From b4ee6122909f038f4b38293912e9d54b378d82eb Mon Sep 17 00:00:00 2001
From: Pompolic <pompolic@special-circumstanc.es>
Date: Wed, 19 Feb 2020 16:41:12 +0100
Subject: [PATCH] Ascii85Decode semantic actions and grammar
---
pdf.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 92 insertions(+), 13 deletions(-)
diff --git a/pdf.c b/pdf.c
index cf3c308..1db9e37 100644
--- a/pdf.c
+++ b/pdf.c
@@ -240,7 +240,7 @@ act_ahextruncated(const HParseResult *p, void *u)
HParsedToken *
act_a85zero(const HParseResult *p, void *u)
{
- uint8_t b = 0;
+ uint32_t b = 0;
return H_MAKE_UINT(b);
}
@@ -278,40 +278,118 @@ act_a85fivedigits(const HParseResult *p, void *u)
return H_MAKE_UINT(fourbytes);
}
+/* Checking the following condition in the spec:
+ * The value represented by a group of 5 characters is greater than 2^32 - 1.
+ */
+bool
+validate_a85fivedigits(HParseResult *p, void *u)
+{
+ /* "s8W-!" should be the highest accepted value */
+ return H_CAST_UINT(p->ast) <= A85GRPMAX;
+}
+
HParsedToken *
act_a85group(const HParseResult *p, void *u)
{
+ uint8_t *bytes = h_arena_malloc(p->arena, 4);
+ uint32_t fourbytes = H_CAST_UINT(p->ast);
+
+ bytes[0] = (fourbytes & 0xFF000000) >> 24;
+ bytes[1] = (fourbytes & 0x00FF0000) >> 16;
+ bytes[2] = (fourbytes & 0x0000FF00) >> 8;
+ bytes[3] = (fourbytes & 0x000000FF);
+ HParsedToken *b = H_MAKE_BYTES(bytes, 4);
+ return b;
}
HParsedToken *
act_a85partial2group(const HParseResult *p, void *u)
{
+ uint64_t fourbytes = 0;
+ HCountedArray *seq = H_CAST_SEQ(p->ast);
+ HParsedToken **digits = h_seq_elements(p->ast);
+ assert(seq->used == 2);
+ fourbytes += H_CAST_UINT(digits[0]) * ((uint64_t) pow(85,4));
+ fourbytes += H_CAST_UINT(digits[1]) * ((uint64_t) pow(85,3));
+
+ assert(fourbytes <= A85GRPMAX);
+ return H_MAKE_UINT(fourbytes);
+}
+
+bool
+validate_a85partial2group(HParseResult *p, void *u)
+{
+ return H_CAST_UINT(p->ast) <= A85GRPMAX;
}
HParsedToken *
act_a85partial3group(const HParseResult *p, void *u)
{
+ uint64_t fourbytes = 0;
+ HCountedArray *seq = H_CAST_SEQ(p->ast);
+ HParsedToken **digits = h_seq_elements(p->ast);
+
+ assert(seq->used == 3);
+ fourbytes += H_CAST_UINT(digits[0]) * ((uint64_t) pow(85,4));
+ fourbytes += H_CAST_UINT(digits[1]) * ((uint64_t) pow(85,3));
+ fourbytes += H_CAST_UINT(digits[2]) * ((uint64_t) pow(85,2));
+ assert(fourbytes <= A85GRPMAX);
+ return H_MAKE_UINT(fourbytes);
+}
+
+bool
+validate_a85partial3group(HParseResult *p, void *u)
+{
+ return H_CAST_UINT(p->ast) <= A85GRPMAX;
}
HParsedToken *
act_a85partial4group(const HParseResult *p, void *u)
{
+ uint64_t fourbytes = 0;
+ HCountedArray *seq = H_CAST_SEQ(p->ast);
+ HParsedToken **digits = h_seq_elements(p->ast);
+
+ assert(seq->used == 4);
+ fourbytes += H_CAST_UINT(digits[0]) * ((uint64_t) pow(85,4));
+ fourbytes += H_CAST_UINT(digits[1]) * ((uint64_t) pow(85,3));
+ fourbytes += H_CAST_UINT(digits[2]) * ((uint64_t) pow(85,2));
+ fourbytes += H_CAST_UINT(digits[3]) * ((uint64_t) pow(85,1));
+ assert(fourbytes <= A85GRPMAX);
+ return H_MAKE_UINT(fourbytes);
}
-/* Checking the following condition in the spec:
- * The value represented by a group of 5 characters is greater than 2^32 - 1.
-*/
bool
-validate_a85fivedigits(HParseResult *p, void *u)
+validate_a85partial4group(HParseResult *p, void *u)
{
- // XXX test with "s8W-!"
return H_CAST_UINT(p->ast) <= A85GRPMAX;
}
+HParsedToken *
+act_a85partialgroup(const HParseResult *p, void *u)
+{
+ uint8_t bytes_helper[4];
+ size_t bytes_used = 1;
+ uint8_t *bytes;
+
+ uint32_t fourbytes = H_CAST_UINT(p->ast);
+
+ for (size_t i; i < 4; ++i)
+ {
+ bytes_helper[i] = (fourbytes >> (3-i * 8)) & 0xFF;
+ bytes_used += 1;
+ }
+
+ bytes = h_arena_malloc(p->arena, bytes_used);
+ return H_MAKE_BYTES(bytes, bytes_used);
+}
+
+// TODO: flatten sequence in a85string semantic action
+
HParsedToken *
act_nat(const HParseResult *p, void *u)
{
@@ -1186,15 +1264,16 @@ ASCII85Decode(const Dict *parms, HBytes b, HParser *p)
/* This encoding of zero is not allowed */
H_RULE(a85fiveexcl, h_repeat_n(MANY_LWS(h_ch('!')), 5));
H_VARULE(a85fivedigits, SEQ(h_and(h_not(a85fiveexcl)), h_repeat_n(MANY_LWS(a85digit), 5)));
- //H_RULE(a85digitws, SEQ(a85digit, OPT(
- H_ARULE(a85group, CHX(a85zero, h_repeat_n(MANY_LWS(a85digit), 5)));
- // XXX semantic actions need cleaning
- H_ARULE(a85partial2group, h_repeat_n(MANY_LWS(a85digit), 2));
- H_ARULE(a85partial3group, h_repeat_n(MANY_LWS(a85digit), 3));
- H_ARULE(a85partial4group, h_repeat_n(MANY_LWS(a85digit), 4));
+ H_ARULE(a85group, CHX(a85zero, a85fivedigits));
+
+ H_VARULE(a85partial2group, h_repeat_n(MANY_LWS(a85digit), 2));
+ H_VARULE(a85partial3group, h_repeat_n(MANY_LWS(a85digit), 3));
+ H_VARULE(a85partial4group, h_repeat_n(MANY_LWS(a85digit), 4));
+
+ H_ARULE(a85partialgroup, CHX(a85partial4group, a85partial3group, a85partial4group));
- H_RULE(a85string, SEQ(h_many(a85group), OPT(CHX(a85partial2group, a85partial3group, a85partial4group)), a85eod));
+ H_RULE(a85string, SEQ(h_many(a85group), OPT(a85partialgroup), IGN(a85eod)));
res = h_parse(a85string, b.token, b.len);
if(!res)
--
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