lzw__map_write_fn()

static fl::u32 fl::third_party::lzw__map_write_fn ( struct lzw_ctx * ctx, void * output_data, fl::u32 output_length, fl::u32 output_used, fl::u16 code, fl::u16 left )

inlinestatic

Write colour mapped values for this code to the output.

If there isn't enough space in the output stack, this function will write the as many as it can into the output. If ctx->output_left > 0 after this call, then there is more data for this code left to output. The code is stored to the context as ctx->output_code.

Parameters

[in]	ctx	LZW reading context, updated.
[in]	output_data	Array to write output values into.
[in]	output_length	Size of output array.
[in]	output_used	Current position in output array.
[in]	code	LZW code to output values for.
[in]	left	Number of values remaining to output for code.

Returns

Number of pixel values written.

Definition at line 542 of file lzw.cpp.hpp.

{
    fl::u32 * output_pos = (fl::u32 *)output_data + output_used;
    const struct lzw_table_entry * const table = ctx->table;
    fl::u32 space = output_length - output_used;
    fl::u16 count = left;
 
    if (count > space) {
        left = count - space;
        count = space;
    } else {
        left = 0;
    }
 
    ctx->output_code = code;
    ctx->output_left = left;
 
    for (unsigned i = left; i != 0; i--) {
        const struct lzw_table_entry *entry = table + code;
        code = entry->extends;
    }
 
    output_pos += count;
    if (ctx->has_transparency) {
        for (unsigned i = count; i != 0; i--) {
            const struct lzw_table_entry *entry = table + code;
            --output_pos;
            if (entry->value != ctx->transparency_idx) {
                *output_pos = ctx->colour_map[entry->value];
            }
            code = entry->extends;
        }
    } else {
        for (unsigned i = count; i != 0; i--) {
            const struct lzw_table_entry *entry = table + code;
            *--output_pos = ctx->colour_map[entry->value];
            code = entry->extends;
        }
    }
 
    return count;
}

References fl::third_party::lzw_ctx::colour_map, fl::third_party::lzw_table_entry::extends, FL_NOEXCEPT, fl::third_party::lzw_ctx::has_transparency, fl::third_party::lzw_ctx::output_code, fl::third_party::lzw_ctx::output_left, fl::third_party::lzw_ctx::table, fl::third_party::lzw_ctx::transparency_idx, and fl::third_party::lzw_table_entry::value.

Referenced by lzw_decode_map().

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