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authorJoshua Haberman <joshua@reverberate.org>2010-07-09 20:20:33 -0700
committerJoshua Haberman <joshua@reverberate.org>2010-07-09 20:20:33 -0700
commit28ec9a1fa0f9b1d741920dfa8afc91fa2532c43d (patch)
tree6849230180a254424f4c1f385b919632211f3ac1 /src/upb_decoder.c
parent604c1a78bcbcc5b282ac6aab01a425baeaebdfbd (diff)
Split src/ into core/ and stream/.
Diffstat (limited to 'src/upb_decoder.c')
-rw-r--r--src/upb_decoder.c577
1 files changed, 0 insertions, 577 deletions
diff --git a/src/upb_decoder.c b/src/upb_decoder.c
deleted file mode 100644
index e3fdc49..0000000
--- a/src/upb_decoder.c
+++ /dev/null
@@ -1,577 +0,0 @@
-/*
- * upb - a minimalist implementation of protocol buffers.
- *
- * Copyright (c) 2008-2009 Joshua Haberman. See LICENSE for details.
- */
-
-#include "upb_decoder.h"
-
-#include <inttypes.h>
-#include <stddef.h>
-#include <stdlib.h>
-
-#define UPB_GROUP_END_OFFSET UINT32_MAX
-
-// Returns true if the give wire type and field type combination is valid,
-// taking into account both packed and non-packed encodings.
-static bool upb_check_type(upb_wire_type_t wt, upb_field_type_t ft) {
- return (1 << wt) & upb_types[ft].allowed_wire_types;
-}
-
-// Performs zig-zag decoding, which is used by sint32 and sint64.
-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); }
-
-
-/* upb_decoder ****************************************************************/
-
-// The decoder keeps a stack with one entry per level of recursion.
-// upb_decoder_frame is one frame of that stack.
-typedef struct {
- upb_msgdef *msgdef;
- upb_fielddef *field;
- upb_strlen_t end_offset; // For groups, -1.
-} upb_decoder_frame;
-
-struct upb_decoder {
- upb_src src; // upb_decoder is a upb_src.
-
- upb_msgdef *toplevel_msgdef;
- upb_bytesrc *bytesrc;
-
- // The buffer of input data. NULL is equivalent to the empty string.
- upb_string *buf;
-
- // Holds residual bytes when fewer than UPB_MAX_ENCODED_SIZE bytes remain.
- uint8_t tmpbuf[UPB_MAX_ENCODED_SIZE];
-
- // The number of bytes we have yet to consume from "buf" or tmpbuf. This is
- // always >= 0 unless we were just reset or are eof.
- int32_t buf_bytesleft;
-
- // The offset within "buf" from where we are currently reading. This can be
- // <0 if we are reading some residual bytes from the previous buffer, which
- // are stored in tmpbuf and combined with bytes from "buf".
- int32_t buf_offset;
-
- // The overall stream offset of the beginning of "buf".
- uint32_t buf_stream_offset;
-
- // Fielddef for the key we just read.
- upb_fielddef *field;
-
- // Wire type of the key we just read.
- upb_wire_type_t wire_type;
-
- // Delimited length of the string field we are reading.
- upb_strlen_t delimited_len;
-
- upb_strlen_t packed_end_offset;
-
- // We keep a stack of messages we have recursed into.
- upb_decoder_frame *top, *limit, stack[UPB_MAX_NESTING];
-};
-
-
-/* upb_decoder buffering. *****************************************************/
-
-static upb_strlen_t upb_decoder_offset(upb_decoder *d)
-{
- return d->buf_stream_offset - d->buf_offset;
-}
-
-static bool upb_decoder_nextbuf(upb_decoder *d)
-{
- assert(d->buf_bytesleft < UPB_MAX_ENCODED_SIZE);
-
- // Copy residual bytes to temporary buffer.
- if(d->buf_bytesleft > 0) {
- memcpy(d->tmpbuf, upb_string_getrobuf(d->buf) + d->buf_offset,
- d->buf_bytesleft);
- }
-
- // Recycle old buffer.
- if(d->buf) {
- d->buf = upb_string_tryrecycle(d->buf);
- d->buf_offset -= upb_string_len(d->buf);
- d->buf_stream_offset += upb_string_len(d->buf);
- }
-
- // Pull next buffer.
- if(upb_bytesrc_get(d->bytesrc, d->buf, UPB_MAX_ENCODED_SIZE)) {
- d->buf_bytesleft += upb_string_len(d->buf);
- return true;
- } else {
- // Error or EOF.
- if(!upb_bytesrc_eof(d->bytesrc)) {
- // Error from bytesrc.
- upb_copyerr(&d->src.status, upb_bytesrc_status(d->bytesrc));
- return false;
- } else if(d->buf_bytesleft == 0) {
- // EOF from bytesrc and we don't have any residual bytes left.
- d->src.eof = true;
- return false;
- } else {
- // No more data left from the bytesrc, but we still have residual bytes.
- return true;
- }
- }
-}
-
-static const uint8_t *upb_decoder_getbuf_full(upb_decoder *d, uint32_t *bytes)
-{
- if(d->buf_bytesleft < UPB_MAX_ENCODED_SIZE) {
- // GCC is currently complaining about use of an uninitialized value if we
- // don't set this now. I think this is incorrect, but leaving this in
- // to suppress the warning for now.
- *bytes = 0;
- if(!upb_decoder_nextbuf(d)) return NULL;
- }
-
- assert(d->buf_bytesleft >= UPB_MAX_ENCODED_SIZE);
-
- if(d->buf_offset >= 0) {
- // Common case: the main buffer contains at least UPB_MAX_ENCODED_SIZE
- // contiguous bytes, so we can read directly out of it.
- *bytes = d->buf_bytesleft;
- return (uint8_t*)upb_string_getrobuf(d->buf) + d->buf_offset;
- } else {
- // We need to accumulate UPB_MAX_ENCODED_SIZE bytes; len is how many we
- // have so far.
- upb_strlen_t len = -d->buf_offset;
- if(d->buf) {
- upb_strlen_t to_copy =
- UPB_MIN(UPB_MAX_ENCODED_SIZE - len, upb_string_len(d->buf));
- memcpy(d->tmpbuf + len, upb_string_getrobuf(d->buf), to_copy);
- len += to_copy;
- }
- // Pad the buffer out to UPB_MAX_ENCODED_SIZE.
- memset(d->tmpbuf + len, 0x80, UPB_MAX_ENCODED_SIZE - len);
- *bytes = len;
- return d->tmpbuf;
- }
-}
-
-// Returns a pointer to a buffer of data that is at least UPB_MAX_ENCODED_SIZE
-// bytes long. This buffer contains the next bytes in the stream (even if
-// those bytes span multiple buffers). *bytes is set to the number of actual
-// stream bytes that are available in the returned buffer. If
-// *bytes < UPB_MAX_ENCODED_SIZE, the buffer is padded with 0x80 bytes.
-//
-// After the data has been read, upb_decoder_consume() should be called to
-// indicate how many bytes were consumed.
-static const uint8_t *upb_decoder_getbuf(upb_decoder *d, uint32_t *bytes)
-{
- if(d->buf_bytesleft >= UPB_MAX_ENCODED_SIZE && d->buf_offset >= 0) {
- // Common case: the main buffer contains at least UPB_MAX_ENCODED_SIZE
- // contiguous bytes, so we can read directly out of it.
- *bytes = d->buf_bytesleft;
- return (uint8_t*)upb_string_getrobuf(d->buf) + d->buf_offset;
- } else {
- return upb_decoder_getbuf_full(d, bytes);
- }
-}
-
-static bool upb_decoder_consume(upb_decoder *d, uint32_t bytes)
-{
- assert(bytes <= UPB_MAX_ENCODED_SIZE);
- d->buf_offset += bytes;
- d->buf_bytesleft -= bytes;
- if(d->buf_offset < 0) {
- // We still have residual bytes we have not consumed.
- memmove(d->tmpbuf, d->tmpbuf + bytes, -d->buf_offset);
- }
- assert(d->buf_bytesleft >= 0);
- return true;
-}
-
-static bool upb_decoder_skipbytes(upb_decoder *d, int32_t bytes)
-{
- d->buf_offset += bytes;
- d->buf_bytesleft -= bytes;
- while(d->buf_bytesleft < 0) {
- if(!upb_decoder_nextbuf(d)) return false;
- }
- return true;
-}
-
-
-/* Functions to read wire values. *********************************************/
-
-// Parses remining bytes of a 64-bit varint that has already had its first byte
-// parsed.
-INLINE bool upb_decoder_readv64(upb_decoder *d, uint32_t *low, uint32_t *high)
-{
- upb_strlen_t bytes_available;
- const uint8_t *buf = upb_decoder_getbuf(d, &bytes_available);
- const uint8_t *start = buf;
- if(!buf) return false;
-
- *high = 0;
- uint32_t b;
- b = *(buf++); *low = (b & 0x7f) ; if(!(b & 0x80)) goto done;
- b = *(buf++); *low |= (b & 0x7f) << 7; if(!(b & 0x80)) goto done;
- b = *(buf++); *low |= (b & 0x7f) << 14; if(!(b & 0x80)) goto done;
- b = *(buf++); *low |= (b & 0x7f) << 21; if(!(b & 0x80)) goto done;
- b = *(buf++); *low |= (b & 0x7f) << 28;
- *high = (b & 0x7f) >> 3; if(!(b & 0x80)) goto done;
- b = *(buf++); *high |= (b & 0x7f) << 4; if(!(b & 0x80)) goto done;
- b = *(buf++); *high |= (b & 0x7f) << 11; if(!(b & 0x80)) goto done;
- b = *(buf++); *high |= (b & 0x7f) << 18; if(!(b & 0x80)) goto done;
- b = *(buf++); *high |= (b & 0x7f) << 25; if(!(b & 0x80)) goto done;
-
- if(bytes_available >= 10) {
- upb_seterr(&d->src.status, UPB_STATUS_ERROR, "Varint was unterminated "
- "after 10 bytes, stream offset: %u", upb_decoder_offset(d));
- } else {
- upb_seterr(&d->src.status, UPB_STATUS_ERROR, "Stream ended in the middle "
- "of a varint, stream offset: %u", upb_decoder_offset(d));
- }
- return false;
-
-done:
- return upb_decoder_consume(d, buf - start);
-}
-
-// Gets a varint -- called when we only need 32 bits of it. Note that a 32-bit
-// varint is not a true wire type.
-static bool upb_decoder_readv32(upb_decoder *d, uint32_t *val)
-{
- uint32_t high;
- if(!upb_decoder_readv64(d, val, &high)) return false;
-
- // We expect the high bits to be zero, except that signed 32-bit values are
- // first sign-extended to be wire-compatible with 64 bits, in which case we
- // expect the high bits to be all one.
- //
- // We could perform a slightly more sophisticated check by having the caller
- // indicate whether a signed or unsigned value is being read. We could check
- // that the high bits are all zeros for unsigned, and properly sign-extended
- // for signed.
- if(high != 0 && ~high != 0) {
- upb_seterr(&d->src.status, UPB_STATUS_ERROR, "Read a 32-bit varint, but "
- "the high bits contained data we should not truncate: "
- "%ux, stream offset: %u", high, upb_decoder_offset(d));
- return false;
- }
- return true;
-}
-
-// Gets a fixed-length 32-bit integer (wire type: UPB_WIRE_TYPE_32BIT). Caller
-// promises that 4 bytes are available at buf.
-static bool upb_decoder_readf32(upb_decoder *d, uint32_t *val)
-{
- upb_strlen_t bytes_available;
- const uint8_t *buf = upb_decoder_getbuf(d, &bytes_available);
- if(!buf) return false;
- if(bytes_available < 4) {
- upb_seterr(&d->src.status, UPB_STATUS_ERROR,
- "Stream ended in the middle of a 32-bit value");
- return false;
- }
- memcpy(val, buf, 4);
- // TODO: byte swap if big-endian.
- return upb_decoder_consume(d, 4);
-}
-
-// Gets a fixed-length 64-bit integer (wire type: UPB_WIRE_TYPE_64BIT). Caller
-// promises that 8 bytes are available at buf.
-static bool upb_decoder_readf64(upb_decoder *d, uint64_t *val)
-{
- upb_strlen_t bytes_available;
- const uint8_t *buf = upb_decoder_getbuf(d, &bytes_available);
- if(!buf) return false;
- if(bytes_available < 8) {
- upb_seterr(&d->src.status, UPB_STATUS_ERROR,
- "Stream ended in the middle of a 64-bit value");
- return false;
- }
- memcpy(val, buf, 8);
- // TODO: byte swap if big-endian.
- return upb_decoder_consume(d, 8);
-}
-
-// Returns the length of a varint (wire type: UPB_WIRE_TYPE_VARINT), allowing
-// it to be easily skipped. Caller promises that 10 bytes are available at
-// "buf". The function will return a maximum of 11 bytes before quitting.
-static uint8_t upb_decoder_skipv64(upb_decoder *d)
-{
- uint32_t bytes_available;
- const uint8_t *buf = upb_decoder_getbuf(d, &bytes_available);
- if(!buf) return false;
- uint8_t i;
- for(i = 0; i < 10 && buf[i] & 0x80; i++)
- ; // empty loop body.
- if(i > 10) {
- upb_seterr(&d->src.status, UPB_STATUS_ERROR, "Unterminated varint.");
- return false;
- }
- return upb_decoder_consume(d, i);
-}
-
-
-/* upb_src implementation for upb_decoder. ************************************/
-
-bool upb_decoder_skipval(upb_decoder *d);
-
-upb_fielddef *upb_decoder_getdef(upb_decoder *d)
-{
- // Detect end-of-submessage.
- if(upb_decoder_offset(d) >= d->top->end_offset) {
- d->src.eof = true;
- return NULL;
- }
-
- // Handles the packed field case.
- if(d->field) return d->field;
-
- uint32_t key = 0;
-again:
- if(!upb_decoder_readv32(d, &key)) return NULL;
- upb_wire_type_t wire_type = key & 0x7;
- int32_t field_number = key >> 3;
-
- if(wire_type == UPB_WIRE_TYPE_DELIMITED) {
- // For delimited wire values we parse the length now, since we need it in
- // all cases.
- if(!upb_decoder_readv32(d, &d->delimited_len)) return NULL;
- } else if(wire_type == UPB_WIRE_TYPE_END_GROUP) {
- if(d->top->end_offset == UPB_GROUP_END_OFFSET) {
- d->src.eof = true;
- } else {
- upb_seterr(&d->src.status, UPB_STATUS_ERROR, "End group seen but current "
- "message is not a group, byte offset: %zd",
- upb_decoder_offset(d));
- }
- return NULL;
- }
-
- // Look up field by tag number.
- upb_fielddef *f = upb_msg_itof(d->top->msgdef, field_number);
-
- if (!f) {
- // Unknown field. If/when the upb_src interface supports reporting
- // unknown fields we will implement that here.
- upb_decoder_skipval(d);
- goto again;
- } else if (!upb_check_type(wire_type, f->type)) {
- // This is a recoverable error condition. We skip the value but also
- // return NULL and report the error.
- upb_decoder_skipval(d);
- // TODO: better error message.
- upb_seterr(&d->src.status, UPB_STATUS_ERROR, "Incorrect wire type.\n");
- return NULL;
- }
- d->field = f;
- d->wire_type = wire_type;
- return f;
-}
-
-bool upb_decoder_getval(upb_decoder *d, upb_valueptr val)
-{
- switch(upb_types[d->field->type].native_wire_type) {
- case UPB_WIRE_TYPE_VARINT: {
- uint32_t low, high;
- if(!upb_decoder_readv64(d, &low, &high)) return false;
- uint64_t u64 = ((uint64_t)high << 32) | low;
- if(d->field->type == UPB_TYPE(SINT64))
- *val.int64 = upb_zzdec_64(u64);
- else
- *val.uint64 = u64;
- break;
- }
- case UPB_WIRE_TYPE_32BIT_VARINT: {
- uint32_t u32;
- if(!upb_decoder_readv32(d, &u32)) return false;
- if(d->field->type == UPB_TYPE(SINT32))
- *val.int32 = upb_zzdec_32(u32);
- else
- *val.uint32 = u32;
- break;
- }
- case UPB_WIRE_TYPE_64BIT:
- if(!upb_decoder_readf64(d, val.uint64)) return false;
- break;
- case UPB_WIRE_TYPE_32BIT:
- if(!upb_decoder_readf32(d, val.uint32)) return false;
- break;
- default:
- upb_seterr(&d->src.status, UPB_STATUS_ERROR,
- "Attempted to call getval on a group.");
- return false;
- }
- // For a packed field where we have not reached the end, we leave the field
- // in the decoder so we will return it again without parsing a key.
- if(d->wire_type != UPB_WIRE_TYPE_DELIMITED ||
- upb_decoder_offset(d) >= d->packed_end_offset) {
- d->field = NULL;
- }
- return true;
-}
-
-bool upb_decoder_getstr(upb_decoder *d, upb_string *str) {
- // A string, bytes, or a length-delimited submessage. The latter isn't
- // technically a string, but can be gotten as one to perform lazy parsing.
- const int32_t total_len = d->delimited_len;
- if (d->buf_offset >= 0 && (int32_t)total_len <= d->buf_bytesleft) {
- // The entire string is inside our current buffer, so we can just
- // return a substring of the buffer without copying.
- upb_string_substr(str, d->buf,
- upb_string_len(d->buf) - d->buf_bytesleft,
- total_len);
- upb_decoder_skipbytes(d, total_len);
- } else {
- // The string spans buffers, so we must copy from the residual buffer
- // (if any bytes are there), then the buffer, and finally from the bytesrc.
- uint8_t *ptr = (uint8_t*)upb_string_getrwbuf(
- str, UPB_MIN(total_len, d->buf_bytesleft));
- int32_t len = 0;
- if(d->buf_offset < 0) {
- // Residual bytes we need to copy from tmpbuf.
- memcpy(ptr, d->tmpbuf, -d->buf_offset);
- len += -d->buf_offset;
- }
- if(d->buf) {
- // Bytes from the buffer.
- memcpy(ptr + len, upb_string_getrobuf(d->buf) + d->buf_offset,
- upb_string_len(str) - len);
- }
- upb_decoder_skipbytes(d, upb_string_len(str));
- if(len < total_len) {
- // Bytes from the bytesrc.
- if(!upb_bytesrc_append(d->bytesrc, str, total_len - len)) {
- upb_copyerr(&d->src.status, upb_bytesrc_status(d->bytesrc));
- return false;
- }
- // Have to advance this since the buffering layer of the decoder will
- // never see these bytes.
- d->buf_stream_offset += total_len - len;
- }
- }
- d->field = NULL;
- return true;
-}
-
-static bool upb_decoder_skipgroup(upb_decoder *d);
-
-bool upb_decoder_startmsg(upb_decoder *d) {
- d->top->field = d->field;
- if(++d->top >= d->limit) {
- upb_seterr(&d->src.status, UPB_ERROR_MAX_NESTING_EXCEEDED,
- "Nesting exceeded maximum (%d levels)\n",
- UPB_MAX_NESTING);
- return false;
- }
- upb_decoder_frame *frame = d->top;
- frame->msgdef = upb_downcast_msgdef(d->field->def);
- if(d->field->type == UPB_TYPE(GROUP)) {
- frame->end_offset = UPB_GROUP_END_OFFSET;
- } else {
- frame->end_offset = upb_decoder_offset(d) + d->delimited_len;
- }
- return true;
-}
-
-bool upb_decoder_endmsg(upb_decoder *d) {
- if(d->top > d->stack) {
- --d->top;
- if(!d->src.eof) {
- if(d->top->field->type == UPB_TYPE(GROUP))
- upb_decoder_skipgroup(d);
- else
- upb_decoder_skipbytes(d, d->top->end_offset - upb_decoder_offset(d));
- }
- d->src.eof = false;
- return true;
- } else {
- return false;
- }
-}
-
-bool upb_decoder_skipval(upb_decoder *d) {
- upb_strlen_t bytes_to_skip;
- switch(d->wire_type) {
- case UPB_WIRE_TYPE_VARINT: {
- return upb_decoder_skipv64(d);
- }
- case UPB_WIRE_TYPE_START_GROUP:
- if(!upb_decoder_startmsg(d)) return false;
- if(!upb_decoder_skipgroup(d)) return false;
- if(!upb_decoder_endmsg(d)) return false;
- return true;
- default:
- // Including UPB_WIRE_TYPE_END_GROUP.
- assert(false);
- upb_seterr(&d->src.status, UPB_STATUS_ERROR, "Tried to skip an end group");
- return false;
- case UPB_WIRE_TYPE_64BIT:
- bytes_to_skip = 8;
- break;
- case UPB_WIRE_TYPE_32BIT:
- bytes_to_skip = 4;
- break;
- case UPB_WIRE_TYPE_DELIMITED:
- // Works for both string/bytes *and* submessages.
- bytes_to_skip = d->delimited_len;
- break;
- }
- return upb_decoder_skipbytes(d, bytes_to_skip);
-}
-
-static bool upb_decoder_skipgroup(upb_decoder *d)
-{
- // This will be mututally recursive with upb_decoder_skipval() if the group
- // has sub-groups. If we wanted to handle EAGAIN in the future, this
- // approach would not work; we would need to track the group depth
- // explicitly.
- while(upb_decoder_getdef(d)) {
- if(!upb_decoder_skipval(d)) return false;
- }
- // If we are at the end of the group like we want to be, then
- // upb_decoder_getdef() returned NULL because of eof, not error.
- if(!&d->src.eof) return false;
- return true;
-}
-
-upb_src_vtable upb_decoder_src_vtbl = {
- (upb_src_getdef_fptr)&upb_decoder_getdef,
- (upb_src_getval_fptr)&upb_decoder_getval,
- (upb_src_skipval_fptr)&upb_decoder_skipval,
- (upb_src_startmsg_fptr)&upb_decoder_startmsg,
- (upb_src_endmsg_fptr)&upb_decoder_endmsg,
-};
-
-
-/* upb_decoder construction/destruction. **************************************/
-
-upb_decoder *upb_decoder_new(upb_msgdef *msgdef)
-{
- upb_decoder *d = malloc(sizeof(*d));
- d->toplevel_msgdef = msgdef;
- d->limit = &d->stack[UPB_MAX_NESTING];
- d->buf = NULL;
- upb_src_init(&d->src, &upb_decoder_src_vtbl);
- return d;
-}
-
-void upb_decoder_free(upb_decoder *d)
-{
- upb_string_unref(d->buf);
- free(d);
-}
-
-void upb_decoder_reset(upb_decoder *d, upb_bytesrc *bytesrc)
-{
- upb_string_unref(d->buf);
- d->top = d->stack;
- d->top->msgdef = d->toplevel_msgdef;
- // The top-level message is not delimited (we can keep receiving data for it
- // indefinitely), so we set the end offset as high as possible, but not equal
- // to UINT32_MAX so it doesn't equal UPB_GROUP_END_OFFSET.
- d->top->end_offset = UINT32_MAX - 1;
- d->bytesrc = bytesrc;
- d->buf = NULL;
- d->buf_bytesleft = 0;
- d->buf_stream_offset = 0;
- d->buf_offset = 0;
-}
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