Implement zero-dependency Wasm binary parser

package/version

@@ -1 +1 @@
-0.1.148
+0.1.149

pykwasm/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "pykwasm"
-version = "0.1.148"
+version = "0.1.149"
 description = ""
 readme = "README.md"
 requires-python = "~=3.10"

pykwasm/src/pykwasm/binary/combinators.py

@@ -0,0 +1,53 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from .integers import u32
+from .utils import WasmParseError, reset
+
+if TYPE_CHECKING:
+    from .utils import A, InputStream, Parser
+
+
+def iterate(f: Parser[A], s: InputStream) -> list[A]:
+    results = []
+    while True:
+        try:
+            results.append(f(s))
+        except (WasmParseError, IndexError, ValueError):
+            break
+    return results
+
+
+def sized(p: Parser[A], s: InputStream) -> A:
+    size = u32(s)
+    start_pos = s.tell()
+    res = p(s)
+    end_pos = s.tell()
+    if end_pos - start_pos != size:
+        raise WasmParseError('Size mismatch')
+    return res
+
+
+def parse_n(p: Parser[A], n: int, s: InputStream) -> list[A]:
+    results = []
+    for _ in range(n):
+        x = p(s)
+        results.append(x)
+    return results
+
+
+def list_of(p: Parser[A], s: InputStream) -> list[A]:
+    n = u32(s)
+    return parse_n(p, n, s)
+
+
+def either(ps: list[Parser[A]], s: InputStream) -> A:
+    for p in ps:
+        pos = s.tell()
+        try:
+            return p(s)
+        except WasmParseError:
+            reset(pos, s)
+            continue
+    raise WasmParseError('None of the alternatives succeeded')

pykwasm/src/pykwasm/binary/floats.py

@@ -0,0 +1,21 @@
+from __future__ import annotations
+
+import struct
+from typing import TYPE_CHECKING
+
+from .utils import read_bytes
+
+if TYPE_CHECKING:
+    from .utils import InputStream
+
+
+def f32(s: InputStream) -> float:
+    bs = read_bytes(4, s)
+    f = struct.unpack('<f', bs)[0]
+    return f
+
+
+def f64(s: InputStream) -> float:
+    bs = read_bytes(8, s)
+    f = struct.unpack('<d', bs)[0]
+    return f

pykwasm/src/pykwasm/binary/indices.py

@@ -0,0 +1,69 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import pykwasm.kwasm_ast as wast
+
+from .integers import u32
+from .utils import WasmParseError, read_byte
+
+if TYPE_CHECKING:
+    from pyk.kast.inner import KInner
+
+    from .utils import InputStream
+
+
+def typeidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def funcidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def tableidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def memidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def globalidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def tagidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def elemidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def dataidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def localidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def labelidx(s: InputStream) -> int:
+    return u32(s)
+
+
+def externidx(s: InputStream) -> KInner:
+    match read_byte(s):
+        case 0x00:
+            return wast.externidx_func(funcidx(s))
+        case 0x01:
+            return wast.externidx_table(tableidx(s))
+        case 0x02:
+            return wast.externidx_memory(memidx(s))
+        case 0x03:
+            return wast.externidx_global(globalidx(s))
+        case 0x04:
+            return wast.externidx_tag(tagidx(s))
+        case x:
+            raise WasmParseError(f'Invalid externidx descriptor: {x}')