diff options
Diffstat (limited to 'src/cff/cf2stack.c')
-rw-r--r-- | src/cff/cf2stack.c | 90 |
1 files changed, 85 insertions, 5 deletions
diff --git a/src/cff/cf2stack.c b/src/cff/cf2stack.c index 8332b5d..8f3adb6 100644 --- a/src/cff/cf2stack.c +++ b/src/cff/cf2stack.c @@ -53,14 +53,14 @@ cf2_stack_init( FT_Memory memory, FT_Error* e ) { - FT_Error error = FT_Err_Ok; /* for FT_QNEW */ + FT_Error error = FT_Err_Ok; /* for FT_NEW */ CF2_Stack stack = NULL; - if ( !FT_QNEW( stack ) ) + if ( !FT_NEW( stack ) ) { - /* initialize the structure; FT_QNEW zeroes it */ + /* initialize the structure; FT_NEW zeroes it */ stack->memory = memory; stack->error = e; stack->top = &stack->buffer[0]; /* empty stack */ @@ -145,7 +145,7 @@ /* Note: type mismatch is silently cast */ - /* TODO: check this */ + /* TODO: check this */ FT_LOCAL_DEF( CF2_Fixed ) cf2_stack_popFixed( CF2_Stack stack ) { @@ -170,7 +170,7 @@ /* Note: type mismatch is silently cast */ - /* TODO: check this */ + /* TODO: check this */ FT_LOCAL_DEF( CF2_Fixed ) cf2_stack_getReal( CF2_Stack stack, CF2_UInt idx ) @@ -195,6 +195,86 @@ } + FT_LOCAL( 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; + } + + 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 ) { |