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-rw-r--r--upb/pb/decoder.c469
1 files changed, 469 insertions, 0 deletions
diff --git a/upb/pb/decoder.c b/upb/pb/decoder.c
new file mode 100644
index 0000000..218c780
--- /dev/null
+++ b/upb/pb/decoder.c
@@ -0,0 +1,469 @@
+/*
+ * upb - a minimalist implementation of protocol buffers.
+ *
+ * Copyright (c) 2008-2011 Google Inc. See LICENSE for details.
+ * Author: Josh Haberman <jhaberman@gmail.com>
+ */
+
+#include <inttypes.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include "upb/bytestream.h"
+#include "upb/msg.h"
+#include "upb/pb/decoder.h"
+#include "upb/pb/varint.h"
+
+// Used for frames that have no specific end offset: groups, repeated primitive
+// fields inside groups, and the top-level message.
+#define UPB_NONDELIMITED UINT32_MAX
+
+#ifdef UPB_USE_JIT_X64
+#define Dst_DECL upb_decoder *d
+#define Dst_REF (d->dynasm)
+#define Dst (d)
+#include "dynasm/dasm_proto.h"
+#include "upb/pb/decoder_x86.h"
+#endif
+
+// It's unfortunate that we have to micro-manage the compiler this way,
+// especially since this tuning is necessarily specific to one hardware
+// configuration. But emperically on a Core i7, performance increases 30-50%
+// with these annotations. Every instance where these appear, gcc 4.2.1 made
+// the wrong decision and degraded performance in benchmarks.
+#define FORCEINLINE static __attribute__((always_inline))
+#define NOINLINE static __attribute__((noinline))
+
+static void upb_decoder_exit(upb_decoder *d) { siglongjmp(d->exitjmp, 1); }
+static void upb_decoder_exit2(void *_d) {
+ upb_decoder *d = _d;
+ upb_decoder_exit(d);
+}
+static void upb_decoder_abort(upb_decoder *d, const char *msg) {
+ upb_status_setf(d->status, UPB_ERROR, msg);
+ upb_decoder_exit(d);
+}
+
+/* Decoding/Buffering of wire types *******************************************/
+
+static size_t upb_decoder_bufleft(upb_decoder *d) { return d->end - d->ptr; }
+static void upb_decoder_advance(upb_decoder *d, size_t len) {
+ assert((size_t)(d->end - d->ptr) >= len);
+ d->ptr += len;
+}
+
+size_t upb_decoder_offset(upb_decoder *d) {
+ size_t offset = d->bufstart_ofs;
+ if (d->ptr) offset += (d->ptr - d->buf);
+ return offset;
+}
+
+static void upb_decoder_setmsgend(upb_decoder *d) {
+ upb_dispatcher_frame *f = d->dispatcher.top;
+ size_t delimlen = f->end_ofs - d->bufstart_ofs;
+ size_t buflen = d->end - d->buf;
+ if (f->end_ofs != UINT64_MAX && delimlen <= buflen) {
+ d->delim_end = (uintptr_t)(d->buf + delimlen);
+ } else {
+ // Buffers must not run up against the end of memory.
+ assert((uintptr_t)d->end < UINTPTR_MAX);
+ d->delim_end = UINTPTR_MAX;
+ }
+}
+
+// Pulls the next buffer from the bytesrc. Should be called only when the
+// current buffer is completely empty.
+static bool upb_trypullbuf(upb_decoder *d) {
+ assert(upb_decoder_bufleft(d) == 0);
+ if (d->bufend_ofs == d->refend_ofs) {
+ d->refend_ofs += upb_bytesrc_fetch(d->bytesrc, d->refend_ofs, d->status);
+ if (!upb_ok(d->status)) {
+ d->ptr = NULL;
+ d->end = NULL;
+ if (upb_iseof(d->status)) return false;
+ upb_decoder_exit(d);
+ }
+ }
+ d->bufstart_ofs = d->bufend_ofs;
+ size_t len;
+ d->buf = upb_bytesrc_getptr(d->bytesrc, d->bufstart_ofs, &len);
+ assert(len > 0);
+ d->bufend_ofs = d->bufstart_ofs + len;
+ d->ptr = d->buf;
+ d->end = d->buf + len;
+#ifdef UPB_USE_JIT_X64
+ d->jit_end = d->end - 20;
+#endif
+ upb_decoder_setmsgend(d);
+ return true;
+}
+
+static void upb_pullbuf(upb_decoder *d) {
+ if (!upb_trypullbuf(d)) upb_decoder_abort(d, "Unexpected EOF");
+}
+
+void upb_decoder_commit(upb_decoder *d) {
+ d->completed_ptr = d->ptr;
+ if (d->refstart_ofs < d->bufstart_ofs) {
+ // Drop our ref on the previous buf's region.
+ upb_bytesrc_refregion(d->bytesrc, d->bufstart_ofs, d->refend_ofs);
+ upb_bytesrc_unrefregion(d->bytesrc, d->refstart_ofs, d->refend_ofs);
+ d->refstart_ofs = d->bufstart_ofs;
+ }
+}
+
+NOINLINE uint64_t upb_decode_varint_slow(upb_decoder *d) {
+ uint8_t byte = 0x80;
+ uint64_t u64 = 0;
+ int bitpos;
+ const char *ptr = d->ptr;
+ for(bitpos = 0; bitpos < 70 && (byte & 0x80); bitpos += 7) {
+ if (upb_decoder_bufleft(d) == 0) {
+ upb_pullbuf(d);
+ ptr = d->ptr;
+ }
+ u64 |= ((uint64_t)(byte = *ptr++) & 0x7F) << bitpos;
+ }
+ if(bitpos == 70 && (byte & 0x80)) upb_decoder_abort(d, "Unterminated varint");
+ return u64;
+}
+
+// For tags and delimited lengths, which must be <=32bit and are usually small.
+FORCEINLINE uint32_t upb_decode_varint32(upb_decoder *d) {
+ const char *p = d->ptr;
+ uint32_t ret;
+ uint64_t u64;
+ // Nearly all will be either 1 byte (1-16) or 2 bytes (17-2048).
+ if (upb_decoder_bufleft(d) < 2) goto slow; // unlikely.
+ ret = *p & 0x7f;
+ if ((*(p++) & 0x80) == 0) goto done; // predictable if fields are in order
+ ret |= (*p & 0x7f) << 7;
+ if ((*(p++) & 0x80) == 0) goto done; // likely
+slow:
+ u64 = upb_decode_varint_slow(d);
+ if (u64 > 0xffffffff) upb_decoder_abort(d, "Unterminated 32-bit varint");
+ ret = (uint32_t)u64;
+ p = d->ptr; // Turn the next line into a nop.
+done:
+ upb_decoder_advance(d, p - d->ptr);
+ return ret;
+}
+
+FORCEINLINE bool upb_trydecode_varint32(upb_decoder *d, uint32_t *val) {
+ if (upb_decoder_bufleft(d) == 0) {
+ // Check for our two normal end-of-message conditions.
+ if (d->bufend_ofs == d->end_ofs) return false;
+ if (!upb_trypullbuf(d)) return false;
+ }
+ *val = upb_decode_varint32(d);
+ return true;
+}
+
+FORCEINLINE uint64_t upb_decode_varint(upb_decoder *d) {
+ if (upb_decoder_bufleft(d) >= 10) {
+ // Fast case.
+ upb_decoderet r = upb_vdecode_fast(d->ptr);
+ if (r.p == NULL) upb_decoder_abort(d, "Unterminated varint");
+ upb_decoder_advance(d, r.p - d->ptr);
+ return r.val;
+ } else if (upb_decoder_bufleft(d) > 0) {
+ // Intermediate case -- worth it?
+ char tmpbuf[10];
+ memset(tmpbuf, 0x80, 10);
+ memcpy(tmpbuf, d->ptr, upb_decoder_bufleft(d));
+ upb_decoderet r = upb_vdecode_fast(tmpbuf);
+ if (r.p != NULL) {
+ upb_decoder_advance(d, r.p - tmpbuf);
+ return r.val;
+ }
+ }
+ // Slow case -- varint spans buffer seam.
+ return upb_decode_varint_slow(d);
+}
+
+FORCEINLINE void upb_decode_fixed(upb_decoder *d, char *buf, size_t bytes) {
+ if (upb_decoder_bufleft(d) >= bytes) {
+ // Fast case.
+ memcpy(buf, d->ptr, bytes);
+ upb_decoder_advance(d, bytes);
+ } else {
+ // Slow case.
+ size_t read = 0;
+ while (read < bytes) {
+ size_t avail = upb_decoder_bufleft(d);
+ memcpy(buf + read, d->ptr, avail);
+ upb_decoder_advance(d, avail);
+ read += avail;
+ }
+ }
+}
+
+FORCEINLINE uint32_t upb_decode_fixed32(upb_decoder *d) {
+ uint32_t u32;
+ upb_decode_fixed(d, (char*)&u32, sizeof(uint32_t));
+ return u32; // TODO: proper byte swapping
+}
+FORCEINLINE uint64_t upb_decode_fixed64(upb_decoder *d) {
+ uint64_t u64;
+ upb_decode_fixed(d, (char*)&u64, sizeof(uint64_t));
+ return u64; // TODO: proper byte swapping
+}
+
+INLINE upb_strref *upb_decode_string(upb_decoder *d) {
+ uint32_t strlen = upb_decode_varint32(d);
+ d->strref.stream_offset = upb_decoder_offset(d);
+ d->strref.len = strlen;
+ if (upb_decoder_bufleft(d) == 0) upb_pullbuf(d);
+ if (upb_decoder_bufleft(d) >= strlen) {
+ // Fast case.
+ d->strref.ptr = d->ptr;
+ upb_decoder_advance(d, strlen);
+ } else {
+ // Slow case.
+ while (1) {
+ size_t consume = UPB_MIN(upb_decoder_bufleft(d), strlen);
+ upb_decoder_advance(d, consume);
+ strlen -= consume;
+ if (strlen == 0) break;
+ upb_pullbuf(d);
+ }
+ }
+ return &d->strref;
+}
+
+INLINE void upb_push(upb_decoder *d, upb_fhandlers *f, uint32_t end) {
+ upb_dispatch_startsubmsg(&d->dispatcher, f)->end_ofs = end;
+ upb_decoder_setmsgend(d);
+}
+
+
+/* Decoding of .proto types ***************************************************/
+
+// Technically, we are losing data if we see a 32-bit varint that is not
+// properly sign-extended. We could detect this and error about the data loss,
+// but proto2 does not do this, so we pass.
+
+#define T(type, wt, valtype, convfunc) \
+ INLINE void upb_decode_ ## type(upb_decoder *d, upb_fhandlers *f) { \
+ upb_value val; \
+ upb_value_set ## valtype(&val, (convfunc)(upb_decode_ ## wt(d))); \
+ upb_dispatch_value(&d->dispatcher, f, val); \
+ } \
+
+static double upb_asdouble(uint64_t n) { double d; memcpy(&d, &n, 8); return d; }
+static float upb_asfloat(uint32_t n) { float f; memcpy(&f, &n, 4); return f; }
+static int32_t upb_zzdec_32(uint32_t n) { return (n >> 1) ^ -(int32_t)(n & 1); }
+static int64_t upb_zzdec_64(uint64_t n) { return (n >> 1) ^ -(int64_t)(n & 1); }
+
+T(INT32, varint, int32, int32_t)
+T(INT64, varint, int64, int64_t)
+T(UINT32, varint, uint32, uint32_t)
+T(UINT64, varint, uint64, uint64_t)
+T(FIXED32, fixed32, uint32, uint32_t)
+T(FIXED64, fixed64, uint64, uint64_t)
+T(SFIXED32, fixed32, int32, int32_t)
+T(SFIXED64, fixed64, int64, int64_t)
+T(BOOL, varint, bool, bool)
+T(ENUM, varint, int32, int32_t)
+T(DOUBLE, fixed64, double, upb_asdouble)
+T(FLOAT, fixed32, float, upb_asfloat)
+T(SINT32, varint, int32, upb_zzdec_32)
+T(SINT64, varint, int64, upb_zzdec_64)
+T(STRING, string, strref, upb_strref*)
+
+static void upb_decode_GROUP(upb_decoder *d, upb_fhandlers *f) {
+ upb_push(d, f, UPB_NONDELIMITED);
+}
+static void upb_endgroup(upb_decoder *d, upb_fhandlers *f) {
+ (void)f;
+ upb_dispatch_endsubmsg(&d->dispatcher);
+ upb_decoder_setmsgend(d);
+}
+static void upb_decode_MESSAGE(upb_decoder *d, upb_fhandlers *f) {
+ upb_push(d, f, upb_decode_varint32(d) + (d->ptr - d->buf));
+}
+
+
+/* The main decoding loop *****************************************************/
+
+static void upb_decoder_checkdelim(upb_decoder *d) {
+ while ((uintptr_t)d->ptr >= d->delim_end) {
+ if ((uintptr_t)d->ptr > d->delim_end)
+ upb_decoder_abort(d, "Bad submessage end");
+
+ if (d->dispatcher.top->is_sequence) {
+ upb_dispatch_endseq(&d->dispatcher);
+ } else {
+ upb_dispatch_endsubmsg(&d->dispatcher);
+ }
+ upb_decoder_setmsgend(d);
+ }
+}
+
+static void upb_decoder_enterjit(upb_decoder *d) {
+ (void)d;
+#ifdef UPB_USE_JIT_X64
+ if (d->jit_code && d->dispatcher.top == d->dispatcher.stack && d->ptr < d->jit_end) {
+ // Decodes as many fields as possible, updating d->ptr appropriately,
+ // before falling through to the slow(er) path.
+ void (*upb_jit_decode)(upb_decoder *d) = (void*)d->jit_code;
+ upb_jit_decode(d);
+ }
+#endif
+}
+
+INLINE upb_fhandlers *upb_decode_tag(upb_decoder *d) {
+ while (1) {
+ uint32_t tag;
+ if (!upb_trydecode_varint32(d, &tag)) return NULL;
+ upb_fhandlers *f = upb_dispatcher_lookup(&d->dispatcher, tag);
+
+ // There are no explicit "startseq" or "endseq" markers in protobuf
+ // streams, so we have to infer them by noticing when a repeated field
+ // starts or ends.
+ if (d->dispatcher.top->is_sequence && d->dispatcher.top->f != f) {
+ upb_dispatch_endseq(&d->dispatcher);
+ upb_decoder_setmsgend(d);
+ }
+ if (f && f->repeated && d->dispatcher.top->f != f) {
+ // TODO: support packed.
+ assert(upb_issubmsgtype(f->type) || upb_isstringtype(f->type) ||
+ (tag & 0x7) != UPB_WIRE_TYPE_DELIMITED);
+ uint32_t end = d->dispatcher.top->end_ofs;
+ upb_dispatch_startseq(&d->dispatcher, f)->end_ofs = end;
+ upb_decoder_setmsgend(d);
+ }
+ if (f) return f;
+
+ // Unknown field.
+ switch (tag & 0x7) {
+ case UPB_WIRE_TYPE_VARINT: upb_decode_varint(d); break;
+ case UPB_WIRE_TYPE_32BIT: upb_decoder_advance(d, 4); break;
+ case UPB_WIRE_TYPE_64BIT: upb_decoder_advance(d, 8); break;
+ case UPB_WIRE_TYPE_DELIMITED:
+ upb_decoder_advance(d, upb_decode_varint32(d)); break;
+ default:
+ upb_decoder_abort(d, "Invavlid wire type");
+ }
+ // TODO: deliver to unknown field callback.
+ upb_decoder_commit(d);
+ upb_decoder_checkdelim(d);
+ }
+}
+
+void upb_decoder_onexit(upb_decoder *d) {
+ if (d->dispatcher.top->is_sequence) upb_dispatch_endseq(&d->dispatcher);
+ if (d->status->code == UPB_EOF && upb_dispatcher_stackempty(&d->dispatcher)) {
+ // Normal end-of-file.
+ upb_status_clear(d->status);
+ upb_dispatch_endmsg(&d->dispatcher, d->status);
+ } else {
+ if (d->status->code == UPB_EOF)
+ upb_status_setf(d->status, UPB_ERROR, "Input ended mid-submessage.");
+ }
+}
+
+void upb_decoder_decode(upb_decoder *d, upb_status *status) {
+ if (sigsetjmp(d->exitjmp, 0)) {
+ upb_decoder_onexit(d);
+ return;
+ }
+ d->status = status;
+ upb_dispatch_startmsg(&d->dispatcher);
+ while(1) { // Main loop: executed once per tag/field pair.
+ upb_decoder_checkdelim(d);
+ upb_decoder_enterjit(d);
+ // if (!d->dispatcher.top->is_packed)
+ upb_fhandlers *f = upb_decode_tag(d);
+ if (!f) upb_decoder_exit2(d);
+ f->decode(d, f);
+ upb_decoder_commit(d);
+ }
+}
+
+static void upb_decoder_skip(void *_d, upb_dispatcher_frame *top,
+ upb_dispatcher_frame *bottom) {
+ (void)top;
+ (void)bottom;
+ (void)_d;
+#if 0
+ upb_decoder *d = _d;
+ // TODO
+ if (bottom->end_offset == UPB_NONDELIMITED) {
+ // TODO: support skipping groups.
+ abort();
+ }
+ d->ptr = d->buf.ptr + bottom->end_offset;
+#endif
+}
+
+void upb_decoder_initforhandlers(upb_decoder *d, upb_handlers *handlers) {
+ upb_dispatcher_init(
+ &d->dispatcher, handlers, upb_decoder_skip, upb_decoder_exit2, d);
+#ifdef UPB_USE_JIT_X64
+ d->jit_code = NULL;
+ if (d->dispatcher.handlers->should_jit) upb_decoder_makejit(d);
+#endif
+ // Set function pointers for each field's decode function.
+ for (int i = 0; i < handlers->msgs_len; i++) {
+ upb_mhandlers *m = handlers->msgs[i];
+ for(upb_inttable_iter i = upb_inttable_begin(&m->fieldtab); !upb_inttable_done(i);
+ i = upb_inttable_next(&m->fieldtab, i)) {
+ upb_fhandlers *f = upb_inttable_iter_value(i);
+ switch (f->type) {
+ case UPB_TYPE(INT32): f->decode = &upb_decode_INT32; break;
+ case UPB_TYPE(INT64): f->decode = &upb_decode_INT64; break;
+ case UPB_TYPE(UINT32): f->decode = &upb_decode_UINT32; break;
+ case UPB_TYPE(UINT64): f->decode = &upb_decode_UINT64; break;
+ case UPB_TYPE(FIXED32): f->decode = &upb_decode_FIXED32; break;
+ case UPB_TYPE(FIXED64): f->decode = &upb_decode_FIXED64; break;
+ case UPB_TYPE(SFIXED32): f->decode = &upb_decode_SFIXED32; break;
+ case UPB_TYPE(SFIXED64): f->decode = &upb_decode_SFIXED64; break;
+ case UPB_TYPE(BOOL): f->decode = &upb_decode_BOOL; break;
+ case UPB_TYPE(ENUM): f->decode = &upb_decode_ENUM; break;
+ case UPB_TYPE(DOUBLE): f->decode = &upb_decode_DOUBLE; break;
+ case UPB_TYPE(FLOAT): f->decode = &upb_decode_FLOAT; break;
+ case UPB_TYPE(SINT32): f->decode = &upb_decode_SINT32; break;
+ case UPB_TYPE(SINT64): f->decode = &upb_decode_SINT64; break;
+ case UPB_TYPE(STRING): f->decode = &upb_decode_STRING; break;
+ case UPB_TYPE(BYTES): f->decode = &upb_decode_STRING; break;
+ case UPB_TYPE(GROUP): f->decode = &upb_decode_GROUP; break;
+ case UPB_TYPE(MESSAGE): f->decode = &upb_decode_MESSAGE; break;
+ case UPB_TYPE_ENDGROUP: f->decode = &upb_endgroup; break;
+ }
+ }
+ }
+}
+
+void upb_decoder_initformsgdef(upb_decoder *d, upb_msgdef *m) {
+ upb_handlers *h = upb_handlers_new();
+ upb_accessors_reghandlers(h, m);
+ upb_decoder_initforhandlers(d, h);
+ upb_handlers_unref(h);
+}
+
+void upb_decoder_reset(upb_decoder *d, upb_bytesrc *bytesrc, uint64_t start_ofs,
+ uint64_t end_ofs, void *closure) {
+ upb_dispatcher_frame *f = upb_dispatcher_reset(&d->dispatcher, closure);
+ f->end_ofs = end_ofs;
+ d->end_ofs = end_ofs;
+ d->refstart_ofs = start_ofs;
+ d->refend_ofs = start_ofs;
+ d->bufstart_ofs = start_ofs;
+ d->bufend_ofs = start_ofs;
+ d->bytesrc = bytesrc;
+ d->buf = NULL;
+ d->ptr = NULL;
+ d->end = NULL; // Force a buffer pull.
+#ifdef UPB_USE_JIT_X64
+ d->jit_end = NULL;
+#endif
+ d->delim_end = UINTPTR_MAX; // But don't let end-of-message get triggered.
+ d->strref.bytesrc = bytesrc;
+}
+
+void upb_decoder_uninit(upb_decoder *d) {
+#ifdef UPB_USE_JIT_X64
+ if (d->dispatcher.handlers->should_jit) upb_decoder_freejit(d);
+#endif
+ upb_dispatcher_uninit(&d->dispatcher);
+}
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