack->top--;
switch ( stack->top->type )
{
case CF2_NumberInt:
return cf2_intToFixed( stack->top->u.i );
case CF2_NumberFrac:
return cf2_fracToFixed( stack->top->u.f );
default:
return stack->top->u.r;
}
}
/* Note: type mismatch is silently cast */
/* TODO: check this */
FT_LOCAL_DEF( CF2_Fixed )
cf2_stack_getReal( CF2_Stack stack,
CF2_UInt idx )
{
FT_ASSERT( cf2_stack_count( stack ) <= stack->stackSize );
if ( idx >= cf2_stack_count( stack ) )
{
CF2_SET_ERROR( stack->error, Stack_Overflow );
return cf2_intToFixed( 0 ); /* bounds error */
}
switch ( stack->buffer[idx].type )
{
case CF2_NumberInt:
return cf2_intToFixed( stack->buffer[idx].u.i );
case CF2_NumberFrac:
return cf2_fracToFixed( stack->buffer[idx].u.f );
default:
return stack->buffer[idx].u.r;
}
}
/* provide random access to stack */
FT_LOCAL_DEF( void )
cf2_stack_setReal( CF2_Stack stack,
CF2_UInt idx,
CF2_Fixed val )
{
if ( idx > cf2_stack_count( stack ) )
{
CF2_SET_ERROR( stack->error, Stack_Overflow );
return;
}
stack->buffer[idx].u.r = val;
stack->buffer[idx].type = CF2_NumberFixed;
}
/* discard (pop) num values from stack */
FT_LOCAL_DEF( void )
cf2_stack_pop( CF2_Stack stack,
CF2_UInt num )
{
if ( num > cf2_stack_count( stack ) )
{
CF2_SET_ERROR( stack->error, Stack_Underflow );
return;
}
stack->top -= num;
}
FT_LOCAL_DEF( void )
cf2_stack_roll( CF2_Stack stack,
CF2_Int count,
CF2_Int shift )
{
/* we initialize this variable to avoid compiler warnings */
CF2_StackNumber last = { { 0 }, CF2_NumberInt };
CF2_Int start_idx, idx, i;
if ( count < 2 )
return; /* nothing to do (values 0 and 1), or undefined value */
if ( (CF2_UInt)count > cf2_stack_count( stack ) )
{
CF2_SET_ERROR( stack->error, Stack_Overflow );
return;
}
/* before C99 it is implementation-defined whether */
/* the result of `%' is negative if the first operand */
/* is negative */
if ( shift < 0 )
shift = -( ( -shift ) % count );
else
shift %= count;
if ( shift == 0 )
return; /* nothing to do */
/* We use the following algorithm to do the rolling, */
/* which needs two temporary variables only. */
/* */
/* Example: */
/* */
/* count = 8 */
/* shift = 2 */
/* */
/* stack indices before roll: 7 6 5 4 3 2 1 0 */
/* stack indices after roll: 1 0 7 6 5 4 3 2 */
/* */
/* The value of index 0 gets moved to index 2, while */
/* the old value of index 2 gets moved to index 4, */
/* and so on. We thus have the following copying */
/* chains for shift value 2. */
/* */
/* 0 -> 2 -> 4 -> 6 -> 0 */
/* 1 -> 3 -> 5 -> 7 -> 1 */
/* */
/* If `count' and `shift' are incommensurable, we */
/* have a single chain only. Otherwise, increase */
/* the start index by 1 after the first chain, then */
/* do the next chain until all elements in all */
/* chains are handled. */
start_idx = -1;
idx = -1;
for ( i = 0; i < count; i++ )
{
CF2_StackNumber tmp;
if ( start_idx == idx )
{
start_idx++;
idx = start_idx;
last = stack->buffer[idx];
}
idx += shift;
if ( idx >= count )
idx -= count;
else if ( idx < 0 )
idx += count;
tmp = stack->buffer[idx];
stack->buffer[idx] = last;
last = tmp;
}
}
FT_LOCAL_DEF( void )
cf2_stack_clear( CF2_Stack stack )
{
stack->top = stack->buffer;
}
/* END */