diff options
Diffstat (limited to 'archival/libunarchive/rangecoder.h')
-rw-r--r-- | archival/libunarchive/rangecoder.h | 147 |
1 files changed, 0 insertions, 147 deletions
diff --git a/archival/libunarchive/rangecoder.h b/archival/libunarchive/rangecoder.h deleted file mode 100644 index b806eeb..0000000 --- a/archival/libunarchive/rangecoder.h +++ /dev/null @@ -1,147 +0,0 @@ - -#include "libbb.h" - -#ifdef CONFIG_FEATURE_LZMA_FAST -# define speed_inline ATTRIBUTE_ALWAYS_INLINE -#else -# define speed_inline -#endif - - -typedef struct { - int fd; - uint8_t *ptr; - uint8_t *buffer; - uint8_t *buffer_end; - int buffer_size; - uint32_t code; - uint32_t range; - uint32_t bound; -} rc_t; - - -#define RC_TOP_BITS 24 -#define RC_MOVE_BITS 5 -#define RC_MODEL_TOTAL_BITS 11 - - -/* Called twice: once at startup and once in rc_normalize() */ -static void rc_read(rc_t * rc) -{ - rc->buffer_size = read(rc->fd, rc->buffer, rc->buffer_size); - if (rc->buffer_size <= 0) - bb_error_msg_and_die("unexpected EOF"); - rc->ptr = rc->buffer; - rc->buffer_end = rc->buffer + rc->buffer_size; -} - -/* Called once */ -static void rc_init(rc_t * rc, int fd, int buffer_size) -{ - int i; - - rc->fd = fd; - rc->buffer = xmalloc(buffer_size); - rc->buffer_size = buffer_size; - rc->buffer_end = rc->buffer + rc->buffer_size; - rc->ptr = rc->buffer_end; - - rc->code = 0; - rc->range = 0xFFFFFFFF; - for (i = 0; i < 5; i++) { - if (rc->ptr >= rc->buffer_end) - rc_read(rc); - rc->code = (rc->code << 8) | *rc->ptr++; - } -} - -/* Called once. TODO: bb_maybe_free() */ -static ATTRIBUTE_ALWAYS_INLINE void rc_free(rc_t * rc) -{ - if (ENABLE_FEATURE_CLEAN_UP) - free(rc->buffer); -} - -/* Called twice, but one callsite is in speed_inline'd rc_is_bit_0_helper() */ -static void rc_do_normalize(rc_t * rc) -{ - if (rc->ptr >= rc->buffer_end) - rc_read(rc); - rc->range <<= 8; - rc->code = (rc->code << 8) | *rc->ptr++; -} -static ATTRIBUTE_ALWAYS_INLINE void rc_normalize(rc_t * rc) -{ - if (rc->range < (1 << RC_TOP_BITS)) { - rc_do_normalize(rc); - } -} - -/* Called 9 times */ -/* Why rc_is_bit_0_helper exists? - * Because we want to always expose (rc->code < rc->bound) to optimizer - */ -static speed_inline uint32_t rc_is_bit_0_helper(rc_t * rc, uint16_t * p) -{ - rc_normalize(rc); - rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS); - return rc->bound; -} -static ATTRIBUTE_ALWAYS_INLINE int rc_is_bit_0(rc_t * rc, uint16_t * p) -{ - uint32_t t = rc_is_bit_0_helper(rc, p); - return rc->code < t; -} - -/* Called ~10 times, but very small, thus inlined */ -static speed_inline void rc_update_bit_0(rc_t * rc, uint16_t * p) -{ - rc->range = rc->bound; - *p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS; -} -static speed_inline void rc_update_bit_1(rc_t * rc, uint16_t * p) -{ - rc->range -= rc->bound; - rc->code -= rc->bound; - *p -= *p >> RC_MOVE_BITS; -} - -/* Called 4 times in unlzma loop */ -static int rc_get_bit(rc_t * rc, uint16_t * p, int *symbol) -{ - if (rc_is_bit_0(rc, p)) { - rc_update_bit_0(rc, p); - *symbol *= 2; - return 0; - } else { - rc_update_bit_1(rc, p); - *symbol = *symbol * 2 + 1; - return 1; - } -} - -/* Called once */ -static ATTRIBUTE_ALWAYS_INLINE int rc_direct_bit(rc_t * rc) -{ - rc_normalize(rc); - rc->range >>= 1; - if (rc->code >= rc->range) { - rc->code -= rc->range; - return 1; - } - return 0; -} - -/* Called twice */ -static speed_inline void -rc_bit_tree_decode(rc_t * rc, uint16_t * p, int num_levels, int *symbol) -{ - int i = num_levels; - - *symbol = 1; - while (i--) - rc_get_bit(rc, p + *symbol, symbol); - *symbol -= 1 << num_levels; -} - -/* vi:set ts=4: */ |