Support creating and matching bitstrings that are in fact binaries (size divisible by 8)

Signed-off-by: Mateusz Front <[email protected]>

Author: mat-hek

src/libAtomVM/opcodesswitch.h

@@ -5447,20 +5447,21 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                     term bs_bin = term_get_match_state_binary(src);
                     avm_int_t bs_offset = term_get_match_state_offset(src);
 
-                    if (unit != 8) {
-                        TRACE("bs_get_binary2: Unsupported: unit must be 8.\n");
-                        RAISE_ERROR(UNSUPPORTED_ATOM);
-                    }
                     avm_int_t size_val = 0;
                     if (term_is_integer(size)) {
-                        size_val = term_to_int(size);
+                        size_val = term_to_int(size) * unit;
+                        if (size_val % 8) {
+                            TRACE("bs_get_binary2: Unsupported: size must be divisible by 8, got: %ld\n", size_val);
+                            RAISE_ERROR(UNSUPPORTED_ATOM);
+                        }
+                        size_val = size_val / 8;
                     } else if (size == ALL_ATOM) {
                         size_val = term_binary_size(bs_bin) - bs_offset / 8;
                     } else {
                         TRACE("bs_get_binary2: size is neither an integer nor the atom `all`\n");
                         RAISE_ERROR(BADARG_ATOM);
                     }
-                    if (bs_offset % unit != 0) {
+                    if (bs_offset % 8 != 0) {
                         TRACE("bs_get_binary2: Unsupported.  Offset on binary read must be aligned on byte boundaries.\n");
                         RAISE_ERROR(BADARG_ATOM);
                     }
@@ -5471,11 +5472,11 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
 
                     TRACE("bs_get_binary2/7, fail=%u src=%p live=%u unit=%u\n", (unsigned) fail, (void *) bs_bin, (unsigned) live, (unsigned) unit);
 
-                    if ((unsigned int) (bs_offset / unit + size_val) > term_binary_size(bs_bin)) {
+                    if ((unsigned int) (bs_offset / 8 + size_val) > term_binary_size(bs_bin)) {
                         TRACE("bs_get_binary2: insufficient capacity -- bs_offset = %d, size_val = %d\n", (int) bs_offset, (int) size_val);
                         JUMP_TO_ADDRESS(mod->labels[fail]);
                     } else {
-                        term_set_match_state_offset(src, bs_offset + size_val * unit);
+                        term_set_match_state_offset(src, bs_offset + size_val * 8);
 
                         TRIM_LIVE_REGS(live);
                         // there is always room for a MAX_REG + 1 register, used as working register
@@ -6940,7 +6941,12 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                                     }
                                 } else {
                                     VERIFY_IS_INTEGER(size, "bs_create_bin/6", fail);
-                                    avm_int_t signed_size_value = term_to_int(size);
+                                    avm_int_t signed_size_value = term_to_int(size) * segment_unit;
+                                    if (UNLIKELY(signed_size_value % 8)) {
+                                        TRACE("bs_create_bin/6: Unsupported: size must be dvisible by 8, got: %ld\n", signed_size_value);
+                                        RAISE_ERROR(UNSUPPORTED_ATOM);
+                                    }
+                                    signed_size_value = signed_size_value / 8;
                                     if (UNLIKELY(signed_size_value < 0)) {
                                         if (fail == 0) {
                                             RAISE_ERROR(BADARG_ATOM);
@@ -6957,6 +6963,7 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                                         }
                                     }
                                     segment_size = signed_size_value;
+                                    segment_unit = 8;
                                 }
                                 break;
                             }
@@ -7109,7 +7116,12 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                                         TRACE("bs_create_bin/6: size value less than 0: %i\n", (int) signed_size_value);
                                         RAISE_ERROR(BADARG_ATOM);
                                     }
-                                    size_value = (size_t) signed_size_value;
+                                    size_value = (size_t) signed_size_value * segment_unit;
+                                    if (UNLIKELY(size_value % 8)) {
+                                        TRACE("bs_create_bin/6: Unsupported: bitstring size (%d) is not evenly divisible by 8\n", (int) size_value);
+                                        RAISE_ERROR(UNSUPPORTED_ATOM);
+                                    }
+                                    size_value = size_value / 8;
                                     if (size_value > src_size) {
                                         if (fail == 0) {
                                             RAISE_ERROR(BADARG_ATOM);