From 13c5188c0198ae45dace6ad80e49b04eeeefa975 Mon Sep 17 00:00:00 2001
From: Pompolic <pompolic@special-circumstanc.es>
Date: Fri, 14 Feb 2020 17:52:05 +0100
Subject: [PATCH] Semantic action for a85 group (4 bytes)
Also bytes aren't bits
---
pdf.c | 38 +++++++++++++++++++++++++++++++-------
1 file changed, 31 insertions(+), 7 deletions(-)
diff --git a/pdf.c b/pdf.c
index 5c8dc7f..de83c95 100644
--- a/pdf.c
+++ b/pdf.c
@@ -240,18 +240,42 @@ act_ahextruncated(const HParseResult *p, void *u)
HParsedToken *
act_a85zero(const HParseResult *p, void *u)
{
- uint8_t nybble = 0;
- /* Remember, this only represents 4 bytes. */
- return H_MAKE_UINT(nybble);
+ uint8_t b = 0;
+ return H_MAKE_UINT(b);
}
HParsedToken *
-act_a85digit(const HParseResult *p void *u)
+act_a85digit(const HParseResult *p, void *u)
{
- uint8_t nybble = H_CAST_UINT(p->ast);
- nybble -= '!';
+ uint8_t b = H_CAST_UINT(p->ast);
+ b -= '!';
- return H_MAKE_UINT(nybble);
+ /* At this point we have the base85 value of one byte out of 5 */
+ return H_MAKE_UINT(b);
+}
+
+HParsedToken *
+act_a85group(const HParseResult *p, void *u)
+{
+ uint64_t b = 0;
+ HCountedArray *seq = H_CAST_SEQ(p->ast);
+ HParsedToken **digits = h_seq_elements(p->ast);
+
+ /* 2^32-1, the max value the group can hold as per spec */
+ #define A85GRPMAX 4294967296
+
+ /* Only for groups that do not need to padded to 5 */
+ assert(seq->used == 5);
+ b += H_CAST_UINT(digits[0]) * ((uint64_t) pow(85,4));
+ b += H_CAST_UINT(digits[1]) * ((uint64_t) pow(85,3));
+ b += H_CAST_UINT(digits[2]) * ((uint64_t) pow(85,2));
+ b += H_CAST_UINT(digits[3]) * ((uint64_t) pow(85,1));
+ b += H_CAST_UINT(digits[4]);
+
+ assert(b <= A85GRPMAX);
+ // TODO: make it generic with H_ACT_APPLY
+
+ return H_MAKE_UINT(b);
}
HParsedToken *
--
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