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Merged
merged 2 commits into from
Nov 1, 2025
Merged

Minimal bigint pattern matching #1938

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310c0f6
intn: intn_from_integer_bytes: set sign when sign != NULL
bettio Oct 28, 2025
950c9ae
Implement minimal bigint binary pattern matching
bettio Oct 28, 2025
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17 changes: 17 additions & 0 deletions src/libAtomVM/bitstring.c
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Original file line number Diff line number Diff line change
Expand Up @@ -406,3 +406,20 @@ bool bitstring_extract_f64(
return false;
}
}

intn_from_integer_options_t bitstring_flags_to_intn_opts(enum BitstringFlags bf)
{
intn_from_integer_options_t converted = IntnUnsignedBigEndian;
if (bf & LittleEndianInteger) {
converted |= IntnLittleEndian;
}
if (bf & SignedInteger) {
converted |= IntnSigned;
}
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
if (bf & NativeEndianInteger) {
converted |= IntnLittleEndian;
}
#endif
return converted;
}
3 changes: 3 additions & 0 deletions src/libAtomVM/bitstring.h
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
#ifndef _BITSTRING_H_
#define _BITSTRING_H_

#include "intn.h"
#include "term.h"
#include "unicode.h"

Expand Down Expand Up @@ -528,6 +529,8 @@ bool bitstring_extract_f32(
bool bitstring_extract_f64(
term src_bin, size_t offset, avm_int_t n, enum BitstringFlags bs_flags, avm_float_t *dst);

intn_from_integer_options_t bitstring_flags_to_intn_opts(enum BitstringFlags bf);

#ifdef __cplusplus
}
#endif
Expand Down
2 changes: 2 additions & 0 deletions src/libAtomVM/intn.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1182,6 +1182,8 @@ int intn_from_integer_bytes(const uint8_t in[], size_t in_size, intn_from_intege
sign = IntNNegativeInteger;
}
*out_sign = sign;
} else if (out_sign) {
*out_sign = IntNPositiveInteger;
}

memset(out, filler, INTN_MAX_RES_LEN * sizeof(intn_digit_t));
Expand Down
63 changes: 54 additions & 9 deletions src/libAtomVM/jit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1244,19 +1244,64 @@ static term jit_term_alloc_bin_match_state(Context *ctx, term src, int slots)
return term_alloc_bin_match_state(src, slots, &ctx->heap);
}

static term jit_bitstring_extract_integer(Context *ctx, JITState *jit_state, term *bin_ptr, size_t offset, int n, int bs_flags)
static term extract_bigint(Context *ctx, JITState *jit_state, const uint8_t *bytes,
size_t bytes_size, intn_from_integer_options_t opts)
{
TRACE("jit_bitstring_extract_integer: bin_ptr=%p offset=%d n=%d bs_flags=%d\n", (void *) bin_ptr, (int) offset, n, bs_flags);
union maybe_unsigned_int64 value;
bool status = bitstring_extract_integer(((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);
if (UNLIKELY(!status)) {
intn_integer_sign_t sign;
intn_digit_t bigint[INTN_MAX_RES_LEN];
int count = intn_from_integer_bytes(bytes, bytes_size, opts, bigint, &sign);
// count will be always >= 0, caller ensures that bits <= INTN_MAX_UNSIGNED_BITS_SIZE

size_t intn_data_size;
size_t rounded_res_len;
term_bigint_size_requirements(count, &intn_data_size, &rounded_res_len);

Heap heap;
if (UNLIKELY(memory_init_heap(&heap, BOXED_BIGINT_HEAP_SIZE(intn_data_size)) != MEMORY_GC_OK)) {
set_error(ctx, jit_state, 0, OUT_OF_MEMORY_ATOM);
return FALSE_ATOM;
}
term t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
if (UNLIKELY(term_is_invalid_term(t))) {
set_error(ctx, jit_state, 0, OUT_OF_MEMORY_ATOM);

term bigint_term
= term_create_uninitialized_bigint(intn_data_size, (term_integer_sign_t) sign, &heap);
term_initialize_bigint(bigint_term, bigint, count, rounded_res_len);

memory_heap_append_heap(&ctx->heap, &heap);

return bigint_term;
}

static term jit_bitstring_extract_integer(
Context *ctx, JITState *jit_state, term *bin_ptr, size_t offset, int n, int bs_flags)
{
TRACE("jit_bitstring_extract_integer: bin_ptr=%p offset=%d n=%d bs_flags=%d\n",
(void *) bin_ptr, (int) offset, n, bs_flags);
if (n <= 64) {
union maybe_unsigned_int64 value;
bool status = bitstring_extract_integer(
((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);
if (UNLIKELY(!status)) {
return FALSE_ATOM;
}
term t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
if (UNLIKELY(term_is_invalid_term(t))) {
set_error(ctx, jit_state, 0, OUT_OF_MEMORY_ATOM);
}
return t;
} else if ((offset % 8 == 0) && (n % 8 == 0) && (n <= INTN_MAX_UNSIGNED_BITS_SIZE)) {
term bs_bin = ((term) bin_ptr) | TERM_PRIMARY_BOXED;
unsigned long capacity = term_binary_size(bs_bin);
if (8 * capacity - offset < (unsigned long) n) {
return FALSE_ATOM;
}
size_t byte_offset = offset / 8;
const uint8_t *int_bytes = (const uint8_t *) term_binary_data(bs_bin);

return extract_bigint(
ctx, jit_state, int_bytes + byte_offset, n / 8, bitstring_flags_to_intn_opts(bs_flags));
} else {
return FALSE_ATOM;
}
return t;
}

static term jit_bitstring_extract_float(Context *ctx, term *bin_ptr, size_t offset, int n, int bs_flags)
Expand Down
145 changes: 95 additions & 50 deletions src/libAtomVM/opcodesswitch.h
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Expand Up @@ -1814,6 +1814,40 @@ static bool maybe_call_native(Context *ctx, atom_index_t module_name, atom_index
#endif

#ifndef AVM_NO_EMU
static term extract_nbits_integer(Context *ctx, const uint8_t *bytes, size_t bytes_size, intn_from_integer_options_t opts)
{
intn_integer_sign_t sign;
intn_digit_t bigint[INTN_MAX_RES_LEN];
int count = intn_from_integer_bytes(bytes, bytes_size, opts, bigint, &sign);
if (UNLIKELY(count < 0)) {
// this is likely unreachable, compiler seem to generate an external term
// and to encode this as SMALL_BIG_EXT, so I don't think this code is executed
ctx->x[0] = ERROR_ATOM;
ctx->x[1] = OVERFLOW_ATOM;
return term_invalid_term();
}

size_t intn_data_size;
size_t rounded_res_len;
term_bigint_size_requirements(count, &intn_data_size, &rounded_res_len);

Heap heap;
if (UNLIKELY(
memory_init_heap(&heap, BOXED_BIGINT_HEAP_SIZE(intn_data_size)) != MEMORY_GC_OK)) {
ctx->x[0] = ERROR_ATOM;
ctx->x[1] = OUT_OF_MEMORY_ATOM;
return term_invalid_term();
}

term bigint_term
= term_create_uninitialized_bigint(intn_data_size, (term_integer_sign_t) sign, &heap);
term_initialize_bigint(bigint_term, bigint, count, rounded_res_len);

memory_heap_append_heap(&ctx->heap, &heap);

return bigint_term;
}

static size_t decode_nbits_integer(Context *ctx, const uint8_t *encoded, term *out_term)
{
const uint8_t *new_encoded = encoded;
Expand All @@ -1826,41 +1860,9 @@ static bool maybe_call_native(Context *ctx, atom_index_t module_name, atom_index
len += 9;

if (out_term) {
intn_integer_sign_t sign;
intn_digit_t bigint[INTN_MAX_RES_LEN];
int count = intn_from_integer_bytes(new_encoded, len, IntnSigned, bigint, &sign);
if (UNLIKELY(count < 0)) {
// this is likely unreachable, compiler seem to generate an external term
// and to encode this as SMALL_BIG_EXT, so I don't think this code is executed
ctx->x[0] = ERROR_ATOM;
ctx->x[1] = OVERFLOW_ATOM;
*out_term = term_invalid_term();
goto return_size;
}

size_t intn_data_size;
size_t rounded_res_len;
term_bigint_size_requirements(count, &intn_data_size, &rounded_res_len);

Heap heap;
if (UNLIKELY(
memory_init_heap(&heap, BOXED_BIGINT_HEAP_SIZE(intn_data_size)) != MEMORY_GC_OK)) {
ctx->x[0] = ERROR_ATOM;
ctx->x[1] = OUT_OF_MEMORY_ATOM;
*out_term = term_invalid_term();
goto return_size;
}

term bigint_term
= term_create_uninitialized_bigint(intn_data_size, (term_integer_sign_t) sign, &heap);
term_initialize_bigint(bigint_term, bigint, count, rounded_res_len);

memory_heap_append_heap(&ctx->heap, &heap);

*out_term = bigint_term;
*out_term = extract_nbits_integer(ctx, new_encoded, len, IntnSigned);
}

return_size:
return (new_encoded - encoded) + len;
}
#endif
Expand Down Expand Up @@ -5298,25 +5300,44 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
union maybe_unsigned_int64 value;
term bs_bin = term_get_match_state_binary(src);
avm_int_t bs_offset = term_get_match_state_offset(src);
bool status = bitstring_extract_integer(bs_bin, bs_offset, increment, flags_value, &value);
if (UNLIKELY(!status)) {
TRACE("bs_get_integer2: error extracting integer.\n");
JUMP_TO_ADDRESS(mod->labels[fail]);
} else {
term_set_match_state_offset(src, bs_offset + increment);
term t;
if (increment <= 64) {
bool status = bitstring_extract_integer(bs_bin, bs_offset, increment, flags_value, &value);
if (UNLIKELY(!status)) {
TRACE("bs_get_integer2: error extracting integer.\n");
JUMP_TO_ADDRESS(mod->labels[fail]);
} else {
term_set_match_state_offset(src, bs_offset + increment);

term t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
if (UNLIKELY(term_is_invalid_term(t))) {
t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
if (UNLIKELY(term_is_invalid_term(t))) {
HANDLE_ERROR();
}
}
} else if ((bs_offset % 8 == 0) && (increment % 8 == 0) && (increment <= INTN_MAX_UNSIGNED_BITS_SIZE)) {
unsigned long capacity = term_binary_size(bs_bin);
if (8 * capacity - bs_offset < (unsigned long) increment) {
JUMP_TO_ADDRESS(mod->labels[fail]);
}
size_t byte_offset = bs_offset / 8;
const uint8_t *int_bytes = (const uint8_t *) term_binary_data(bs_bin);

t = extract_nbits_integer(ctx, int_bytes + byte_offset, increment / 8,
bitstring_flags_to_intn_opts(flags_value));
term_set_match_state_offset(src, bs_offset + increment);
if (term_is_invalid_term(t)) {
HANDLE_ERROR();
}
} else {
JUMP_TO_ADDRESS(mod->labels[fail]);
}
#endif

DEST_REGISTER(dreg);
DECODE_DEST_REGISTER(dreg, pc);

#ifdef IMPL_EXECUTE_LOOP
WRITE_REGISTER(dreg, t);
}
WRITE_REGISTER(dreg, t);
#endif
break;
}
Expand Down Expand Up @@ -7273,15 +7294,35 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
avm_int_t size_val = term_to_int(size);
avm_int_t increment = size_val * unit;
union maybe_unsigned_int64 value;
bool status = bitstring_extract_integer(bs_bin, bs_offset, increment, flags_value, &value);
if (UNLIKELY(!status)) {
TRACE("bs_match/3: error extracting integer.\n");
term t;
if (increment <= 64) {
bool status = bitstring_extract_integer(bs_bin, bs_offset, increment, flags_value, &value);
if (UNLIKELY(!status)) {
TRACE("bs_match/3: error extracting integer.\n");
goto bs_match_jump_to_fail;
}
//FIXME: handling of 64-bit unsigned integers is not reliable
t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
if (UNLIKELY(term_is_invalid_term(t))) {
RAISE_ERROR(OUT_OF_MEMORY_ATOM);
}
} else if ((bs_offset % 8 == 0) && (increment % 8 == 0) && (increment <= INTN_MAX_UNSIGNED_BITS_SIZE)) {
unsigned long capacity = term_binary_size(bs_bin);
if (8 * capacity - bs_offset < (unsigned long) increment) {
goto bs_match_jump_to_fail;
}
size_t byte_offset = bs_offset / 8;
const uint8_t *int_bytes
= (const uint8_t *) term_binary_data(bs_bin);

t = extract_nbits_integer(ctx, int_bytes + byte_offset,
increment / 8, bitstring_flags_to_intn_opts(flags_value));
if (term_is_invalid_term(t)) {
HANDLE_ERROR();
}
} else {
goto bs_match_jump_to_fail;
}
term t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
if (UNLIKELY(term_is_invalid_term(t))) {
RAISE_ERROR(OUT_OF_MEMORY_ATOM);
}
#endif
DEST_REGISTER(dreg);
DECODE_DEST_REGISTER(dreg, pc);
Expand Down Expand Up @@ -7388,6 +7429,10 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
DECODE_LITERAL(pattern_value, pc);
j++;
#ifdef IMPL_EXECUTE_LOOP
if (size > 64) {
// TODO: implement support for big integers also here
RAISE_ERROR(BADARG_ATOM);
}
union maybe_unsigned_int64 matched_value;
bool status = bitstring_extract_integer(bs_bin, bs_offset, size, 0, &matched_value);
if (UNLIKELY(!status)) {
Expand Down
39 changes: 39 additions & 0 deletions tests/erlang_tests/bigint.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -72,6 +72,7 @@ start() ->
test_is_number() +
test_gt_lt_guards() +
to_external_term() +
test_pattern_match() +
test_band() +
test_bxor() +
test_bor() +
Expand Down Expand Up @@ -2138,6 +2139,44 @@ to_external_term() ->

0.

test_pattern_match() ->
<<Int72:72/integer-little-signed>> = ?MODULE:id(<<23, 4, 222, 66, 172, 197, 113, 183, 80>>),
<<"50B771C5AC42DE0417">> = erlang:integer_to_binary(?MODULE:id(Int72), 16),
<<Int80:80/integer-little-signed>> = ?MODULE:id(
<<165, 63, 196, 58, 33, 96, 209, 59, 244, 213>>
),
<<"-2A0BC42E9FDEC53BC05B">> = erlang:integer_to_binary(?MODULE:id(Int80), 16),
<<Int120:120/unsigned-big-integer>> = ?MODULE:id(
<<0, 242, 138, 221, 68, 111, 58, 120, 145, 135, 164, 56, 164, 12, 205>>
),
<<"F28ADD446F3A789187A438A40CCD">> = erlang:integer_to_binary(?MODULE:id(Int120), 16),
<<Int256:256/unsigned-big-integer>> = ?MODULE:id(
<<202, 196, 64, 150, 63, 238, 50, 47, 214, 81, 247, 55, 151, 242, 169, 106, 162, 211, 73,
155, 211, 85, 164, 237, 153, 138, 191, 77, 87, 183, 204, 111>>
),
<<"CAC440963FEE322FD651F73797F2A96AA2D3499BD355A4ED998ABF4D57B7CC6F">> = erlang:integer_to_binary(
?MODULE:id(Int256), 16
),

<<"foo", Int128:128/unsigned-little-integer, Bar/binary>> = ?MODULE:id(
<<102, 111, 111, 183, 226, 155, 102, 249, 246, 168, 101, 53, 36, 21, 10, 133, 223, 231, 10,
98, 97, 114>>
),
<<"AE7DF850A15243565A8F6F9669BE2B7">> = erlang:integer_to_binary(?MODULE:id(Int128), 16),
<<"bar">> = ?MODULE:id(Bar),

ok =
case
?MODULE:id(
<<102, 111, 111, 183, 226, 155, 102, 249, 246, 168, 101, 53, 36, 21, 10, 133, 223,
231>>
)
of
<<"foo", _I128:128/unsigned-little-integer, Bar/binary>> -> error;
_ -> ok
end,
0.

test_band() ->
MaxPatternBin = <<"FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF">>,
MaxPattern = erlang:binary_to_integer(?MODULE:id(MaxPatternBin), 16),
Expand Down
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