Gitweb links:
...log
http://git.netsurf-browser.org/libnsgif.git/shortlog/51074f364244b2a556ba72592940bc4a6015d4fe
...commit
http://git.netsurf-browser.org/libnsgif.git/commit/51074f364244b2a556ba72592940bc4a6015d4fe
...tree
http://git.netsurf-browser.org/libnsgif.git/tree/51074f364244b2a556ba72592940bc4a6015d4fe
The branch, tlsa/lzw has been updated
via 51074f364244b2a556ba72592940bc4a6015d4fe (commit)
from 0ac1f4582eee1769db326c3cdaa8b82e58303a35 (commit)
Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.
- Log -----------------------------------------------------------------
commitdiff
http://git.netsurf-browser.org/libnsgif.git/commit/?id=51074f364244b2a556ba72592940bc4a6015d4fe
commit 51074f364244b2a556ba72592940bc4a6015d4fe
Author: Michael Drake <[email protected]>
Commit: Michael Drake <[email protected]>
New LZW decoder: Real-world fix; continue after dictionary is full.
diff --git a/src/lzw.c b/src/lzw.c
index baeba0a..4877ed7 100644
--- a/src/lzw.c
+++ b/src/lzw.c
@@ -301,7 +301,7 @@ lzw_result lzw_decode(struct lzw_ctx *ctx,
lzw_result res;
uint32_t code_new;
uint32_t code_out;
- struct lzw_dictionary_entry *entry;
+ uint8_t last_value;
uint8_t *stack_pos = ctx->stack_base;
uint32_t clear_code = ctx->clear_code;
uint32_t current_entry = ctx->current_entry;
@@ -323,28 +323,28 @@ lzw_result lzw_decode(struct lzw_ctx *ctx,
return LZW_EOI_CODE;
}
- if (current_entry >= (1 << LZW_CODE_MAX)) {
- /* No space in table for new entries, only Clear and
- * End of Information codes were allowed. */
- return LZW_BAD_DATA;
- }
-
- entry = table + current_entry;
if (code_new > current_entry) {
/* Code is invalid */
return LZW_BAD_CODE;
} else if (code_new < current_entry) {
/* Code is in table */
code_out = code_new;
- entry->last_value = table[code_new].first_value;
+ last_value = table[code_new].first_value;
} else {
/* Code not in table */
*stack_pos++ = ctx->previous_code_first;
code_out = ctx->previous_code;
- entry->last_value = ctx->previous_code_first;
+ last_value = ctx->previous_code_first;
+ }
+
+ /* Add to the dictionary, only if there's space */
+ if (current_entry < (1 << LZW_CODE_MAX)) {
+ struct lzw_dictionary_entry *entry = table + current_entry;
+ entry->last_value = last_value;
+ entry->first_value = ctx->previous_code_first;
+ entry->previous_entry = ctx->previous_code;
+ ctx->current_entry++;
}
- entry->first_value = ctx->previous_code_first;
- entry->previous_entry = ctx->previous_code;
/* Ensure code size is increased, if needed. */
if (current_entry == ctx->current_code_size_max) {
@@ -354,7 +354,6 @@ lzw_result lzw_decode(struct lzw_ctx *ctx,
(1 << ctx->current_code_size) - 1;
}
}
- ctx->current_entry++;
ctx->previous_code_first = table[code_new].first_value;
ctx->previous_code = code_new;
@@ -363,7 +362,7 @@ lzw_result lzw_decode(struct lzw_ctx *ctx,
* Note, in the case of "code not in table", the last entry of the
* current code has already been placed on the stack above. */
while (code_out > clear_code) {
- entry = table + code_out;
+ struct lzw_dictionary_entry *entry = table + code_out;
*stack_pos++ = entry->last_value;
code_out = entry->previous_entry;
}
-----------------------------------------------------------------------
Summary of changes:
src/lzw.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/src/lzw.c b/src/lzw.c
index baeba0a..4877ed7 100644
--- a/src/lzw.c
+++ b/src/lzw.c
@@ -301,7 +301,7 @@ lzw_result lzw_decode(struct lzw_ctx *ctx,
lzw_result res;
uint32_t code_new;
uint32_t code_out;
- struct lzw_dictionary_entry *entry;
+ uint8_t last_value;
uint8_t *stack_pos = ctx->stack_base;
uint32_t clear_code = ctx->clear_code;
uint32_t current_entry = ctx->current_entry;
@@ -323,28 +323,28 @@ lzw_result lzw_decode(struct lzw_ctx *ctx,
return LZW_EOI_CODE;
}
- if (current_entry >= (1 << LZW_CODE_MAX)) {
- /* No space in table for new entries, only Clear and
- * End of Information codes were allowed. */
- return LZW_BAD_DATA;
- }
-
- entry = table + current_entry;
if (code_new > current_entry) {
/* Code is invalid */
return LZW_BAD_CODE;
} else if (code_new < current_entry) {
/* Code is in table */
code_out = code_new;
- entry->last_value = table[code_new].first_value;
+ last_value = table[code_new].first_value;
} else {
/* Code not in table */
*stack_pos++ = ctx->previous_code_first;
code_out = ctx->previous_code;
- entry->last_value = ctx->previous_code_first;
+ last_value = ctx->previous_code_first;
+ }
+
+ /* Add to the dictionary, only if there's space */
+ if (current_entry < (1 << LZW_CODE_MAX)) {
+ struct lzw_dictionary_entry *entry = table + current_entry;
+ entry->last_value = last_value;
+ entry->first_value = ctx->previous_code_first;
+ entry->previous_entry = ctx->previous_code;
+ ctx->current_entry++;
}
- entry->first_value = ctx->previous_code_first;
- entry->previous_entry = ctx->previous_code;
/* Ensure code size is increased, if needed. */
if (current_entry == ctx->current_code_size_max) {
@@ -354,7 +354,6 @@ lzw_result lzw_decode(struct lzw_ctx *ctx,
(1 << ctx->current_code_size) - 1;
}
}
- ctx->current_entry++;
ctx->previous_code_first = table[code_new].first_value;
ctx->previous_code = code_new;
@@ -363,7 +362,7 @@ lzw_result lzw_decode(struct lzw_ctx *ctx,
* Note, in the case of "code not in table", the last entry of the
* current code has already been placed on the stack above. */
while (code_out > clear_code) {
- entry = table + code_out;
+ struct lzw_dictionary_entry *entry = table + code_out;
*stack_pos++ = entry->last_value;
code_out = entry->previous_entry;
}
--
NetSurf GIF Decoder
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